Designing and Building Sustainable Trails

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IMBA Resources: Trail Building and Maintenance: Designing and Building Sustainable Trails

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Designing and Building Sustainable Trails Presented at the 2006 IMBA Summit/World Mountain Bike Conference Speakers: Rich Edwards, IMBA; Woody Keen, Trail Dynamics; Tony Boone, Arrowhead Trails Facilitators: Kristin Butcher and Ryan Schutz, IMBA The speakers, all master trailbuilders, began by offering three goals they all strive for when designing and building trails: 1) limit environmental impacts; 2) keep maintenance requirements to a minimum; 3) avoid user conflicts. They continued by offering a checklist for building sustainable contour trails. A contour trail is a path that gently traverses a hill or sideslope. It's characterized by a gentle grade, undulations called grade reversals, and a tread that usually tilts or outslopes slightly toward the outer edge. These features minimize tread erosion by allowing water to drain in a gentle, non-erosive manner called sheet flow. When water drains in thin, dispersed sheets, dirt stays where it belongs - on the trail.

Contour Trail Tips: 1. 2. 3. 4. 5. 6. 7. 8. 9.

Do everything you can to keep the water off the tread, and users on it Build on the contour and use frequent grade reversals - surf the hillside Follow the half-rule: A trail's grade shouldn't exceed half the grade of the sideslope Maximum grade should be 15 percent (except for natural or built rock structures) Average grade should stay under 10 percent (with grade reversals) Route trails to positive control points (viewpoints, water, other attractions) Use bench-cut construction, and excavate soil from the hillside For reroutes, reclaim old trail thoroughly - the visual corridor as well as the trail tread For highly technical trails where grade will sometimes exceed 15 percent, use natural rock, rock armoring or other rock features to add challenge and improve sustainability.

Two Critical Trailbuilding Tips 1. Avoid the Fall Line Fall-line trails usually follow the shortest route down a hill - the same path that water flows. The problem with fall-line trails is that they focus water down their length. The speeding water strips the trail of soil, exposing roots, creating gullies, and scarring the environment. 2. Avoid Flat Areas Flat terrain lures many trailbuilders with the initial ease of trail construction. However, if a trail is not located on a slope, there is the potential for the trail to become a collection basin for water. The trail tread must always be slightly higher than the ground on at least one side of it so that water can drain properly.

An ideal trail will simultaneously incorporate all five sustainable trail principles. 1. 2. 3. 4. 5.

The Half Rule The 10-Percent Average Guideline Maximum Sustainable Grade Grade Reversals Outslope

Additional IMBA Resources: Trail Solutions: IMBA's Guide to Building Sweet Singletrack file:///Volumes/USB%20DISK/Final%20DCNR/Impact%20Studies/IMBA%20Re…ce:%20Designing%20and%20Building%20Sustainable%20Trails.webarchive

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IMBA Resources: Trail Building and Maintenance: Designing and Building Sustainable Trails

12/15/07 5:42 PM

Trailbuilding Resources Toughen Trails With Ups and Downs Using Rock to Harden Trails

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IMBA News: News Releases: New Study Examines Mountain Biking Impacts (10-24-06)

12/15/07 5:44 PM

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http://www.imba.com > news > news_releases > 10_06 > 10_24_mtb_impacts.html

New Study Examines Mountain Biking Impacts For Immediate Release 10-24-06 Contact: Mark Eller, IMBA Communications Manager [email protected] 303-545-9011 A study published in the summer 2006 Journal of Park and Recreation Administration (Volume 24, Number 12) takes a close look at the environmental impacts of mountain biking. Researchers measured trail erosion and other impacts on 31 trails used for mountain biking in the southwestern U.S. The study concludes that, "certain impacts to mountain bike trails, especially width, are comparable or less than hiking or multiple-use trails, and significantly less than impacts to equestrian or off-highway vehicle trails." Recreational ecologists Dave White from Arizona State University and Pam Foti from Northern Arizona University led the three-year research project titled "A Comparative Study of Impacts to Mountain Bike Trails in Five Common Ecological Regions of the Southwestern U.S." The researchers used "Common Ecological Regions" (CERs) to provide consistency in comparing the ecological effects of mountain biking with those of other recreational activities. The team also published a 60-page guidebook titled "Planning and Managing Environmentally Friendly Mountain Bike Trails" that includes a condensed version of the study, recommendations for trail management, and tips for responsible mountain biking. Funding for the research and guidebook was provided by a Shimano American Corporation donation, along with administrative contributions by Arizona State University, Northern Arizona University, and the Bureau of Land Management (BLM). Download a PDF of the research paper: A Comparative Study of Impacts to Mountain Bike Trails in Five Common Ecological Regions of the Southwestern U.S. Download a PDF of the guidebook: Planning and Managing Environmentally Friendly Mountain Bike Trails The conclusions reached by the authors are consistent with previous trail research that suggest the impacts of mountain biking are similar or less than other trail use. "Our study contributes to the growing consensus that mountain biking can be a sustainable activity on properly managed trails," said researcher Dave White. Don Applegate of the BLM said, "These new trail monitoring techniques are defendable methods to sustain trail systems that respect the natural environment as well as the need for high quality recreational opportunities." IMBA has long worked to develop and share trail management techniques that minimize resource impacts and provide high quality visitor experiences. IMBA Trailbuilding Schools, held weekly for bike clubs, land managers and volunteers, highlight the principals of sustainable trail management. IMBA offers state-of-the-art trail design and construction services through its professional trail consulting program Trail Solutions, and has published a book on the topic of sustainable trailbuilding. Titled Trail Solutions: IMBA's Guide to Building Sweet Singletrack, the 272-page resource has drawn widespread praise from land managers.

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Journal of Park and Recreation Administration Summer 2006

Volume 24, Number 212 pp. 21-41

A Comparative Study of Impacts to Mountain Bike Trails in Five Common Ecological Regions of the Southwestern U.S. Dave D. White M. Troy Waskey Grant P. Brodehl Pamela E. Foti

EXECUTIVE SUMMARY: A rapid increase in mountain biking participation over the past thirty years has led to concerns about ecological impacts to recreation environments, especially trails. It is widely accepted that recreational use of natural areas inevitably results in some degree of change to resource conditions, and managers must consider the social acceptability and ecological significance of such changes in their decision making. The ecological impacts of mountain biking, however, and relationships between impacts and trail features remain poorly understood. This study uses Common Ecological Regions (CERs) as a mapped ecological framework to guide comparative analysis of differences in maximum trail incision and trail width at varying slope levels for mountain bike trails in five CERs in the southwest U.S. A point-measurement trail assessment procedure was utilized to measure maximum incision and width for 163.2 miles of mountain bike trails. Results show a significant effect of CER on trail width and maximum incision and a significant effect of trail slope on maximum trail incision. Maximum trail width and incision were greatest in the Arizona/New Mexico Mountains region, perhaps due to environmental features such as erodable soils and sparse trailside vegetation, higher use, and/or user behavior. Maximum incision increased consistently with slope for three of five CERs. Relative to other trail impact research, the sites assessed in this study were in similar condition to other trails on the specific parameters measured. The findings from this study reinforce results from previous research that certain impacts to mountain bike trails, especially width, are comparable or less than hiking or multiple-use trails, and significantly less than impacts to equestrian or off-highway vehicle trails. KEYWORDS: Recreation ecology, recreation impacts, ecological impacts, impact assessment, trail management AUTHORS: Dave D. White is with the School of Community Resources and Development, Arizona State University, Tempe, AZ 85287-4703; Phone (480) 965-8429, Fax: (480) 965-5664, E-mail: [email protected]. Troy Waskey is with the same department. Grant P. Brodehl and Pamela E. Foti are with the Department of Geography, Planning, and Recreation, Northern Arizona University.

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Mountain biking is an increasingly popular outdoor recreation activity in North America. Although use estimates vary, according to the recent National Survey on Recreation and the Environment (2003), general bicycling was the second most popular land-based recreation activity in the United States. Of those who bicycled, an estimated 45.2 million people, or nearly 21% of the American public biked on backcountry roads, trails, or cross country on a mountain bike at least once in the twelve months prior to the survey. Mountain biking provides important individual benefits (e.g., physical exercise and opportunities to experience nature), social benefits (e.g., family bonding), environmental benefits (e.g., preservation of natural areas for trails), and economic benefits (e.g., local and regional economic stimulus). Over the past two decades, technological improvements in mountain bike materials, components, and designs have facilitated dramatic increases in participation, allowing more and more people to realize the benefits of this recreation activity. The rapid expansion of mountain biking also has led to concerns over the potential for undesirable social and ecological impacts to recreation environments. Management issues include safety of trail users, conflict, crowding, and resource degradation. The increase in mountain biking popularity thus far has outpaced efforts to understand this activity’s associated impacts, leading to confusion, user conflict, and, in some cases, strict regulations for mountain biking on public lands (Edger, 1997). In some cases, managers have implemented actions such as spatial and temporal zoning, dispersal strategies, and trail closures to address concerns. Such direct management actions that limit access can be controversial and raise issues of equity. Furthermore, the lack of scientific understanding of ecological impacts on mountain bike trails limits informed decision making. A nationwide study of U.S. state park directors conducted by Schuett (1997) demonstrated the potential for uninformed management actions. Schuett found that 67% of state park directors felt that resource degradation from mountain biking was a problem in their parks, but less than 13% of the park systems had actually conducted any studies to assess the resource impacts from mountain biking. Similarly, Chavez (1993) cited studies that suggested U.S. Forest Service and U.S. National Park Service managers were concerned about resource degradation from mountain biking, but managers “could not discern whether damage was specifically because of mountain bike use” (p. 1). As Hendricks, Ramthun and Chavez (2001) noted, “Resource impacts attributable to mountain bikes have remained debatable and understudied. At this time there is not a well-developed body of research on the environmental impacts of off-road cycling” (p. 40). It is widely accepted that recreational use of natural areas inevitably results in some degree of change to resource conditions, and managers must consider the magnitude, social acceptability, and ecological significance of such changes in their decision-making processes. In the absence of sound scientific information, however, managers may apply a precautionary principle, and choose to restrict use or take regulatory action that is based

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on intuition, influence from advocacy groups, and questionable studies. Clearly, further research is needed to inform the development of best management practices to support sustainable mountain biking on established and properly constructed recreation trails. Among the key factors affecting trail impacts deserving further study are: ecological attributes, such as vegetation and soil composition; userelated factors, such as amount and timing of use; and management factors such as trail design, alignment, and slope (Hammit & Cole, 1998; Leung & Marion, 1996). Although these significant influential factors and associated impacts have been identified, there have been relatively few quantitative studies of mountain bike trail impacts published to date that serve as building blocks for establishing relationships among the variables. Furthermore, although there has been an increasing focus on the ecosystem concept in conservation and resource management in parks and recreation areas, the field of recreation ecology to date has not adopted a standardized mapped ecological region framework for organizing and comparing the studies that are conducted. Theoretically informed mapped ecological region frameworks are useful for classifying landscapes into hierarchical spatial units that represent characteristic patterns in the biophysical environment, human activities and impacts, and social and cultural meanings associated with landscapes (McMahon et al., 2004). Such frameworks are useful for describing and interpreting status and change in landscapes. McMahon et al. summarized the use of such frameworks by resource agencies in the U.S. and Canada which had mandated landscape assessments, biodiversity analysis, environmental monitoring and assessment, and selected indicators and standards for understanding environmental stressors and responses. According to McMahon et al., “The use of regions to stratify the underlying variability in natural conditions may increase the likelihood of detecting and understanding an environmental response generated by human activities” (p. 113). As recreation impacts are known to be related to both biophysical characteristics (e.g., soil, vegetation, and topography) as well as human activity (e.g., recreation type and amount, management intervention) it seems apparent that integrating impact studies with ecological regional frameworks might be fruitful. Also, using a standardized ecological region framework may facilitate the integration of recreation impact research into the widely accepted ecosystem research, assessment, and management framework. To address these research needs, the goals of this study are twofold: one, to propose the use of Common Ecological Regions (CERs) (McMahon et al., 2001) as a mapped ecological region framework to guide comparative recreation impact research; and two, to evaluate the relationships between two influential factors and two common trail impacts. Specifically, this study assessed differences in maximum trail incision and trail width at varying slope levels for mountain bike trails in five common ecological regions in the southwest U.S.

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Trail Impacts and the Emergence of Mountain Bike Research The study of ecological impacts, often referred to as recreation ecology, has been, and continues to be a prominent field of inquiry for researchers, land managers, and academic professionals. Cole (1987) suggested that the field of recreation ecology began over 65 years ago with Meinecke’s (1928) work on recreation impacts in the California Redwood State Parks. Recreation impacts research intensified during the 1960s and early 1970s as federal land management agencies sponsored studies to improve recreation management in natural areas. According to Leung and Marion (2000), the essence of today’s ecological impact research and management lies in the desire to gain knowledge and to understand relationships among key causal and influential factors and significant effects. This knowledge is necessary to prevent, mitigate, and manage resource impacts. Campsites and trails receive the most attention from recreation impact researchers, with studies taking place in both remote backcountry and semi-remote front country settings. The primary impact to recreation resources associated with trails occurs during initial trail design and construction (Birchard & Proudman, 2000; Sun & Walsh, 1998). Although this impact has the greatest magnitude and highest ecological significance, it is widely viewed as socially acceptable as the individual, social, and economic benefits of trail-based recreation typically outweigh the associated environmental costs (Cole, 1987). Most trail impact literature and recent research is organized around environmental and visitor-related factors (Hammit & Cole, 1998; Leung & Marion, 1996). Environmental impacts can be divided into four general categories: impacts to wildlife, water, vegetation, and soil. Visitor-related factors include amount of use, type of use, and user behavior. The foundation of recreation ecology research provides a platform for examining impacts associated with mountain biking. The unprecedented explosion in mountain biking as a trail activity was sparked in the 1970s when cyclists began modifying bikes for off-road use (Schwartz, 1994). With balloon tires, a low, flat headset, and high clearance frame, mountain bikes brought drastic changes to places like Marin County, California. Fisher describes the early days: “In the mid-’70s we had a kind of cult riding everywhere on these clunkers” (Schwartz, 1994, p. 77). In 1981, Specialized Bicycle Components produced the first off-the-rack mountain bike, the Stumpjumper, and by 1999 mountain bike sales accounted to one-half of all units sold and one-third of all gross revenue for U.S. bicycle retailers (Bicycle Retailer & Industry News, 1999). In magazine articles from the 1980s, headlines portrayed mountain bikes as “TwoWheel Terrors” (Foote, 1987) and “Vicious Cycles?” (Coello, 1989), and questioned whether mountain biking was “Sport or Spoil-Sport?” (Staub, 1984). Sensational captions depicted the “impacts” typical of mountain biking. Below a photo of bikers maneuvering a set of switchbacks, Foote included, “On the trail: cyclists pose a threat to nature” (p. 72). Next to a photo of two parallel bike tracks, Coello added the caption, “Along the

