Powerpoint Presentation Slide 1 - Butterflies, Bees, and Weeds: Improving habitat for pollinators through management of Minnesota's tallgrass prairies Julia Leone, University of Minnesota, Conservation Biology Graduate Program Patrick Pennarola, University of Minnesota, Entomology Graduate Program Diane L. Larson, U.S. Geological Survey, Northern Prairie Wildlife Research Center Jen Larson, University of Minnesota Karen Oberhauser, University of Wisconsin, Madison Susan Galatowitsch, University of Minnesota Slide 2 - Why do we care about butterflies, bees, and weeds? * Pollinators are in decline worldwide * Minnesota prairies are home to several imperiled bee and butterfly species * Weeds reduce native prairie plant diversity and make it less fit as habitat for beneficial insects and grassland birds Photo 1 - Picture of a butterfly Photo 2 - Picture of a bee Slide 3 - How are tallgrass prairies managed? Grazing and Fire Photo 1 - Picture of cows grazing in a prairie field Photo 2 - Picture of a prescribed burn Slide 4 - Why manage Minnesota'stallgrass prairie? The wildfires and wide-ranging herds of bison are no longer present Photo 1 - Picture of bison grazing in a prairie field Photo 2 - Picture of a prescribed burn Slide 5 - Why manage Minnesota's tallgrass prairie? Lacking fire and/or grazing, shrubs and trees would likely invade Photo of the woods Slide 6 - Ideal Management Outcome: - Weeds - Butterflies - Bees 3 Photos of Butterflies, Bees, Weeds Slide 7 - Where did we survey? * 73 vegetation sites * Including 20 insect sites Picture of Map showing the Burn versus Grazing Study Sites 2016-2017 Slide 8 - 3 pictures of different landscapes Slide 9 - Butterflies Photo 1 - Picture of a butterfly Photo 2 - Picture of a prairie Slide 10 - How do butterflies depend on prairie habitat? * Nectar for adults * Larval host plants * Over-wintering shelters Photo 1 - Picture of a monarch caterpillar Photo 2 - Picture of a monarch butterfly Photo 3 - Picture of flowers Photo 4 and 5 - Picture of plants Slide 11 - How did we survey butterflies? Pollardtransect walk: Observer walk: 30 –120 min. Photo of someone taking a survey Slide 12 - What butterflies did we find *All 5 families of Minnesota butterflies * 40 BUTTERFLY SPECIES * 9 prairie associated species * 1,222 individuals * 35 species at burned prairies * 35species at grazed prairies * 30 species were the same at burned and grazed prairies Slide 13 - Graph showing Butterfly Abundance by Management Type Individuals at burned sites: 789 Individuals at grazed sites: 473 Slide 14 - Fire and Grazing management are both important for butterflies * There are more butterflies at burned sites * There are more common species at burned sites * Many rarer species and prairie specialists are found at grazed sites Repeat showing of the graph on Slide 13 Slide 15 - Some butterflies were only found at grazed sites Graze-only (includes picture of each butterfly) - Broad-winged Skipper - Prairie Ringlet - Silvery Checkerspot - European Skipper - Tawny-edged Skipper Slide 16 - and some butterflies were only found at burned sites Burn-only (includes picture of each butterfly) - Common Checkered-Skipper - Reakirt's Blue - Arogos Skipper - Acadian Edwards' - Edwards' Hairstreak Slide 17 - Regal Fritillar(Speyeria idalia) (includes pictures of the butterfly) Slide 18 - Regal Abundance by Site Regals at burned sites: 31 Regals at grazed sites: 12 Graph showing abundance at each site Map of Minnesota Slide 19 - Bees Photo of a bee and prairie Slide 20 - Bees globally are facing threats from habitat loss,pesticide exposure, and pathogens Photo of two different bees Slide 21 - How do bees depend on prairie habitat? * Adult bees feed on nectar, and provide larvae with pollen and nectar * Some bees nest in hollow stems * Many bees nest in soils Photo 1 - A larva on a provisioned ball of pollen Photo 2 - A wool carder bee feeding on bird’s foot trefoil. Photo 3 - A solitary bee emerging from its nest (Colletes sp.) Photo 4 - Lasioglossum pruinosum feeding on a purple prairie