2021 Minnesota bumble bee survey data
Data files
Aug 03, 2023 version files 96.67 KB
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2021MNBumbleBeeData.xlsx
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README.md.txt
Abstract
Mounting evidence of bumble bee declines has stimulated an interest in monitoring and conservation. Understanding the influence of land use on occupancy patterns of imperiled species is crucial to successful recovery planning. Using detection data from community surveys, we assessed land use associations for seven bumble bee species in Minnesota, U.S.A., including an endangered species (Bombus affinis Cresson). We used multi-species occupancy models to assess the effect of three major land use types (developed, agricultural, and natural) within 0.5 and 1.5 km on occupancy of seven Bombus species, while accounting for detection uncertainty. Bombus affinis was positively associated with developed landscapes at both scales, suggesting that urban areas can provide conservation benefits for this species in the Midwest. Further, we show that B. affinis occupancy and detection are highest in developed landscapes and lowest in agricultural landscapes, representing an inverse relationship with the relative land use ratios of these landscapes in Minnesota. Occupancy of two bumble bee species had strong positive associations with natural landscapes within 1.5 km and two species had strong negative associations with agricultural landscapes within 1.5 km. Our results suggest that best practices for imperiled Bombus monitoring and recovery planning depends upon the surrounding major land use patterns. We provide recommendations for urban planning to support B. affinis based on conservation success in the metropolitan areas of Minneapolis-St. Paul. We also encourage substantial survey effort be employed in agricultural and natural regions of the state historically occupied by B. affinis to determine the current occupancy state.
Methods
Bumble bee surveys
Each site was visited five times between June 14 and September 1, 2021, and we followed U.S. Fish and Wildlife Service (USFWS 2019) recovery monitoring survey protocols for B. affinis in high-potential zones. A single observer (MLB) with previous experience conducting bumble bee surveys in the region completed all the bee surveys. At each site, the observer actively searched a 3-acre area for 1 hour. During active search time, the observer walked freely within the survey area looking for bees on flowers, while occasionally observing individuals perching on foliage or entering and exiting nests. They recorded the species/species group and sex of every bumble bee detected. They also recorded a checklist of all floral species on which each bumble bee species was observed foraging. During every survey, one individual bee of each species was netted and photographed for identification verification and to serve as a photo record. The timer was stopped when handling and photographing individual bumble bees. Prior to the survey season, the observer completed additional identification training, including an advanced bumble bee identification workshop led by taxonomic experts (ZP and E. Evans). Additional effort was spent learning to distinguish between B. borealis Kirby and B. fervidus, two species with similar color patterns, by examining specimens in the Native Bee Lab in the Department of Entomology at the University of Minnesota. The primary character used to distinguish between these two species in the field was the lateral prothoracic hair color, which is typically yellow in the B. fervidus color morph in our region and black in B. borealis.
Usage notes
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