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White Rim Trail, a jeep road in Canyonlands National Park, cyclists have gouged furrows on their way to the canyon rim” (p. 52). Cessford (1995a) questioned whether tread marks were an easy target, and one wonders if Coello would have made a similar statement about footprints leading to the canyon rim. Countering these claims, Grost (1989) noted that bikes “don’t eat hay, grass ... or defecate” (p. 50) and “weigh about 872 pounds less than a horse” (p. 76). In the 1980s and 1990s researchers began serious study of the social and environmental consequences of mountain biking. Hendricks (1997) recognized that “the 1990s have seen the mountain bike controversy mature from social and environmental issues debated with anecdotal evidence in board meetings, in popular magazines and through newspaper editorials to a land management issue supported by serious inquiry and examination” (p. 3). Researchers studied mountain biker demographics, preferences, and perceptions (Antonakos, 1993; Bowker & English, 2002; Cessford, 1995b; Goeft, 2000; Hollenhorst et al., 1995; Ruff & Mellors, 1993; Symmonds et al., 2000); manager preferences and management strategies (Baker, 1990; Chavez, 1996a, 1996b; Hendricks et al., 2001; Leberman & Mason, 2000; Mason & Leberman, 2000; Moore & Barhlow, 1997; Ruddell & Hendricks, 1997; Schuett, 1997); and social conflict (Banister et al., 1992; Carothers et al., 2001; Cessford, 2002; Ramthun, 1995; Watson et al., 1991). The ecological impacts of mountain biking, however, remained poorly understood. In fact, several researchers indicated a need for further study in this area (Cessford, 1995a, 1995b; Chavez, 1996a; Chavez et al., 1993; Goeft, 2000; Goeft & Alder, 2001; Hendricks, 1997; Jacoby, 1990; Schuett, 1997; Thurston & Reader, 2001; Wilson & Seney, 1994). The absence of concrete information was evident in the earliest publications. In an early summary of mountain biking literature, Cessford (1995a) discussed ecological impacts and presented several astute observations, though the majority of his conclusions were derived from other forms of recreation, such as hiking and off-road motorcycling. His most notable inference was that mountain bikes will generate the most torque during uphill travel, but considerably less pressure on the trail in comparison to other users when moving downhill, although degradation is possible “in extremely wet conditions, on uncompacted surfaces, or due to poor braking practices” (p. 9). Cessford also admitted that the research available at that time could not reliably discern whether mountain biking was any more or less impacting than hiking, a sentiment shared by Ruff and Mellors (1993). At the time of Cessford’s (1995a) literature review, few physical impact studies included mountain biking. Wilson and Seney’s (1994) quasiexperimental approach examined the effects of a mountain bike, hiker, horse, and motorcycle on runoff and sediment yield for trail sample plots in the Gallatin National Forest, Montana. The results of this analysis indicated that the four uses did not significantly alter runoff. With respect to sediment yield on pre-wetted plots, the horse and hiker dislodged more

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material than the motorcycle and mountain bike. On dry plots, the hiker, mountain bike, and motorcycle produced similar sediment yields, but again the horse produced highest yield. Sediment yield for each use was greater for pre-wetted plots than for dry plots. Wilson and Seney acknowledged that soil texture and slope are equally important factors as used in determining sediment yield. Another comparative quasi-experimental design was applied to mountain biking by Thurston and Reader (2001), who assessed the effects of hiking and mountain biking on vegetation loss, species loss, and soil exposure. Their most pertinent finding was that there was no significant difference between the impacts of hiking and mountain biking for the three variables. Bjorkman’s (1998) dissertation included two studies conducted in Wisconsin’s forests. In the first project, Bjorkman determined that sediment yield and erosion associated with mountain biking were lower on a surface treated with a nylon/polypropylene liner and covered with a material made from recycled tires than on an untreated trail. For the second analysis, Bjorkman monitored a variety of impact variables over the first five seasons of, and 90,000 passes on, two newly opened mountain biking trails. The primary findings were: the greatest change in vegetation loss, compaction, cross sectional area and centerline depth on steep slopes, and mean trampled width occurred early in trail use; impacts were largely confined to the trail centerline; and erosion and trail width were greatest on slopes with ≥ 24 percent grade, though erosion was not significant on less steep slopes. In similar research, Goeft and Alder (2001) examined changes in soil compaction, erosion, trail width, and vegetation cover over one year on both recreation and racing trails in southwestern Australia. They noted that erosion was greatest on downhill slopes and at curves, and that erosion and compaction were strictly on-trail impacts. Off-trail vegetation impacts and changes in trail width proved insignificant, though both were most pronounced following a race. Widening was also more likely on wet soils and during the rainy season. From these studies, several key points are evident. The magnitude of ecological impacts attributed to mountain biking appear to be comparable to those of hiking, and appear less than motorized trail use and equestrian use. In many cases, soil structure, slope, and environmental factors are as influential as type and amount of use in determining impacts such as soil loss. If managed properly, impacts such as compaction and vegetation loss can be confined to the trail, with minimal damage to trail peripheries. Mountain bikes have the greatest potential to damage trails in wet and muddy conditions and on steep uphill (spinning tires) and downhill slopes (skidding), which may prove problematic for managers, as many mountain bikers prefer challenging technical sections. In Bjorkman’s (1998) words, “Usage has little influence in explaining impacts to the trail... The first several thousand passes create the most change whether later total use levels are 10,000 or 90,000” (p., 122). Though these limited findings acknowl-

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edge an incomplete understanding of the physical impacts of mountain biking, they do provide an early indication of conditions that may exist in the field. Study Methods Common Ecological Regions (CERs) Provide an Organizing Spatial Framework This study was conducted in five common ecological regions in the southwest U.S.: Sonoran Basin and Range; Arizona/New Mexico Mountains; Colorado Plateau; Southern Rocky Mountains; and Wasatch and Uinta Mountains (see Figure 1). These ecological regions are a subset of a larger spatial framework developed through a cooperative partnership of nine U.S. federal earth science and resource management agencies. The CER spatial framework “is a mapped set of geographic regions that supports agency programs or studies” that was developed to guide cooperative ecosystem research efforts and facilitate “regionally generalized results from local investigations” (McMahon et al., 2001, p. 293-294). Thus, by using the ecological regions framework developed by the cooperating agencies, which include the Forest Service, Bureau of Land ManFigure 1 Map of Study Sites

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agement, Fish and Wildlife Service, and National Park Service, researchers may obtain an “increased measure of confidence in moving from the results of their investigations to characterizing the region as a whole” (McMahon et al., p. 301). The common ecological regions are based on similarities in biotic, abiotic, terrestrial, and aquatic features of the environment as well as social and cultural meanings attached to those environments (McMahon et al., 2004). These various factors were incorporated into the CERs from the amalgamation of three preliminary spatial frameworks developed by the Forest Service (USFS), Environmental Protection Agency (EPA), and National Resource Conservation Service (NRCS) (McMahon et al., 2001). Each of these three prevailing frameworks was created according to agency agendas and management directions. The latest Forest Service framework, for example, was spawned from an agency focus on ecosystem-based approach to managing national forests and grasslands. The NRCS major land resources framework was shaped from practical USDA requirements for soil classifications necessary for assessing agriculture potential and land use. The MLRA and other NRCS frameworks and soil maps work in a hierarchical manner when placed under the umbrella of the CER framework. Similar to the original USFS approach, the EPA framework is aligned with an overall ecosystem view. McMahon et al. (2001) provided a thorough review of how these three original and contributing frameworks have undergone subsequent quantitative and qualitative analysis to create the interagency coordinated CERs. The five CERs in which data were collected for this study are characterized by vegetation, soils, physiographic, land use, land cover, and geology elements represented in the contributing frameworks mentioned above. The Sonoran Basin and Range region is characterized by extensive areas of palo verde-cactus shrub and giant saguaro cactus and has large tracts of federally managed lands. The basins are marked by grama-tobosa shrubsteppe while the ranges are covered with oak-juniper woodlands, and ponderosa pine on the higher elevations. The Arizona/New Mexico Mountains region is a relatively dry, warm environment, with chaparral at lower elevations, pinyon-juniper, and oak woodlands at lower to middle elevations, and higher elevations covered by Ponderosa pine forests and smaller areas of spruce, fir, Douglas fir, and aspen. In the Colorado Plateau region, differences in elevation distinguish this region from nearby Arizona/New Mexico Plateau where it reaches lower and Wyoming Basin to the north as it is generally more elevated. In large, low-lying areas, saltbrush-greasewood vegetation is dominant. The pinyon-juniper woodlands of the elevated plateaus of this region include sheer sidewalls of abrupt changes in local relief, ranging from 300-600 meters. The Wasatch and Uinta Mountains region, also the westernmost region in this study, encompasses a central area of high, precipitous mountains with intermittent valleys, plateaus, and open high mountains. Vegetation is manifest in a banded pattern where aspen, chaparral, and juniper-pinyon and oak are

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common at middle elevations. The region is also typified by less lodgepole pine and a greater emphasis on grazing livestock than in the neighboring Middle Rockies region to the north. Finally, the Southern Rockies region, which marks the eastern extent of the areas studied, includes high elevations and steep, rocky mountains. Large portions of this region are covered by coniferous forest, while the highest elevations take on alpine characteristics. Similar to the Wasatch and Uinta Mountains region, elevation banding dictates vegetation, soil, and land use in the Southern Rockies region. Lower elevations contain grasses and shrubs and are grazed heavily. Moderate elevations include grazing and are covered by Douglas fir, ponderosa pine, aspen, and juniper and oak woodlands. Higher elevations are abundant with coniferous forests that receive minimal grazing activity (US Environmental Protection Agency, 2005). Although there is variability in biotic and abiotic elements within ecological regions, this spatial framework provides a useful system for segmenting the region and providing context for interpretation and extrapolation of environmental research findings. Trail Selection The goal of the trail selection procedure was to identify mountain bike trails or trail segments within each ecological region that were generally typical of trail conditions in that region. A comprehensive list of potential trail segments was developed in cooperation with land management agencies and mountain bike and trail associations. The focus was to identify trail segments identified by the responsible management agency as system trails—in keeping with the purpose of the research to examine impacts to existing trails where mountain biking might be sustained as a legitimate activity. Some trail segments were initially user-created but had been adopted into the agency trail system if design parameters were within agency specifications. To isolate impacts associated with mountain bike trails to the greatest extent possible in a field research setting, trail segments were excluded from the sample frame if motorized use, equestrian use, or multiple-use was dominant. We initially planned to use a 3 x 3 x 5 full factorial design with three levels of use (low/medium/high) and three levels of slope (low/medium/high) across five ecological regions; however, once candidate trail segments were identified, the necessary diversity in use level in each region was lacking, given the use-type restrictions. Specifically, there were inadequate data points to fill cells for low use levels for four of the five CERs and medium use level for two of the five CERs. Ultimately, a total of 162.3 miles of trails were purposively selected in the five common ecological regions. Thus, several limitations of the completed sample should be noted, including the lack of diversity in use levels across the five study regions, the lack of verifiable use level information, and the small number of sample points collected in the Colorado Plateau region, which resulted from time and resource limitations for the field research data collection. Future researchers should consider collecting systematic trail use level information using trail counters or other methods.

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The completed sample of trail segments in each region cannot be determined to be representative of that region and extrapolation of the study findings to the ecological region as a whole, is inappropriate at this time, and thus our findings should be cautiously interpreted at larger spatial scales. By adopting the common ecological regions as an eco-spatial framework for recreation impact research, however, we aim to encourage the long-term development of a comprehensive knowledge base of impact conditions across these regions. The CER framework is available for download as a GIS layer (US Environmental Protection Agency, 2005) and subsequent research utilizing this framework would facilitate comparative spatial analyses and ultimately confident generalizations about the relationships between specific causative and non-causative but related factors and specific impacts across different regions of the U.S., thus overcoming one of the limitations of recreation impact research—namely that research tends to be opportunistic, site-specific and driven by specific management concerns. Trail Impact Assessment Procedures A point-measurement trail assessment procedure was utilized in this study, focusing on measuring maximum incision and trail width. The point sampling method is most appropriate for assessing trail impacts, such as incision and width, which are continuous along the trail (Marion & Leung, 2001). For the point measurement method, a bicycle wheel measuring computer was used to identify systematic sampling points at intervals located every 805m (1/2 mile) along the trail after a random start point near the trailhead. Leung and Marion (1999) examined the influence of sampling interval on the accuracy of trail impact assessments for frequency of occurrence and lineal extent for four common impacts (tread incision, wet soil, exposed roots, multiple trailing) and found that intervals of less than 100m provided the most accurate estimate of lineal extent. Recognizing the inefficiency of such sampling intensity for most settings, however, the authors concluded that “sampling intervals between 100m-500m are therefore recommended to achieve an appropriate balance between estimate accuracy and efficiency of field work” (p. 178). Thus, a limitation of this study is a large sampling interval relative to other studies and the potential for loss in accuracy. The justification for this approach was to include as large a sample of trail miles as possible across a broad geographic region in this exploratory investigation. At each sample point, trail boundaries were defined to include the area where the vast majority of trail use (>90%) occurred by identifying visually obvious disturbance indicated by changes in ground vegetation height, cover and composition. Temporary stakes were placed at the trail boundaries to establish a transect perpendicular to the trail tread. Trail width was defined as the distance between the trail boundary points and measured in inches to the nearest inch. A taut nylon cord was stretched between the base of the stakes and maximum trail incision (MIC) was measured as the maximum depth from the string to the trail surface in inches to the nearest

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quarter inch. At each measurement point, technicians used digital camera to capture site images and recorded locations using Global Positioning System (GPS) receiver. Data were collected between May 2003 and March 2005 during the primary use season for each ecological region, entered into an online Microsoft Access 2003 database and analyzed using SPSS (Version 12). Results Data for the study were collected from 162.3 miles of mountain bike trails across five common ecological regions, which resulted in 319 point measurements (see Table 1). Of the 162.3 miles of trails assessed, 91.7 miles were managed by the U.S. Forest Service, 27.5 miles by a county parks and recreation agency, 16.4 miles by a state government agency, 17.8 miles by the Bureau of Land Management, and 8.9 miles by a city government. Table 1 Mileage of Mountain Bike Trails Assessed and Number of Sample Points Across Three Categories of Slope for Five Common Ecological Regions

Mountain biking was the dominant activity on all trail segments, with three trails engineered specifically for this use. Trail slope is a key factor influencing potential for impacts to soil and vegetation on recreation trails (Goeft, 2000; Wilson & Seney, 1994) with trail slopes greater than 12% typically associated with higher potential for degradation. As shown in Table 2, 37% of the sample points had a slope of less than 5%, 35% had a slope of 5% to 10%, and 27% had a slope greater than 10%. The mean slope for all sample points in the study was 7.6% with a minimum of 0% and a maximum of 38%. Considering the trail segments in each of the CERs, the mean slopes were: Sonoran Basin and Range (7%); Arizona/New Mexico Mountains (8%); Colorado Plateau (7%); Southern Rocky Mountains (7%); Wasatch and Uinta Mountains (8%). The mean maximum trail incision, or trail depth, across all sample points was 1.48 in. with a median of 1.0 in. and maximum 10.0 in. The

32 Table 2 Mean Trail Width and Maximum Incision at Three Slope Levels Across Five Common Ecological Regions

mean trail width across all sample points was 32 in., with a median of 26 in. and a maximum of 109 in. Table 3 displays the values for trail width and maximum trail incision by each trail slope category and across the five ecological regions. Multiple analysis of variance (MANOVA) was used to examine the relationships between the influential factors of CER and slope and the impacts of trail width and maximum trail incision. For MANOVA, the assumption is that dependent variables are multivariate normal; however analysis of variance is robust to departures from normality. The results, displayed in Table 4, showed a significant main effect of CER on both trail width and maximum trail incision. Average trail width for the sample points was significantly higher in the Arizona/New Mexico Mountains than all other regions; this was followed by Sonoran Basin and Range, Wasatch and Uinta Mountains, Southern Rocky Mountains, and Colorado Plateau. MIC was highest for the sample points in the Arizona/New Mexico

