Last week a college student majoring in ecology asked what my favorite turtle is. My answer: the diamondback terrapin. Anyone who has held this charismatic creature would agree it’s hard to find a more captivating turtle. Terrapins, the only U.S. turtle that lives exclusively in coastal brackish waters, are highly variable in color, ranging from black to milky gray, sometimes with splashes of yellow, green or orange. Brightly colored, concentric diamond-shaped markings often adorn the upper shell.
Despite their charm, terrapins are on the decline in many tidal saltmarsh ecosystems throughout their geographic range, from Cape Cod to Corpus Christi. I recently received a questionnaire about terrapins from a conservation organization. Their goal is to seek “stronger protections for the diamondback terrapin.” They wanted to know if I had “any insight on the species” based on previous ecological research. Below is the Q&A.
Q. Of the terrapin populations you have worked with, would you say that their numbers are increasing, stable, or declining?
A. In 1983 researchers began studying terrapins in the salt marshes around Kiawah Island, South Carolina. Scientific publications based on 4 decades of research demonstrate unequivocally that dramatic population declines have occurred in the last few years. Colleagues from other parts of the country have also reported declines in terrapin numbers.
Q. In your opinion, what are the most severe threats to the diamondback terrapin?
A. The first threat is unregulated, unchecked coastal development. This results in land erosion that leads to heavy silt loads, loss of nesting habitat near salt marshes and increased road traffic (which means increased highway mortality of terrapins). The second is unnecessary terrapin deaths because of commercial (and to some degree, recreational) crab traps that are not fitted with an exclusion device. These devices do not hamper the entry of crabs but do prevent terrapins from entering.
Q. Which threats do you believe will be the most difficult to resolve. Why?
A. I think both these threats will be difficult to resolve because of privileged attitudes, pursuit of the almighty dollar and an aversion to government oversight. Some developers spend millions every year to skirt the spirit of environmental laws without regard for negative ecological impacts. Crabbers may care about their impact on terrapins but they worry that government regulations will reduce their profit margin. A simple exclusion device consisting of a metal bar placed vertically in front of a crab trap opening will prevent most terrapins from entering—and drowning—without hindering entry by blue crabs, which will turn sideways to get into the trap. Requiring crab traps to have an exclusion bar installed prior to sale would alleviate the need for commercial and recreational crabbers to outfit their own traps. And save terrapin lives.
Q. Are there particular populations you are most concerned about?
A. Of particular concern are those in any state where legal safeguards fail to protect terrapin habitats from development and individual animals from drowning in crab traps. What matters for the terrapins is where the species lives—and whether citizens in the area want to protect terrapins.
Q. What conservation action is most critical to protect diamondback terrapins from further declines?
A. Environmental education is one of the most effective tools for instilling positive conservation attitudes in the general public. For example, when people are taught that diamondback terrapins take up to 10 years to reach maturity, live up to 40 or 50 years in the wild and are a vital component of the saltmarsh habitat they become advocates for these magnificent creatures. Widespread education programs in coastal areas can accomplish this. Informing local communities of negative impacts on terrapins that can be reduced or eliminated will have powerful, far-reaching effects. As with most conservation issues, shedding light on a problem can be an effective approach. It puts perpetrators in the position of having to publicly defend their actions, which isn’t always easy to do.
Send environmental questions to ecoviews@gmail.com.
