Alexandra Kanonik  M.S. Demographics of the Jamaica Bay Diamondback terrapin population. Started in summer 2009.

Neil Duncan  M.S. Overwintering behavior of newly emerged diamondback terrapins and the importance of Norway rats as predators. Started in summer 2009.

Colleen Scully M.A. Evaluating turtle conservation techniques.

Elizabeth Reif  M.S. Defence expected in fall 2010.  Movement patterns of post-oviposition diamondback terrapins.

Kayleigh Erazmus  M.S. Defense expected Fall 2010.  Diamondback terrapin diets and foraging patterns.

Kerry Muldoon  Defense expected spring 2010. Post-emergence Movement, Survivorship, and Overwintering Strategies of Diamondback Terrapin (Malaclemys terrapin) Hatchlings at Jamaica Bay, New York

  The adult size and propagule size of many species vary along a latitudinal gradient, although the reasons for these patterns are not well understood.  Using diamondback terrapins (Malaclemys terrapin) as a model species, I examined some of the hypotheses that have been proposed to explain the relationship between size and latitude, including Bergmann’s Rule, optimal egg size theory, the summer length hypothesis, and the seasonality hypothesis.  I collected average female plastron lengths from 21 sites throughout the range of terrapins to examine Bergmann’s Rule.  I found that diamondback terrapins do not follow Bergmann’s Rule.  To test the optimal egg size theory, the summer length hypothesis, and the seasonality hypothesis, I collected eggs from four sites within the range of the northern diamondback terrapin (M. terrapin terrapin) and reared the hatchlings under common garden conditions.  Eggs were evaluated for size, growth, and incubation duration.  I investigated hatchling fitness by evaluating size, growth, locomotor performance, shell abnormalities, and survivorship.  I did not find a relationship between clutch size or egg size and latitude.  Terrapins did not adhere to the optimal egg size theory; shell abnormalities, locomotor performance, and survivorship were not related to egg size, although there was a significant relationship between hatchling growth and initial egg mass.  I also found that northern terrapins do not follow the summer length hypothesis; initial egg mass was not related to summer length.  I found that northern diamondback terrapins follow the seasonality hypothesis: egg size variation had a negative relationship with annual temperature variability.  However, there was no relationship between egg size variation and summer temperature variation in northern diamondback terrapins. Future work should be done to evaluate eggs and hatchlings from throughout the entire range of diamondback terrapins to further test these hypotheses.  

Eric Rulison M.S. 2009.  Diet and movements of raccoons and Norway rats in Gateway National Recreation Area.
Both raccoons (Procyon lotor) and Norway rats (Rattus norvegicus) may be problem species at Jamaica Bay Unit of Gateway National Recreation Area (GNRA) because of their potential predation on native wildlife. I trapped 54 different raccoons (24m, 30f), calculating an average density of 0.31 raccoons per hectare from 2006-07. Male raccoons were larger in body weight (5.2 kg for males and 5.6 kg for females) and males had larger hind-foot length. Fifteen Norway rats were analyzed (9m, 6f) from two different locations tern nesting area (TNA) and metropolitan transit authority (MTA). TNA total length averaged 31.9 cm for males 36.8 cm for females. MTA males averaged 35.8 cm and 39.2 cm for females. Weight was not taken. Additionally, I determined the consumption of rare species by using fecal and gut analysis, for raccoon and Norway rats respectively. My analysis of 161 raccoon scat samples collected over 13 months demonstrated that fiddler crabs (Uca pugnax) were their main food species (79% percent frequency of occurrence (PFO)) followed by plant matter (55% PFO) and mast (e.g. nuts and fruit; 39% PFO), which was similar to other coastal locations. As with similar studies on Rattus spp., vegetation was the most important diet item in 15 rat digestive tracts I examined, but this is poorly resolved due to small sample sizes and the difficulty of identifying gut contents. No government-listed protected species occurred in the samples. However, three exploitable vulnerable plants (American holly, bayberry, prickly-pear cactus) and one species of regional concern, diamond-back terrapin, were consumed by raccoons. The plant species do not appear to be at risk from raccoons or rats, but terrapin eggs and perhaps hatchlings appear to be important raccoon diet items. Similarly, terrapin hatchlings might be seasonally important diet item of rats.  Higher resolution diet studies are needed to further quantify the role of problem species as predators of rare wildlife at GNRA.

Amanda Scholz (Widrig)  M.S. 2007.  The effects of diamondback terrapin nest site choice on emergence time and offspring sex ratio. M.S. Thesis, Department of Biology, Hofstra University.
Nest site choice andnest construction have the potential to play significant roles in the reproductive fitness of organisms.  In turtles, nest site choice can affect offspring size, offspring sex, offspring locomotor performance, and offspring survivorship.  I observed diamondback terrapins (Malaclemys terrapin) nesting at the Jamaica Bay National Wildlife Refuge in Queens, New York in 2004 and 2005.  These years differed dramatically in average monthly and daily summer temperatures and rainfall.  I recorded microhabitat characteristics in a one-meter area around each nest and four randomly chosen sites nearby.  I also collected data on nest temperature at each nest, protected nests from predators, monitored nests for hatching, and measured hatchling survivorship.

