Floral resource preference, occupancy, and detection of bumblebee species in northeastern Illinois

Many pollinators, including bumblebees, are declining, and effective monitoring programs need to be developed to understand distribution and habitat preferences to better guide conservation management decisions. Without concrete information on detection probabilities, recommended survey efforts are often based on life history information for various bumblebee species, but such recommendations have not been vetted for efficacy. In Illinois, there has been a recent increase in bumblebee community monitoring due to the Federal listing of the rusty-patched bumblebee (Bombus affinis Cresson 1863). I conducted bumblebee assemblage surveys in grassland areas of nature preserves throughout northeastern Illinois and collected data on floral resource use and availability. I used compositional analysis of bumblebee floral resource use and floral availability data for floral taxa recorded on my survey transects at different preserves to identify floral preferences for bumblebee species. I determined two common bumblebee species, B. impatiens, and B. griseocollis, did not show significantly divergent preferences for floral taxa; they were significantly affected by site identity, suggesting they adapted their selection based on available resources. At larger spatial scales, six bumblebee species – B. impatiens, B. griseocollis, B. bimaculatus, B. auricomus, B. fervidus, and B. rufocinctus – showed significantly divergent foraging patch preferences, but again preference was driven primarily by site identity. As expected, due to flowering phenology, survey date was also a significant factor in foraging preference. To identify optimal survey effort, I modeled occupancy with imperfect detection for three common bumblebee species: B. impatiens, B. griseocollis, and B. auricomus. I found grassland area, survey date, observer walking speed, temperature, and observer experience were important for predicting occupancy and detection probabilities. My results suggest an optimal survey effort and a more nuanced approach are necessary for managing the floral resources of generalist pollinators with a relatively long colony lifespan and exhibiting foraging elasticity in response to habitat context.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Schrage, Alma

Contributors dc:contributor

• Dreslik, Michael J
• Robinson, Jason L
• Matthews, Jeffrey

• Bumblebee
• Bumble Bee
• Occupancy
• Detection
• Resource Selection
• Resource Preference
• Illinois
• Pollinator Monitoring
• Pollinator Conservation
• Pollinator

Statement dc:rights

• Copyright 2023 Alma C. Schrage

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/122066

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F122066