Browsing by Author "Boone, Michelle"

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    Monitoring and Habitat Assessment of Declining Bumble Bees in Roadsides in the Twin Cities Metro Area of Minnesota
    (University of Minnesota Center for Transportation Studies, 2019-06) Evans, Elaine; Boone, Michelle; Cariveau, Dan
    Several bumble bee species have declined dramatically, including the endangered rusty-patched bumble bee, Bombus affinis. Roadsides offer a unique opportunity to increase habitat for these declining species. The objectives of this study are to: (1) characterize the bumble bee community and floral availability within roadsides in the Minneapolis and Saint Paul, Minnesota, metro area, (2) estimate detection probabilities and occupancy for bumble bees using occupancy modeling, (3) determine the effort needed to detect rusty-patched bumble bees, and (4) examine the relationship of the bumble bee community to the surrounding landscape. We use rapid and broad-scale sampling at randomly selected locations. Despite overall low floral abundance, many bumble bee species, including rare and declining species, use roadsides. Occupancy models predict rusty-patched bumble bees occupy 4% of sites, with a 30% chance of detection if it is at the site. We recommend performing nine surveys in a single season to be 95% sure that B. affinis is detected if it is there. Bumble bee abundances and species numbers increase with more wooded area and floral cover. Crops are negatively associated with bee abundance, species numbers, and the presence of rare bumble bees. Our management recommendations for roadsides to support rare and declining bumble bees are: (1) incorporate additional bumble bee forage, (2) when weed control requires elimination of flowering plants, replace with bumble bee forage, (3) use our estimates for occupancy and abundance as a baseline to assess conservation efforts for bumble bees within roadsides in the metropolitan area of Minneapolis and Saint Paul.
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    Non-lethal DNA extraction methods for genetic analyses of endangered bumble bee species
    (2021-08-27) Kuhlmey, Eiley E; Boone, Michelle; Lindsey, Amelia; Rao, Sujaya
    Several North American bumble bees (Hymenoptera: Bombus) are faced with decline as factors such as climate change, pollution, and urbanization threaten their existence, thus raising concern regarding genetic diversity as populations diminish. Consequently, genetic analysis of these susceptible species is essential when considering appropriate conservation efforts. One species, Bombus affinis, has experienced such sharp population declines that it was listed as federally endangered within the United States and Canada. This necessitates methods for collecting genetic samples from bumble bees that do not require euthanizing specimens or removing legs. A previous pilot study used 50 mL conical tubes fitted with sugar water soaked swabs to passively collect genetic material from Bombus affinis. Approximately 50% of the 63 samples obtained contained usable amounts of DNA. To further improve this technique, samples were collected from Bombus impatiens using two non-lethal, minimally-invasive DNA extraction methods that can be applied to declining and endangered species. In one method, bumble bee thoraxes were swabbed directly to collect hairs from the immobilized bumble bees, whereas the second technique involved the passive DNA collection method utilized in the pilot study. The results of these two techniques were compared using PCR and gel electrophoresis to determine which of these methods, direct swabbing or passive DNA collection, works best for gathering genetic samples without causing unnecessary harm to susceptible and endangered species. It was concluded that the passive technique resulted in distinguishable DNA approximately 1.8 times more consistently than the active technique and is the better option among these methods.
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    Non-lethal monitoring for endangered insects: Making inferences about imperiled bumble bees while accounting for heterogeneity in the detection process
    (2023-05) Boone, Michelle
    Insect declines are of mounting concern, yet evidence for widespread declines is limited due to a lack of standardized, long-term datasets. Furthermore, practitioners often fail to account for heterogeneity in the detection process when making inferences from survey data. As more insects are petitioned for listing under the Endangered Species Act, it is imperative that monitoring schemes implement standardized sampling protocols and adopt analytical methods that account for imperfect detection of target species during surveys. To optimize sampling for endangered insects, we must better understand the effects of biotic and abiotic factors on occupancy and detection probability of target species. In addition to understanding key factors that influence detectability of rare species to improve monitoring, it is crucial to identify habitat preferences of endangered insects to implement effective recovery and conservation planning. Bumble bees (Hymenoptera: Apidae: Bombus) are among the insect taxa with the best evidence of widespread declines. Bumble bee declines were reported in the United Kingdom as early as the 1970’s. In North America, the rusty patched bumble bee (B. affinis Cresson) was listed as federally endangered in Canada in 2012 and the United States in 2017. Franklin’s bumble bee (B. franklini Frison) was also listed in the U.S. in 2021. Additional species have been petitioned and are under consideration for listing. This has led to calls from scientists for a national bee monitoring framework to support conservation planning. For my doctoral research, I investigated the relationships between site, weather, and survey covariates with detection and occupancy probabilities for a suite of bumble bee species in Minnesota, USA, including B. affinis. I also investigated associations between habitat type and occupancy and detection probabilities. I collected bumble bee data during the summers of 2018, 2019, and 2021 for three distinct studies and used single-season, multi-species occupancy models to address my research questions.Assessing factors related to Bombus occupancy and detection probabilities is an emerging area of research, thus basic information about these relationships is sparce. For my first study, I investigated the effects of impervious surface and floral area on Bombus occupancy probability, and whether date, time of day, or observer were related to detection probabilities. I conducted roadside surveys in the seven-county metropolitan area of Minneapolis-St.Paul. This study was among the first to quantify detection uncertainty for B. affinis and to use multi-species occupancy models to draw inferences about imperiled Bombus detection. For the second study, I tested the efficacy of single-species versus multi-species occupancy models for estimating species-specific detection and occupancy probabilities. I also investigated whether bumble bees in our study system exhibited associations between occupancy probability and landscape habitat type (developed, natural, and agricultural) from surveys conducted across the state of Minnesota. I found that developed habitat had the most variable effect on Bombus occupancy probability out of the three landscape types investigated, which led to my third study, in which I delved deeper into developed landscapes. In this study, I investigated whether detection probabilities were related to adjacent habitat type (woodland, wetland, or crops) in the heterogenous, mixed-use landscape of Washington County, one of the seven metropolitan counties that serve as the human population center of Minnesota and which represents a transitional zone from a dense urban environment to a rural agricultural landscape. The results of my dissertation research provide some of the first investigations into the effects of biotic and abiotic factors on the bumble bee detection process. This information can be used to develop survey and monitoring protocols for community and species-specific monitoring. The results can also inform recovery monitoring for the endangered B. affinis or be adapted to investigate factors that influence the detection process for other imperiled insects. The finding that B. affinis occupancy probability is associated with developed areas lends support to the idea that urban areas may provide important refuge for this species in our study region. The associations between Bombus detection probabilities and survey, weather, and site covariates can be used to optimize sampling design for rare species. Taken together, this dissertation provides a framework for imperiled species monitoring that accounts for uncertainty in the detection process and can be adapted to other insect species.