DOI
https://doi.org/10.25772/F7E2-YK79
Defense Date
2019
Document Type
Thesis
Degree Name
Master of Science
Department
Biology
First Advisor
Dr. Julie Zinnert
Second Advisor
Dr. Rima Franklin
Third Advisor
Dr. Chris Gough
Fourth Advisor
Dr. Daniel McGarvey
Abstract
Morella cerifera is a rapidly expanding native shrub on the Virginia barrier islands which displaces other native coastal species and may interrupt normal sediment dynamics. Barrier islands are considered stressful environments with low nutrients, high solar load, and frequent drought and salt exposure; facilitation often dominates in stressful environments according to the Stress Gradient Hypothesis. The objective of this project was to understand the importance of species interactions with grasses on the growth and physiology of M. cerifera at the seedling life stage through both field and lab experiments. Grasses provided ~1.3°C insulation to shrubs during winter freeze events and a freezing threshold for M. cerifera seedlings was experimentally found between -6°C and -11°C. Seedlings competed for light with grasses during warm months and grew more where grasses were clipped, revealing a tradeoff between winter insulation and summer light competition. M. cerifera shows evidence of ecosystem engineering at the seedling stage by significantly reducing summer maximum temperatures. This enables rapid expansion of M. cerifera across the landscape. As M. cerifera expands, island migration is altered, leading to decreased island stability and increased erosion. Although seedlings are small and relatively vulnerable, this life stage appears to have significant implications for the ecosystem trajectory and stability of the Virginia barrier islands.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-7-2019