33 Table 3 Multiple Analysis of Variance (MANOVA) for Impact Parameters

Table 4 Multiple Analysis of Variance (MANOVA) for Impact Parameters

34

Mountains, followed by Southern Rocky Mountains, Wasatch and Uinta Mountains, Sonoran Basin and Range, and Colorado Plateau. There was a significant main effect of trail slope on maximum trail incision—as slope increased, maximum incision increased. MIC for slopes of less than 5% was significantly lower than slopes of 5% to 10% and significantly lower than for slopes of greater than 10%. The latter two slope categories were not significantly different. There was not a significant main effect of trail slope on trail width, but, generally, as slope increased, trail width increased. Average trail width was 30 in. for slopes less than 5%, 32 in. for slopes 5% to 10%, and 34 in. for slopes greater than 10%. Figure 2 displays the findings for MIC across three categories of trail slope for each CER. For three of the five CERs—Arizona/New Mexico Mountains, Sonoran Basin and Range, and Wasatch and Uinta Mountains—incision was smallest on slopes less than 5%, higher on slopes 5% to 10%, and highest on slopes greater than 10%. In the two other regions, different patterns emerged. In the Colorado Plateaus, MIC increased from 0.78 in. at slopes less than 5% to 1.14 in. at slopes of 5% to 10%, but fell to 1.00 in. at slopes of greater than 10%. MIC for sample points in the Southern Rockies CER was 1.73 in. at less than 5% slope and increased to 2.00 in. at 5% to 10% slopes, but MIC lowest at slopes of greater than 10% (1.67 in.). The effects of slope and CER on trail width are graphed in Figure 3. As noted earlier, slope did not have a significant effect on width for the sample points in the study, although in general higher slopes were associated with Figure 2 Mean Maximum Trail Incision at Three Different Slope Levels Across Five Common Ecological Regions

35 Figure 3 Mean Trail Width at Three Different Slope Levels Across Five Common Ecological Regions

higher trail width. For sample points in three of the five CERs—Arizona/ New Mexico Mountains, Wasatch and Uinta Mountains, and Southern Rockies, the trend lines show higher slopes to be associated with increasing width, but the differences are small. Trail width for the sample points in the Arizona/New Mexico Mountains was significantly greater than all other regions at each slope level. In this region, width increased from 42 in. at less than 5% slope to 50 in. at 5% to 10% slopes and 48 in. at greater than 10% slope. For sample points in Colorado Plateaus, width increased from 22 in. at the lower slopes to 27 in. at the middle slopes, but then dropped to 22 in. at the steeper slopes. On the contrary, trail width for points in the Sonoran Basin and Range was lowest in the 5% to 10% slope category. The interaction between CER and slope was not significant. Conclusions Data for this study were collected from 319 sample points gathered from 162.3 miles of mountain bike trails in five common ecological regions of the southwest United States. Significant differences were identified between trails in different common ecological regions for both trail width and maximum incision. Trail width at sample points in the Arizona/New Mexico Mountains was significantly higher than sample points for all other

36

regions. These finding may be explained by environmental features such as vegetation associations or soil, or by use-related variables or management factors at the specific trails included in this study. Without adequate controls, it is not possible to isolate the effects of each contributing factor, but several explanations are plausible. Environmentally, the dominant vegetation for most trail segments in the Arizona/New Mexico Mountains was sparse chapparal and pinyon-juniper and the soil was mostly sandyloam to loam. Such relatively sparse vegetation and fine, homogenous soils may not prevent trail widening as effectively as, for instance, the imposing trailside cactus vegetation and rockier soils in the Sonoran Basin and Range or the more densely forested portions of the Southern Rockies and Wasatch and Uinta Mountains. Regarding use-related factors, the sampled trails in the Arizona/New Mexico Mountains region are located in the Coconino National Forest near Sedona and Flagstaff, Arizona and these trails were the most heavily used in the study. The trails are popular for day hiking and it is hypothesized that heavy use and user behavior contributed to increased width. For instance, although systematic observation of recreation behavior was not part of this study, field researchers’ notes suggest that as mountain bikers passed others on the higher-use trails, users leave the main tread, disturbing soil and vegetation. This use-related explanation is consistent with Marion and Leung’s (2001) study of trails in Great Smoky Mountains National Park, which found that trail width was the only impact condition significantly related to use level. Regarding maximum incision, values were significantly higher in the Arizona/New Mexico Mountains and Southern Rockies regions than all other regions. Consistent with previous mountain bike trail research (Goeft & Alder, 2001; Wilson & Seney, 1994), increasing slope was associated with greater impact; in this case maximum incision. Specifically, MIC was greater at slopes of 5% to 10% than at slopes of less than 5% in all five CERs. This finding is significant, suggesting a direct relationship between slope and MIC, especially at small to moderate slopes. Future research might test this hypothesis through a multiple regression analyses to isolate the relative contribution of slope and ecological characteristics, as well as use level, and management agency. Although the interaction between CER and slope was not statistically significant, the pattern of results in the data show that MIC on sample points from two regions—Southern Rockies and Colorado Plateaus—was lower at slopes of greater than 10% than at slopes of 5% to 10%. This pattern may be explained by increased management attention to those trail segments at greater slopes, lower use on steep trail segments, or by more resistant soils. Further investigation is necessary to determine if environmental features, use-related variables, or management factors mediate the relationship between slope and incision at higher slopes. Trail slope was related to maximum incision but not trail width. Relative to other trail impact research, the sites assessed in this study were in similar condition on the specific parameters measured. Average overall trail width for all sample points in our study was 32 in., with a median

37

of 26 in., and average maximum incision was 1.48 in. with a range of 0 to 10 and median of 1.0 in. The width and depth of the trails in this study are similar to the multiple use trails Great Smoky Mountains National Park discussed by Marion and Leung (2001), where point sampling method found the range of width to be 9 in. to 57 in. with a median of 17 in., and a range of incision within current tread boundary of 0 in. to 6 in. and a median of 0 in. Average width in our study was similar to lower use mountain bike trails in Australia studied by Goeft and Alder (2001), which found width to range from 17 in. to 26 in., and mountain bike trails in Tennessee assessed by Marion and Olive (2004), which found average width to be 24 in. In the Marion and Olive study, average width for horse trails was 81 in. and average width on ATV trails was 104 in.; in that study, bike trails had significantly less erosion as measured by cross-sectional area, and less muddiness than horse and ATV trails as well. Similarly, Aust et al. (2005) found an average width of 82 in. for equestrian trails in Hoosier National Forest in Indiana. The findings from our study thus reinforce results from previous research that certain impacts to mountain bike trails, especially width, are comparable or less than hiking or multiple-use trails, and significantly less than impacts to equestrian or off-highway vehicle trails. Although our study focused on only two impacts, when combined with the findings of previous studies (Goeft & Alder, 2001; Wilson & Seney, 1994), a consensus seems to be emerging that recreation impacts to mountain bike trails are largely confined to the main tread and mountain biking is likely a sustainable activity on properly managed trails, at least in the environments studied thus far. To determine the sustainability of mountain biking, however, further research is warranted into other, potentially more ecologically significant impacts, such as wildlife disturbance or introduction and spread of invasive species, and across a broad range of ecological regions. Our study does suggest that moderate to severe slopes are an area of management concern for increased incision; although we did not assess erosion (e.g., through cross sectional area), this is also a concern for moderate to severe slopes. This is potentially problematic as studies have shown that mountain bikers tend to prefer trails with steeper slopes, downhill features, and sharp curves (Cessford, 1995b; Goeft & Alder, 2001; Hollenhorst et al., 1995). For the trails in our study, the impacts were relatively modest, but systematic monitoring would be prudent. Managers may also want to clearly define and encourage a narrow trail tread in environments, such as the Arizona/New Mexico Mountains, that facilitate free travel along the trail periphery and on multiple-use trails where hikers and bikers frequently pass one another. A final contribution of this study is the introduction of CERs as an organizing eco-spatial framework for recreation impact research. Additional studies that use this framework will facilitate comparisons of findings and ultimately allow for increased statistical power and meta-analyses to isolate the relative importance of various causal and influential factors on a

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wide range of impacts. Such studies, especially when using GIS analyses, have the potential to assist researchers and managers in moving from localized investigations to regionalized generalizations. Despite limitations, this study represents an exploratory first step in this progression. Acknowledgments: This research was supported through a Cooperative Agreement between the Bureau of Land Management, Arizona State University, and Northern Arizona University, and facilitated by the Colorado Plateau Cooperative Ecosystem Studies Unit. The authors would like to acknowledge Don Applegate from BLM Arizona and Phil Morlock from Shimano American Corporation for their support and assistance with this project. References Antonakos, C. (1993). Environmental and travel preferences of cyclists. Unpublished Dissertation, University of Michigan, Ann Arbor. Aust, M. W., Marion, J. L., & Klye, K. (2005). Research for the development of best management practices to minimize horse trail impacts on the Hoosier National Forest. Blacksburg, VA: Virginia Tech, Department of Forestry. Baker, N. (1990). Mountain bike management: A tale of three cities. Western Wildlands, 16(3), 36-39. Banister, C., Groome, D., & Pawson, G. (1992). The shared use debate—A discussion on the joint use of canal towing paths by walkers, anglers and cyclists. Journal of Environmental Management, 34(2), 149-158. Bicycle Retailer & Industry News. (1999). Bicycle Retailer & Industry News statistics. Retrieved May 25, 2005, from http://www.bicycleretailer.com/ bicycleretailer/images/pdf/statistics.pdf Birchard, W., & Proudman, R. D. (2000). Appalachian Trail design, construction, and maintenance (2nd ed.). Harpers Ferry, WV: Appalachian Trail Conference. Bjorkman, A. (1998). Biophysical impacts on and user interactions with mountain bicycle off-road trail corridors. Unpublished Dissertation, University of Wisconsin, Madison. Bowker, J., & English, D. (2002). Mountain biking at Tsali: An assessment of users, preferences, conflicts, and management alternatives (General Technical Report No. SRS-GTR-059). Asheville, NC: USDA Forest Service, Southern Research Station. Carothers, P., Vaske, J. J., & Donnelly, M. P. (2001). Social values versus interpersonal conflict among hikers and mountain bikers. Leisure Sciences, 23(1), 47-61. Cessford, G. (1995a). Off-road impacts of mountain bikes: A review and discussion. Wellington, NZ: Department of Conservation (Science & Research Series No. 92). Cessford, G. (1995b). Off-road mountain biking: A profile of riders and their recreation setting and experience preferences. Wellington, NZ: Department of Conservation (Science & Research Series No. 93). Cessford, G. (2002). Perception and reality of conflict: Walkers and mountain bikes on the Queen Charlotte track in New Zealand. Bodenkultur University Vienna, Austria.

39 Chavez, D. J. (1993). Recreational mountain biking: A management perspective. Journal of Park and Recreation Administration, 11(3), 29-36. Chavez, D. J. (1996a). Mountain biking: Direct, indirect, and bridge building management styles. Journal of Park and Recreation Administration, 14(4), 21-35. Chavez, D. J. (1996b). Mountain biking: Issues and actions for USDA Forest Service managers (Research Paper No. PSW-RP-226-Web). Albany, CA: USDA Forest Service, Pacific Southwest Research Station. Chavez, D. J., Winter, P., & Baas, J. (1993). Recreational mountain biking: A management perspective. Journal of Park and Recreation Administration, 11(3), 29-36. Coello, D. (1989). Vicious cycles? Sierra, 74, 50-54. Cole, D. N. (1987). Research on soil and vegetation and wilderness: A state-ofknowledge review (General Technical Report No. INT-220). Fort Collins, CO: USDA Forest Service. Edger, C. O. (1997). Mountain biking and the Marin Municipal Water District watershed. Trends, 34(3), 5-10. Foote, J. (1987). Two-wheel terrors. Newsweek, 28 September, 72. Goeft, U. (2000). Managing mountain biking in Western Australia. Australian Parks and Leisure, 3, 29-31. Goeft, U., & Alder, J. (2001). Sustainable mountain biking: A case study from the southwest of Western Australia. Journal of Sustainable Tourism, 9(3), 193211. Grost, R. (1989). Managing the mountain bike. American Forests, 95(3/4), 50-53. Hammit, W. E., & Cole, D. N. (1998). Wildland recreation: Ecology and management (2nd ed.). New York: John Wiley and Sons. Hendricks, W. W. (1997). Mountain bike management and research: An introduction. Trends, 34(3), 2-4. Hendricks, W. W., Ramthun, R., & Chavez, D. J. (2001). The effects of persuasive message source and content on mountain bicyclists’ adherence to trail guidelines. Journal of Park and Recreation Administration, 19(3), 38-61. Hollenhorst, S. J., Schuett, M., Olson, D., & Chavez, D. J. (1995). An examination of the characteristics, preferences, and attitudes of mountain bike users of the national forests. Journal of Park and Recreation Administration, 13(3), 41-51. Jacoby, J. (1990). Mountain bikes: A new dilemma for wildlife recreation managers. Western Wildlands, 16, 25-28. Leberman, S., & Mason, P. (2000). Mountain biking in the Manawatu Region: Participants, perceptions, and management decisions. New Zealand Geographer, 56(1), 30-38. Leung, Y. F., & Marion, J. L. (1996). Trail degradation as influenced by environmental factors: A state-of-the-knowledge review. Journal of Soil and Water Conservation, 51(2), 130-136. Leung, Y. F., & Marion, J. L. (1999). Assessing trail conditions in protected areas: Application of a problem-assessment method in Great Smoky Mountains National Park, USA. Environmental Conservation, 26(4), 270-279. Leung, Y. F., & Marion, J. L. (2000). Recreation impacts and management in wilderness: A state-of-knowledge review. In D. N. Cole, S. F. McCool, W. T. Borrie & J. O’Loughlin (Eds.), Wilderness science in a time of change conference—Volume 5: Wilderness ecosystems, threats, and management (pp. 23-48). Ogden, UT: USDA Forest Service, Rocky Mountain Research Station.

40 Marion, J. L., & Leung, Y. F. (2001). Trail resource impacts and an examination of alternative assessment techniques. Journal of Park and Recreation Administration, 19(3), 17-37. Marion, J. L., & Olive, N. (2004). Assessing and understanding trail degradation: Results from Big South Fork National River and Recreational Area (Draft Research Report). Blacksburg, VA: U.S. Geological Survey, Patuxent Wildlife Research Center, Virginia Tech Field Unit. Mason, P., & Leberman, S. (2000). Local planning for recreation and tourism: A case study of mountain biking from New Zealand’s Manawatu region. Journal of Sustainable Tourism, 8(2), 97-115. McMahon, G., Gregonis, S. M., Waltman, S. W., Omernik, J. M., Thorson, T. D., Freeouf, J. A., et al. (2001). Developing a spatial framework of common ecological regions for the conterminous United States. Environmental Management, 28(3), 293-316. McMahon, G., Wiken, E. B., & Gauthier, D. A. (2004). Toward a scientifically rigorous basis for developing mapped ecological regions. Environmental Management, 34, S111-S124. Meinecke, E. P. (1928). The effect of excessive tourist travel on the California Redwood parks. Sacramento, CA: California Department of Natural Resources, Division of Parks. Moore, R., & Barhlow, K. (1997). Principles for minimizing trail conflicts: Applications to mountain biking. Trends, 34(3), 2-4. Ramthun, R. (1995). Factors in user group conflict between hikers and mountain bikers. Leisure Sciences, 17(3), 159-169. Ruddell, E., & Hendricks, W. (1997). Martial arts, Confucius, and managing mountain bikes: The role of etiquette in conflict management. Trends, 34(3), 41-44. Ruff, A., & Mellors, O. (1993). The mountain bike—the dream machine? Landscape Research, 18(3), 104-109. Schuett, M. A. (1997). State park directors’ perceptions of mountain biking. Environmental Management, 21(2), 239-246. Schwartz, D. (1994). Over hill, over dale, on a bicycle built for...goo. Smithsonian, 25(3), 74-87. Staub, F. (1984). Backcountry bicycling—Sport or spoil-sport? American Forests, 90(9), 41-41. Sun, D., & Walsh, D. (1998). Review of studies on environmental impacts of recreation and tourism in Australia. Journal of Environmental Management, 53(4), 323-338. Symmonds, M. C., Hammitt, W. E., & Quisenberry, V. L. (2000). Managing recreational trail environments for mountain bike user preferences. Environmental Management, 25(5), 549-564. Thurston, E., & Reader, R. J. (2001). Impacts of experimentally applied mountain biking and hiking on vegetation and soil of a deciduous forest. Environmental Management, 27(3), 397-409. US Environmental Protection Agency. (2005). Level III Ecoregions. Retrieved December 13, 2005, from http://www.epa.gov/wed/pages/ecoregions/ level_iii.htm. USDA Forest Service. (2003). Americans’ participation in outdoor recreation: Results from NSRE (with weighted data). Retrieved May 5, 2003, from http:/ /www.srs.fs.usda.gov/trends/Nsre/Rnd1t13weightrpt.pdf.

41 Watson, A., Williams, D., & Daigle, J. (1991). Sources of conflict between hikers and mountain bike riders in the Rattlesnake NRA. Journal of Park and Recreation Administration, 9(3), 59-71. Wilson, J. P., & Seney, J. P. (1994). Erosional impact of hikers, horses, motorcycles, and off-road bicycles on mountain trails in Montana. Mountain Research and Development, 14(1), 77-88.

DOI: 10.1007/s002670010157 RESEARCH Impacts of Experimentally Applied Mountain Biking and Hiking on Vegetation and Soil of a Deciduous Forest EDEN THURSTON RICHARD J. READER* Department of Botany University of Guelph Guelph, Ontario, N1G 2W1, Canada ABSTRACT / Many recent trail degradation problems have been attributed to mountain biking because of its alleged capacity to do more damage than other activities, particularly hiking. This study compared the effects of experimentally applied mountain biking and hiking on the understory vegetation and soil of a deciduous forest. Five different intensities of biking and hiking (i.e., 0, 25, 75, 200 and 500 passes) were applied to 4-m-long ⫻ 1-m-wide lanes in Boyne Valley Provincial Park, Ontario, Canada. Measurements of plant stem

Managers of natural areas consider recreational impacts along trails and on campsites to be their most common management problem (Godin and Leonard 1979, Washburne and Cole 1983). The field of recreation ecology, which developed to address this problem, initially focused largely on the impacts of hikers (Cole 1987a). Impacts of recreation on trails can vary between activity types (e.g., hikers, horses, and motorcycles) (Weaver and Dale 1978), so it is important to know the impacts of new forms of recreational activity, such as mountain biking. The addition of mountain biking to trails in recreation areas has caused considerable concern. Some hikers feel that bikers should be excluded from existing trails because of the potential damaging effect of moving wheels (Cessford 1995). The Sierra Club cited potential degradation of the environment as a reason for developing guidelines and policies on biker access to trails (Coello 1989). Some park supervisors and managers have also attributed trail damage to mountain biking (Chavez 1996, Schuett 1997). A number of factors may contribute to trail degradation following the KEY WORDS: Recreational impacts; Mountain bike; Hiking; Forest plants *Author to whom correspondence should be addressed. e-mail: [email protected]

Environmental Management Vol. 27, No. 3, pp. 397– 409

density, species richness, and soil exposure were made before treatment, two weeks after treatment, and again one year after treatment. Biking and hiking generally had similar effects on vegetation and soil. Two weeks after treatment, stem density and species richness were reduced by up to 100% of pretreatment values. In addition, the amount of soil exposed increased by up to 54%. One year later, these treatment effects were no longer detectable. These results indicate that at a similar intensity of activity, the short-term impacts of mountain biking and hiking may not differ greatly in the undisturbed area of a deciduous forest habitat. The immediate impacts of both activities can be severe but rapid recovery should be expected when the activities are not allowed to continue. Implications of these results for trail recreation are discussed.

addition of mountain bikes, including biker behavior and the physical impact of bikes. Numerous studies have focused on the behavior basis for mountain biking impacts (Watson and others 1991, Chavez and others 1993, Ruff and Mellors 1993, Cessford 1995, Schuett 1997, Goeft 1999, Symmonds and others 1999, 2000). Much less research has focused on the physical impacts of mountain biking. One study (Wilson and Seney 1994) appears in the primary literature and several others are unpublished (Petit and Pontes 1987, Goeft 1999). Wilson and Seney (1994) compared the soil erosion caused by mountain bikes, hikers, horses, and motorcycles using experimentally applied passes in Montana. They found that horses made more sediment available to erosion than mountain bikes, hikers or motorcycles, which did not differ significantly from each other or from the control. Their experiment was conducted on an existing trail with a history of prior, multiple use. Additional studies are needed to answer questions about how mountain bikes impact vegetation and soils at early stages of trail formation and how these impacts compare with those caused by other activities (e.g., hiking). In areas with established trail systems, a common problem reported by managers is the tendency of users to go off-trail, creating impromptu paths (Cole 1985). Off-trail use can result in parallel tracks or trail widening where the main trail is more difficult to traverse ©

2001 Springer-Verlag New York Inc.

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than adjacent surfaces (Bayfield 1973, Lance and others 1989), or may result in new, informal trails where users cut through undisturbed vegetation as a shortcut or to gain access to attractions (Coello 1989, Cessford 1995). Because it becomes difficult to discourage the use of obvious impromptu trails, managers need to know how many off-trail passes are needed to create a trail and if this threshold differs for biking and hiking. If the effects of biking and hiking are similar, then managers can make use of previous hiking studies (Cole and Schreiner 1981) to predict where and when biking impacts are likely to occur. The purpose of this study was to compare the effects of mountain biking and hiking on the soil and understory vegetation of an undisturbed deciduous forest at the initial stage of trail formation. To isolate the physical impacts of each activity, the behavior of bikers and hikers was standardized. By measuring soil and vegetation parameters before and after experimentally applied biking and hiking passes, we assessed differences between effects of biking and hiking, under the unique circumstances of the experiment. The study was conducted in a deciduous forest for two reasons. First, deciduous forests with sensitive, forb-dominated understories are among the most susceptible terrestrial habitats to damage by recreational activity (Kuss 1986, Cole 1987b, 1995c). Therefore, potential differences in the amount of impact from biking and hiking should be more easily observed in this vegetation type than in more resistant types. Second, forest is the preferred environment of mountain bikers (Ruff and Mellors 1993) and is therefore a likely setting for future bicycle paths.

Materials and Methods Study Area The study was conducted in Boyne Valley Provincial Park (44°05⬘N, 80°08⬘W), located 60 km northwest of Toronto, Ontario, Canada. A site was selected within the park that satisfied two criteria: (1) a mature deciduous forest with continuous canopy, and (2) absence of timber harvesting. The site occupies an area of approximately 270 ha, at an elevation of 420 – 470 m. The dominant tree cover is sugar maple (Acer saccharum L.), and the predominant soil type is a well-drained fine sandy loam of the Hillsburgh soil series (Hoffman and others 1964). Experimental Design The experiment consisted of two treatments: activity type (hiking or biking) and pass intensity (0, 25, 75,

200, and 500 passes), resulting in ten treatment combinations. A maximum of 500 passes was chosen based on the finding of Cole and Bayfield (1993) that 500 passes was sufficient to cause at least a 50% reduction in vegetation cover for most vegetation types. Each of the ten treatment combinations was randomly assigned to one of ten treatment lanes within a 50-m-long ⫻ 5-mwide block. Lanes were 5 m long and 1 m wide (Figure 1A). Lanes were separated by a buffer zone of 5 m to avoid potential treatment carryover effects and to allow access for taking measurements. The 50 cm at each end of the 5 m lane were used as buffer zones so that the sampled portion was 4 m long ⫻ 1 m wide. The meterwide plots were divided into three zones (center, middle, and outer) to allow for spatial variation in biking and hiking impacts (Figure 1B). The ten blocks were set up at least 5 m away from one another and at least 25 m from the edge of the forest. Treatment Application Each block was positioned on a slope so that the treatment lanes ran perpendicular to slope contours. An effort was made to position each block so that terrain microtopography was as homogeneous as possible from one end to the other. Slopes were measured with a clinometer at each of the ten lanes along the base of each block. The mean slope measurements for the ten chosen blocks ranged from 9.0° to 14.7°. Block locations were also selected to share the same southerly aspect. The centerline of each lane was marked by five wire pegs tied with flagging tape to indicate the path to be followed by bikers and hikers. Biking and hiking treatments were applied by the same four participants, weighing between 57 and 73 kg. To apply hiking passes, three hikers wore lug-soled hiking boots and one wore rubber-soled running shoes. Three mountain bikes, two Norco Kokanees and one Raleigh Legend, each weighing 13.5 kg, were used to apply biking passes. All three bikes had 18-inch chromalloy frames, with heavily lugged tires (65.4 cm diameter, and 4.9 cm width), with 21 speed Shimano front and rear derailleur gears, and Shimano cantilever hand brakes. The total weights of bikes plus riders ranged from 70.5 to 86.5 kg. Biking and hiking treatments were applied from the start of the last week of June to the middle of the second week of August 1997. The total number of passes required for an individual block (1600) was scheduled to be completed over a one-week period. The number of passes to be completed on a particular lane was distributed over the same number of days so that on a given day a 25-pass lane might receive two passes per person while a 500-pass lane would receive

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Figure 1. (A) Location of the ten treatment lanes per 50m ⫻ 5m block. (B) Enlargement of a 1-m ⫻ 1-m quadrat showing the three quadrat zones (center, middle, outer).

40. As well, the number of passes scheduled to be completed on a given day were distributed among all participants in order to balance weight differences. A pass was a one-way walk or bike trip down a lane following the premarked centerline path. Bikers could not make uphill passes, even in the lowest of 21 gears, due to slope, rough terrain, and tree sapling density, so passes by both hikers and bikers were only made downhill. Hikers moved at a natural gait, adjusting their pace on steeper slopes and over rough terrain to maintain balance. During the initial passes down a given lane, hikers would occasionally stumble away from the lane centerline, or slide their boots over steeper sections, until a path developed. Bikers traveled at a moderate speed, usually allowing bicycles to roll down lanes without pedaling where the slope would allow. Brakes were

applied as needed to keep bicycles under control. Over rough terrain, some firm braking, occasional skidding, and some side-to-side movement of the front tire was required to maintain balance until a path developed. Once participants reached the bottom of a lane, they would turn and circle around the nearest end of the block back to the top of the lane to make a second pass. Treatment application schedules were adjusted to avoid heavy rain events for the safety of bikers and hikers. Blocks received approximately 19 mm of rain during treatment application. To calculate the surface area covered by one pass of a hiker or bicycle, and the contact pressure applied by each, boot sole and tire measurements were taken. Hiker footwear had a mean single sole contact area of 215.1 cm2 (range 200.0 –228.8 cm2). The surface area

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contacted by two bicycle tires on the ground at any given moment (without a load being applied) was calculated as 224.3 cm2 from an equation based on the tire geometry of agricultural vehicles: S ⫽ 0.7 ⫻ undeflected tire radius ⫻ tire width (Soane and others 1981a, 1981b), where S is the contact area of one tire, radius ⫽ 32.7 cm, and tire width ⫽ 4.9 cm. The total surface area contacted by a hiker would therefore be (assuming six steps per 4 m of lane) 1290.6 cm2, and that by a biker would be tire width ⫻ 4 m ⫻ 2 wheels ⫽ 3920 cm2. The pressure applied over one foot step was calculated as the weight of each hiker divided by the area covered by their boot sole. Hikers applied a mean pressure of 0.29 kg/cm2 (range 0.27– 0.32 kg/cm2). A similar approach was used to calculate the pressure applied over two bicycle tires at rest. Using bike plus biker weights and the contact area calculated above, the mean pressure applied by bicycle and rider was 0.35 kg/cm2 (range 0.31– 0.39 kg/cm2). Response Variables Three variables commonly used to assess recreational impacts were measured. First, the loss of vegetation following treatment application was measured by the change in vascular plant stem density from pretreatment stem density. Second, the loss of species richness was measured by the change in the number of plant species present. Third, the increase in the amount of soil exposed was measured. Measurements were made immediately before biking and hiking passes were applied, and then two weeks after treatment application and again one year after treatment application. Pretreatment measurements. A 1-m2 wooden frame quadrat was positioned on the ground so that the lane centerline marked the center of the quadrat as well. String was attached to the 1 m2 frame to divide it into twenty-five 20-cm ⫻ 20-cm cells (Figure 1B). To accommodate the presence of saplings and other obstacles in the sampling area, a second quadrat was prepared that used removable thin wooden planks, instead of string, to outline the 25 cells. To consider the spatial differences in treatment effects from the center of the lane to its edges, the five columns of quadrat cells were grouped into three categories, or quadrat zones. The center column of five cells was referred to as the center zone, the two columns on either side of the center (i.e., ten cells) were called the middle zone, and the two outside columns of cells (i.e., ten cells) became the outer zone (Figure 1B). Measurements were made and recorded for each individual cell before being summarized for the three zones. Once measurements were completed for a quadrat, its position was marked at

four corners using pegs tied with flagging tape so that the same exact spot would be used again during posttreatment sampling. Vascular plants present in a cell were identified to species and species were each categorized as one of six growth forms: tree-seedlings (stem ⬍1 cm diameter, height ⬍1 m), tree saplings (stem ⬎1 cm diameter, height ⬎1 m), shrubs and vines, ferns, forbs (broadleaved herbaceous plants), and graminoids (grasses and sedges). Mature trees were not encountered within the sampled lane areas. Once identified, the plants in each quadrat cell were counted. To avoid the problem of how to define individual plants (complicated by clonal growth), plants were counted by their aboveground stems only. Due to the dense clustered growth of the graminoids, they could not be enumerated as discrete stems with confidence. Instead, each graminoid species was simply observed as either present or absent in a given quadrat cell. Graminoid data were therefore only used in species richness calculations. Exposed soil was defined as bare ground of the A1 horizon, free of macroscopic vegetation, leaf litter, twigs, moss, or humus. Soil exposure was visually estimated for each quadrat cell using a five-point scale: 0 (0 –20%), 1 (21– 40%), 2 (41– 60%), 3 (61– 80%), and 4 (81–100%). Two weeks after treatment application. Effects of biking and hiking were first measured two weeks after treatment application. A two-week waiting period was recommended by Cole and Bayfield (1993) as the amount of time required to allow damage to vegetation to become apparent. Quadrats were repositioned using corner markers to ensure identical placement and the procedure used to measure pretreatment conditions was repeated during posttreatment sampling. Vascular plant stems present were classified as intact, damaged, dead, or absent. Intact stems were those found in their original condition. Damaged stems were those found with evident tissue loss (missing leaves), with impactinduced injury (broken stems, crushed plant body), or with yellowing or wilting plant parts. Dead stems were those with no green pigment and were brittle to the touch. Absent stems were simply missing. New shoots (⬍10 in total) were not included in the posttreatment vegetation survey. Soil exposure was estimated visually as in the pretreatment sampling, using the same fivepoint scale (0 – 4). One year after treatment application. Posttreatment sampling was repeated one year after treatment application. A one-year period was recommended by Cole and Bayfield (1993) as the amount of time required for damage to either diminish or become more apparent, depending on the resiliency of the vegetation type.

Impacts of Mountain Biking and Hiking

Vascular plant stems were classified as present or absent. Soil exposure was estimated visually as in pretreatment sampling, using the same five-point scale (0 – 4).

