COS 48-8
Land use interacts with seasonal phenology in pollinator communities
Understanding how native pollinator communities respond to anthropogenic change is critical for maintaining pollination in human-dominated landscapes. Here we ask how human land use interacts seasonal phenology to determine pollinator community structure. Our study design consists of 9 sites evenly divided into three land use types (forest, urban, and agriculture), replicated within four northeastern USA ecoregions. First we used repeated-measures ANOVAs to determine whether pollinator abundance and richness differed by land use type or season. Second, we used a repeated-measures PERMANOVA based on the Simpson index of community dissimilarity to understand how species composition changes with land use type and season. This statistic allowed us to test three competing hypotheses: that pollinator community composition responds to neither season or land use; that pollinator community composition responds only to either season or land use; or that pollinator community composition responds to each combination of season and land use as a distinct spatiotemporal habitat.
Results/Conclusions
Between April and September 2013, we collected 1840 native bee pollinators of 155 species. Aggregate abundance and species richness were not affected by land use. However, there was a phenological pattern, with abundance and richness being higher in forest in spring and higher in urban and agricultural land use in summer (repeated-measures ANOVA for abundance F=5.6, df=2,31, p=0.001). Species composition changed both between sites as a function of land use (repeated-measures PERMANOVA F=8.7, df=2,34, p=0.01) and within sites as a function of season (F=23.2, df=1,31, p=0.001). Our results support the hypothesis that pollinator community composition responds to each combination of season and land use as a distinct spatiotemporal habitat.