Beneficial Invertebrates in Your Field Margins: Predators, Pollinators, and Their Potential for Helping Your Bottom Line
Sandy DeBano Hermiston Agricultural Research and Extension Center
Today’s Talk: 1.Why invertebrates in riparian areas may benefit us economically 2.How they may be impacted by future changes 3.How we’re studying these issues in the Umatilla Subbasin
How many species of invertebrates are there? Don’t know – but over 1 million ANIMAL species have been described…and 98% are invertebrates Over 300,000 described species of beetles alone!!!
Invertebrates (animals without backbones) The good, the
BAD, and the UGLY
But less than 2% of all invertebrate species are pests!!
Invertebrates are important providers of ecosystem services What’s an ecosystem service? Benefits that humans obtain from ecosystems
Invertebrates are key providers of supporting services. Necessary for production of other ecosystem services and maintenance of conditions conducive to life on Earth
• food for other organisms people value (birds, fish) • conveyors of energy across habitats (e.g., stream/riparian/upland interfaces)
• agents of pest control (e.g., predatory beetles and spiders)
• decomposers (e.g., Collembola)
• insects as pollinators (e.g., flies, bees)
Agents of Pest Control - Natural Predators or Enemies Invertebrates known to eat a variety of important crop pests Common and effective natural predators:
Spiders
Rove beetles (Staphylinidae)
Ground beetles (Carabidae)
These generalist predators eat a variety of economically important pests: • aphids • moth larvae (such as armyworm, cutworm and gypsy moth larvae) • herbivorous beetle larvae (such as wireworms, CPB) • slugs • some carabids even eat weed seeds!
Much attention now paid to increasing the density and activity of natural predators in agricultural fields Beetle banks, and other habitat manipulations Cultural practices Benefit: Natural predators can decrease the need for pesticide applications
Who are the important pollinators?
B. Marlin
European honey bee (Apis mellifera)
Who are the important pollinators? Vertebrates
Invertebrates
B. Marlin
Native bees
Diversity of bees ~ 20,000 species of bees world-wide - More than the combined number of bird and mammal species
European honey bees are declining Colony collapse disorder Example: Varroa, tracheal mites
Why Care? Pollinate natural vegetation • Reproduction of flowering plants • Increase fruit set and size • Increase seed production and viability • Promote genetic diversity
What’s their economic importance? They pollinate a wide variety of crops (e.g., almonds, apples, watermelon, canola, cucumber, squash, blueberries, citrus) Native bees can be more efficient pollinators of some crops (e.g., bumble bees for blueberries, alkali bees for alfalfa)
Importance of native bees 1) Contribute up to $6.7 billion per year economically 2) Some can tolerate severe conditions 3) Environmentally friendly 4) Cheap 5) Appear not to be affected by honeybee parasites and pathogens
Today’s Talk: 1.Why invertebrates in riparian areas may benefit us economically 2.How they may be impacted by future changes 3.How we’re studying these issues in the Umatilla Subbasin
How might an uncertain future affect ECOSYSTEM SERVICES associated with riparian areas and streams in the Umatilla Subbasin?
What uncertainty? Climate Change: Stream drying or increased intermittency Agricultural Intensification: Less area in riparian buffer
Part of larger study: Steelhead Production
Crop Production
Beneficial Invertebrates: Pollinators and Natural Predators
Aquatic Invertebrates
Our previous work in the subbasin has shown that riparian areas support a species-rich and abundant community of beneficial invertebrates
Questions 1. How does size and type of buffer (whether it’s herbaceous or woody) affect the number and types of beneficial riparian invertebrates? • Larger buffers may support a higher density and diversity of bees and natural predators • Herbaceous buffers might be better habitat for bees.
2. How does the drying of streams affect beneficial riparian invertebrates? • Less green vegetation next to dried streams in the middle of summer, so fewer floral resources for pollinators • Less moisture available, so more hostile physical environment
Today’s Talk: 1.Why invertebrates in riparian areas may benefit us economically 2.How they may be impacted by future changes 3.How we’re studying these issues in the Umatilla Subbasin
Methods: Selected 40 sites in the • Wildhorse Drainage • Mission Drainage
½ with woody buffers and ½ with herbaceous buffers
½ perennial and ½ are intermittent
Sampled Predators with Pitfall Traps:
Sampled pollinators three ways: • Hand-netting on transects • Pan traps • Blue-vane traps in adjacent fields
Measured floral resources and substrate characteristics
Laboratory methods: Bees were frozen until pinned, labeled, sexed, and identified Spiders and predatory beetles stored in alcohol and identified
Lasioglossum (Sweat bees) • • • •
< 1.8 cm Solitary to communal Generalist Nest in burrows in banks or flat soil
Bombus (Bumble bees)
• • • •
1.0 – 2.3 cm Eusocial Generalists Ground nesters
• • • •
Melissodes (long-horned bees) 0.8 to 1.8 cm Specialists on asters Solitary Nest in the ground
Next Steps: Finish laboratory analyses (identification of >10,000 invertebrates) Analyze results Work with the economist (Bruce Sorte) to quantify economic value of both
What do we want to be able to say at the end of the study? What’s the relationship between size of buffer and predator/pollinator abundance and species richness (is it linear)? What kind of buffers are best habitats for these pollinators? How will stream drying affect the ecosystem services provided by these invertebrates?
Acknowledgements John Williams, USDA-ARS Tom Straughan, ODA Cheryl Shippentower, CTUIR Faculty Research Assistants Chiho Kimoto Anne Madsen Student Workers Alicia Arey Reed Janke Ruben Marchosky Samantha Pack Hannah Mabbot Marcus Anderson All the landowners who graciously allowed us to work on their property
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