Mountain ecosystems in western North America are highly sensitive to climate change and are warming faster than the global average. Found at the tops of these mountains, the alpine tundra ecosystem is especially threatened due to its fragmented distribution (so called “sky islands”), limited area, and the impossibility of alpine species moving to higher elevations. As a result, alpine sky islands are considered a “sentinel system” for detecting the effects of climate change, and rapid changes in the genetic composition of alpine populations and the species composition of the alpine communities are expected in the coming decades. I investigated these changes in the Rocky Mountains of Colorado by collecting genetics samples from six alpine species and sampling species composition in seven alpine sky islands which had previously been sampled a decade earlier. While data analysis for the genetics portion of my project is still on-going, I found that species composition in these alpine sky islands is already shifting, with increases in the number of species, the number of evolutionary lineages, and the abundance of species possessing traits which enable greater drought tolerance. Importantly, these changes were more pronounced in sky islands with smaller areas. Overall, these results suggest that the alpine tundra is already responding to climate change and that shifts in biodiversity patterns are detectable over relatively short time frames. Land managers wishing to protect this ecosystem should prioritize the conservation of large areas of alpine tundra which may be more resilient to climate impacts.

Admin note: Due to border closures during the COVID pandemic, Jared was unable to come to Canada so ACA enabled him to complete his project in the USA.