Authored by Chris Jenkins
The Appalachian Mountains contain some of the last remaining wild places in eastern North America. Stretching from Alabama north into Quebec, much of the Appalachian Mountain range is protected as a series of national and state parks, national forests and wilderness areas. You can walk the length of these mountains on the Appalachian Trail, and the majority of your trek would take place on protected lands. Despite being the primary remaining stronghold for wildlife and wild places, the Appalachian Mountains have experienced the extinction of many of their top predators, species such as brown bears, wolves and mountain lions. What remains is a predator community made up of primarily mesocarnivores; animals that consume a diet of a large portion of meat, but can also survive on non-vertebrate foods. This includes animals such as coyotes and raccoons. But there is one great predator of the Appalachians that despite years of deforestation, road development and direct human persecution has survived, the Timber Rattlesnake (Crotalus horridus)—perhaps the greatest remaining icon for the wild places of the Appalachian Mountains.
The Orianne Society has worked on science, conservation and education programs for Timber Rattlesnake conservation throughout the Appalachian Chain since its inception in 2008. Beginning our work in the North where many populations are critically endangered, we completed a research project with the Vermont Department of Fish and Wildlife, The Nature Conservancy and The Vermont Herp Atlas. The results from this study were synthesized into a spatially-explicit model that prioritized specific parcels of land for protection based on the seasonal use by snakes. For example, the model would put priority on the care areas used by rattlesnakes for summer foraging. This project also worked with local landowners to lower persecution rates through community presentations, individual discussions and an organized rattlesnake translocation program to reduce people killing them around their homes. In 2010, we launched a series of projects in the southern Appalachian region of Georgia, North Carolina and Tennessee where some of the highest acreage of wild-protected land and where some of the greatest remaining populations of Timber Rattlesnakes live. This area is defined as the Southern Blue Ridge Ecoregional Unit in the Timber Rattlesnake Conservation Action Plan, which is soon to be published.
Each season, we put on our snake gaiters and climb some of the steepest mountains in North America, often scaling exposed rock faces as we search for this great Appalachian icon. We started with a rattlesnake inventory of hundreds of potential gestation/shedding sites in multiple mountains ranges on both sides of the Georgia-North Carolina border. From these sites we selected a series of gestation sites (i.e., sites females snakes use for giving birth), which we survey three times per summer. These surveys document the presence and abundance of gravid females and shedding snakes, and they allow us to calculate occupancy rates across the region and to monitor how those rates change over time. As you may imagine, rattlesnake reproduction is very cyclic and synchronized, with high numbers of gravid females in some years (such as this year) and low numbers in other years (such as last year). Due to this cyclic pattern, to effectively monitor rattlesnake populations, we also want to understand the primary reasons for these cycles. Thus, we also monitor hard mast such as acorns because the small mammal prey that are linked to rattlesnake reproductive cycles are themselves closely linked to mast production. If there is a low mast year, it will likely be followed by low rodent numbers and ultimately affect the timing of rattlesnakes giving birth. Monitoring both snake reproduction and an index of their prey, we will have a better idea if something is negatively affecting them. For example, if hard mast predicts there should be a high numbers of gravid females but there are not, it can cue us in that something else may be affecting their populations.
Unfortunately last season we discovered something that could potentially disrupt this predator prey cycle. We discovered Snake Fungal Disease (SFD) on Timber Rattlesnakes at two sites in the Blue Ridge Mountains of Georgia along the North Carolina border. SFD is an emerging issue, but one that biologists have been aware of for years. It has been found in over 16 states and on many species of snakes, but it seems to be especially prevalent in Timber and Massasauga Rattlesnake populations. Scientists are now rapidly trying to determine the distribution and cause of SFD. There are some people that think this may have always been around, and there are others who compare the disease distribution to white-nosed syndrome in bats and suspect it is something new that is spreading. In either case the important issue is whether it is affecting snake populations in a negative way. In the near future we are hopeful that scientists will continue to monitor the distribution and prevelance of SFD but also that resources go into determining how it is impacting snake populations and what can be done to mitigate any impacts. Given our discovery in the Blue Ridge, we are inventorying rattlesnakes for SFD this season, keeping an eye towards the impacts it is having and thinking about strategies for dealing with the disease.
The future of rattlesnake conservation in the Appalachians and beyond rests heavily on the shoulders of people. If we decide to conserve this species by protecting land and dealing with emerging issues such as SFD, this great icon should remain for many generations. We think that the best way to do this is through education, and this is why we have put such a focus on education in our work in Vermont and why we have developed a rattlesnake education series in the Southern Appalachians to teach and inspire local communities. Everyone can play a part in rattlesnake conservation by providing education regarding the importance of these species to our ecosystems at every opportunity you have.