Factors influencing bee movement between habitat patches in a naturally fragmented landscape

The persistence of organisms in fragmented landscapes often depends on the ability of individuals to move between patches. For bees, species, patch, and matrix traits are all factors that likely influence access to new patches. Our objective was to determine how such characteristics interact to affect the movement of native bees between patches in the naturally fragmented Ozark Mountain Glade ecosystem (Missouri, USA). We conducted a mark-recapture study across pairs of glades to explore how bee size, nesting biology, the distance between patches, patch resources, matrix characteristics, and their interactions affect the probability that an individual bee moves between patches. We marked 4513 bees and recaptured 833 (18.5%), 8% of which were caught in a glade other than where they were marked (e.g., movement detected). Below-ground nesting bees were more likely to move, and movement probability declined with increasing distance between glades. Small bees were unlikely to move, and large bee movement was positively associated with resources in the "away" patch. Overall, bees were unlikely to move between two low- or two high-resource patches. Instead, bee movement was most likely when the "home" patch was resource-poor and the "away" patch was resource-rich. Finally, bees were less likely to reach the "away" patch if the matrix provided supplementary resources. Our results suggest a complex interplay between species, patch, and matrix traits influence bee movement across fragmented landscapes. While conservation efforts focused on patch quality are justified, improving matrix quality may be equally important for bee conservation.