Globally, invasive predators pose a major threat to native biodiversity. This threat most obviously applies to potential prey species, which can be affected both directly and indirectly, but another suite of impacts can occur through competition with native predators. Understanding the new predator’s realized niche in the invaded system is therefore important for predicting and managing the potential effects of these invasives, including protecting native species threatened by both predation and competition. The Burmese python is an invasive predator in the Greater Everglades Ecosystem (GEE) that has caused major damage to the native food webs and drastically changed the mammal community in the core of the invaded range. Eradication of pythons is not feasible in the short-term, so management efforts will likely focus on protecting imperiled native species. Predicting which species are most vulnerable to pythons is crucial for this effort. Although the concept of the niche is widespread in ecology, quantifying niche space has always posed a significant challenge. Recently, the isotopic niche – a space measured through stable isotope analysis of carbon and nitrogen – has emerged as an effective method to quantify both the habitat and dietary components of an organism’s niche.
Results/Conclusions
We analyzed the isotopic composition of muscle tissue from 403 individual Burmese pythons captured throughout the southern half of the GEE. We calculated standard ellipse areas (SEAs) for pythons from six regions of the GEE, and following a thorough literature review, compared python SEAs in each of these regions to published values from diverse animal taxa. Across the entire ecosystem, python SEAs were large (8.99 ‰2) compared to values from other taxa in the literature (mean = 4.06 ‰2), suggesting a generalist diet. However, python SEAs varied widely throughout the landscape, with pythons from the central Everglades having the smallest SEA (3.58 ‰2) and pythons from the west coast of southern Florida having the largest SEA (17.0 ‰2). These values likely reflect the diversity of available prey and habitats in the respective areas, and this high niche plasticity is likely a major contributing factor in their invasion success. Further research into the niche size of native predators would give a strong indication of which species are most vulnerable to the impacts of the python invasion.