Long-term ecological studies in Northern Fennoscandia Workshop at Kilpisjärvi 13-15 March, 2013

© Mikko Jokinen

Participants (p) project member (i) invited guest

Per-Arne Amundsen (i)

Department of Arctic and Marine Biology, University of Tromsø

Brian Hayden

Department of Environmental Sciences, University of Helsinki

Tuomas Heikkilä (p)

Kilpisjärvi Biological Station , University of Helsinki

Heikki Henttonen (i)

Finnish Forest Research Institute (Metla), Vantaa Research Unit

Mikko Hyppönen (i)

Finnish Forest Research Institute (Metla), Rovaniemi Research Unit

Mikko Jokinen (p)

Finnish Forest Research Institute (Metla), Kolari Research Unit

Antero Järvinen [chair] (p)

Kilpisjärvi Biological Station, University of Helsinki

Kimmo Kahilainen (i)

Department of Environmental Sciences, University of Helsinki

Heikki Kauhanen

Finnish Forest Research Institute (Metla), Kolari Research Unit

Reima Leinonen (i)

Kainuu Regional centre for Economic Development, Transport and the Environment (ELY-Kainuu)

Ben Li

Department of Information Processing Science, University of Oulu

Karl-Birger Strann (i)

Norwegian Institute for Nature Research, NINA

Poster: Aleksi Lehikoinen1*, Martin Green2, Magne Husby3, John Atle Kålås4, Åke Lindström2 1 Finnish Museum of Natural History, University of Helsinki, Finland, *[email protected] 2 Department of Biology, Biodiversity unit, Lund University, Ecology Building, SE‑223 62 Lund, Sweden 3 Nord-Trøndelag University College, Røstad, NO-7600 Levanger, Norway 4 Norwegian Institute for Nature Research, P.O. Box 5685 Sluppen, NO-7485 Trondheim, Norway

Programme at Kilpisjärvi Wednesday, March 13 18:00: Get-together, cold dinner & wine, lake-shore sauna available Thursday, March 14 8:00 Breakfast 9:00 Opening words by director (Antero Järvinen, Kilpisjärvi biological station) 9:15 Invited talks (c. 20 mins) and discussion - Small mammal study and data at Kilpisjärvi (Project manager Tuomas Heikkiä) - Vole and lemming fluctuations at Kilpisjärvi over 60 years (Heikki Henttonen) - Sea vs. Mountain, Pied Flycatchers Ficedula hypoleuca: results of 26-year population studies in Skibotn & Kilpisjärvi (Antero Järvinen) -More than 20 years of monitoring of breeding Tengmalm's owl in Troms county, Norway (Karl-Birger Strann) 12:00 Lunch break 13:00 Invited talks (c. 20 mins) and discussion - Long-term botanical research at Kilpisjärvi (Tuomas Heikkilä repl. Kari Laine) - The changes of forest timberline in Northern Finland during 1983-2009 (Mikko Hyppönen) - Climate change and shifts in the distribution of moth species in Finland (Reima Leinonen) 15:00 Coffee break 15:30 Invited talks (c. 20 mins) and discussion - Ecology of whitefish (Coregonus lavaretus L.) in subarctic Lake Kilpisjärvi (Kimmo Kahilainen) - Long-term studies following experimental density depletion of a stunted Arctic charr population (Per-Arne Amundsen) 17:00 Break 18:00 Dinner Lake-shore sauna available Friday, March 15

8:00 Breakfast 9:00 Conclusions and discussion 11:00 Lunch & farewell

Long-term ecological studies in Northern Fennoscandia

Long-term studies following experimental density depletion of a stunted Arctic charr population - ecological and management implications Per-Arne Amundsen Department of Arctic and Marine Biology, Faculty for Biosciences, Fisheries and Economics, University of Tromsø, Norway, [email protected]

