Connectivity and edge effects increase bee colonization in an experimentally fragmented landscape

Though landscape corridors increase dispersal of many animals and plants, it remains unknown whether increased dispersal increases colonization and establishment of new populations in connected fragments. Working in experimentally fragmented landscapes, we tested how two aspects of habitat fragments altered by corridors- connectivity and edge-to-area ratio- determine patterns of colonization by a solitary, cavity-nesting bee (Megachile rotundata). We found that though higher connectivity initially increased rates of nest-site occupation, higher edge-to-area ratio ultimately increased patch occupation and nest building, likely due to habitat selection by our focal species. Bee colonization was also higher in patches with higher abundances of their preferred food resources, flowers from the Fabaceae family. Our results show the importance of considering the effects of both connectivity and edge on population dynamics in habitat-based conservation in fragmented landscapes.
Methods
See manuscript (Griffin & Haddad 2021) for full methods.