Despite years of research, drivers of vascular plant species richness in alpine tundra habitats are largely unknown. Aridity is one factor that has not been well studied but shows promise in explaining species richness. In Patagonia and the Swiss Alps, increasing aridity correlates with higher species richness. Here, a full species assessment was conducted on nine mountains in fell field and dry meadow communities. These nine sites covered the precipitation gradient in Colorado from driest to wettest conditions (425mm-1941mm) found above 3657 meters.
Results/Conclusions
We found that the abiotic factors of increased precipitation, substrate pH, rather than aridity, offered a better explanation of what drives higher species richness. Additionally, we discuss an ecotone between fell fields and dry meadows that can form between these two communities or where topography creates intermediate communities with conditions and species composition shared by both communities. We define a new addition to alpine vegetation communities, pseudo-fell field. This community develops where environmental conditions are similar to true fell fields and include traditional fell field species, but the overall species composition is unique to this community. Defining specie of the pseudo-fell field are Frasera speicosa, Bistorta bistortoides, Paronychia pulvinata, and Phlox condensata. Species composition was also higher in pseudo-fell fields with 29-33 species versus 16-23 found in traditional fell fields. If we can more accurately characterize in-situ community types, researchers will better understand alpine environments and how future changes will impact them.