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More than a dozen volunteers planting shrubs on a sandy beach
Information icon On Volunteer Day at Crocodile Lake National Wildlife Refuge, volunteers planted native torchwood and wild lime on a site that had recently been full of debris that could have hidden invasive pythons. Photo by Jeremy Dixon, USFWS.

Coastal Program project helps Florida Keys refuge withstand possible python invasion

Invasive species surveillance and control is front and center for Crocodile Lake National Wildlife Refuge in the Florida Keys. Just a short 18 mile drive north is the Florida Everglades, where invasive pythons are wreaking havoc on the ecosystem, a situation that would have devastating effects on endangered Keys fauna if the species were to take hold. Indeed, several pythons (one measuring 16 feet long) have already been discovered in the refuge and removed.

To make matters more serious, the refuge is home to two federally endangered species that would be prime prey for pythons: the Key Largo cotton mouse and the Key Largo woodrat. They are already vulnerable to habitat loss, sea level rise, and other non-native predators, and the establishment of a large python population could be the final tipping point for these imperiled species.

A gray and brown mouse perched on a vine
Key Largo woodrat. Photo by Clayton DeGayner, USFWS volunteer.

During the 60s and 70s, Crocodile Lake was home to the Nike Missile Base. When the base left, many small buildings and debris piles were left. They still provide perfect places for pythons to hide, allowing the large snakes to go undetected. In fact, python detection dogs have identified pythons in debris piles but were never located for removal.

To help reduce the risk posed by the pythons, the U.S. Fish and Wildlife Service’s Coastal Program funded a project to remove several debris piles from the refuge.

By employing the Service’s Maintenance Action Team, we were able to successfully leverage the resources of the Service to conduct the work. The team broke down and hauled out much of the debris and solved unexpected problems as they arose.

As part of the project, the areas where the debris was removed received further habitat restoration. Refuge biologist Jeremy Dixon enlisted volunteers to plant native trees and shrubs on the now cleared lands. Not only were the plants native, but they were specifically chosen because they were host and nectar plants for the endangered Schaus swallowtail butterfly. To offset any potential negative impact of the debris removal activities on the Key Largo woodrat, 21 supplementary woodrat nests were constructed in adjacent habitat. In all, 168 hours of volunteer time contributed to the success of this project.

The removal of the debris piles and remnant buildings have made snake detection easier. Dixon and his python detecting dog are now able to more easily seek out the menacing snakes. While not a large project, it will have played a role in further protecting and securing the populations of a few of the endangered species found in the Florida Keys. Establishing and maintaining strong surveillance to non-native and invasive species in Key Largo provides a barrier and an extra line of protection for imperiled species further down the Keys.


Kevin Kalasz, South Florida Coastal Program coordinator, (305) 780-7514

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information on our work and the people who can make it happen, visit Connect with the Service on Facebook, follow our tweets, watch the YouTube Channel and download photos from Flickr.

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