North Central Branch Annual Meeting Online Program
Local and landscape determinants for populations of pollinating bees and natural enemies within an agricultural landscape
Authors: Jason M. Nelsona and Thomas O. Crista,b
aDepartment of Zoology, Miami University, Oxford, OH nelsonj7@muohio.edu
bInstitute for the Environment and Sustainability, Miami University, Oxford, OH cristto@muohio.edu
Beneficial insects play important roles in the ecosystem by controlling populations of insect pests and pollination of orchards, cover crops, and native plants. In agricultural landscapes, both patch- and landscape-level variables affect the biodiversity and species composition of beneficial insects and understanding how these processes regulate beneficial insect species is important for conservation efforts. We studied bee (Hymenoptera: Apoidea) and natural enemy richness (Coleoptera, Hemiptera, and Hymenoptera) and species composition in 10 warm-season grasslands that were established as part of the USDA Conservation Reserve Program and USFWS Habitat Enhancement Grants. We tested the hypotheses that species richness and composition of bees and natural enemies were determined by patch size, age, and vegetative composition, and that the surrounding land use/cover types would influence insect species richness and composition. Bee species richness was a positively correlated with patch area (Deviance = 4.14, df = 1,8, p = 0.0418), predator species richness was positively correlated with proportion of intensive agriculture and semi-natural habitat in the surrounding landscape (Deviance = 8.53, df = 2,6, p = 0.016), and parasitoid species richness was positively correlated with the Shannon-Weiner diversity of land use / cover at 525 m radius (Deviance = 8.5822, df = 1,7, p = 0.0034). Overall, we showed that patch-level processes regulated the species richness and composition of bees, whereas the surrounding landscape context was more important to the species richness and composition of natural enemies.
