Invasive Species in Florida
with Frank Ridgley DVM, Zoo/Wildlife Veterinarian for Zoo Miami's Conservation & Research Department
Florida has more invasive reptile and amphibian species than anywhere else in the world. In the U.S., it is estimated that more than $120 billion dollars in economic damages a year is incurred from invasive species. Although it is difficult to estimate the economic costs of many of the invasive species in Florida it is known that they have a very large environmental cost and cause tremendous ecosystem damage. This has been demonstrated through many different studies that show severe declines in native species where many of these invasives become established. Zoo Miami staff has been on the front lines of helping develop effective management strategies to combat invasive species, actively involved in field removal efforts, and support our partners in their own initiatives.
Zoo Miami staff has been active in the management of Burmese pythons in Florida since 2007. Our current role is supporting the United States Geological Survey (USGS) and the National Park Service (NPS) research efforts to learn about this invasive snakes impacts in our National Park System and to develop better detection and removal management strategies in conjunction with the Florida Fish and Wildlife Conservation Commission (FWC) programs.
Zoo Miami's veterinary team has utilized the zoo hospital facilities and staff expertise to provide surgical services to researchers in these different agencies over the last decade. Due to snakes' unique anatomy, biologists cannot attach monitoring equipment via collars or harnesses like they typically do for other wildlife ecological studies. Zoo Miami veterinary staff ensure good animal welfare and better outcomes in the behavioral studies for the biologists by safely surgically implanting tracking devices, data recording microdevices and sometimes prolonged release drug implants in the zoo hospital's surgical suite. This collaboration allows for the best research result outcome for our partners and for us to help fulfill our mission to protect natural resources.
Media coverage of this project can be found here:
WLRN - September 2, 2022
Washington Examiner - August 22, 2022
WLRN - November 12, 2019
WLRN Sundial - July 22, 2019
AP - June 15, 2019
USA Today - April 9, 2019
Star Tribune - January 6, 2013
Although Burmese pythons tend to get a lot of the attention and news press, there is another large constrictor reproducing and having environmental impacts where it has established on the eastern coastal areas of Miami-Dade County. Boa constrictors are native to Central and South America but there has been a population in Miami since likely the 1970's. Unlike Burmese pythons that lay eggs (oviparous) the boa constrictor appears to give live birth (ovoviviparous) but both species are very large constrictor snakes that kill their prey by squeezing them to death before consuming them whole. Boa constrictor females reach a larger body size than males and can get between 30-60 lbs and reach lengths of 12-14 ft in length. They are opportunists and will eat a wide variety of prey. Most of these boas can be found inhabiting some of the delicate protected ecosystems of South Florida such as Hardwood Hammocks, Pine Rocklands and Mangrove Swamps.
Since 2012, Zoo Miami staff have been conducting research on this established population to learn about what impacts they may be having on the ecosystems, develop better detection and removal strategies, and make sound management recommendations for land managers. Veterinarians from Zoo Miami implanted transmitters in boas to enable staff to track them and find out how they were using the habitats. Unlike a study in Puerto Rico of the invasive boa constrictor snakes where they were being tracked primarily in the trees, the population here in Miami were surprisingly spending the majority of their time in solution holes and burrows in the ground. The studies have also shown that the boas maintain distinct home ranges, helped profile what is their prey, and has traced their genetic heritage to a combination of many South American subspecies and likely several introductions to form the current population.
ECISMA Conference 2014
The sacred ibis is a bird species native to portions of Africa and has caused problems as an invasive species where it has been introduced around Europe. After Hurricane Andrew in 1992, a few sacred ibis began being seen in Palm Beach, Broward and Miami-Dade Counties that had escaped from private collections. Some reports have erroneously attributed their appearance in South Florida to escaping from Zoo Miami, formerly the Miami Metrozoo, because we had sacred ibis in our collection when our large aviary was destroyed in Hurricane Andrew. But, the aviary contained Asian species, our sacred ibis were banded and kept in a different area and all of our birds were accounted for following the storm. In 2005, sacred ibis were first discovered breeding in the Everglades at the Arthur R. Marshall Loxahatchee National Wildlife Refuge in Palm Beach County.
In 2007, Zoo Miami staff began to notice sacred ibis flying onto Zoo Miami grounds every morning and competing with native white ibis and the collection animals for food. Realizing that this was a potentially injurious non-native species, Zoo Miami began to make plans to try and capture and remove as many of these non-native birds as possible utilizing different methodologies and staff animal behavior expertise. Before launching their program Zoo Miami staff learned that simultaneously the Everglades Cooperative Invasive Species Management Area (ECISMA) Steering Committee had decided to contract with USDA APHIS Wildlife Services to attempt to eliminate sacred ibis from South Florida. The two agencies joined forces to help each other in this effort. Zoo Miami staff were able to able to capture the first two ibis and the Wildlife Services were able to then attach wing tags and satellite transmitter backpacks to discover their nightly roosting locations.
It turned out that the sacred ibis visiting the zoo were roosting and reproducing on an island of an abandoned golf course about seven miles north of Zoo Miami. This led to the discovery of a larger population in the Kendall area of Miami.
After an intensive year of capture attempts, 75 sacred ibis were removed from the joint effort. Zoo Miami staff were able to live capture and remove 33 sacred ibis while the USDA APHIS Wildlife Services concentrated on removing them from other sightings in the tri-county area. The birds captured by Zoo Miami staff were then pinioned by staff veterinarians to ensure they could not escape into the environment again and placed at other AZA-accredited institutions under an agreement that no possible offspring would be allowed to remain flighted due to their risk to natural ecosystems.
Since the joint effort in 2008, USDA APHIS Wildlife Services responded and removed two more single sacred ibis reported in 2011, one at a landfill in Palm Beach County and another in Palmetto Bay, FL. There have also been credible sightings of single individuals that have been seen in 2015 and 2017 but no more pairs or breeding populations have been documented since this joint effort.
The likely eradication of sacred ibis from South Florida is one of the few success stories in the battle with invasive species in Florida that costs hundreds of millions of dollars a year in losses and removal efforts.
USDA APHIS WIldlife Services Case Study