Environmental DNA surveys of Burmese pythons in the Greater Everglades Ecosystem

Improving the probability of detecting invasive giant snakes is vital for the management of emerging or established populations. Burmese pythons occupy thousands of square kilometers of mostly inaccessible habitats in Florida. Environmental DNA (eDNA) methods have been shown to be time and cost effective in a number of systems and may be preferable to traditional detection methods for constrictor snakes, having been shown to be effective at detecting Burmese pythons where traditional and novel detection methods have failed. The purposes of this study were (1) to estimate Burmese python eDNA occurrence in the Greater Everglades Ecosystem based on land-use type; and (2) to conduct preliminary surveys within the Greater Everglades Ecosystem for positive eDNA detections. Twenty-eight sites were sampled in the Greater Everglades Ecosystem, with 5 field replicate samples per site, for a total of 140 water samples collected. Python eDNA was detected in samples from 25 of the 28 sites by using droplet digital polymerase chain reaction amplification. Abiotic parameters were collected and explored, but we found no conclusive relationship among them and python eDNA detections. eDNA monitoring of aquatic habitats can assist in identifying newly colonized areas where pythons have not been previously detected, as well as movement corridors and pathways of dispersal. This information could be used to delimit a population boundary as it expands further to the north in peninsular Florida.