Abstract Overcrowding and stunting is a widespread phenomenon among several freshwater fish species in temperate and subarctic lakes, and frequently constitutes a large management problem in respect to the utilization of these fish populations. Stunted populations are typically characterized by an accumulation of old, small-sized and slowly growing fish. In the early 1980’s, the subarctic Lake Takvatn (15 km2), northern Norway, hosted an overcrowded and stunted population of Arctic charr, whereas the original brown trout population in the lake nearly had vanished. During the period from 1984 to 1989, a total of 666.000 individuals or 32.3 tons of Arctic charr were removed in a whole-lake experiment aiming to rehabilitate the fish community in the lake. The goal was to establish a new ecological state with enhanced somatic growth rates of the charr and increased population density of brown trout. The effects of the experiment have been followed by long-term annual studies including the periods prior to, under and following the density manipulation and covering a total time span of 30 years. The large-scale manipulation resulted in a severe density depletion accompanied by large enhancements of somatic growth rate and other population characteristics of the charr. Concurrently there has been a strong increase in the abundance of brown trout. The extensive changes in the fish community are related to complex trophic interactions both within and between species; including intra- and interspecific competition, piscivore predation and cannibalism. The positive effects have been sustained over an extended time period, suggesting that a new stable state has established in the system.

Long-term ecological studies in Northern Fennoscandia

Long-term botanical research at Kilpisjärvi Biological Station

Tuomas Heikkilä Kilpisjärvi Biological Station, University of Helsinki, [email protected]

Abstract After 25 years of intensive rodent research, long-term botanical studies were launched at Kilpisjärvi. Key motivator was to study relationships between plant production and rodent cyclicity. Since 1972 to mid-1980s, a wide repertoire of fell plant species was included in the monitoring scheme, including shrubs, graminoids and tree. Since late 1980s, some follow-up studies were cancelled, and effort was put on five species: the bilberry (Vaccinum myrtillus), the mountain birch (Betula pubescens ssp. czerepanovii), the dwarf birch (Betula nana), the globeflower (Trollius europaeus) and the mountain avens (Dryas octopetala). Preliminary results of selected studies are presented. Seed crop of the mountain birch has been followed since the early 1960s. Seed crop study was initiated in the nation-wide tree seed crop study, and was later continued by KBS. “Good” seed crops vary every 5 to 10 years, but the general trend at the study area is declining. This may be due to several factors, including ageing of the trees, herbivore by reindeer or outbreaks of the caterpillar (the autumnal moth, Epirrita autumnata). Other mountain birch and dwarf birch data, including leaf dry weights, is at the moment scattered. On the other hand, a wide range of bilberry data is available since the early 1970s. Data set includes standard plots, nitrogen and temperature treatment plots and herbivore enclosure plots. In the standard plots, number of the bilberry flowers is increasing both in the mountain birch forest and in the open mountain heath. Berry production is in the increase in the open mountain heath. Further investigation on these trends is encouraged.

Long-term ecological studies in Northern Fennoscandia

Small mammal study and data at Kilpisjärvi

Tuomas Heikkilä Kilpisjärvi Biological Station, University of Helsinki, [email protected]

Abstract At the present, Kilpisjärvi LTSER-project has been running for about 2½ years. Project is connected to Finnish LTSER-scheme, which is a network of research infrastructures and scientists with a longterm approach to ecosystem and biodiversity processes. Main goal of Kilpisjärvi LTSER-project is to gather and digitize long-term ecological data, and to enhance research connections of Kilpisjärvi biological station and Kolari research unit of Finnish forest research institute (Metla). One of the biggest efforts in the project was to organize various small mammal study material and data at Kilpisjärvi. Small mammal studies sparked the launch of research activities at Kilpisjärvi in 1946. Data sets cover records of nearly 40 000 individuals and over 2000 separate trapping sessions. Roughly 3/4 of data is gathered at Kilpisjärvi, and the rest in various places in Northern Finland in efforts to study movements of the wood lemming (Myopus schisticolor). However, most of the catch consists of the Norwegian lemming (Lemmus lemmus), the grey-sided vole (Myodes rufocanus) and the common shrew (Sorex araneus). Data is supplemented by private studies at Kilpisjärvi by late Johan Tast and late Asko Kaikusalo. In addition to small mammal studies, a small sample of other mammal data has been digitized. Since 1953 small mammal studies have been running during both summer and fall periods. In the data set, there is a clear tendency towards more repeatable methods over the decades. Most of the catch is caught during vole population peak years, as in 1960, 1964, 1969-70 and 1974. Since small mammal studies have been done with similar methods, and similar sites, over the years, data sets offers reliable and unparalleled image of long-lasting density variation of the vole populations in the subarctic area. However, scientists using this data should pay a good deal of attention to various methods and sites used during the decades, which can potentially distort conclusions.

