Biodiversity patterns are key to understanding ecosystem function, and yet they are often difficult to predict in human-impacted systems. This is in part because separate taxonomic groups may respond uniquely to changes in habitat composition. Further, the spatial scale at which habitat composition impacts each group can vary. Incorporating life history traits can provide a mechanistic, predictive understanding of how habitat loss or fragmentation alters biodiversity. We investigated the impacts of local and landscape habitat features on distinct guilds of pollinating insects that vary in key life history traits. In particular, we asked (1) how insects’ food and shelter resource requirements drive biodiversity relationships with local habitat and (2) whether mobility explain the differential impacts of landscape-scale habitat availability on insect biodiversity. We sampled 43 sites in northern Texas and southern Oklahoma for diverse pollinators: bees, butterflies, beetles, flies and wasps. Sites included private, federal and state land where stakeholders were enthusiastic to support research on how to conserve pollinators. The focal insects vary in their flower utilization, dependence on litter and bare ground for shelter, and mobility. We also quantified food and shelter resource availability at each site, and used land cover data to determine landscape-scale habitat availability.
Results/Conclusions
Habitat availability at both the local and landscape scale differentially impacted the distinct pollinator taxa that we surveyed. At the local scale, overall insect abundance increased when sites had greater availability of exposed ground. This habitat feature provides nest sites for ground-nesting bees (the predominant bee type in our system) and mud-puddling sites for butterflies. Our data also highlighted a potential trade-off in habitat that provides shelter resources for bees versus beetles. In particular, beetle abundance correlated positively with dead vegetation, while bee abundance responded negatively to dead vegetation. At the landscape scale, the amount of semi-natural habitat surrounding the sites markedly impacted pollinator richness. However, the magnitude and direction of this relationship varied for the distinct pollinator taxa. Sites surrounded by more semi-natural habitat contained more beetle species but fewer fly species, with no impact on bees or wasps. Given the greater presumed vagility of bees and wasps relative to beetles, these patterns suggest that species’ mobilities alone do not drive abundance and diversity patterns. Overall, our results highlight the importance of incorporating life histories to better understand habitat-biodiversity relationships, and to design conservation management that incorporates the resource requirements of a diverse suite of organisms.