Plant Community Assembly Dynamics on Rock Walls: The Role of Environmental Filtering and Dispersal Syndrome

Author: Alison Kryger

Field of Study: Science, Technology, Engineering, and/or Math

Program Affiliation: Summer Scholars and Artists Program (SSAP)

Faculty Mentors: Eliza Grames

Easel: 28

Timeslot: Morning

Abstract: Natural rock walls serve as habitat patches for plants, offering protection from competition, predation, and disturbance. We examined plant community assembly on rock walls, assessing whether colonization is primarily influenced by top or bottom communities and how dispersal methods affect establishment. Across six locations in New York, 97 plant genera were identified, with 15 (15.5%) found exclusively on rock walls, dispersed by wind (48%), gravity (7%), ballistic (3%), ants (6%), and other animals (36%). Sampling along 0–18 meter transects, it was found that similarity to top communities increased with height (p = 0.005), while no significant effect was found for bottom communities. Slope influenced dissimilarity to both top (p < 0.001) and bottom (p < 0.001) communities, with colonization favoring shallower slopes. Micro-features (cracks, faces, ledges) significantly impacted dissimilarity (p = 0.013). These results suggest plant communities are primarily filtered from top communities, shaping their persistence in extreme environments.