Long-term ecological studies in Northern Fennoscandia

Long-term patterns in arvocoline rodent dynamics in northern Finnish Lapland

Heikki Henttonen Finnish Forest Research Institute, Vantaa Research Unit, [email protected]

Abstract Dynamics of voles and lemmings in northern Finnish Lapland have been monitored at Kilpisjärvi since late 1940's and at Pallasjärvi since 1970. Basic work consists both of spring and autumn monitoring on permanent study sites and various experimental field approaches on the role of interspecific competition in shaping the community patterns and of supplemental food in modifying the seasonal and long-term dynamics. A drastic change in the population dynamics took place in mid and late 1980's. Earlier "beautiful" cycles turned to primarily seasonal dynamics. However, during the last years the cycle has returned! In the cyclic times, vole dynamics were characterized by synchronous cycles, particularly the deepest crash phase was synchronous in all sympatric species, though in the increase and peak phases some moderate inverse density changes were observed among competing species. Synchronous crashes in all sympatric species, with different food repertoires, speak for predation by weasels. In the long-term time series, linear delayed density dependence was a dominating factor, suggesting trophic interactions as a cause of cycles. Still, non-linear direct dd was also observed. The last lemming peak, and the large geographic synchony of simultaneous vole peak in N Fennosfcandia in 2010-11 coinicded with two favourable winters without warm spells and subnivean ice.

Long-term ecological studies in Northern Fennoscandia

The changes of forest timberline in Northern Finland during 1983–2009 Mikko Hyppönen Finnish Forest Research Institute (Metla), Rovaniemi Research Unit, [email protected]

Abstract Seedling (≤ 2 m) density and tree (> 2 m) density of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were monitored five (5) times in the timberline areas of Northern Finland during the period 1983–2009. Monitoring was carried out in nine (9) circular plots in 13 localities in four (4) regions: pine-dominated northern and southern regions and spruce-dominated western and eastern regions. The measurements were made in three (3) altitudinal zones: in the forest, at the coniferous timberline (where forest canopy closure ends), and at the tree line (where coniferous trees > 2 m end). Changes in timberline advancement were assessed on the basis of the repeated measurements of the chosen variables.

The density of spruce seedlings and the density of spruce trees have clearly increased in all the regions and zones during the monitoring period. The density of pine seedlings and pine trees is slowly increasing in all the regions and zones, as well. The preliminary results indicate a clear potential for the spruce timberline and spruce tree line to advance upwards and northwards. In addition, the results indicate a slight potential for the timberline and tree line of pine to advance.

Key words: forest, timberline, tree line, Scots pine, Norway spruce, regeneration, seedling establishment, survival, seedling density, tree density, climate change

Long-term ecological studies in Northern Fennoscandia

“Sea” versus “mountain” Pied Flycatchers (svarthvit fluesnapper, Ficedula hypoleuca): results of 26-year population studies in Skibotn (Norway) and Kilpisjärvi (Finland) Antero Järvinen Kilpisjärvi Biological Station, University of Helsinki, [email protected]

Abstract Results of long-term population studies of the Pied Flycatcher in Skibotn (69°20’N) and Kilpisjärvi (69°03’N) in 1987-2012 are presented. Both time-series are among the longest in northern Europe. The geographical distance between the study areas is only 35 km. In Skibotn the species has belonged to the breeding avifauna for over 100 years, in Kilpisjärvi over 50 years. The “sea” population of Skibotn nested in boxes close to the Arctic Ocean (90-180 m asl), the “mountain” population of Kilpisjärvi in boxes close to the tree-line (475-600 m asl). Population sizes did not fluctuate in synchrony. According to the ringing statistics of breeding females and nestlings, there was no immigration or emigration between the populations. These facts indicate that the migration routes of the nearby populations are different: birds breeding in Skibotn migrate along the Norwegian coast, those breeding in Kilpisjärvi along the Gulf of Bothnia. Population size varied relatively more in the mountain area than in the sea side area. Annual temperature during the egg-laying period varied in parallel between the areas, but was about 3°C colder in the mountain area. Thus, in the more northern “sea” population egg-laying occurred in warm weather and about 7 days after the leafing of the birches, in the “mountain” population in cold weather and about 5 days before leafing, i.e., in an early phenological phase. During the study period “sea” flycatcher showed a tendency for earlier breeding. This trend was not so much due to the warming of climate but to the fact that females have adapted to breed in colder weather. The “sea” population produced about one fledgling/nest more than the “mountain” population. However, annual mean nesting success did not correlated between the areas because the reasons (predation and starvation) for poor nesting success varied regionally and annually.