401

% exposed soil (2 weeks or 1 year) after ⫺ % exposed soil before Statistical Analysis

Treatment Effects Measurements taken during pretreatment and posttreatment sampling were used to calculate the following response variables. For each variable, data for the four quadrats per treatment lane were summed for each quadrat zone (center, middle, outer). Loss of vegetation after two weeks. This was defined as the percentage of original vegetation found damaged, dead, or absent two weeks following treatment application. It was calculated as follows: number of original stems found damaged, dead, or absent 2 weeks after ⫻ 100% number of stems present before where the words before and after refer to pre- and posttreatment measurements. Loss of vegetation after one year. This was defined as the percentage of original vegetation that was absent one year following treatment application. It was calculated as follows: number of original stems found absent 1 year after ⫻ 100% number of stems present before Treatment lanes where no plant stems were present initially (14 of 300 lanes) were not included in the analysis. Loss of species after two weeks. This was defined as the percentage of initial species that were not present (i.e., all stems were dead or absent) two weeks following treatment application. It was calculated as follows: number of species found dead or absent 2 weeks after ⫻ 100% number of species present before Loss of species after one year. This was defined as the percentage of initial species that were absent one year following treatment application. It was calculated as follows: number of species found absent 1 year after ⫻ 100% number of species present before Increase in soil exposure after two weeks or one year. This was defined as the difference in cover estimates before and either two weeks or one year after treatment application. It was calculated as follows:

To determine whether there were any preexisting differences among lanes assigned to different treatments, pretreatment (before) values for each response variable were compared using a three-factor split-plot analysis of variance (ANOVA). The two whole-plot factors were activity type (biking or hiking) and pass intensity (number of passes made). The split-plot factor was quadrat zone. This analysis was carried out using the PROC MIXED procedure of SAS (SAS Institute Inc., 1996). Data were square-root transformed to help meet assumptions of normality and equality of variance. This analysis revealed no significant pretreatment effects (Thurston 1998). To assess statistical significance of posttreatment (after) effects, the three-factor analysis described above was repeated for each of the three response variables. Significant interaction terms involving quadrat zone made it necessary to analyze treatment effects for each zone separately. Data for each zone were analyzed with a two-factor ANOVA for a randomized complete-block design, using the PROC GLM procedure of SAS (SAS Institute Inc., 1996). The two treatment effects were activity type (biking and hiking) and pass intensity (0, 25, 75, 200, and 500 passes). Data were arcsine squareroot-transformed for loss of vegetation and loss of species data after two weeks, square-root-transformed for soil exposure data, and log-transformed for loss of vegetation after one year data.

Results Vegetation Composition Fifty-five vascular plant species were encountered in pretreatment sampling (Appendix 1). The most common species were two forbs, Arisaema triphyllum (L.) Schott. (20 stems per lane), and Caulophyllum thalictroides (L.) Michx. (11 stems per lane), and seedlings of the tree Acer saccharum (7 stems per lane). A total of six different growth forms were encountered: forbs, tree seedlings, ferns, shrubs and vines, tree saplings, and graminoids. Based on total stem density, forbs ranked first with 77% of all stems, followed in turn by tree seedlings (17%), ferns (3%), shrubs and vines (2%), and tree saplings (1%). Treatment Effects After Two Weeks Loss of vegetation. Vegetation loss was significantly affected by pass intensity, by quadrat zone, and by the

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Table 1. Analysis of variance results for treatment effects on loss of vegetation, species richness, and increase in soil exposure after two weeks in three quadrat zones (Combined or Separated)a F value

Source of variation Combined Activity type (A) Pass intensity (P) A ⫻ P Quadrat zone (Z) A ⫻ Z P ⫻ Z A ⫻ P ⫻ Z Separated Center zone Activity type Pass intensity A ⫻ P Middle zone Activity type Pass intensity A ⫻ P Outer zone Activity type Pass intensity A ⫻ P

Loss of vegetation

Loss of species richness

Increase in soil exposure

0.6 40.1** 1.8 223.2** 2.4 11.8** 0.9

0.5 16.3** 0.8 188.6** 1.1 6.0*** 0.4

2.3 53.7** 0.8 186.6** 0.9 25.0** 0.3

0.01 48.7** 1.6

3.0 19.4** 0.6

0.7 37.8** 0.3

3.6 20.9** 0.6

0.04 6.5** 0.3

0.3 5.5* 33.7**

0.3 2.0 1.5

0.07 1.2 0.6

0.2 2.3 1.0

Blank ⫽ P ⬎ 0.05, *P ⬍ 0.05, **P ⬍ 0.01, ***P ⬍ 0.001.

a

interaction effect of pass intensity ⫻ zone. This interaction reflects the significant pass intensity effect detected in the center and middle zones but not in the outer zone (Table 1, Separated). In contrast, neither activity type nor any interaction effect including activity type was significant (Table 1). Vegetation loss generally increased with increasing pass intensity for the two activity types combined (Figure 2a). In the center zone, mean vegetation loss increased significantly from 16%–31% on control lanes (0 passes), to 86%–100% on treated lanes (25–500 passes). In the middle zone, vegetation loss increased significantly from 14% on control lanes (0 passes) to 58%–79% on treated lanes (25–500 passes). In the outer zone, vegetation loss did not differ significantly with the number of passes made, ranging from 14% to 28%. Mean vegetation loss did not differ significantly between biking and hiking treatments (Table 1, Combined). Nor were there any significant interactions between activity type and pass intensity, in any zone (Table 1, Separated). Mean vegetation loss over all pass intensities was greatest in the center zone (80% for biking, 81% for hiking), moderate in the middle zone

(55% for biking, 47% for hiking), and least in the outer zone (19% for biking, 22% for hiking) (Figure 3a). Loss of species. Species loss was significantly affected by pass intensity, by quadrat zone, and by the interaction effect of pass intensity ⫻ zone (Table 1, Combined). Again, this interaction effect reflects the significant pass-intensity effect detected in both the center and middle zones but not in the outer zone (Table 1, Separated). Species loss was not affected by activity type or by any other interaction (Table 1). Species loss generally increased with increasing pass intensity for the two activity types combined (Figure 2b). In the center zone, species loss increased significantly from 28% on control lanes (0 passes) to 74%– 99% on treated lanes (25–500 passes). In the middle zone, species loss differed significantly from 4% on control lanes (0 passes) to 22%– 41% on treated lanes (25–500 passes). In the outer zone, no significant treatment effects were found, with species loss ranging from 6% to 14%. Mean species loss did not differ significantly between biking and hiking treatments (Table 1, Combined), or were there any significant interactions between activity type and pass intensity in any zone (Table 1, Separated). Mean species loss over all pass intensities was greatest in the center zone (80% for biking, 71% for hiking), moderate in the middle zone (27% for biking, 26% for hiking), and least in the outer zone (8% for biking, 11% for hiking) (Figure 3b). Increase in soil exposure. Soil exposure was significantly affected by pass intensity, by quadrat zone, and by the interaction of the two (Table 1, Combined). The interaction resulted from the significant pass intensity effect being detected in both the center and middle zones but not in the outer zone (Table 1, Separated). Neither activity type nor any interaction involving activity type was statistically significant when all three zones were considered together (Table 1). In the center zone, mean soil exposure increased gradually and significantly from 1% on control lanes (0 passes) to 49% on treated lanes (Figure 2c). In the middle zone, mean soil exposure increased significantly with pass intensity but to a lesser extent than in the center zone, ranging from 1% for control lanes (0 passes) to a maximum increase of 21% for treated lanes. In the outer zone, no significant treatment effects were found. Mean increase in soil exposure ranged from ⫺0.2% to 1%. Mean soil exposure did not differ significantly between biking and hiking treatments in any zone (Table 1, Separated). Mean soil exposure over all pass intensities was greatest in the center zone (30% for biking lanes, 23% for hiking lanes), moderate in the middle

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Figure 2. Effect of increasing pass intensity on the mean (⫾1 SE) loss of vegetation, loss of species richness, and increase in soil exposure two weeks after treatment in the three quadrat zones for the two activity types (biking and hiking) combined.

zone (10% for biking lanes, 8% for hiking lanes), and least in the outer zone (0.6% for both activities) (Figure 3c). Analysis of variance results for soil exposure in the middle zone indicated a significant interaction between activity type and pass intensity (Table 1, Separated). This interaction was due to the fact that soil exposure following biking was only significantly greater than hiking at one pass-intensity (i.e., 500 passes) (Thurston 1998).

Treatment Effects After One Year Loss of vegetation. Vegetation loss did not differ significantly between activity types or among pass intensities (Table 2). There was a significant difference among zones, however. Mean vegetation loss in the outer zone (7%) and in the middle zone (11%) were significantly less than in the center zone (31%) for all pass intensities and activity types combined. None of the interaction effects involving zone, activity type or pass intensity were statistically significant.

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Table 2. Analysis of variance results for treatment effects on loss of vegetation, species richness, and increase in soil exposure after one year in the three quadrat zones (Combined or Separated)a F value

Source of variation Combined Activity type (A) Pass intensity (P) A ⫻ P Quadrat zone (Z) A ⫻ Z P ⫻ Z A ⫻ P ⫻ Z Separated Center zone Activity type Pass intensity A ⫻ P Middle zone Activity type Pass intensity A ⫻ P Outer zone Activity type Pass intensity A ⫻ P a

Figure 3. Effect of activity type (biking or hiking) on the mean (⫾1 SE) loss of vegetation, loss of species richness, and increase in soil exposure two weeks after treatment in the three quadrat zones for the five pass intensities combined.

Mean vegetation loss for all pass intensities combined ranged from 1% in the outer zone to 34% in the center zone (Figure 4a). Mean vegetation loss for activity types combined ranged from ⫺2% in the outer zone to 42% in the center zone (Figure 5a). The negative value indicates an increase in posttreatment stem density over pretreatment stem density. Species loss. Species loss did not differ significantly between treatments but it did differ among zones (Ta-

Loss of vegetation

Loss of species richness

Increase in soil exposure

0.07 0.8 1.1 6.1** 1.0 0.3 0.3

0.9 0.6 1.6 6.1** 0.6 0.4 0.4

0.2 1.8 4.1** 9.0*** 0.2 0.9 0.5

1.0 0.8 0.7

0.4 0.6 1.2

0.03 2.1 0.7

0.8 0.5 0.5

1.3 0.7 0.5

0.4 2.2 1.9

0.04 0.5 0.9

1.0 0.3 0.8

0.3 0.9 1.5

Blank ⫽ P ⬎ 0.05, **P ⬍ 0.01, ***P ⬍ 0.001.

ble 2, Combined). Mean species losses in the outer zone (6%) and in the middle zone (8%) were significantly less than species loss in the center zone (24%) for all pass intensities and activity types combined. None of the interaction effects involving zone, activity type or pass intensity were statistically significant. Mean species loss for activity types combined ranged from ⫺3% in the outer zone to 30% in the center zone (Figure 4b). Mean species loss for all pass intensities combined ranged from 2% in the outer zone to 25% in the center zone (Figure 5b). Increase in soil exposure. Soil exposure did not differ significantly between activity types or among pass intensities (Table 2, Combined). However, the interaction of activity type ⫻ pass intensity was significant. This interaction resulted from soil exposure being greater on biking 500 pass lanes than hiking 500 pass lanes but not at lower pass intensities (0 –200 passes) (Thurston 1998). There was also a significant difference in soil exposure among quadrat zones, with the center (4%) and middle zones (2.4%) greater than the outer zone (0.2%). None of the other interaction effects involving zone, activity type, or pass intensity were statistically

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405

Figure 4. Effect of increasing pass intensity on the mean (⫾1 SE) loss of vegetation, loss of species richness and increase in soil exposure one year after treatment in the three quadrat zones for the two activity types (biking and hiking) combined.

significant. Mean values for exposed soil over both activity types ranged from ⫺1.1% to 7.0% (Figure 4c). Mean soil exposure for all pass intensities combined ranged from ⫺0.6% to 4% (Figure 5c).

of the trail centerline. These findings are discussed in turn below, followed by suggestions for future research and the management implications of our results.

Discussion

In the center zone, both vegetation loss and species loss occurred rapidly with biking or hiking activity. After only 25 passes nearly every plant stem present in the center zone was damaged. Effects were less pronounced in the middle and outer zones because bikers and hikers only came in contact with vegetation when they strayed from the lane centerline. The asymptotic

Three principal findings emerged from this study. First, impacts on vegetation and soil increased with biking and hiking activity. Second, the impacts of biking and hiking measured here were not significantly different. Third, impacts did not extend beyond 30 cm

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leaves, such as the erect forb species observed in this study, are easily crushed and broken by recreational activity, while growth forms with narrow leaves and flexible stems, such as graminoids, are more resistant (Sun and Liddle 1993a, b). Second, rare species are more likely to be lost than common species. Both attributes may have contributed to species loss in this study because erect forbs dominated the sampled lanes and approximately one third (35%) of the species present initially in treatment lanes were represented by five or fewer stems. Soil exposure increased almost linearly from the lowest pass lanes to the highest rather than asymptotically, as was observed for vegetation loss. Mean values for increased soil exposure did not exceed 49% on the 500 pass lanes of the center zone, whereas vegetation loss reached 99% on the same lanes. These results indicate that the loss of organic horizons does not occur as rapidly or does not become as severe at low trampling intensities as does vegetation loss. This is explained simply by the fact that as vegetation is damaged and killed by low levels of use, surface organic layers (i.e., leaf litter) are only just beginning to be scuffed away (Cole 1987a). Cole (1987b) found that soil exposure below 100 passes per year was negligible, and Quinn and others (1980) observed that bare ground did not appear until after at least 250 passes were made. Pass-Intensity Effects After One Year

Figure 5. Effect of activity type (biking or hiking) on the mean (⫾1 SE) loss of vegetation, loss of species richness and increase in soil exposure one year after treatment in the three quadrat zones for the five pass-intensities combined.

pattern of vegetation loss with increasing amount of recreational activity found here is characteristic of deciduous forests with understories dominated by erect forbs. Numerous studies have identified closed-canopy forests among the habitats most susceptible to recreational impact (Kuss 1986, Cole 1979, 1987a, b, 1995a, b). The loss of species due to recreational activity is likely controlled by several species attributes. First, growth forms with tall, succulent stems and broad

One year following treatments, neither vegetation loss nor species loss was significantly greater on treated lanes than on control lanes. Most of the herbaceous plant species at the study site were perennials, with their perennating buds located at or below the soil surface (Gleason and Cronquist 1991). In these species, aboveground stems may be damaged or removed in a given season, but if the perennating organ remains intact, plants should be able to replace lost stems in following seasons. Presumably, resprouting from dormant buds would account for the absence of any treatment effect after one year. Our results support Cole’s (1987a, 1995b) suggestion that deciduous forest understory plants have high resilience (i.e., the ability to subsequently recover) when the recreational activity is not continuous. The amount of soil still exposed after one year in treated lanes did not differ significantly from control lanes. The absence of a detectable treatment effect was likely due to the addition of deciduous tree leaves to the forest floor in the autumn following treatment application. Over-winter reduction in exposed soil has been attributed to leaf fall by a number of investigators

