Ecology of and Control Strategies for Invasive Burmese Pythons (Python molurus bivitattus) in the Greater Everglades

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Telemetry tracking of captured pythons reveals movement patterns of the invasive Burmese python in the Greater Everglades, information that managers can use to prioritize python control efforts.

Ecology of and Control Strategies for Invasive Burmese Pythons (Python molurus bivitattus) in the Greater Everglades
Burmese Pythons (Python molurus bivitattus)

The Science Issue and Relevance: The Burmese python, Python molurus bivittatus, is an invasive exotic species established across thousands of square kilometers of southern Florida, including virtually all of Everglades National Park (ENP). Detection probabilities of these giant constrictors are low, and much of the Everglades are virtually inaccessible. Pythons are believed to be severely affecting this ecosystem, but this impact is difficult to quantify. Apparently high python densities, rapid growth and excellent body condition of pythons, and their large body size all suggest that pythons are consuming large numbers of native prey animals, including federally endangered species (e.g., Key Largo woodrats, wood storks) and species of concern in the state of Florida (e.g., limpkin, round-tailed muskrats). A better understanding of the ecological impacts of pythons is required to protect natural resources and prioritize python control efforts.

Methodology for Addressing the Issue:  In an effort to quantify home ranges, determine movement patterns across the Everglades over time, and evaluate the efficacy of using “Judas” snakes to find additional pythons, we have conducted multi-year radio telemetry tracking of captured pythons determine their location and habitat. Suitably large females were also implanted with accelerometer and GPS tags. Pairing GPS with the 3-D movement data from accelerometers is providing a finer-scale habitat-use model than data based on VHF telemetry alone. The GPS tags are still being refined, and we have currently developed a model suitable for application in average-sized males and females. We are also collecting python data on diet, isotopes, and genetic variation, as well as mercury loads in python tissue. Gut and various tissue samples are obtained after each snake is euthanized and necropsied; these samples are identified/analyzed and input into a growing database to be used for future research and comparisons. We are currently developing eDNA (i.e., the detection of small quantities of shed DNA in the environment) as a tool for detecting pythons and other giant constrictors. We recently completed construction of an IAUCUC-approved python facility, suitable for both holding and captive trials.

Ecology of and Control Strategies for Invasive Burmese Pythons (Python molurus bivitattus) in the Greater Everglades
Burmese Pythons (Python molurus bivitattus) in the Greater Everglades

Future Steps: Future efforts will include the continued use of telemetry to track pythons within ENP, and we are working with collaborators to expand our tracking beyond ENP. GPS technology will continue to play an increasing role, allowing us to refine our understanding of python spatial distributions far beyond our current technology. The latest tags can give us 15x more locations per week than VHF technology. Gut, isotopic, and genetic samples will continue to be inventoried and analyzed with respect to environmental parameters. We will continue developing the cutting-edge eDNA tool for practical field use to inform land managers. Finally, we will begin developing captive trials and experiments housed in our python facility. All of these efforts will provide a better understanding of the biology and ecological impact of invasive pythons within Everglades National Park and provide insight into ways to exploit their biology to control their population.  

Additional Related Project(s) and Product(s):

Hunter ME, Oyler-McCance SJ, Reed RN, Fike J, Smith BJ, Hunter III CT, Hart KM (in Review). Environmental DNA (eDNA) detection of invasive giant constrictor snakes in Florida, USA. Biological Conservation.

Fujisaki I, Hart KM, Mazzotti FJ, Rice, KG, Snow R, Rochford MR (2009) Risk assessment of potential invasiveness of exotic reptiles to south Florida based on import pathway. Biological Invasions doi:10.1007/s10530-009-9667-1.

Ecology of and Control Strategies for Invasive Burmese Pythons (Python molurus bivitattus) in the Greater Everglades
Ecology of and Control Strategies for Invasive Burmese Pythons (Python molurus bivitattus) in the Greater Everglades