Species #25: Eastern box turtle (Terrapene c. carolina)
Location: Colliers Mills Wildlife Management Area (Ocean County, New Jersey)
Date: 14 May 2017
Species #26: Northern diamondback terrapin (Malaclemys t. terrapin)
Location: Great Bay Blvd. (Ocean County, New Jersey)
Date: 14 May 2017
Species #27: Bog turtle (Glyptemys muhlenbergii)
Species #28: Wood turtle (Glyptemys insculpta)
Location: Sussex County, New Jersey
Date: 15 May 2017
Species #29: Common map turtle (Graptemys geographica)
Species #30: Northern red-bellied cooter (Pseudemys rubriventris)
Location: Raritan River and D&R Canal (Somerset County, New Jersey)
Date: 15 May 2017
Post by Timothy J. Walsh
As part of The Big Turtle Year, George L. Heinrich and I met up with our partner and friend, Jim Angley, in New Jersey. While the Northeast United States may not have the diversity of species that the Southeast has, it more than makes up for it with some of the most enigmatic North American species. George flew in from Florida and I took the train from Connecticut and we hit the ground running by driving down to the New Jersey Pine Barrens. This large expanse of woodland encompasses approximately 1.1 million acres of nutrient-poor sandy soil. This habitat was saved from cultivation due to the fact that normal cash crops were not able to be grown there. The area was preserved in 1978 as the Pinelands National Reserve. Not only did Jim want to show us the beauty of the area, but it is also great habitat for one of our target species, the common box turtle (Terrapene carolina). We stopped at a site within Colliers Mills Wildlife Management Area where Jim has frequently seen numerous box turtles in the past. Within about fifteen minutes (and with gunshots ringing in the background) Jim found a beautiful male eastern box turtle (Terrapene c. carolina). This subspecies inhabits much of the woodlands east of the Mississippi River from north Florida to southern Maine. Although still fairly common through much of its range, this species has declined due to forest fragmentation and destruction, as well as collection for the pet trade. A large factor in their decline is the great number of roadways that now bisect their habitats. Box turtles have very small home ranges (~6.6 acres or roughly 5x the size of a football field). As more and more roads are built, box turtles increasingly have to navigate across them as they seek out food, water, and shelter. Sadly, many never make it across the road successfully, especially in high traffic areas. While exploring other nearby areas, we also observed a northern black racer (Coluber c. constrictor), a northern red salamander (Pseudotriton ruber), and a large 5+ foot northern pine snake (Pituophis m. melanoleucus).
That evening we drove down Great Bay Boulevard, which transects northern diamondback terrapin (Malaclemys t. terrapin) habitat. Diamondback terrapins are the only species of turtle that lives entirely in brackish water ecosystems. Seven subspecies range along the Atlantic and Gulf Coasts from Cape Cod, Massachusetts to southern Texas. Along its entire range, the species is threatened by coastline development, shoreline armoring, drowning in crap traps, collection for the pet and food trade, as well as adult females and hatchlings being killed on roadways. In many areas, nearly 100% of all nests are taken by predators such as raccoon and fox. The site that we visited is one where numerous females come to the roadside to nest, and unfortunately, high numbers are killed by cars as they navigate this dangerous area. In many terrapin habitats, the shoreline has been modified to the point where nesting is virtually impossible. Coastal armoring (bulkheads, seawalls, riprap, etc) can make historical nesting areas completely inaccessible to the female terrapins. Roadways which transect these aquatic habitats make for tempting nesting areas as they are above the high tide line and are usually in fairly sunny locations.
This roadway has portions of temporary fencing to keep the turtles off of the road and safe. After braving the hordes of no-see-ums and their painful bites, we found two carapaces of deceased terrapins (probably car struck females) and two live hatchlings. Terrapin eggs in the Northeast hatch around September, yet, often the young do not exit the nest. Tiny hatchlings will sometimes overwinter in the nest cavity until the following spring when conditions are more appropriate. Both hatchlings were found at the edge of the roadway and were probably drawn out of their nest by heavy rain the previous night. Many hatchlings are killed on roadways either directly by cars or by insolation on the hot pavement before they can make their way to tidal debris. This is where they live for approximately their first year, much like a terrestrial box turtle, feeding on invertebrates and small mollusks.
The following day we met up with Brian Zarate (Biologist, New Jersey Division of Fish and Wildlife, Endangered and Nongame Species Program) and his colleague Kevin Pollack. Brian conducts field surveys for bog turtles (Glyptemys muhlenbergii) and wood turtles (Glyptemys insculpta). Both are threatened species in New Jersey and face a great deal of pressure from illegal collection for the pet trade throughout their range. As with other sensitive species that we have observed during The Big Turtle Year, we will only be stating what county we were in and not divulging the locality. We also take great precaution with these types of species and 'scrub' location data from any photos taken with mobile phones. In this day and age, poachers can obtain locality information from multiple sources such as digital photos, social media, popular writing, and scientific publications. One cannot be too careful to prevent sites from being discovered. In fact, we were lucky enough, even with our credentials to be taken to these sites to observe these fantastic species.
