Description of Research Projects
The CCRP scientists collaborate on conservation and research activities in a number of locations in southern New Jersey. Research activities for summer 2013 may include:
- Terrapin Research and Conservation Project
- Food Web Structure in the Salt Marsh
- Delaware Bay Horseshoe Crab Spawning Survey
- Beach Biology in the Wake of Super Storm Sandy
- Sea Level Rise Issues in the Coastal Salt Marshes
- Crooked Creek Snapping Turtle Population Dynamics
Terrapin Research and Conservation Project
The Terrapin Conservation Project was established at The Wetlands Institute in 1989. The project assesses the impact of human activities on diamondback terrapins (Malaclemys terrapin terrapin) and ways to reduce those impacts. During terrapin nesting season (late May – early July), we monitor local salt marsh roads for female terrapin mortalities. (Only female terrapins are found on land because they are looking for a place to lay their eggs.) Injured terrapins are brought back to the lab for first aid. Dead female terrapins struck by motor vehicles are also taken back to the lab so that any potentially viable eggs can be retrieved from the female’s carcass in a procedure called an “eggectomy.” These eggs are placed in containers and incubated at the Wetlands Institute and at Stockton University. After seven to eight weeks, tiny newborn hatchlings emerge from these orphan eggs. These hatchling terrapins are reared in our animal rearing facility for ten months. The resulting head-started terrapins are microchipped and released back into the wild. We continue to evaluate the impacts of our headstarting program on the local terrapin population. We also determine the distribution, movements, and abundance of terrapins using mark, release, and recapture experiments. In addition, our terrapin conservation activities include installing terrapin barrier fences along roadways, which reduce the number of female terrapins entering the road, and installing exclosure cages over terrapin nest sites, which protects buried eggs from predators. Finally, we conduct basic and applied studies on terrapin life history, reproduction, and ecology.
Food Web Structure in the Salt Marsh
The two primary prey types for the northern diamondback terrapin (Malaclemys terrapin terrapin) in the marshes around the Wetland Institute are snails and fiddler crabs (Uca spp.). There is increasing evidence from Atlantic coast salt marshes that the loss of diamondback terrapins may lead to complete devegetation of the marsh, the result of the release of an herbivorous snail, the marsh periwinkle (Littorina irrorata) from the predator pressure of the terrapin. Although we do not currently have evidence that the local terrapin population is decreasing, the large numbers of female terrapins killed each year on local roadways and in abandoned crab traps leads us to consider what the impact of a local population decrease might be. This study will focus on quantifying the population structure of marsh periwinkle in marshes with different levels of human activity/proximity and in relation to the different plant community types that comprise the salt marsh. From these results, we will model the potential effect of various levels of terrapin loss on the periwinkle population and the marsh vegetation.
Delaware Bay Horseshoe Crab Spawning Survey
Horseshoe crabs (Limululs polyphemus) are often described as “living fossils” and fill important niches both in their native environments and in human pharmacology. Owing to localized horseshoe crab population declines and increased fishing pressure on the crabs for bait, annual Horseshoe Crab Spawning Surveys were initiated in 1990. Surveys take place annually on Delaware Bay beaches during new and full moons in May and June. Volunteers from the Wetlands Institute are responsible for two local beaches along the Cape May Peninsula. In addition, we hope to begin monitoring horseshoe crab egg/nest density along the same beaches that we conduct the nesting survey.
Beach Biology in the Wake of Superstorm Sandy
Super Storm Sandy produced major changes along the beaches of both the Atlantic Ocean and Delaware Bay. In some areas, aggressive beach renourishment projects will attempt to reverse some of these changes. The many species of birds that nest and forage along the beaches depend to a great extent on just a few species of invertebrates for their food supply. Mole crabs (Emerita talpoidea) is a species of burrowing crab that inhabits the beach zone between the high and low tide lines (the “swash” zone). As mole crabs vary from a few mm in size in juveniles to 3 cm in adults, they serve as a major food supply for birds ranging from the smallest sanderlings to the largest gulls. Mole crabs are particularly sensitive to aspects of the physical structure of the beach slope (i.e. the beach profile) and to the coarseness of the sand, both of which have been effected by Super Storm Sandy and by subsequent beach renourishment efforts. Ghost crabs (Ocypode quadrata) are nocturnal crabs that live in deep burrows above the high tide line. They are food for a variety of shorebirds and mammals and, in turn, they are important predators of the nests of shorebirds and diamondback terrapins. Ghost crabs are sensitive to changes in the beach profile and to vehicular beach traffic, and may well have suffered both from the storm and from the subsequent management efforts. In this project we will sample mole crabs and ghost crabs along beaches that vary in how strongly they were affected by Sandy and in how they have been managed since that time.
Sea Level Rise Issues in the Coastal Salt Marshes
Sea level rise along the eastern coast of North America is occurring at a rate greater than along most other temperate coasts. How this will affect the coastal salt marshes so important as buffers between the ocean and the land is a major concern, particularly given the apparent increase in the frequency of major storms along the coast. During 2012, the Wetlands Institute began a long term study to determine the potential impacts of general sea level rise and of major storm flooding events on the plants, animals, and ecological communities of the salt marshes in which the Institute is located. Using a combination of field measurements, storm tracking, and GIS technology we are developing flooding threat maps for various sea level rise scenarios. The models that come from this continuing effort will play a significant role in the broader planning for coastal marsh management into the future.
Crooked Creek Snapping Turtle Study
The physical parameters of an ecosystem greatly influence the flora and fauna able to survive in that particular place. The transition between coastal salt marshes and freshwater wetlands are particularly influenced by salinity, which is driven by tidal flux. This study will explore the effects of the salinity gradient on the ecology and population dynamics of Crooked Creek snapping turtles (Chelydra serpentine). Scientists from the Wetlands Institute have been capturing, measuring, and marking snapping turtles for some years, and the time now is ripe to repeat the capture efforts and use the results to model snapping turtle population size and determine if the population is steady, increasing or decreasing. With construction on the nearby Garden State Parkway beginning this year, understanding the status of this important reptile in the waters near the Parkway is an important effort for us.