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Interdisciplinary Approaches Help to Save Turtle Nesting Grounds

By Elisa Livengood, SNRE PhD Student

The Florida panhandle (from Escambia County to Franklin County) contains some of the fastest eroding beaches in the state and is home to endangered loggerhead (Caretta caretta) sea turtles' nesting grounds. To prevent further erosion and a loss of shoreline development, local officials often implement a common mitigation strategy known as beach nourishment. Environmental concerns arise if the newly nourished sand has different properties from that of the natural beach. SNRE graduate student, Lori Brinn, utilizes her interdisciplinary training to explore the crossroads of beach management practices with the impact on native Florida sea turtles.

An Interdisciplinary Ecology masters student working under Dr. Ray Carthy (Assistant Unit Leader, Florida Cooperative Fish & Wildlife Research Unit), Lori hopes to address these concerns by examining differences in the physical properties of nourished sand verses natural beach sand. The differences could explain this mitigation strategy's impact and influence on sea turtle nesting patterns. Lori's study expanded on previous research that only addressed beach compaction, the difficulty of moving sand in a vertical motion. "We thought that measuring compaction alone might not provide a complete picture of a sea turtle's perception of the beach," Lori explained.

To address this, Lori created an artificial paddle-like turtle arm to measure shear resistance, the difficulty of moving sand in a sideways motion, because "sea turtles move sand not only vertically, but also horizontally when they crawl onto the beach and excavate a nest chamber," said Lori. Additionally, Lori compared her measurements on sand properties (compaction, bulk density, water content, grain size, and color) with data from the Florida Marine Research Institute on patterns of the loggerhead sea turtle nesting.

"We found that the property differences of sand on nourished beaches decreased over time, recovering to a state more similar to that of the natural beach. As beaches are often nourished in three-year cycles, in many cases additional sand is added to the system just as the beach recovers," explained Lori, "potential impacts caused by differences in sand properties could be reduced by spacing out nourishment episodes over a longer time period."

Lori's findings suggest that coastal managers in northwest Florida are doing a good job of keeping consistent with regard to sand quality by trying to acquire nourished sands from sources that have properties close to those from the natural beach.

"My project isn't just purely science driven, we bring together elements of many disciplines; from understanding beach ecology dynamics, coastal engineering, sea turtle biology and conservation, to the politics of beach nourishment," Lori explains. Creating beach nourishment procedures and policies required interdisciplinary efforts with the purpose of reducing the environmental impact and posing less risk to sea turtles utilizing these beaches. Lori's research findings will ultimately assist managers in developing better management strategies and tools for the U.S. Fish and Wildlife Service.

The highly political nature of beach nourishment programs posed a challenge of finding an appropriate method for communicating Lori's research to local communities on the panhandle. "Public relations is something we had to deal with on a constant basis because beach nourishment is a big political hot topic. Often when taking samples, people would directly approach us with curiosity about what we were doing. Staying neutral about the area's management practices while explaining my research was important and it was something I had to train my field assistants on as well."

Thanks to: Committee members Ray Carthy, Jim Jawitz, and Bob Dean. Research assistants Burnie Brinn and Lindsey Thurman. Lorna Patrick and the U.S. Fish and Wildlife Service for funding and support. Blair Witherington and Beth Brost with the Fish and Wildlife Research Institute for design contributions and for providing sea turtle nesting data.