At the first site visited (Sussex County) we were able to find eight bog turtles, including one deceased specimen. When we started searching, the air temperature was 56˚F and it was sunny out. This was great weather for finding basking turtles, however, bog turtles are cryptic baskers and search out the rays of the warm sun in hidden spots. Some were tucked into grass clumps with just a portion of their carapaces exposed. One that I found was fully exposed and had her entire shell positioned with the best angle toward the sun. Of the eight specimens we located, five were recaptures and three were previously undiscovered. Turtles which are caught are given a unique mark which identifies them with a number. This is done so that individual movements, weight, growth, and reproduction can be tracked through time. Each bog and wood turtle that we come across during our visit had its GPS coordinates, morphometric measurements, and weight recorded, along with being given a unique mark as above if a new specimen. I also found remnants of a few hatched nests.
Later that day, we traveled to another site in Sussex County to search for wood turtles. Wood turtles are medium-sized (up to about 9 inches) and live within a mosaic of habitats. It seasonally can be found in streams, woodlands, fields, and even higher elevation ridges. This time of year, the turtles are exiting the streams and are moving around on land. Within a few minutes of searching Jim spotted an individual diving from the bank into the stream. A few minutes later he would spot another. Soon after, we came across two females (unmarked, new specimens) basking in tall grass and briars. Later we found a large male (1,464 grams). It was great to see that a site which has been surveyed extensively still has previously undiscovered individuals being found. Wood turtles face numerous threats such as habitat destruction and fragmentation, road mortality, and collection for the pet trade. Being an animal that moves through large areas of diverse landscapes, it is constantly faced with these threats.
When we are traveling and searching for turtles, we try and make the most of our time in the field. Even after being out for many hours, the sun was still shining! Jim, George, and I headed to the Raritan River and Delaware and Raritan Canal. This canal is adjacent to the Raritan River and is used as a drinking water reservoir. It was excavated by hand using Chinese and Irish immigrants in the 1830s. Today, it is flanked with hiking and biking trails, fishing spots, and is a popular area for stillwater kayaking. It also contains two of our target species, the northern red-bellied cooter (Pseudemys rubriventris) and common map turtle (Graptemys geographica). This map turtle population was recently documented as a range extension by Jim (and colleague, Kurt Buhlmann). Please read about this study here. We observed more than a dozen of both species basking in both the river and canal. We also spotted two eastern painted turtles (Chrysemys picta) and one non-native red-eared slider (Trachemys scripta elegans). Unfortunately, the lighting by this time was not great for photography and we were not able to obtain good photos.
The following day we met back up with Brian Zarate to visit additional bog and wood turtle sites. This time we were joined by Eric Goode, Maurice Rodrigues, James Liu (Turtle Conservancy), Robert Zappalorti (Herpetological Associates), and Craig Stanford (University of Southern California and Chairman, IUCN Tortoise and Freshwater Turtle Specialist Group). The first site that we visited was on private land. Habitat for the bog turtle (and wood turtle) is challenging to conserve and survey as it is made up of a mix of public and private ownership. State wildlife staff, such as Brian, have to carefully maintain good relationships with landowners in order to have access to these lands and it is great to see these individuals take an interest in protecting imperiled species.
This site contains a large population of bog turtles, but is highly challenging to survey. Invasive Phragmites grass covers much of the site as well as cattail (Typha sp.). When searching this site, both plants tower overhead and make seeing anything on the ground nearly impossible. Members of the group were, however, able to find four wood turtles (all unmarked). Other species seen were meadow vole (Microtus pennsylvanicus), garter snake (Thamnophis s. sirtalis), northern watersnake (Nerodia sipedon), and eastern milksnake (Lampropeltis t. triangulum). In addition to the Phragmites, another invasive plant, purple loosestrife (Lythrum salicaria) are quite harmful to this type of habitat as they both can degrade wetlands due to their water absorption characteristics.
The second site that we visited was somewhat picturesque, with green fields and rolling hills in the surrounding landscape. Two bog turtle specimens were found, a recaptured male and an unmarked female. The third and final site was a wetland behind a shopping center, not exactly where you would think to look for a threatened species! Three bog turtles (two new and one recapture) were found. All in all, this was a fantastic trip and we were fortunate enough to be in the company of great turtle people. The highlight for me was certainly viewing bog turtles in the wild. I had previously worked with them in captivity, at the Tennessee Aquarium, and even bred them, but seeing them in their natural environment and learning about their conservation challenges was rewarding. The only thing that put a damper on the trip, and I hesitate to mention it, was the vast amount of ticks at the various sites! At times we were removing 15-20 from our clothing at once! The Northeast had a very mild winter which made the spring very bountiful with these parasitic arachnids. Luckily, the vast majority were dog ticks and not the Lyme disease-carrying deer ticks.
The following day, Jim, George, and I headed into New York City. We stopped in at the Osteology Prep Lab at the American Museum of Natural History and perused a few exhibit halls. We spent a lot of time in the Theodore Roosevelt Memorial Hall and John Burroughs Corridor learning about these two great naturalists. We also made a visit to Central Park to do some turtle watching. We walked to Belvedere Castle to get a good overview of Turtle Pond. This pond is habitat for at least eight species of turtles. The vast majority are non-native and are the result of released pets and their progeny. The most numerous species is the red-eared slider for which we observed well over 60 individuals. We also spotted one Mississippi map turtle (Graptemys pseudogeographica kohnii), one painted turtle (Chrysemys picta), and one red-bellied turtle (either Pseudemys rubriventris or P. nelsoni).
This was a long but rewarding trip and we were excited to add six new species for The Big Turtle Year. Next, we traveled to Massachusetts to visit two sites associated with the northern red-bellied turtle.