The influence of biotic interactions and abiotic factors on fine-scale variation in plant species richness and performance on sub-Antarctic Marion Island

Abstract

Traditionally studies examining the determinants of species ranges have focused on abiotic variables (specifically climatic conditions.. The recent explicit consideration of biotic interactions in these studies represents an important advance in the field. However, while these studies support the importance of biotic interactions for species distributions, only the influence of a single species and/or a single interaction is examined by most studies (despite species distributions potentially being affected by multiple biotic interactions.. Moreover, the impact of biotic interactions on community composition and richness may vary through space and time, suggesting that the influences of interactions on species distributions and diversity may be environmentally contingent (as predicted by the stress-gradient hypothesis.. Therefore, the aim of this study was to examine the influence of biotic interactions, after accounting for the influence of abiotic factors, on plant community richness along fine-scale environmental gradients. Specifically, we tested whether incorporating biotic interactions into high-resolution models improved predictions of species richness and diversity, allowing the influence of specific interactions to vary based on abiotic conditions. This was achieved by including the cover of dominant plant species (as a proxy for the intensity and frequency of their interaction with other plant species. into two methodologically-divergent species richness modelling frameworks – stacked species distribution models (SSDM. and macroecological models (MEM. – for two evolutionary- and ecologically-distinct taxonomic groups (vascular plants and bryophytes.. Predictions from models including biotic interactions were compared to the predictions of models based on abiotic data only. The results from these analyses will be discussed. - Abstract as displayed in the - Abstract booklet. There was no presentation.