Impacts of Mountain Biking and Hiking

(e.g., Legg and Schneider 1977, Cole 1987b, Hammitt and Cole 1987). Activity-Type Effects For the response variables measured in this study, there were no significant differences between hiking and mountain biking treatments. One possible explanation is that when vulnerable plants are directly contacted by a weight-bearing surface they will be affected no matter what the weight-bearing surface is, once a certain weight threshold is met. If weights of user groups are only slightly different, as with hikers (e.g., 60 kg) and mountain bikers (e.g., 75 kg, bike and biker included), there should be little difference in their impact on vegetation and soil. In this study, the weight applied per unit area of ground contacted (i.e., contact pressure) was very similar. Biker contact pressure (0.35 kg/cm2) was only 0.06 kg/cm2 more than the contact pressure of a hiker balanced on one foot (0.29 kg/ cm2). However, when the weights of two user-groups are considerably different, as with hikers (e.g., 85 kg) and horses (e.g., 550 kg), the magnitude of damage to vegetation is clearly greater for the larger weight-bearing activity (Weaver and Dale 1978). Spatial Dependency of Effects The magnitude of biking and hiking effects on vegetation and soil declined sharply with distance from the center of the treatment lane. After a maximum of 500 passes, visible impact was concentrated within a narrow zone, no greater than 30 cm from the lane centerline. The center zone of a treatment zone received the most concentrated use, and consequently, revealed the most severe impact even at low pass intensities. The middle zone received only occasional passes of bikers and hikers when they strayed from the lane centerlines, therefore revealing only moderate impact. In the outer zone almost no foot or bike tire contacted the ground and no changes in parameters could be detected after treatments were applied. Identifying the scale of impact for recreational activities puts into perspective the relative amount of damage they cause. Future Research Our study compared the impacts of biking and hiking under a particular set of conditions so additional studies conducted under other conditions are needed to test the generality of our findings. In these studies, it would be useful to compare impacts for (1) a maximum of more than the 500 passes applied here, (2) uphill rather than downhill passes, (3) established rather than

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new trails, (4) habitats other than deciduous forest, and (5) wet rather than dry conditions. If future research confirms our finding that the physical impacts of mountain biking on vegetation and soil seem to be no worse than those of hiking, then there must be other reasons for the belief that mountain biking is to blame for recent trail degradation problems. One possibility is that behavioral differences between bikers and hikers are responsible for reports of greater biking impact. Bikers, in general, enjoy the challenge of obstacles on the trail, such as bumps and jumps, gullies, roots, rocks, and surface water (Symmonds and others 1999, 2000). Many of these features are the result of erosion. If mountain bikers seek out eroded areas, and hikers do not, then bikes will in fact contribute further to soil erosion problems. A second possibility is that mountain bikers simply contribute further to the overuse of trails. In other words, it may not be the activity of mountain biking per se that is to blame for these problems but rather the addition of this user group to hikers and others that has exacerbated overuse problems on already crowded trails (Ruff and Mellors 1993). Mountain bikes are also be alleged to cause damage because of the inherent conflict between recreational user groups sharing the same space. Conflicts between user groups that differ in technology and methods of travel are common, such as between cross-country skiers and snowmobilers, or canoeists and those using motorboats (Watson and others 1991). Bikers move faster than hikers and equestrians, and these slowerpaced users have complained that bikers startle them and present a safety hazard (Keller 1990). Mountain bikes have also been characterized as mechanized by hikers and managers and are therefore judged as inappropriate in a natural setting (Cessford 1995). In recreational conflict research, conventional wisdom states that users of more physically obtrusive technologies are resented by users of less obtrusive technologies (Devall and Harry 1981). Since mountain bikes are visually obtrusive, objectionable to other users, and leave easily identifiable evidence of their passing in the form of tire marks, they are commonly assigned as the cause of environmental damage (Cessford 1995). Management Implications Resource managers have no objective basis for managing biking activity in natural areas without research results. If further research on mountain biking impacts confirms our finding that biking and hiking can have similar physical impacts, then managers should be able to use results of past hiking impact studies to predict where and when biking impacts are likely to occur.

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Appendix 1. Species composition and mean stem density of vascular plants present in the 100 experimental lanes before treatments were applieda Species Forbs Arisaema triphyllum Caulophyllum thalictroides Other species Total Tree seedlings Acer saccharum Fraxinus americana Other species Total Ferns Dryopteris carthusiana Athyrium filix-femina Other species Total Shrubs and vines Cornus alternifolia Solanum dulcamara Other species Total Tree saplings Acer saccharum Ostrya virginiana Other species Total Graminoids Carex pedunculata Carex radiata Other species Total

Mean stem density (stems per lane) 20.05 11.43 14.84 46.32 6.86 1.76 1.53 10.15 0.54 0.40 0.82 1.76 0.55 0.51 0.08 1.14 0.62 0.12 0.05 0.79 4.21 0.42 0.44 5.07

a

Species are grouped by growth form. Nomenclature follows Gleason and Cronquist (1991). Other species include: Forbs—Maianthemum canadense, Trillium spp., Circaea quadrisculata, Veronica officinalis, Taraxacum officinale, Polygonatum pubescens, Geranium robertianum, Ranunculus abortivus, Smilacina racemosa, Viola pubescens, Hieracium aurantiacum, Waldstenia fragariodes, Actaea pachypoda, Ranunculus recurvatus, Galium triflorum, Epipactus helleborine, Thalictrum pubescens, Aralia nudicaulis, Aquilegia canadensis, Allium tricoccum, Oxalis stricta, Scrophularia marilandica, Asarum canadense, Aster lanceolatus, Impatiens pallida; Tree seedlings—Prunus serotina, Tsuga canadensis, Ostrya virginiana, Ulmus rubra, Populus grandidentata, Thuja occidentalis, Fagus grandifolia, Tilia americana; Ferns—Onoclea sensibilis, Matteuccia struthiopteris, Dryopteris marginalis; Shrubs and vines—Sambucus canadensis, Vitis riparia, Ribes cynosbati; Tree saplings—Fraxinus americana, Prunus serotina, Fagus grandifolia; Graminoids—sedges: Carex arctata, Carex deweyana; grasses: Poa alsodes, Elymus hystrix, Glyceria striata, Schizachne purpurescens.

Managers of natural areas also need to know how quickly impromptu or informal trails can form when people leave the main path and whether this threshold number of passes differs for hiking or biking. From the results of this study, it would appear that informal trails should not form any more quickly for biking than for hiking. However, managers should be aware that the

immediate impacts of both activities can be severe, and obvious trails will form after relatively very few passes (i.e., less than 500). If these initial trails are not allowed to persist, rapid recovery should be expected in a deciduous forest habitat with a forb-dominated understory, at least for the range of use intensities employed here.

Acknowledgments We thank the Natural Sciences and Engineering Research Council of Canada, Ontario Parks, and Mountain Equipment Co-op for their financial support. We also appreciated the assistance of Brian Huis and Brad Warren of Ontario Parks. Sincere thanks are extended to Pete Kelly for fieldwork and analysis, Carol Ann Lacroix for plant identification, and to Doug Larson, Brian Husband, David Cole, Michael Schuett, and Kenneth Barrick for their helpful comments on previous versions of the paper.

Literature Cited Bayfield, N. G. 1973. Use and deterioration of some Scottish hill paths. Journal of Applied Ecology 10:635– 644. Cessford, G. R. 1995. Off-road impacts of mountain bikes: A review and discussion. Science and Research Series Report No. 92. Department of Conservation, Wellington, New Zealand, 38 pp. Chavez, D. J., P. L. Winter, and J. M. Baas. 1993. Recreational mountain biking: A management perspective. Journal of Park and Recreation Administration 11:29 –36. Chavez, D. J. 1996. Mountain biking: Direct, indirect, and bridge building management styles. Journal of Park and Recreation Administration 14:21–35. Coello, D. 1989. Vicious cycles? Sierra 74:50 –54. Cole, D. N. 1979. Reducing the impact of hikers on vegetation—an application of analytical research methods. Pages 71–78 in R. Ittner, D. R. Potter, J. K. Agee, and S. Anschell (eds.), Recreational impact on wildlands. R-6-001-1979. USDA Forest Service, Pacific Northwest Region, Portland, Oregon. Cole, D. N. 1985. Management of ecological impacts in wilderness areas in the United States. Pages 138 –154 in N. G. Bayfield and G. C. Barrow (eds.), The ecological impacts of outdoor recreation on mountain areas in Europe and North America. Recreation Ecology Research Group Report No. 9. Cole, D. N. 1987a. Research on soil and vegetation in wilderness: A state-of-knowledge review. Pages 138 –154 in R. C. Lucas (comp.) Proceedings, national wilderness research conference: Issues, state-of-knowledge, future directions. General Technical Report INT-220. USDA Forest Service, Intermountain Research Station, Ogden, Utah. Cole, D. N. 1987b. Effects of three seasons of experimental trampling on five montane forest communities and a grassland in western Montana, USA. Biological Conservation 40: 219 –244.

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Cole, D. N. 1995a. Experimental trampling of vegetation. I. Relationship between trampling intensity and vegetation response. Journal of Applied Ecology 32:203–214.

Quinn, N. W., R. P. C. Morgan, and A. J. Smith. 1980. Simulation of soil erosion induced by human trampling. Journal of Environmental Management 10:155–165.

Cole, D. N. 1995b. Experimental trampling of vegetation. II. Predictors of resistance and resilience. Journal of Applied Ecology 32:215–224.

Ruff, A. R., and O. Mellors. 1993. The mountain bike—the dream machine? Landscape Research 18:104 –109.

Cole, D. N. 1995c. Disturbance of natural vegetation by camping: Experimental applications of low-level stress. Environmental Management 19:405– 416. Cole, D. N., and N. G. Bayfield. 1993. Recreational trampling of vegetation: Standard experimental procedures. Biological Conservation 63:209 –215. Cole, D. N., and E. G. S. Schreiner. 1981. Impacts of backcountry recreation: Site management and rehabilitation—an annotated bibliography. General Technical Report INT-121. USDA Forest Service, Intermountain Forest and Range Experiment Station. Devall, B., and J. Harry. 1981. Who hates whom in the great outdoors: The impact of recreational specialization and technologies of play. Leisure Sciences 4:399 – 418. Gleason, H. A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. The New York Botanical Garden, New York, 910 pp. Godin, V. B., and R. E. Leonard. 1979. Management problems in designated wilderness areas. Journal of Soil and Water Conservation 34:141–143. Goeft, U. 1999. Managing mountain bike impacts in the south west of Western Australia: Combining biophysical impact studies with rider preferences for better trail design. BS thesis. Edith Cowan University, Perth, Australia. Hammitt, W. E., and D. N. Cole. 1987. Wildland recreation: Ecology and management. John Wiley & Sons, New York, 335 pp. Hoffman, D. W., B. C. Matthews, and R. E. Wicklund. 1964. Soil survey of Dufferin County, Ontario. Soil Research Institute, Research Branch, Canada Department of Agriculture, Ottawa. Keller, K. J. D. 1990. Mountain bikes on public lands: A manager’s guide to the state of practice. Bicycle Federation of America, Washington, DC. Kuss, K. R. 1986. A review of major factors influencing plant responses to recreation impacts. Environmental Management 10:637– 650. Lance, A. N., I. A. Baugh, and J. A. Love. 1989. Continued footpath widening in the Cairngorm Mountains, Scotland. Biological Conservation 49:201–214. Legg, M. H. and G. Schneider. 1977. Soil deterioration on campsites: Northern forest types. Soil Science Society American Journal 41:437– 441. Petit, B., and P. Pontes. 1987. “Kepner-Trego analysis”: Mountain bicycle situation on Santa Barbara front trails managed by the USDA Forest Service. Unpublished report. Santa Barbara Ranger District, Los Padres National Forest, USDA Forest Service (in Chavez and others 1993).

SAS Institute Inc. 1996. SAS Software Release 6.12. SAS Institute Inc., Cary, North Carolina. Schuett, M. A. 1997. State park directors’ perceptions of mountain biking. Environmental Management 21:239 –246. Soane, B. D., P. S. Blackwell, J. W. Dickson, and D. J. Painter. 1981a. Compaction by agricultural vehicles: A review. I. Soil and wheel characteristics. Soil and Tillage Research 1:207– 237. Soane, B. D., P. S. Blackwell, J. W. Dickson, and D. J. Painter. 1981b. Compaction by agricultural vehicles: A review. II. Compaction under tires and other running gear. Soil and Tillage Research 1:373– 400. Sun, D., and M. J. Liddle. 1993a. Plant morphological characteristics and resistance to simulated trampling. Environmental Management 17:511–521. Sun, D., and M. J. Liddle. 1993b. Trampling resistance, stem flexibility and leaf strength in nine Australian grasses and herbs. Biological Conservation 65:35– 41. Symmonds, M. C., W. E. Hammitt, and V. L. Quisenberry. 1999. Mountain biking and soil erosion: User preference of factors of erosion and management techniques. Pages 89 –94 in D. Harmon (ed.), On the Frontiers of Conservation: Proceedings of the tenth conference on research and resource management in parks and on public lands. The George Wright Society Biennial Conference, Asheville, North Carolina. Symmonds, M. C., W. E. Hammitt, and V. L. Quisenberry. 2000. Managing recreational trail environments for mountain bike user preferences. Environmental Management 25: 549 –564. Thurston, E. 1998. An experimental examination of the impacts of hiking and mountain biking on deciduous forest vegetation and soil. MS thesis. University of Guelph, Guelph, Canada. Washburne, R. F., and D. N. Cole. 1983. Problems and practices in wilderness management: A survey of managers. Research Paper INT-304. USDA Forest Service, Intermountain Research Station, Moscow, Idaho. Watson, A. E., D. R. Williams, and J. J. Daigle. 1991. Sources of conflict between hikers and mountain bike riders in the Rattlesnake NRA. Journal of Park and Recreation Administration 9:59 –71. Weaver, T., and D. Dale. 1978. Trampling effects of hikers, motorcycles and horses in meadow and forests. Journal of Applied Ecology 15:451– 457. Wilson, J. P., and J. P. Seney. 1994. Erosional impact of hikers, horses, motorcycles and off-road bicycles on mountain trails in Montana. Mountain Research and Development 14:77– 88.

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Journal of Environmental Management 85 (2007) 791–800 www.elsevier.com/locate/jenvman

Review

Impacts of recreation and tourism on plant biodiversity and vegetation in protected areas in Australia Catherine Marina Pickering, Wendy Hill International Centre for Ecotourism Research, Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, Qld. 9726, Australia Received 23 March 2006; received in revised form 30 October 2006; accepted 12 November 2006 Available online 17 January 2007

Abstract This paper reviews recent research into the impact of recreation and tourism in protected areas on plant biodiversity and vegetation communities in Australia. Despite the international significance of the Australian flora and increasing visitation to protected areas there has been limited research on recreational and tourism impacts in Australia. As overseas, there are obvious direct impacts of recreation and tourism such as clearing of vegetation for infrastructure or damage from trampling, horse riding, mountain biking and off road vehicles. As well, there are less obvious but potentially more severe indirect impacts. This includes self-propagating impacts associated with the spread of some weeds from trails and roads. It also includes the severe impact on native vegetation, including many rare and threatened plants, from spread of the root rot fungus Phytopthora cinnamomi. This review highlights the need for more recreational ecology research in Australia. r 2006 Elsevier Ltd. All rights reserved. Keywords: Australia; Conservation; Plant biodiversity; Protected areas

Contents 1. 2. 3.

4. 5. 6. 7.

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recreation in protected areas in Australia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recreation and tourism impacts on vegetation in protected areas in Australia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Impacts associated with infrastructure for tourism and recreation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Impacts associated with tourism activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. Factors that affect impacts from recreation and tourism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Indirect impacts from tourism and recreation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.1. Addition of nutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.2. Impacts of weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.3. Impact of pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tourism impacts on rare and threatened plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recommendations for future ecological research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Research needs for managing/monitoring of impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Corresponding author. Tel.: +61 7 5594 8259; fax: +61 7 55948067.

