17 Nearshore and Estuarine Research: Dynamics and Future Resiliency in the Coastal Zone

This session focuses on drivers of change in coastal environments as well as planning for future resiliency in tidal marshes, mudflats, estuaries, and barrier systems, including human activity impacts, sea level rise, & changing sediment supply.

Monday, 23 March 2026
8:00 AM - 12:00 PM
CCC, Room 22/23

Sediment Controls on Nesting Site Selection of Northern Diamondback Terrapins (Malaclemys terrapin terrapin) at Aucoot Marsh, MA

Paper number: 17-5
Program: Technical Sessions
Time: 9:25 AM – 9:45 AM

Authors

Abstract

Terrapins are a “keystone” species in coastal saltmarshes along the United States East and Gulf Coasts. Their diverse diet keeps in check populations of mollusks, crabs, snails, and small fish (Brennessel, 2006). In turn, terrapin eggs and hatchlings provide food for many saltmarsh species, such as crabs, skunks, foxes, raccoons, crows, and laughing gulls (Feinburg and Burke, 2003). As a result, protecting this species is important for conserving saltmarsh ecosystems. However, the Northern Diamondback terrapin (Malaclemys terrapin terrapin) is considered a “threatened” species in Massachusetts (under the Massachusetts Endangered Species Act), due to its slow recovery from overharvesting in the early 20th century and ongoing threats from car strikes, crab pots, pollution, and predation.

 

To effectively support population recovery, suitable nesting sites for terrapins must be identified and protected. However, the distribution of terrapin nests within a site is heterogenous. This suggests that there are some aspects of their nesting environment that make some areas more favorable to terrapins than others. Identifying these factors will be key to their conservation.

 

Previous studies have examined slope angle, beach orientation, solar irradiance, distance from the high tide line, sediment grain size distribution, soil moisture (Hegarty, 2016); and vegetation cover (Burger and Montevecchi, 1975; Clowes, 2013; Hegarty, 2016). The results from these studies are mixed and may have a strong geographic component. Our study will be the first to examine the terrapin population at Aucoot Marsh in Marion, MA.

 

We sampled 174 locations at four different depths (0, 6, 12, and 18 cm) from 27 shore-perpendicular transects spanning the beach at Aucoot Marsh in May 2017 (696 samples total) and 40 locations from the same beach in May 2025 (before the nesting season). The grain size distribution and soil moisture were measured for each sample. The GPS locations of terrapin nests were collected later each summer. The sediment and soil moisture data were plotted in ArcGIS and extrapolated across the beach using a Kriging function. Values were extracted from the GPS locations corresponding to the terrapin nests. This presentation will show the results of this analysis and discuss the implications for terrapin conservation.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411190

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