Context‐dependent effects of geographic, climate and land cover factors on hemipteran assemblages in different ecoregions of China

Abstract

Understanding variation in assemblage composition (i.e., beta diversity) along geographic and environmental gradients is a central topic in biogeography and ecology. We compared relationships between hemipteran beta diversity (overall dissimilarity: βtotal, Sorensen dissimilarity; turnover component: βsim, the replacement of species between assemblages; nestedness‐resultant component: βsne, the nested difference in richness between assemblages) and geographic, climatic and land cover distances among four ecoregions (Northeast Ecoregion; Northern Ecoregion; Tibet Ecoregion; Southern Ecoregion) across China. The hemipteran assemblage composition differed markedly among ecoregions. In general, βtotal and βsim both significantly increased with increasing geographic, climatic and land cover distances. Intercepts and slopes of dissimilarity‐distance relationships all varied significantly among different ecoregions, suggesting different levels of within‐ecoregion assemblage heterogeneity and change rate in assemblage composition. Moreover, the slopes of βtotal and βsim were highest in Northeast Ecoregion but lowest in Northern Ecoregion, exhibiting latitudinal and longitudinal dissimilarity pattern. According to variation partitioning analysis, although the overall explained variance was relatively low, spatial variables explained a much greater proportion of variance compared to climate and land cover variables. To conclude, our results showed significant regional differences in assemblage composition and biodiversity among ecoregions. Both dispersal‐related and niche‐related processes affect hemipteran assemblage structure, while the low overall explained variance indicates that high dissimilarity in hemipteran composition is affected by multiple factors and processes that remained undetected in this study. Our results may be relevant for wider insect groups because hemipterans constitute a highly diverse group in terms of phylogenetic origins and functional significance.