E-mail address: c.pickering@griffith.edu.au (C.M. Pickering). 0301-4797/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2006.11.021

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1. Introduction Nature-based tourism and recreation, including in protected areas, is increasing worldwide and in Australia (Newsome et al., 2002a; Worboys et al., 2005). Overseas, a range of direct and indirect impacts of recreation activities in protected areas on vegetation have been documented in both observational and experimental studies (see recent reviews by Liddle, 1997; Leung and Marion, 2000; Newsome et al., 2002a; Buckley, 2004a, b; Cole, 2004; Newsome et al., 2004). Some impacts cause such damage that they alter the value of areas for tourism and recreation itself. In Australia, research into recreation ecology lags behind other regions, such as North America, despite there being equal need and it being of equivalent land area (Sun and Walsh, 1998; Buckley, 2005). Damage to the Australian flora from recreation and tourism is important, as the flora is recognised internationally as important due to its high biodiversity, endemism, ancient origins and distinctive adaptations (Barlow, 1994; DEST, 1994; Williams et al., 2001). For example, Australia is recognised as one of the world’s 17 mega diverse countries with 23,000 native vascular plant species, 85% of which are endemic (DEST, 1994). There are also 14 endemic plant families, including several representing early stages in the evolution of flowering plants (DEST, 1994; Williams et al., 2001). Unfortunately, despite this recognition of the importance of the native flora, Australia currently has the fifth highest rate of land clearance in the world which is the highest of any developed nation with more than 564,800 ha of native vegetation cleared in 2000 (Williams et al., 2001). Land clearance since European settlement has resulted in the extinction of 61 plant species with an additional 1241 plant species vulnerable or threatened with extinction (DEH, 2005). In part, to preserve important ecosystems and maintain populations of rare and threatened species, over 80,895,000 ha (over 10% of the Australian landmass) is currently conserved in over 7720 protected areas (CAPAD, 2004, Table 1). The importance of the flora in many of these protected areas is reflected in their international recognition, with many World Heritage Areas (Worboys et al., 2005). Recently, 15 Australian biodiversity hotspots have been recognised in areas that have many endemic species and are under immediate threat from human activities (DEH, 2003). 2. Recreation in protected areas in Australia Nature-based recreation and tourism is popular in Australia, with large numbers of local and international tourists attracted by the numerous rich and diverse natural systems in national parks including World Heritage areas (Worboys et al., 2005). It is estimated that there are 84 million visits annually to protected areas in Australia, most of which is domestic tourism (Newsome et al., 2002a;

Table 1 Extent of Australian terrestrial protected areas categorised by World Conservation Union (formerly International Union for the Conservation of Nature) IUCN protected area management categories (CAPAD, 2004) IUCN category

Number

Area (ha)

IA IB II III IV

2090 38 644 2019 2060

18,212,695 4,099,515 29,678,100 970,517 2,818,936

Total V VI

6851 139 730

55,779,762 919,746 24,195,591

Total

869

25,115,337

Total

7720

80,895,099

Categories I–IV are reserved primarily for conservation.

Worboys et al., 2005). With this rise in tourism numbers there follows an inevitable increase in negative environmental impacts (Whinam and Chilcott, 2003; Liddle, 1997; Leung and Marion, 2000; Newsome et al., 2002a; Buckley, 2004a, b). In some cases impacts can even effect the quality of the tourism experience itself (Newsome et al., 2004). Recreation and tourism activities in protected areas in Australia are usually restricted to those that have been considered to have less environmental impact and emphasise enjoyment of the natural values of the area (Buckley, 2004a; Worboys et al., 2005). Also, use of protected areas is often zoned, with some areas highly developed and extensively modified through provision of infrastructure such as sealed roads, carparks, toilets, visitor centres, picnic areas, camping areas and accommodation. These areas often attract large numbers of people. In contrast, other zones within the same protected areas may be classified remote (which can be designated as ‘wilderness’) where there is limited access, no or few facilities, and only small numbers of visitors, with restriction on the types of activities permitted (Worboys et al., 2005). For example, activities permitted under certain conditions in urban/developed zones of New South Wales national parks include snow sports (alpine skiing, snowboarding, cross-county skiing, ice climbing), camping in formal campsites, scenic driving, canoeing/kayaking/white water rafting, motorised boating, sailing/sail boarding, fishing, cycling, bushwalking on formal tracks, caving, organised mountain biking, powered and non-powered flight (Worboys et al., 2005). In contrast in remote/wilderness areas, activities are mainly limited to bushwalking on nonhardened trails, fishing, camping without facilities, and crosscountry skiing.

3. Recreation and tourism impacts on vegetation in protected areas in Australia Associated with increasing visitation to protected areas, there is increasing recognition of, and research into, the

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impacts from recreation and tourism. This paper provides a review of research on recreation and tourism impacts on vegetation in Australia with an emphasis on research published since Sun and Walsh’s (1998) general review of environmental impacts of recreation and tourism in Australia. We concentrate on Australian research that is international significant, which examines impacts not previously described, or ecosystems for which there is limited existing research or that tests current models in recreation ecology theory. 3.1. Impacts associated with infrastructure for tourism and recreation Recreation and tourism results in impacts in Australian protected areas, both from infrastructure and the activities themselves. The most obvious and direct impact is vegetation clearance in order to provide infrastructure. Although recreation and tourism infrastructure within protected areas is limited, there are often tracks, trails, roads, lookouts, fixed campsites and other types of accommodation provided, all of which have impacts (Table 2, Newsome et al., 2002a). In the construction of huts, lodges, hotels, roads, campgrounds and other facilities, native vegetation is cleared and replaced by either non-native vegetation or a built environment (Table 2, Spellerberg, 1998). However, damage is not just restricted to the initial removal of native vegetation. For example, the construction and use of roads and tracks can result in changes to hydrology and soils including erosion, sedimentation and pollutant runoff in adjacent areas (Table 2, Buckley and Pannell, 1990; Spellerberg, 1998; Newsome et al., 2002a). In addition roads and campsites can act as corridors/sites for the introduction and spread of pathogens and weeds (Table 2, Spellerberg, 1998; Newsome et al., 2002a; Buckley et al., 2004). Two of the classic studies examining the role of cars as vectors for weed seeds were conducted in Australia (Wace, 1977; Lonsdale and Lane, 1994). A recent study comparing vegetation and soils on road verges and adjacent areas in the subalpine zone of

793

Kosicuszko National Park in New South Wales (Johnston and Johnston, 2004) found that soils on the road verges had significantly lower levels of humus, more gravel and sand, lower levels of nutrients and lower pH and electrical conductivity than soils sampled 10 m away from the roads where there was native vegetation. In drainage areas just below the road, soils were also affected with significantly higher amounts of sediment, soil pH, and exchangeable levels of calcium and potassium than the roadside or natural areas. Vegetation composition and cover also differed, with roadsides having more bare ground (28%), and weed cover, than the nearby natural areas (2% bare ground, 6% weed cover). The drainage areas were dominated by one weed (Achillea millefolium—yarrow), which accounted for 91% of the ground cover (Johnston and Johnston, 2004). Although the total area allocated to recreation and tourism infrastructure may be relatively small compared to the total area of a park, the impacts at that site are severe and often permanent (Smith and Newsome, 2002; Pickering and Buckley, 2003; Turton, 2005; Scherrer and Pickering, 2006). Also with linear disturbances such as those due to tracks and roads, the total area of disturbance may appear small, but due to the length of the road and verge effects and the area of impact on the verges, the actual footprint can be much larger (Spellerberg, 1998; Priskin, 2003; Donaldson and Bennet, 2004; Johnston and Johnston, 2004; Turton, 2005; Hill and Pickering, 2006). For example, a study on different track types in the alpine zone in Australia, demonstrated that the direct footprint on native vegetation (e.g. area of exotic plants or bare ground associated with the track) was 4290 m2/km for wide gravel tracks (1 car width), 2940 m2/km for narrow gravel tracks, and 2680 m2/km for a track made from pavers (Hill and Pickering, 2006). However, a raised steel mesh walkway that was installed in the 1980s was not associated with either bare ground or a significant cover of exotics, indicating that careful selection of track type can dramatically reduce the direct environmental impact of such infrastructure on vegetation. A common problem is that increasing recreation and tourism use of a site can often result in park managers

Table 2 Recent Australian research that has commented impacts on vegetation of recreation and tourism infrastructure Impacts\type of activities

Campgrounds

Huts

Lodges, hotels, etc.

Roads

Tracks

Vegetation damage Change in hydrology Changes in soil conditions Spread of weeds Spread of pathogens

1, 2, 3 2 1, 2, 3 2, 3

4

4 4 4, 10 4, 12

5 5 5 5, 12, 13,18,19 5, 14, 15, 16, 17

6, 7, 8, 9, 11 8 8, 9, 11 8,12 15,16

4 4

References: (1) Turton et al. (2000a); (2) Smith and Newsome (2002); (3) Turton (2005); (4) Buckley et al. (2000); (5) Donaldson and Bennet (2004); (6) McDougall and Wright (2004); (7) Hill and Pickering (2006); (8) Johnston and Johnston (2004); (9) Turton et al. (2000b); (10) Walker (1991); (11) Day and Turton (2000); (12) Johnston and Pickering (2001); (13) McDougall (2001); (14) Weste (1998); (15) Worboys and Gadek (2004); (16) Newsome (2003); (17) Cowie and Werner (1993); (18) Bear et al. (in press); (19) Johnston et al. (in press).

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hardening the site with a gradual change from natural to urban environment (Buckley and Pannell, 1990; Pickering and Buckley, 2003; Donaldson and Bennet, 2004; Worboys et al., 2005). Also, there can be changes in the expectations of visitors, with those participating in mass tourism in protected areas often requiring more sophisticated, hardened facilities than those engaging in backcountry activities. An alternative strategy is closure of some sites and/or education programs for visitors (Worboys et al., 2005). These approaches can be very successful as has been found on Fraser Island World Heritage area, where appropriate education has reduced the number of badly impacted camping sites even during peak usage periods (Hockings and Twyford, 1997). 3.2. Impacts associated with tourism activities In addition to the impacts associated with infrastructure, there are impacts associated with recreation and tourism activities that do not require infrastructure, particularly those that occur in the backcountry. The most obvious impacts on vegetation from popular back country activities such as camping, horse riding, walking, off-road driving and mountain biking include vegetation being crushed, sheared off, and uprooted (Table 3, Liddle, 1997; Newsome et al., 2002a). These impacts result in changes to the vegetation including loss of height, biomass, reproductive structures (flowers, fruit, etc.), reduction in cover, increased litter, damage to seedlings and change in species composition (Table 3). Just as for tourism infrastructure, back country activities can also be associated with changes to the hydrology of the site, soil conditions including nutrients

and erosion, as well as the introduction of weeds and pathogens (Table 3). Direct impacts of recreation and tourism activities that are often less recognised/reported include root damage to trees by tethered horses or holes dug for human or other waste, trees cut for firewood and/or vandalism of vegetation at sites, and wildflowers and epiphytes harvested (Liddle, 1997; Newsome et al., 2002b; Phillips and Newsome, 2002; Smith and Newsome, 2002; Bridle and Kirkpatrick, 2003). For example, a common minimum impact guideline for camping and walking in backcountry areas is to dispose of human faeces and toilet paper by burying it small holes. However, when the impacts of digging these ‘‘cat-holes’’ was experimentally tested across a range of vegetation types in Tasmania it was found that digging holes damaged vegetation with lower overlapping cover after digging compared to before digging for a wide range of communities (Bridle and Kirkpatrick, 2003). 3.3. Factors that affect impacts from recreation and tourism The extent of damage to vegetation from recreation and tourism will be influenced by factors such as the type of infrastructure provided, the amount of use of areas, the type of activity, the behaviour of tourists and the season of use (Liddle, 1997; Cole, 2004; Table 4). Some of the impacts of infrastructure have already been described in previous sections. When comparing different recreation activities it is commonly considered that cars tend to cause more damage that horse riding, which causes more damage than mountain bikes, which in turn cause more damage

Table 3 Recent Australian research that has documented impacts on vegetation from tourism and recreation activities Impacts\type of activities

4WD

Horse-riding

Walking of tracks

Backcountry camping

Mountain-biking

Vegetation clearing/damage Reduction in height Reduced living biomass Reduced cover Change in litter Damage to seedlings Changes in species composition Damage to trees (cutting, etc), eating

1, 2

2, 3, 4, 5 11, 12 4 3, 4, 11, 12 3

2, 6, 7, 8, 9, 10 10 7, 13, 16 6, 7, 9, 10, 13, 15, 16 9, 10

2, 8 10

2

11, 12

2, 10, 15

8 10 8 8

12

8, 10

4 3, 11, 12 11

7, 8, 13 2 9, 10

8, 10

14 14

5 2, 4, 5, 11 2, 11

2, 9 2 2

8 2, 8 2

2 2 2

Reduction in surface profile Soil loss Soil compaction/change in soil moisture Change in hydrology Spread of weeds Spread of pathogens

1

2

1, 2

1 2 2

References: (1) Priskin (2002) (inferred from changes in number of tracks on aerial photos); (2) Turton (2005); (3) Whinam and Comfort (1996); (4) Whinam et al. (1994); (5) Landsberg et al. (2001); (6) Hill and Pickering (2006); (7) Whinam and Chilcott (1999); (8) Smith and Newsome (2002); (9) Talbot et al. (2003); (10) Growcock (2005); (11) Newsome et al. (2002b); (12) Phillips and Newsome (2002); (13) Whinam and Chilcott (2003); (14) Goeff and Alder (2001); (15) McDougall and Wright (2004); (16) Whiman et al. (2003).

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Table 4 Recent Australian research into factors that affect the amount of damage from tourism and recreation activities Recent studies Factor associated with activity Type of activity Amount of use

Size of camping group Behaviour of user group Factors associated with environment Resistances/resilience of vegetation

Topography site Soil characteristics including drainage Climatic zone Seasonality

Growcock (2005); Turton (2005). Whinam et al. (1994); Goeft and Alder (2001); Landsberg et al. (2001); Newsome et al. (2002a, b); Phillips and Newsome (2002); Whinam and Chilcott (2003); Whinam et al. (2003); Talbot et al. (2003); Growcock (2005); Turton (2005). Smith and Newsome (2002); Growcock (2005). Newsome et al. (2002a,b); Smith and Newsome (2002); Turton et al. (2000b); Growcock (2005). Whinam et al. (1994); Whinam and Comfort (1996); Turton et al. (2000b); Bridle and Kirkpatrick (2003); Talbot et al. (2003); Whinam and Chilcott (2003); Whinam et al. (2003); Growcock et al. (2004); McDougall and Wright (2004); Growcock (2005). Goeft and Alder (2001); Whinam and Chilcott (2003); Whinam et al. (2003). Whinam et al. (1994); Whinam and Chilcott (1999); Arrowsmith and Inbakaran (2001); Talbot et al. (2003); Whinam et al. (2003); Growcock et al. (2004). Whinam et al. (1994); Bridle and Kirkpatrick (2003); Talbot et al. (2003); Whinam and Chilcott (2003); Whinam et al. (2003); Growcock (2005). Buckley et al. (2004); DPIWE (2005); Turton (2005).

that walking (Liddle, 1997). This was found in recent Australian research in the Wet Tropics of Queensland World Heritage area, where trails used for mountain biking had higher levels of soil erosion and exposed rocks and tree roots than high-use walking trails (Day and Turton, 2000). Correspondingly, in studies comparing trampling and camping impacts in the Australian Alps, short stay camping (three nights) by small groups (four people) had limited impact on vegetation height and cover (although there were fire scars and axe damage to trees), while experimental trampling, particularly at high number of passes had a range of impacts on vegetation and recovery took longer (Growcock, 2005). It is generally recognised that increased tourism use results in increased damage (Liddle, 1997; Newsome et al., 2002a; Cole, 2004; Newsome et al., 2004). This has been found in a wide range of experimental studies including in different vegetation types in Australia (Table 4). However, what is not clear is the form of the relationship with some studies indicating that the proportionally greatest damage occurs at low levels of use (Cole, 1995a, 2004), while other research has found that low levels of use may not cause damage in grassland communities (Growcock, 2005). The size of a user party can also influence the area of damage with larger parties often causing a disproportionate amount of damage. For example, larger groups at campsites tend to cause more damage than smaller groups. In a study comparing impacts at high-use formal campsites and low-use informal campsites, in old growth eucalypt forest in a protected area in Western Australia, the highuse formal campsites were larger (mean size 876 m2), had more tree damage, soil erosion, soil compaction, along with reduced vegetation cover and tree seedlings, greater degradation to riverbanks and more foot pads than

the low-use informal campsites (177 m2) (Smith and Newsome, 2002). Behaviour can affect the intensity of impacts that may occur (Liddle, 1997; Cole, 2004, Table 4). Where user groups are aware of minimal impact behaviour, such as those in ‘leave no trace campaigns’, impacts may be reduced through careful consideration of campsite location, routes for hiking or riding, disposal of waste, etc. (Hercock, 1999; Cole, 2004; Growcock, 2005). Where such codes of behaviour are ignored or unknown, impacts can be more severe (Hercock, 1999; Growcock, 2005). For example the degree of impact from camping in the Wet Tropics in Queensland appeared to be associated with both the behaviour and type of user (Turton et al., 2000b). Lowuse camping areas that were predominantly used by local residents had more litter, with more development of the site (fire rings, seating made from vegetation), more social trails, and more tree damage (including for firewood) compared to high-use camping areas where most visitors were not local. Park managers have legislative requirements to manage recreation in ways that mitigate impacts and ensure that activities are ecologically sustainable. Recreation management includes prescribing the areas where particular activities are conducted and, less commonly limiting, visitor numbers or the size of groups. There appear to be few instances in Australia where either a maximum group size or a maximum number of groups/season are imposed (Hill and Pickering, 2002). There are a range of environmental factors which can affect the amount of damage to vegetation by recreation and tourism activities. These include the characteristics of the vegetation, the topography of the site, soil characteristics, climatic zone and seasonality (Liddle, 1997; Cole, 2004, Table 4).