Long-term ecological studies in Northern Fennoscandia

Ecology of whitefish (Coregonus lavaretus (L.)) in subarctic Lake Kilpisjärvi Kimmo Kahilainen Department of Environmental Sciences, University of Helsinki, [email protected]

Abstract The northern Fennoscandian landscape was modified by the last glaciation and it is currently scattered by lakes and rivers. Salmonid fish were the fish colonizers of these lakes and whitefish (Coregonus lavaretus (L.)) is currently the dominant species in subarctic lakes below treeline including Lake Kilpisjärvi. Whitefish population in this lake belongs to the most common whitefish morph i.e. large sparsely rakered whitefish (named according to body size and number of gill rakers), in this region. As a monomorphic population, Lake Kilpisjärvi is ecomorphologically adapted to use all principal habitat types, littoral, profundal and pelagic, available in the lake. According to stable isotopes the most important long-term energy source is pelagic zooplankton. Due to pelagic copepod diet, whitefish is heavily infected by Diphyllobothrium spp. tapeworms. Growth rate of whitefish is average for region and is subject to yearly fluctuations. Age and size distribution of whitefish is generally dominated by a few abundant year-classes. Whitefish density of Lake Kilpisjärvi is relatively low compared to other whitefish dominated lakes in Lapland. Despite of low density, whitefish is the most abundant species in the lake transferring pelagic energy to top consumers in the lake. Continuous monitoring of Lake Kilpisjärvi whitefish population dynamics may provide important insights of environmental change.

Long-term ecological studies in Northern Fennoscandia

Climate change and shifts in the distribution of moth species in Finland Reima Leinonen Kainuu Regional centre for Economic Development, Transport and the Environment, [email protected]

Abstract Monitoring of nocturnal moths has started in Finland in 1993. The total number of light traps so far involved is 208, with varying trapping periods. Currently the monitoring is composed of 50 traps all over the country in different forest biotopes. Twenty traps have been operating all the time. The sum of trap years is 1441 and the total number of macrolepidopteran species is 712. The data base includes 5.6 million individuals. In addition, from the northern traps we have also identified the so called Microlepidoptera, including 618 species and 640 000 individuals. The analyses of the last mentioned material are under preparation. In the analyses of the moth material, we focused on patterns and trends relevant to the recent climate change. The daily average temperatures and the average lowest temperatures in Finnish Northern Karelia have both greatly risen during the last few years. This has reflected in our material as a continuous increase in the total number of species in the whole Finnish territory. There is a linear increase in species richness at Sotkamo Aarreniemi during the entire monitoring period, even though a slight decrease could be observed during the past three years. Effects of climate warming can also be seen in the form of northward range expansion of single species. On the other hand, there are northern species showing an opposite trend, i.e. their populations have clearly decreased recently. The development of a second annual generation has been observed in more and more species and even in more northern areas than earlier. In 1999, which was a peak year in that respect, even a third generation was observed in Gymnoscelis rufifasciata.

Long-term ecological studies in Northern Fennoscandia

More than 20 years of monitoring of breeding Tengmalm’s owl in Troms County, Norway Karl-Birger Strann Norwegian Institute for Nature Research, NINA, [email protected]

Abstract Since early 1990-ies ringer in Tromsø Ringing Group (TRG) and Norwegian Institute for Nature Research (NINA) has monitored breeding Tengmalm’s owl in Troms County. 150 nest boxes in three main valleys in Troms are checked for breeding birds and production of chicks each year. A total of about 1000 owls were ringed during this period. 50 % of these were pulli ringed in the nest boxes. 200 adults caught and ringed at nest – 300 adults ringed at Dividalen FS (bird station).

One female sitting on eggs in a nest box in Finland carried a Finnish ring. It was ringed as an adult breeder, then controlled the following season with small chicks in a nest box in Skibotn, Troms. Another 42 owls were controlled at Dividalen FS. Three of these were ringed as adults on nest boxes in Finland and controlled at Dividalen the following autumn. One bird was ringed as pulli in Finland. The last 38 were ringed at different nest boxes in Troms.

