"The Onset of Coastal Dune Formation at Different Levels of Ecological Complexity"
Bianca Charbonneau
University of Pennsylvania
May 2, 2025 at 12:00 PM
Cannon 203 + via Zoom in Robinson 202
Hosted by Chris Petrone
Abstract: Gaps in our understanding of the interplay between biotic and abiotic forces that shape coastal dunes inhibit our ability to fully understand their evolution and thus predict topographic changes in periods of relative calm and resulting from episodic storms. The theoretical evolution of a dune system begins with nebkha formation, first around individual dune-builder plants and then around groups or communities. In time, individual nebkha mounds can meld into one another growing with the vegetation community supporting them, eventually creating a linear dune shape that is reinforced, grows in size, and acts as a buffer to upland areas. To better understand ecogeomorphological feedbacks driving these relationships we tested how plant density and configuration, relative to plant biomass and morphology metrics, impact nebkha formation by Ammophila breviligulata in both a back beach lab and field setting. Total number of stems jumps out as a plant density metric common in dune modeling efforts that include vegetation, that also has a strong relationship with nebkha size metrics both in the lab and field. However, in the lab setting we are also able to see how number of leaves is an even stronger predictor of nebkha size/growth than commonly used modeling metrics, where leaf number can integrated into modeling efforts in a simple way by extrapolation. Understanding the underlying ecogeomorphic feedbacks involved in nebkha formation, are critical to scaling up in modeling efforts to forecast coastal foredune evolution, recovery, and storm response in the face of climate change.
Zoom Recording ID: 93222841453
UUID: GeZmNDndR1WkU8nWEJ/hZQ==
Meeting Time: 2025-05-02 03:38:19pmGMT