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Studies in Australia along with those overseas have found that vegetation varies in its resistance and resilience to disturbance (Cole, 1995a, b; Liddle, 1997, Newsome et al., 2002a; Cole, 2004; Newsome et al., 2004, Table 4). Resistance is the relative ability of individual species to withstand disturbance before being damaged while resilience is the relative capacity of the vegetation to recover after disturbance (Liddle, 1997). Aspects of plant morphology can affect resistance to damage, with some life-forms (low growing graminods, etc.) more resistant than others (shrubs, some forbs, etc. Cole, 1995b). As a result communities dominated by resistant life-forms will be damaged at higher use levels than sensitive communities dominated by life-forms such as shrubs (Cole, 1995a, b, Liddle, 1997; Whinam et al., 1994; Whinam and Chilcott, 2003; Growcock, 2005). Correspondingly plants vary in their resilience, resulting in some communities recovering faster from disturbance (Liddle, 1997). Generally there are three types of response: (1) species with high resistances, but are slow to recover once damaged; (2) species with low resistances but are relative fast to recover; and (3) species that have low resistance and low resilience and therefore are susceptible to damage from trampling and other types of visitor use (Liddle, 1997). An example of how vegetation varies in resistance and resilience is seen from experimental trampling trials in the high country of Tasmania (Whinam and Chilcott, 1999; Whinam and Chilcott, 2003; Whinam et al., 2003). Trampling had a range of negative effects on the vegetation, with the degree of damage increasing with the number of passes by a walker. It also varied depending on the life form of the plants, with shrubs, tall tussock graminoids and cushion plants more susceptible to damage than lower growing graminoids (Whinam and Chilcott, 1999, Whinam and Chilcott, 2003; Whinam et al., 2003). The time taken for recovery also varied with intensity of use and life-form, with damage (changes in species richness, more bare ground, lower surface profile) still apparent in many communities 3–5 years after trampling (Whinam et al., 2003). Differences in resistance and resilience to trampling can result in changes in species richness, with those taxa that are susceptible to damage lost from a community, while other taxa may increase in cover or even colonise disturbed areas. Trampling of the fragile feldmark vegetation along the ridges of the highest mountains in Australia resulted in a decrease in native species richness on tracks compared to adjacent vegetation, as well as a decline in the abundance of some species including the dominant prostrate shrub (McDougall and Wright, 2004). The shrubs in the feldmark have low resistance to trampling as the dominant shrub Epacris microphylla has brittle stems that are easily broken. Feldmark species are also characterised by exceptionally slow growth rates, and so will take decades to recovery from damage (McDougall and Wright, 2004).

Much of this and other trampling research has been conducted on low growing vegetation types (Cole, 2004). One of few studies worldwide examining trampling impacts in tropical forests found that species with broad thin leaves, year round growth, and occurring on moist friable soils that are easily compacted, had low resistance to trampling with reduction in vegetation cover occurring after as few as 25 passes (Talbot et al., 2003). Also in the Wet Tropics experimental day-use and camping trials reduced canopy cover and decreased cover of seedlings compared to controls with the extent of damage varying among forest types (rainforests, wet sclerophyll forest and littoral rainforest, Turton et al., 2000b). Abiotic site characteristics such topography and hydrology will also affect the amount of damage from recreation and tourism activities (Table 4). Hiking, walking and bike riding on steep slopes causes greater damage than on flatter terrain (Goeft and Alder, 2001; Whinam and Chilcott, 2003). In Tasmanian alpine national parks, for example, experimental trampling on sloping buttongrass communities caused soil to become exposed and accumulate downslope after just 200 passes (Whinam and Chilcott, 2003). However, substrate type can offset the effect of slope. In a study of impacts of tracks in the Grampians National Park in Victoria, there was more damage to vegetation and soils along tracks at lower elevations where soils were deeper than at higher elevations where the tracks traversed rocky outcrops (Arrowsmith and Inbakaran, 2001). Climatic zone also appears to affect the response of vegetation to recreational and tourism use (Table 4). For example, Australian research confirms overseas research that has found high-altitude vegetation communities are often more susceptible to damage than lower-altitude communities (Liddle, 1997; Table 4). Within a climatic zone, vegetation types can differ in their response to various intensities and types of impacts. In the Wet Tropics of Queensland, for example, rainforest, littoral forests and wet scherlophyll forests differed in the effect of day-use and camping on canopy cover, mineral soil exposure, soil compaction, vegetation cover and seedling density (Turton et al., 2000b). Wet sclerophyll forests were the most resistant, with rainforest intermediate and littoral forest the least resistant. The resistance and resilience of vegetation can vary seasonally affecting the intensity of damage that may occur from a particular activity (Table 4). For example, the spread of pathogens such as the root rot fungus Phytophthora cinnamomi by mud on the boots of walkers and tires of vehicles varies with season, with wet periods resulting in a great risk of spread (Buckley et al., 2004; DPIWE, 2005). In the Wet Tropics of Queensland there were seasonal effects of tourism use with greater soil compaction, and lower seedling densities adjacent to walking tracks in the wet season compared to adjacent unused forest in the dry season (Turton, 2005).

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3.4. Indirect impacts from tourism and recreation Direct impacts from human activities may also be exacerbated by indirect impacts (Good, 1995; Buckley, 2003). Although there has been increasing recognition of the importance of indirect impacts of tourism on native vegetation in protected areas there has been far less research in this area (Buckley, 2003, 2005). Also, some indirect impacts can be self-sustaining: that is they can continue to occur even in the absence of further tourism use of the site (Buckley, 2003). Recent Australian research has highlighted self-sustaining indirect impacts including from increased nutrients and the introduction and spread of weeds and pathogens. 3.4.1. Addition of nutrients Disposal of human waste (such as urine and faecal material) has direct effects such as removal of vegetation in order to dig a hole, but also has indirect effects through the addition of nutrients which can result in a change to species composition due to competitive displacement. This can create feedbacks for continuing change and also benefit weed species, leading to changes in vegetation communities. Research in Tasmania found a beneficial effect of low levels of nutrient addition (artificial urine) on vegetation, with increased growth of many taxa, with the only obvious negative effects on moss at one site (Bridle and Kirkpatrick, 2003). Research on tourism impacts has highlighted how direct introduction of nutrients and/or re-suspension of sediments associated with swimming in dune lakes at Fraser Island in Queensland, affected algal growth, resulting in changes to ecosystem function (Hadwen and Bunn, 2004). This research also found that new methodologies may be required to detect these more subtle effects of recreation and tourism use. 3.4.2. Impacts of weeds Another indirect and potentially self-sustaining impact of tourism is the accidental introduction of weed propagules on visitors’ shoes, clothing and equipment. The risk associated with even low numbers of visitors to remote areas was recently highlighted in a study examining propagule load on people (in this case expeditioners) visiting a remote subantarctic island (Whinam et al., 2005). The study found 981 propagules on the clothing and equipment of just 64 people. High-risk items were equipment cases, daypacks and the cuffs and velcro closures on outer clothing. As a result there have been policy changes regarding clothing for people visiting subantarctic islands as part of expeditions from Australia. Another important issue, in Australia and overseas, is the potential for exotics to spread from areas disturbed by tourism infrastructure into natural vegetation. In Australian protected areas, the verges of tracks and trails are often characterised by high diversity and cover of exotics, however, not all these species spread into undisturbed

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native vegetation and become important environmental weeds (Mallen-Cooper, 1990; Williams and West, 2000; Johnston and Pickering, 2001; Godfree et al., 2004; Johnston, 2005). Recent research in the Snowy Mountains in Australia has compared the ecological traits of species that spread compared with those that remain restricted to road and track verges (Godfree et al., 2004). 3.4.3. Impact of pathogens Another important example of an indirect and selfsustaining impact of tourism is the spread of P. cinnamomi in protected areas in Australia. This root rot fungus is a threat to vegetation including many plants that are already classified as rare and threatened. This is discussed further in the following section. 4. Tourism impacts on rare and threatened plants For rare and threatened plants the impacts of tourism are particularly severe as these species are already at risk of extinction. However, the impacts of tourism on rare flora including that in protected areas has not been generally recognised as a specific type of threat, even though there is evidence of negative environmental impacts from tourism on these taxa in protected areas (Kelly et al., 2003). One clear example of tourism threatening rare and endangered plants is through the spread of the exotic soilborne pathogen P. cinnamomi (Newsome, 2003; Schahinger et al., 2003; Buckley et al., 2004; DPIWE, 2005; Turton, 2005). This threat has been recognised nationally and it is listed as a key threatening process by the Australian Government (Environment Australia, 2001), and by the NSW government in the Threatened Species Conservation Act 1995. Tourism contributes to the spread of P. cinnamomi by transportation of spores in mud on footwear, tent pegs, trowels, horse hooves, bike tires and other types of vehicles. It is also spread during the construction and maintenance of tourism infrastructure (Newsome, 2003; Buckley et al., 2004; Donaldson and Bennet, 2004; Worboys and Gadek, 2004; DPIWE, 2005). Tourism can also contribute to the pathogen’s impact by increasing the stress on plants within infected areas (Buckley et al., 2004). In addition to the damage it causes to more common taxa, in Western Australia P. cinnamomi is a threat to at least 31 plant taxa already at risk of extinction with another 39 possibly susceptible, while in Tasmania, there are 39 plant taxa already at risk of extinction that are susceptible to infection (Barker and Wardlaw, 1995; Environment Australia, 2001; Schahinger et al., 2003; DPIWE, 2005). It is currently found in protected areas in Western Australia (e.g. up to 70% Stirling Range National Park) South Australia (Mount Lofty Ranges, Fleurieu Peninsula, Kangaroo Island), Victoria (Wilson’s Promontory) and Tasmania (Southwest National Park, Freycinet National Park) (Newsome, 2003; Environment Australia, 2001; Newsome et al., 2002a; Schahinger et al., 2003;

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Buckley et al., 2004; Worboys and Gadek, 2004; DPIWE, 2005; Turton, 2005). Quarantine and hygiene are the main strategies that have been implemented by protected area managers to combat this threat. Some parks have permanent or seasonal closures of specific tracks, or sections within a park, or in a few cases whole parks are closed particularly in severely affected areas of Western Australia and South Australia (Newsome, 2003; Newsome et al., 2002a; Buckley et al., 2004). Hygiene procedures to minimise the spread of spores are implemented through education programs (signs, leaflets, etc.) which encourage/require visitors to wash down vehicles, boots, tent pegs, etc. when entering and leaving sites, and in some cases to visit uninfected sites before infected sites (Buckley et al., 2004; DPIWE, 2005).

nationally (Key Threatening Process, Environment Australia, 2001), by park agency staff and researchers (Schahinger et al., 2003). Although a range of studies have examined the fungus and its impacts more research is required into identifying susceptible species and to determine if vegetation eventually recovers. (3) There is limited research into the impact of tourism infrastructure in Australia including comparisons of ecological costs/benefits of various types of tourism infrastructure. 6. Research needs for managing/monitoring of impacts In addition to ecological research there is a need for further research into the best ways to monitor impacts and to manage impacts and tourists. This includes research into:

5. Recommendations for future ecological research In Australia, as overseas, much of the published research on recreation and tourism impacts on vegetation had quite a narrow focus concentrating on trampling and camping and horse riding (Sun and Walsh, 1998; Newsome et al., 2002a; Buckley, 2005, Table 3). There is limited research on the impacts of visitor infrastructure in protected areas, or into indirect impacts, including those that are self-sustaining (Buckley, 2002, 2003, 2005). Based on the review here, consultation with protected area staff, discussions with researchers in recreational ecology, and the findings of Buckley’s (2002) evaluation of ecotourism industry and protected area managers priorities a series of key areas for future ecological research are identified: (1) Research into a range of visitor activities (camping, trampling, etc.) on Australian vegetation looking at levels of resistance and resilience. There are limited data for impacts of camping and trampling in rainforests, arid regions and deserts and swamp/bogs/fens in Australia and overseas. In Australia, there also needs to be more research into the impacts of mountain biking, rock-climbing and off-road driving which are increasing in popularity. (2) Self-propagating, ecologically important indirect impacts of tourism and recreation such as the spread of weeds and pathogens. Weeds have been identified as an important threat to the environment at all levels of government in Australia (Csuches and Edwards, 1998; Williams and West, 2000; Environment Australia, 2006). For protected areas it is important to determine how tourists may be introducing exotics and to identifying and characterising exotic plants that spread from tracks and trails into natural vegetation. Correspondingly there is a need for more research into the dispersal of pathogens such as the fungus, P. cinnamomi, by visitors and vehicles. The severity of the threat from P. cinnamomi has been recognised

(1) Restoration ecology—how far and how fast impacted sites can recover if closed to visitors and how recovery can be accelerated. Rehabilitating sites damaged by infrastructure and visitor use is often expensive, ongoing and unfortunately, not always successful. Evaluating the success of different restoration methods remains a priority for many park agencies. (2) Evaluating the impacts and benefits of different types of infrastructure once introduced through establishing monitoring programmes with ecologically appropriate indicators. (3) Evaluating the success of specific management practices such those associated with limiting the spread of weeds and pathogens. For example, it is important to determine current quarantine practices are limiting the spread of root rot. (4) Evaluating the extent and degree of ‘impact creep’, i.e. the gradual cumulative increase in impacts associated with increasing visitor numbers through incremental hardening of sites or displacement of activities from high-intensity tourism nodes into backcountry areas. (5) Evaluate the success, cost and usefulness of current monitoring programs. 7. Conclusions There are many threats to vegetation in Australian protected areas from tourism. Greater recognition needs to be given to this by protected area managers. Although the flora is internationally significant and protected area tourism is very popular there is still limited research on direct and indirect impacts of tourism for many Australian plant communities. Based on this review it is possible to identify future directions for research, and recommendations for current research. Acknowledgements This research was funded by the Sustainable Tourism Cooperative Research Centre for Sustainable Tourism, an

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