Date of Award
Summer 6-14-2024
Degree Type
Thesis
Degree Name
Master of Integrative Biology
Department
Biology Department of Evolution, Ecology, and Organismal Biology
Committee Chair/First Advisor
Mario Bretfeld
Second Advisor
Nicholas Green
Third Advisor
Joel McNeal; Heather Bowman Cutway
Abstract
Royal catchfly (Silene regia) is a perennial prairie forb known to grow in rocky, alkaline soils within tallgrass prairies of the eastern United States. S. regia is recorded from twelve states, including Georgia, and is now confined to fragmented habitats due to the loss of 95% of its natural environment. The species is now listed as critically imperiled in the state of Georgia. Attempts at reintroduction via outplanting have only shown limited success, necessitating more research on the environmental conditions in which this plant survives in its southern-most distribution. This study investigated the local ecological factors influencing the persistence of a Georgia native S. regia population, focusing on the impact of edge effects near tree lines on plant growth and reproduction. We hypothesized that individuals closer to tree lines will exhibit better growth and reproductive success due to favorable microclimatic conditions. We collected data on growth, fecundity, and edaphic conditions in one of the last remaining natural populations of S. regia in Georgia during the growing season of 2023 following a prescribed fire. This population is situated in a right-of-way characterized by an open grassland area adjacent to a tree line.
Results from the post-fire 2023 growing season are indicative of an edge effect, wherein individual plants located in a 2 m wide band along the tree line displayed significantly increased growth and, likely as a result of larger growth, increased flowering and mature fruiting. Soil nutrient composition or moisture overall was not significantly different across the site’s open grassland, edge, and forested areas, suggesting microclimatic conditions as the main driver. Our findings suggest that in its southern-most distribution, royal catchfly may require partial shade to maximize growth and reproductive success. The study aims to provide insights for improving conservation efforts and identifying optimal translocation sites for S. regia in Georgia.