PS 15-145 - A sky island perspective: New England (USA) alpine plant community change through time and space

Monday, August 15, 2022

5:00 PM – 6:30 PM EDT

Located in: ESA Exhibit Hall

Presenting Author(s)

Andrea J. Tirrell, n/a

Graduate Student
University of Maine, Maine, United States

Coauthor(s)

MC

Michael Cianchette

Undergraduate Researcher
University of Maine, United States
CM

Caitlin McDonough MacKenzie

Professor of Ecology
Colby College
Boston, MA, United States
JG

Jacquelyn Gill

Associate Professor of Paleoecology and Plant Ecology
University of Maine, Maine, United States

Background/Question/Methods

New England alpine plant communities exist as scattered mountaintop islands separated by a matrix of northern hardwood forest. After deglaciation, the region was initially dominated by tundra species found largely in the Arctic today. As climate changed, these species were limited to the highest elevation sites, where high winds and freezing temperatures limit tree growth. New England’s alpine ecosystems are thought to be climatic refugia for these tundra relic species. Understanding their history and present-day assembly could then provide insight into their vulnerability to modern climate change. Because these rare mountaintop communities are often managed by separate agencies, plant distribution surveys have taken place sporadically over the last century, and standardization is lacking. Therefore, it is not entirely clear how interconnected these communities are, or how they may have changed through time.

Results/Conclusions

To address this, in summer 2021 we conducted vegetation transect surveys on 8 peaks to assess whether the size, isolation, and topographic complexity of each “sky island” affects species presence, richness, and diversity. Mountaintop locations were chosen to incorporate various sizes, levels of isolation from other peaks, and the presence of historic surveys. We found that isolation, island size, and topographic factors all influence species richness and diversity on New England alpine islands, which is consistent with island biogeography theory. Small, isolated “sky island” sites may be most vulnerable to changes in climate because they are home to fewer individuals, fewer species, and less species diversity. We also present a new technique for establishing virtual permanent plots using photogrammetry to standardize re-surveys in the future. As climate continues to change, it becomes increasingly important to monitor these fragile communities with non-disruptive methods, in order to track community changes through time.