clover. Slide 22 - Bee sampling methods: Bee bowls and meandering walk (includes graphic) Slide 23 - What bees did we find? * 121 bee species * 30 bee genera * 12,540 individuals * 11species of bumble bees * 98 species at burned prairies * 94species at grazed prairies * 71species were the same at burned and grazed prairies Types of Bees (includes a picture of each) - B. auricomus - B. bimaculatus - B. terricola - B.vagans - B.pensylvanicus - B. borealis - B.ternarius - B. griseocollis - B.fervidus - B.impatiens - B.rufocinctus Slide 24 Bumble bee species occupancy Bar graph showing the difference between burn versus grazing sites Slide 25 Bumble bee species occupancy Bar graph showing the difference between burn versus grazing sites Slide 26 Grazing and fire are equivalent for bees * Slightly more bees were collected at grazed sites than burned sites (6,491 vs. 6,039) * Very similar numbers of species (94 vs. 98) * Most species occur in both managements * No significant difference, statistically, in abundance or richness between burned and grazed sites Photo of bees Slide 27 Beyond management: Other signals * Higher frequencies of flowers in prairies are significantly associated with greater numbers of bee species * Sandier soils are significantly associated with greater numbers of bees and numbers of bee species Photos of the prairie Slide 28 A subset of bees only found with one type or another Graze-only (includes picture of each bee) - Perdita perpallida - Colletes susannae - Svastra obliqua - Nomada articulata - Heriades carinata Burn-only (includes picture of each bee) - Bombus rufocinctus - Bombus rufocinctus - Hylaeus nelumbonis - Bombus terricola - Megachile mendica Slide 29 Plants Photo of prairie Slide 30 Does management with fire result in a different plant community than management with grazing? * No! * Sites closer together on this graph had more similar vegetation Graphic showing the overlap between burned and grazed communities. Slide 31 Weeds: Soil moisture is more important than management type * Canada thistle and Reed canary grass prefer wet prairie * Kentucky bluegrass and Smooth bromegrass prefer mesic prairie * None showed a significant preference for burned or grazed prairies Graph comparing burning versus grazing for Canada thistle Graph comparing burning versus grazing for Kentucky bluegrass Graph comparing burning versus grazing for Smooth Bromegrass Graph comparing burning versus grazing for Reed canarygrass Slide 32 Does prairie “quality” vary between management types? * Mean species richness does not vary between management types. * Average richness: - 24.39 in burned sites - 24.47 in grazed sites * Coefficient of Conservatism is a measure of how restricted species are to high quality remnant prairie (higher=more restricted) * Average Coefficient of Conservatism - 4.06 in burned sites - 3.70 in grazed sites Slide 33 We need both fire and grazing to improve habitat for prairie bees and butterflies Photo of a prairie Slide 34 Why do these results matter? United States Map of North American Tallgrass Prairie (less than one percent remains) Slide 35 There is very little prairie left in Minnesota * Once 18 million acres * Less than two percent remains * Heavily fragmented Photo of Minnesota Map showing remaining native prairie a century after the public land survey Slide 36 How are we sharing this information? * Direct feedback to participating landowners and managers * Webinars * Workshop and field day for land managers * Public website * Public talks * Manuscripts in preparation Photo of a prairie Slide 37 Acknowledgements Botanists: Karin Jokela, Katie Schmidt, Larissa Mottl, Madison Rancour Insect field assistant: Grant Piepkorn Lab technician: Grace Haynes USFWS, Morris WMD: Sara Vacek MN DNR: Fred Harris, Robert Dana, Crystal Boyd, Nicole Gerjets, site managers The Nature Conservancy Private Landowners Sam Droege, USGS A collage of pictures is shown. Slide 38 Thank you! Questions? Diane Larson: dlarson@usgs.gov Julia Leone: leone050@umn.edu Patrick Pennarola: penna041@umn.edu