Consequences of anthropogenic and global change on orchids: An emphasis on biotic interactions

Evidence suggests that human-driven changes to the earth are having clear and profound effects on many species, as well as the species with which they associate. Disruptions in the interactions between species can change the community structure, in turn changing the dynamics of entire ecosystems. The following dissertation examines how the impacts of climate change related events and invasive species may influence biotic interactions and impact orchid populations and range distributions. Here I quantify how orchid pollinators and mycorrhiza vary between species with different life histories, and between and within habitats. The results showed that orchids with wide range distributions (i.e. geographic or elevational) were more generalized in their mycorrhizal fungi requirements than co-occurring rare and/or narrow ranging species; the rarer species were also more likely to be affected by antagonistic fungal interactions. This dissertation makes a critical contribution to understanding plant and orchid ecology, to assisting ongoing orchid recovery efforts worldwide, and ultimately to developing more comprehensive management plans to mitigate future biodiversity losses.