UNCOVERING SPATIAL AND TEMPORAL VARIABILITY IN THE PAST, PRESENT, AND FUTURE RESPONSE OF SOUTHERN CALIFORNIA’S WETLANDS TO ENVIRONMENTAL CHANGE
- Author(s): Doughty, Cheryl
- Advisor(s): Cavanaugh, Kyle
- et al.
Climate change threatens the future of coastal wetlands, one of the most ecologicallyimportant, economically valuable ecosystems on earth. Changes to normal climatic and environmental conditions could throw off the delicate balance of these ecosystems with negative consequences to wetland biological response, productivity, and ultimately, resilience. Wetland response is controlled by biogeomorphic feedbacks relating plant productivity to environmental conditions, a complex interaction that can vary over space, within and among marshes, and over time, with tidal cycles and seasons. Wetland biomass serves as an important measure of spatiallyexplicit and temporally-variable changes that could ultimately impact wetland resiliency to climate change. Southern California’s coastal wetlands are especially threatened by climate change due to other anthropogenic forces like coastal squeeze by urban development. The combination of threats to these wetlands render them at-risk and call for improved understanding of how wetland response will vary across the region or within a given site as sea levels, precipitation, and temperatures change. Remote sensing, fieldwork, and habitat response modeling approaches were combined to gain a holistic perspective of wetland vulnerability and resiliency at scales ranging from plant response to regional overviews of habitat change. This approach also spans temporal scales to investigate climate-related changes over time by predicting future impacts, capturing current, highresolution patterns of biomass production, and uncovering decades of past patterns and drivers of wetland health. In chapter one, we develop a sea level rise (SLR) response model that addresses the scale‐dependent factors controlling SLR response and accommodates different levels of data availability to improve regional predictions of SLR vulnerability. In chapters two and three, we test the application of Unmanned Aerial Vehicles (UAVs) in remotely estimating aboveground biomass in coastal saltmarshes and how such hyperspatial insights can aid in satellite-based approaches to biomass estimation. Lastly, chapter four reveals temporal patterns of productivity in salt marshes spanning the region, allowing us to determine the importance of regional versus local climatic controls on saltmarsh productivity. By quantifying impacts across time and space, we gain a better understanding of how climate change will determine the fate of wetlands throughout southern California.