Recipient Organization
OHIO STATE UNIVERSITY
1680 MADISON AVENUE
WOOSTER,OH 44691
Performing Department
(N/A)
Non Technical Summary
Bumble bees are critically important pollinators for wild plants and agricultural crop production, but are declining globally. Bumble bee population declines have been attributed to several interacting stressors, including land-use alteration and climate change. Little research has investigated the extent to which these stressors interact to alter bumble bee species distributions, habitat associations, and habitat suitability. Impacts of these stressors are further exacerbated on threatened/endangered species, reducing the species' ability to secure long-term viability. Therefore, I propose to 1) evaluate the cumulative effects of climate and landscape structure; 2) assess species distribution and habitat suitability; and 3) conduct targeted surveys in areas with high habitat suitability for two at risk species: rusty patched and yellow-banded bumble bees. I will attain a comprehensive understanding of stressors driving bumble bee population shifts and provide a foundation for reintroducing laboratory raisedcolonies as a conservation mitigation effort to establish new populations. This will generate tangible recommendations to inform land management practices, conserve diverse pollinator populations, and increase pollination services for local food production.
Animal Health Component
67%
Research Effort Categories
Basic
33%
Applied
67%
Developmental
(N/A)
Goals / Objectives
Bumble bee populations are declining as a result of multiple, interacting anthropogenic stressors. The impact of these interacting stressors is further exacerbated for imperiled species with small populations, restricted habitats, and reduced gene flow; ultimately reducing the species ability to secure long-term viability. Further, these declines have subsequent effects on associated ecosystems and pollination services for wild plants and cultivated crops. Therefore, there is a need to create and restore pollinator habitats, monitorbumble beepopulations to increase knowledge of range shifts, and continually evaluatebumble bee species and assemblage responses to a wide range of threats. This project will evaluate key knowledge gaps in the understanding of interacting anthropogenic stressors on imperiled bumble bee species habitat associations and habitat suitability.Using entomological field research practices, geospatial techniques, and mathematical modeling, this project will address three main objectives, 1) evaluate the cumulative effects of climate and landscape structure; 2) assess species distribution and habitat suitability based on historic and current occurrences; and 3) conduct targeted surveys in areas identified as having high habitat suitability for two imperiled species: rusty patched and yellow-banded bumble bees.
Project Methods
Objective 1. We will obtain rusty patched and yellow-banded bumble bee occurrence data throughout the contiguous United States of America in order to evaluate the cumulative effects of climate and landscape structure on two imperiled bumble bee species. Bioclimatic and landscape structure data will also be obtained for each bumble bee occurrence site. A generalized additive model (GAM) will be used to estimate non-linear interactions between bumble bee abundances and the explanatory variables (bioclimatic variables and landscape indices). Additionally, a multivariate regression tree (MRT) will be used to describe the interactions between rusty patched and yellow-banded bumble bee abundances and the environmental variables (bioclimatic variables and landscape indices).Objective 2. We will assess species distribution and habitat suitability for rusty patched and yellow-banded bumble bees based on (a) historic and (b) recent occurrences. Following methodology from Objective 1, we will obtaining bumble bee occurrence and bioclimatic data for the specified time periods. Additionally, elevation, slope, and the proportion of each land-use type (cultivated cropland, pasture, grassland, wetland, forest, urban, and water) will be quantified at a 1 km spatial scale surrounding each site for the historic and current time periods. Occurrence (presence-only) data for rusty patched and yellow-banded bumble bees during both the defined time periods will be used to generate four distribution maps, which will provide a visual aid for distinguishing changes in distributions over time. Poisson point process models will be created to estimate and map species intensity based on the occurrence and environmental covariate data.Objective 3. Given the restrictions with handling and collecting the endangered rusty patched bumble bee, the yellow-banded bumble bee will be used as the focal species in this objective to verify the validity and accuracy of the point process models. As such, we will conduct targeted surveys for yellow-banded bumble bees at 50 sites. Survey sites will be selected based on areas identified as having the highest habitat suitability within the current point process model (Objective 2). One hundred foraging bumble bees will be captured via aerial netting at each survey site between 10:00 and 18:00 local time. Sampling will occur once during the summer under standard weather conditions. All netted bumble bees (except for rusty patch bumble bees) will be placed in individual vials, chilled on ice, and transported back to The Ohio State University. At the lab, all bumble bees will be pin-mounted, labeled, and identified to species using taxonomic keys. Five aspects of bumble bee species composition will be measured for each site: total count, richness, Pielou's evenness, Shannon diversity, and beta-diversity. Presence/absence of yellow-banded bumble bee will be recorded for each site, and the percentage of total sites with yellow-banded bumble bees will be identified. Multiple linear regressions will be performed between yellow-banded bumble bee abundances and habitat suitability to determine the survey sites where bumble bees had a greater fit to the point process model.