Status of Fennoscandian mountain birds Aleksi Lehikoinen11*, Martin Green2, Magne Husby3, John Atle Kålås4, Åke Lindström2 1

Finnish Museum of Natural History, University of Helsinki, Finland, *[email protected] of Biology, Biodiversity unit, Lund University, Ecology Building, SE-223 62 Lund, Sweden 3 Nord-Trøndelag University College, Røstad, NO-7600 Levanger, Norway 4 Norwegian Institute for Nature Research, P.O. Box 5685 Sluppen, NO-7485 Trondheim, Norway

2 Department

Despite current climate change has been expected to shift ranges of alpine species towards mountain tops very little i know is k about b t population l ti d dynamics i off mountain t i species. i We studied population changes of 14 common mountain bird species in Finland, Sweden and Norway using census data of 262 sites from the mountain tundra and birch forests during 2002–2012. Surprisingly nine out of 14 species have declined significantly and analyses indicate that on average populations have declined c. 29%.

(a)

Long-tailed skua population has fluctuated without trend.

(b) FIN SWE NOR

Figure 1. Geometric mean (including 95 % c.i. bars) of 14 mountain birds abundance indices (a) using combined data from Finland, Sweden and Norway and (b) country specific means of the same nine species (Finland = light grey, Sweden = dark grey and Norway = white). Declining pattern was similar in all countries, but Norwegian birds have faced the strongest declines.

Table 1. Estimated population declines of nine mountain bird species in Fennoscandian mountain area. The populations of golden plover Pluvialis apricaria, long-tailed skua Stercorarius longicaudus, bluethroat Luscinia svecica, common redstart Phoenicurus phoenicurus and common wheatear Oenanthe oenanthe fluctuated without significant trend. trend Declines have been equal in mountain tundra and mountain birch forest species. Willow grouse Lagopus lagopus Rock ptarmigan L. muta Meadow pipit Anthus pratensis Redwing Redwing Turdus iliacus Willow warbler Phylloscopus trochilus Brambling Fringilla montifringilla Common redpoll Carduelis flammea Lapland bunting Calcarius lapponicus Snow bunting Plectrophenax nivalis

-83% -70% -30% -42% -39% -49% -65% -43% -32%

Conclusions M t i bi d h li d rapidly idl iin recentt years. Mountain birds have d declined The potential reasons can be related to changes in climate, habitat quality and species interactions. We encourage further investigations to study the mechanisms of the observed population declines.

Population of Lapland Bunting Calcarius lapponicus has declined about 40 % in 11 years.

Acknowledgements We wish to thank all observers that have participated data collection. Census have been funded by Finnish Ministry of Environment, Swedish Environmental Protection Agency and Regional County Boards and The Directorate for Nature Management. Kilpisjärvi Biological Station has also supported the project.

Workshop at Kilpisjärvi on 13 –15 March 2013 Updated results of long-term studies at Kilpisjärvi and invited talks: Per-Arne Amundsen, University of Tromsø Long-term studies following experimental density depletion of a stunted Arctic charr population Heikki Henttonen, Finnish Forest Research Institute, Metla Vole and lemming fluctuations at Kilpisjärvi over 60 years

Mikko Hyppönen, Finnish Forest Research Institute, Metla The changes of forest timberline in Northern Finland during 1983–2009 Antero Järvinen, Kilpisjärvi biological station, University of Helsinki Sea vs. Mountain: Pied Flycatchers Ficedula hypoleuca: results of 26-year population studies in Skibotn & Kilpisjärvi Kimmo Kahilainen, University of Helsinki Ecology of whitefish (Coregonus lavaretus (L.)) in subarctic Lake Kilpisjärvi

Kari Laine, Thule Institute, University of Oulu Long-term botanical research at Kilpisjärvi: background and preliminary results Reima Leinonen, Kainuu Regional centre for Economic Development, Transport and the Environment Climate change and shifts in the distribution of moth species in Finland Karl-Birger Strann, Norsk institut for naturforskning, NINA More than 20 years of monitoring of breeding Tengmalm’s owl in Troms county, Norway

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Long-term ecological studies in Northwestern Scandinavia