            In 2004, 1306 hatchlings emerged from 144 nests.  Nest sites differed from random sites in that nest sites had significantly less overhead cover from the West.  Nest temperature, measured using Pivotal Temperature Units (PTUs), was affected by the percent grass cover surrounding the nest, the nest depth and the percent dicotyledonous plant cover around the nest site.  The average nest temperature during the thermosensitive period was also strongly influenced by the amount of grass cover.  Emergence success (percent of eggs that resulted in hatchlings emerging from the nest) was significantly affected by the average nest temperature during the thermosensitive period, overhead cover from the East and by percent grass cover.
In 2005, 1086 hatchlings emerged from 136 nests.  Nest sites differed from random sites in that nest sites had significantly less overhead cover from the South and North, significantly more bare area and significantly less leaf litter.  PTUs were significantly influenced by nest depth.  Average nest temperature was significantly influenced by nest depth, overhead cover from the North, South and East and the amount of area around the nest site that was bare.  Emergence success was strongly affected by nest depth.

Emergence success was not determined by female carapace size, clutch size or average egg mass for either year.  Emergence success for both years was affected by nest depth, but in different ways.  In 2004, warmer, shallower nests were significantly more successful and in 2005 deeper, cooler nests were significantly more successful.  Nest depth was not correlated with female size, month the nest was laid, average egg weight or clutch size for either year.  These differences in the impact of nest depth were due to the very dissimilar climate patterns in 2004 and 2005.  Emergence success was negatively correlated with the occurrence of grass for both years, although nest depth was more important for determining emergence success in 2005 while grass cover was more important than nest depth in 2004.  This study suggests that shifting climatic patterns may alter selective pressures on nesting turtles.  However, grass predation may be a more consistent pressure, because grasses are important predators of terrapin eggs. 

Pedro Martinez  M.S. 2007.  Culturing and harvesting of turtle lymphocytes for karyology: methods leading to metaphases of Glyptemys (Clemmys) insculpta, Chrysemys picta, and Emys orbicularis.  M.S. Thesis, Department of Biology, Hofstra University.

Click here to view the abstract.

Maria Giambanco (2003: Comparison of fertility rates, hatchling survivorship and sex ratios of field and laboratory incubated nests of the estuarine turtle Malaclemys terrapin)

Malaclemys terrapin, a member of family Emydidae, is one of only a few turtle species worldwide that lives in estuaries, and the only such turtle that inhabits the coastal United States.  Diamondback terrapins feed primarily on mollusks and crustaceans.  Due to their active foraging and mobility, terrapins are crucial macro-consumers in the estuarine ecosystems.  Gateway National Recreation Area (GNRA), a large estuarine park east of the mouth of the Hudson River, NY has a large terrapin population.   Due to habitat loss elsewhere, parks such as GNRA, are vital to the preservation of M. terrapin.  Although terrapin numbers are declining throughout their range, the Jamaica Bay Wildlife Refuge (a unit of GNRA) population is still impressively large.  Therefore it is vital to document the current viability rates, hatchling survivorship, and sex ratios of the JBWR population.  I found that 46.1% of protected nests laid in JBWR were predated by raccoons despite the use of nest protectors, and 2.9% of the undisturbed nests were flooded.  The average clutch size for terrapin nests (including protected nests and nests found post-hatching) over both years was 11.8 eggs.  Egg viability for field-incubated nests was 88.6%, and 86.7% of the non-predated eggs resulting in hatchlings that emerged from the nest successfully (= emergence success).  The viability rate for laboratory-incubated nests was 89.7%.  Viability rates varied with incubation temperature, as did post-hatchling mortality and hatchling sex ratios.  Sex ratios of laboratory incubated turtles varied with incubation temperature.  At 26,28,30,32 and 34oC the sex ratio of hatchlings was 100, 93.3, 11.1, 0 and 7.7% respectively.

Pasquale (Pat) Razzano (1999), who investigated genetic variation in six-lined racerunners (Cnemidophorus sexlineatus), a very fast little lizard that is found over much of North America. This work started with the "discovery" of a tiny population of these lizards in Michigan, 240 miles beyond the previously known range limit of the species. The burning question: is this population a relic of some old invasion, and therefore needing immediate conservation attention, or the result of an introduction by some misguided pet owner? Pat was unable to provide as much resolution as we had hoped, but he did build a good foundation for future work. His research will result in useful information about the patterns of recolonization of North America following glacial melting 18,000 -20,000 years ago. Click here for an abstract of his results.