Browsing by Author "Nordquist, Gerda"
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Item Bat Acoustic Surveys in Minnesota 2015 - 2017(University of Minnesota Duluth, 2018-12) Moen, Ronald; Swingen, Morgan; Walker, Marcus; Baker, Richard; Nordquist, Gerda; Catton, Timothy; Kirschbaum, Kari; Dirks, Brian; Dietz, NancyItem Bat Radiotelemetry in Forested Areas of Minnesota 2015-2017(University of Minnesota Duluth, 2018-12) Swingen, Morgan; Moen, Ronald; Walker, Marcus; Baker, Richard; Nordquist, Gerda; Catton, Timothy; Kirschbaum, Kari; Dirks, Brian; Dietz, NancyItem Northern Long-Eared Bat Roost Tree Characteristics 2015-2017(University of Minnesota Duluth, 2018-12) Swingen, Morgan; Moen, Ronald; Walker, Marcus; Baker, Richard; Nordquist, Gerda; Catton, Timothy; Kirschbaum, Kari; Dirks, Brian; Dietz, NancyFemale northern long-eared bats (Myotis septentrionalis) give birth to a single young, which is raised in a maternity roosting colony in trees. Young are born and lactation occurs from mid-June through at least late July in Minnesota. Bat pups are unable to fly for 3-4 weeks after birth, so the adult females leave the young in the maternity roost while they forage. We tracked bats with VHF radiotransmitters to their roosts each day. At dusk, field crews conducted emergence surveys to count the number of bats emerging and find the roost entrance. In total we found 238 day roost locations of 83 female northern long-eared bats across the forested region of Minnesota. We returned to each roost tree to measure habitat characteristics. Female northern long-eared bats roosted in at least 27 different tree species. Almost all of the roost trees were in upland forests. In northern Minnesota, aspen (Populus tremuloides) was most commonly used as roosts. In central Minnesota, maple (Acer spp.) and aspen trees were most commonly used, and in southern Minnesota, oak trees (Quercus spp.) were most commonly used as roosts. About 90% of roost trees were deciduous species, and 10% of roost trees were coniferous species. Roost trees were more decayed and larger in diameter than available trees. Northern long-eared bats most often roosted in cavities and crevices of trees, although some roosted under loose bark or where branches had broken off. Four roosts were in unoccupied buildings. Each roost tree location buffer and random location was overlaid on NLCD, GAP, and LandFire cover type classifications to calculate percent of area in forest cover variables. Variables related to deciduous forest were characteristic of roost tree locations. The LandFire variable TreeDom was the best predictor variable for identifying potential maternity roost habitat at the landscape level. In the forested area of Minnesota, the 50th percentile of random locations had 55% tree cover on average, compared to 80% tree cover for the roost tree locations. The relationship held at smaller scales, which meant that we could create maps of habitat suitability for northern long-eared bat maternity roosts across the forested region of the state. Northern long-eared bats in southern Minnesota, with more development and agriculture, used roost tree locations in patches of forest. In northern Minnesota, roost trees were within forest stands instead of on the edges of forest stands, and roost trees tended to be located in areas with trees present in most of an 800 m foraging radius. We also tracked 13 little brown bats and 8 big brown bats to roosts in trees and buildings. The 13 little brown bats were tracked to 12 roost trees of at least five species, and five roosts in buildings. The eight big brown bats were tracked to 13 roost trees of at least seven species, and two roosts in buildings. All bats with transmitters that roosted in buildings were females that were either pregnant or lactatingItem Summary of 2016 Northern Long-eared Bat Research in Minnesota(University of Minnesota Duluth, 2016-12) Swingen, Morgan; Baker, Richard; Catton, Timothy; Kirschbaum, Kari; Nordquist, Gerda; Dirks, Brian; Moen, RonaldCrews from the USDA – Forest Service, University of Minnesota - Natural Resources Research Institute, Minnesota Army National Guard (MNARNG), and Minnesota Department of Natural Resources captured 646 bats throughout the forested region of Minnesota from June 6 – July 21, 2016. Bats of 8 species were captured during mist-netting surveys, including the first evening bat (Nycticeius humeralis) confirmed in Minnesota. We captured 95 individuals of our target species, the northern long-eared bat, and attached transmitters to 45 adult females (39 reproductive, 6 non-reproductive or undetermined). These 45 bats were tracked to 111 unique roost trees of at least 20 species. Crews conducted emergence counts at roost trees and observed between 1-71 bats emerging. Roost trees varied in both DBH and height, as well as decay stage. The roosting patterns observed in 2016 were similar to those seen in 2015, where bats appear to be using a variety of available trees.Item Summary of Bat Research in Beaver Creek Valley State Park, MN 2016(University of Minnesota Duluth, 2016-12) Swingen, Morgan; Spak, Christi; Nordquist, Gerda; Baker, RichardCrews from the Minnesota Department of Natural Resources captured eight bats in Beaver Creek Valley State Park on June 18th, 2016. Bats of four species were captured during mist-netting surveys. We captured four individuals of our target species, the northern long-eared bat, and attached transmitters to two pregnant adult females. These two bats were tracked to 7 unique roost trees of 6 species over 5 days. During emergence surveys we counted from 2 to 71 bats emerging from these roost trees. Roost trees varied in both DBH and height, as well as decay stage. The roosting patterns we observed at Beaver Creek Valley State Park were similar to roosting patterns we have observed in other areas of Minnesota, where bats appear to be using a variety of available trees. This report details work done in Beaver Creek Valley State Park as part of a statewide study of northern long-eared bats. A report summarizing results of the statewide project will be available in early 2017Item Summary of Bat Research in Forestville/Mystery Cave State Park, MN 2016(University of Minnesota Duluth, 2016-12) Swingen, Morgan; Swingen, Morgan; Spak, Christi; Nordquist, Gerda; Baker, RichardCrews from the Minnesota Department of Natural Resources captured 86 bats in Forestville/Mystery Cave State Park from June 7th–10th, 2016. Bats of 4 species were captured during mist-netting surveys. We captured six individuals of our target species, the northern long-eared bat, and attached a transmitter to one pregnant female. This bat was tracked to 5 unique roost trees of 3 species. During emergence counts we counted from 1 to 16 bats emerging from these roost trees. Roost trees varied in both DBH and height, as well as decay stage. The roosting patterns we observed at Forestville/Mystery Cave State Park were similar to roosting patterns we have observed in other areas of Minnesota, where bats appear to be using a variety of available trees. This report details work done in Forestville/Mystery Cave State Park as part of a statewide study of northern long-eared bats. A report summarizing results of the statewide project will be available in early 2017.Item Summary of Bat Research in Whitewater State Park and WMA, MN 2016(University of Minnesota Duluth, 2016-12) Swingen, Morgan; Spak, Christi; Nordquist, Gerda; Baker, RichardCrews from the Minnesota Department of Natural Resources captured 51 bats in Whitewater State Park and WMA from June 15th–18th, 2016. Bats of 2 species were captured during mist-netting surveys. We captured five individuals of our target species, the northern long-eared bat, and attached transmitters to four pregnant females. These four bats were tracked to 11 unique roost trees of 7 species. During emergence counts we counted from 1 to 28 bats emerging from these roost trees. Roost trees varied in both DBH and height, as well as decay stage. The roosting patterns we observed at Whitewater State Park and WMA were similar to roosting patterns we have observed in other areas of Minnesota, where bats appear to be using a variety of available trees. This report details work done in Whitewater State Park and WMA as part of a statewide study of northern long-eared bats. A report summarizing results of the statewide project will be available in early 2017.