I am a herpetologist at heart, though my current research extends into coastal ecology and island food web ecology. My research concentrates on the cross-ecosystem linkage support of top predators inhabiting barrier islands of the southeastern United States. I am using isotopic analysis (N and C) to examine the trophic levels and food sources utilized by top predators on Sapelo Island, Georgia. My study organisms include the American alligator (Alligator mississippiensis), wild hog (Sus scrofa), raccoon (Procyon lotor), Eastern Diamondback rattlesnake (Crotalus adamanteus), and various species of lizards (Plestiodon and Anolis). Surrounding much of the interior side of these barrier islands are coastal marshes dominated by marsh grass (Spartina alterniflora). Within these coastal environments, biomass and growth of associated fauna (e.g. fish, oysters, shrimp, snails) is often directly linked to the productivity of S. alterniflora and salinity gradient of the ecosystem. We are proposing to test the hypothesis that due to cross-system linkages in the form of freshwater subsidies from interior habitats (i.e. small and large islands) and protein from marine animals, populations of the before mentioned predators are able to persist in remarkably high population densities on barrier islands. If demonstrated, this could provide evidence to support the relationship of the health of coastal marsh ecosystems with the conservation and management of a wide variety of top predators inhabiting barrier islands of the southeastern United States.
Top Predators of Barrier Islands- What drives population density?
Ecologists have recently placed a great deal of importance on the ability to quantify the relative importance of the bottom-up (resourced-based) and top-down (predator-based) forces in ecosystem regulation. Many have placed emphases on top-down forcing and the potential for trophic cascades by top-down determination through the over consumption of prey resources. Others have shown that top predators and food webs can be strongly influenced by resources and thus bottom-up forces. This is especially true when populations and communities are regulated by the amount of allochthonous input from bordering habitats in the form of food, detritus, nutrients, or water subsides. Such allochthonous input can subsidize consumers in less productive habitats, enabling them to persist in numbers greater than the in situ productivity can support. Since observations in the field suggest that top predators on barrier islands forage in salt marshes and drink freshwater from terrestrial water sources, this bottom-up, cross-ecosystem subsidy likely occurs within the barrier islands of the southeastern United States. However, this linkage has not been tested.
American Alligator- Utilization of saline environments
Though a vast amount of information on the ecology of crocodilians living in saline environments has been produced for genus Crocodylus, little has been documented for Alligator. The presence of American alligators in coastal marshes has been documented throughout the southeastern United States. This occurrence is interesting for two reasons; the alligator has no system of osmoregulation and in the past has been considered to be mainly a freshwater/terrestrial predator. Through GPS/VHF tracking and isotope analysis I am attempting to outline the importance of saline environments in the management of the American alligator in coastal areas of the southeastern United States.
Graduate Fellow at Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR)
Research Assistant; Division of Herpetology, Florida Museum of Natural History, University of Florida
Full Service Volunteer for Florida Fish and Wildlife Conservation Commission
10. Nifong, J.C. and B. R. Silliman. 2012. A large-bodied apex predator’s effects cascade through salt marsh food web. In Review
9. Nifong, J.C., A. E. Rosenblatt, N. Johnson, W. Barichivich, B. R. Silliman, and M. R. Heithaus. 2012. American Alligator Digestion Rate of Blue Crabs and its Implications for Stomach Contents Analysis. Copeia 2012(3): 419-423.
8. Nifong, J. C., M. C. Frick, and S. Eastman. 2011. Putative Predation and Scavenging of Two Sea Turtle Species by the American Alligator, Alligator mississippiensis Daudin 1801, In Coastal Southeastern United States. Herpetological Review 42(4): 511–513.
7. Nifong, J. C., and M. C. Frick. 2011. First Record of American alligator (Alligator mississippiensis) as a Host to the Sea Turtle Barnacle (Chelonibia testudinaria). Southeastern Naturalist 10(3): 557-560.
6. Atkinson, B. K., and J. C. Nifong. 2009. HEMIDACTYLUS GARNOTII (Indo-Pacific Gecko). Herpetological Review 40(1): 112.
5. Rochford, Mike, K. L. Krysko, J. C. Nifong, L.Wilkins, R. W. Snow, and M. S. Cherkiss. 2010. PYTHON MOLURUS BIVITTATUS (Burmese Python) DIET. Herpetological Review 41(1): 97.
4. Krysko, Kenneth L., James C. Nifong, Ray W. Snow, Kevin M. Enge, and Frank J. Mazzotti. 2008. Reproduction of Burmese Python (Python molurus bivittatus) in southern Florida. Applied Herpetology.5: 93-95
3. Townsend, Josiah H., James C. Nifong, and Roberto Downing M. 2006. Oedipina elongata (Schmidt, 1936) in Honduras. Salamandra 42(1):61-62.
2. Townsend, Josiah H., Larry D Wilson , T. Lynette Plenderleith, Brooke L. Talley, and James C. Nifong. 2005. Ninia pavimentata (Squamata: Colubridae): An Addition to the Snake Fauna of Honduras. Caribbean Journal of Science 41: 869-870.
1.Townsend, Josiah H., James C. Nifong, and Larry David Wilson. 2005. First record of the colubrid snake Rhadinaea anachoreta Smith and Campbell from Honduras. Herpetological Bulletin 94:2-3.