Ecological Effects of Reintroducing a Top Predator to Degraded Ecosystems
North America’s largest native snake, the Indigo Snake (Drymarchon couperi) is a federally threatened species that was extirpated from Alabama sometime in the mid-20th century, largely due to habitat loss and fragmentation. Starting in 2009 and coinciding with large-scale habitat restoration, approximately 100 Indigo Snakes have been reintroduced to Conecuh National Forest, with another 200 slated to be released over the next five years. We are using a landscape-scale experimental design and monitoring wildlife populations and assemblages to identify how the reintroduction of the Indigo Snake is changing the longleaf pine ecosystem. Given that (non-Indigo) snakes are the dominant predator of bird nests in the southeastern United States, we expect to find bird nest and fledgling survival to increase in the presence of the Indigo Snake.
Invasive Tegus in the Southeastern United States
An invasive species in southern Florida currently of great concern is the Argentine Black and White Tegu (Tupinambis merianae),in part because these big lizards (up to 4 ft -1.2m- and over 10 lbs -4.5 kg-) are big predators of native species. A pressing question is whether these invasive lizards, currently restricted to southern Florida, will be able to thriver further north. To determine whether this species is physiologically suited to survive in a temperate climate and in cooperation with the United States Geological Survey, we are holding tegus in outdoor enclosures at Auburn University. We conducted surgeries to implant the tegus with radio-transmitters, so that in the case of an escape we can quickly recapture the animal, and we also implanted small temperature recording devices that will enable us to monitor the animal’s temperature and figure out if they are able to adapt to this relatively temperate climate. If the animals survive the winter, we will then play matchmaker and see if the animals can successfully reproduce. Our study will reveal much about the thermoregulatory behavior of tegus while also informing policy makers about the potential for this species to successfully invade Alabama and Georgia.
We are also examining the population demography of tegus captured in the wild in Florida to better understand their population structure and generate insights regarding the efficacy of current removal programs.
Check out a short video describing our tegu work: