HRI Seminar Series - Dr. Stacy Trackenberg

"Evaluating the role of habitat complexity in structuring seagrass communities."

STACY TRACKENBERG
ASSISTANT RESEARCH SCIENTIST
HARTE RESEARCH INSTITUTE FOR GULF OF MEXICO STUDIES

The structure and complexity of biogenic habitats can strongly influence the composition of marine faunal communities and contribute to their roles as nursery areas. It is necessary to understand how nursery areas are defined in the ecological literature as these definitions are applied to nursery area management across the United States. Further, the relative importance of how habitat structural attributes, which are influenced by abiotic and biotic factors, shape faunal communities within these nursery areas is critical to understand these important coastal ecosystems. My dissertation focuses on (1) how nursery frameworks in the ecological literature have evolved and how these frameworks are applied to state management of nursery areas; (2) how habitat complexity influences faunal communities; and (3) how abiotic and biotic factors influence the restoration success and faunal community assembly of seagrass meadows. In my first chapter, we found six overarching frameworks to define and delineate nursery areas in the ecological literature: measures of juvenile abundance and vital rates, habitat characteristics, seascape connectivity, populations fitness and contribution to adult biomass, and persistence. Of the 23 coastal states, only seven explicitly protect nursery areas and of these seven states, the aforementioned frameworks are not equally applied. Trawl surveys conducted for my second chapter revealed that taller canopied seagrass beds support higher faunal abundances and species richness than shorter canopied beds, however this was not true across all species. In a habitat preference experiment, pinfish (Lagodon rhomboides), the most common fish found in North Carolina seagrass meadows, demonstrated a preference for deep seagrass beds, but only preferred taller canopies when these areas also offered increased blade surface area. In my third chapter, transplanted shoal grass (Halodule wrightii) in intertidal locations had increased survival compared to those in the subtidal, however faunal communities were not equal to those in natural seagrass beds. Considerations of both structural complexity and physical setting of the habitat are therefore imperative for a comprehensive approach in understanding how habitats as well as their faunal communities are responding to future changes across ecosystem settings.

Stacy is an assistant research scientist working in the Coastal Conservation and Restoration Lab. She received her B.S. in biology with a minor in marine science from the College of William and Mary in 2016. While at William and Mary, Stacy studied the effects of embryo energy and larval food supply on the development of two species of sea stars. She received her Ph.D. in Biology from East Carolina University in 2023. As a graduate student Stacy was a research fellow with NC Sea Grant and the Albemarle-Pamlico National Estuary Partnership. Her work at ECU focused on faunal communities in seagrass beds, but she collaborated on projects including oyster reef and marsh restoration and clam-seagrass facilitations among others.