Are prairie restorations sources or sinks for bumble bees? A multi-method approach

Habitat loss on local and broad scales is thought to be a main cause of population declines observed in some species of bumble bees (Apidae: Bombus spp.). Previous work suggests that grassland habitat restorations benefit bumble bee communities, as shown through observed increases in abundance, richness, and diversity at restored prairies when compared to sites that had not been restored. However, these relatively coarse metrics do not allow us to understand whether restorations are attracting bees from surrounding areas (trap/sink) or are sustaining populations and allowing them to persist (reproduce/source). Additional, detailed metrics of bumble bee populations are necessary to elaborate on bumble bee responses to restoratio. Here, we will use multiple approaches to investigate whether prairie restorations in the Upper Midwest are sources or sinks for bumble bees. To quantify the potential source-sink dynamics at restorations, I propose using a combination of field-based and molecular approaches. Field surveys will be used to estimate the number of colonies in and across years. Using genetic mark-recapture, we will quantify relatedness, lineage survival, site fidelity, inbreeding, and genetic structure within and across years. Microsatellites will be the primary method with which we will determine relatedness. A subset of samples will be processed using SNPs.