Fine-Scale Models of Bee Species Diversity and Habitat in New York State

Abstract

Anthropogenic drivers of global change threaten bee diversity and the ecosystem services bees provide. Despite their importance, the conservation of bee pollinators is complicated by limited and often heavily biased occurrence data. A recent state-wide survey of insect pollinators across New York, United States generated a large spatial dataset of bee species occurrence records from community scientists, historical collections, and survey efforts. Using a combination of the state survey records with occurrence data from across the contiguous United States, we applied an ensemble modeling approach using balanced random forest and small bivariate generalized linear models to predict the distributions of most of the state's bee species. We predicted the spatial distribution of bee species richness using a stacked species distribution model with climate, land cover, and soil covariates. To inform bee diversity conservation, we predicted spatial variation for each species and groups of species sharing similar life history traits. We also estimated statewide distribution of range-size rarity, ecological uniqueness, and climate exposure. We found that the richness of modeled species is high across the state, with the greatest richness in regions with low soil clay content and intermediate forest cover. The fine spatial scale and extent of our gridded data layers match the scale of conservation action in the state, providing an opportunity to incorporate wild bee diversity into broader statewide conservation planning. Conserving New York State's bee pollinators is not straightforward, and decisions should be based on broader conservation priorities that incorporate bee biodiversity indicators into decision-making. Here, we encourage the inclusion of these vital pollinators in conservation decisions by leveraging the best available data and methods robust to small sample sizes to provide spatially explicit data products representing the distribution of bee diversity across the state of New York.