Audubon Florida News

Topic: Invasive Species

Audubon’s Invader Updater – October 2012

posted on October 1, 2012 in Invasive Species

Welcome to Audubon’s Invader Updater, our new monthly update on invasive animal news, sightings, and information.  For several years our Invasive Species Task Force has focused on addressing the growing problem invasive animals pose to our natural ecosystems through a combination of policy, land management, research and education/outreach, and by partnering with regional invasive species management cooperatives.  New invasive animals are literally showing up every day here in Florida, and it is up to us to help detect and report them before populations establish or grow out of control.

Many of the invasive animals spreading throughout our state pose significant threats to native wildlife and habitats.  As a network of citizens across the state with keen eyes and an appreciation of our most precious ecosystems, Audubon members and friends are perfectly-suited to assist our efforts as our “eyes and ears” on the ground. Visit our new webpage to learn how easy it is to report non-native animals that you see while out birding, visiting your favorite park or even along highways or in your own community.  Reporting only takes minutes online or using a simple smartphone app and can make a big difference to land managers who are trying to get a handle on these growing populations.

Upcoming Event: Have a friend, colleague or neighbor with an unwanted exotic pet?  FFWCC is holding an Exotic Pet Amnesty Day in Broward County on October 20.  This is a no-questions-asked opportunity to surrender unwanted exotic pets (iguanas, ferrets, snakes, you name it!) who will be adopted out to new, caring homes.  The release of unwanted pets is the primary way exotic animals spread through our state—help spread the “Don’t Let It Loose” message!!


Species Spotlight: Black and White Tegu 

Popular pets of reptile enthusiasts, Tegus have become established in parts of Hillsborough and Miami-Dade counties in recent years and are a growing problem. Reaching 4-5 feet long, they are likely to eat the eggs of young ground-nesting birds and turtles and could impact threatened and endangered species, including gopher tortoises, as they invade burrows.  They live 15-20 years and females lay ~5 eggs/clutch, up to twice per year.  Tegu sightings should be reported immediately to (provide photos if possible) or through 1-888-IveGot1 (live animals only).

Notable Invasive Animal Reports This Month (by County):

Have specific questions about invasive animals, how to report a sighting or how you can help in your area?  Feel free to contact Audubon’s Dr. Shawn Liston (

Corkscrew Swamp Sanctuary: Invasive apple snails are on the move in Southwest Florida

posted on March 9, 2011 in Invasive Species

Piles of apple snail shells on Lake Okeechobee are testimony to Kite and Limpkin foraging. (photo by Paul Gray)While invasive apple snails have not yet been observed in Corkscrew Swamp Sanctuary, scientists and land managers know that unfortunately, it’s only a matter of time.

Our native ‘Florida apple snails’ are a common sight in wetlands, along canal banks and in ponds and other permanent water bodies. They are a preferred food source for many animals, including Everglade snail kites (an endangered raptor native to Florida and Cuba), limpkins, turtles and otters. While these snails are well camouflaged to avoid predation, empty shells can often be found in piles along the edges of wetlands. Often more obvious than the adult apple snails, white clusters of Florida apple snail eggs can commonly be seen above the surface of the water on cypress trees, plants and canal banks.

In the last decade or so, three species of invasive apple snails (native to South America) have become established in South Florida and scientists fear they may pose a threat to our native ecosystem. While the shells of adult snails are very difficult to tell apart, apple snails can easily be identified by differences in the egg masses that they lay.

Island apple snails are the most widespread invader in the Southeast U.S., currently established in coastal states from South Carolina to Florida to Texas. At full size, adults are noticeably larger than our native apple snail, but younger individuals cannot be easily distinguished. Island apple snail egg masses are bright pink and the individual eggs are smaller than those of our native (native apple snail eggs are also pink when they are first laid, and they turn white as their outer shell dries).

Spike-topped apple snails are established throughout South Florida and have been collected in several places farther north on the Florida peninsula. Egg masses are salmon-colored.

Titan apple snails are currently established only in Palm Beach County and their egg masses are a seafoam/pastel green color.

While these non-native apple snails rapidly spread throughout our region, scientists are working hard to better understand their potential impacts. Early observations suggest they are displacing native apple snails, perhaps by consuming young native snails.

The effects of these invasions on apple snail predators are unknown. While we currently have no known control methods for adult snails, egg masses can easily be destroyed by crushing or drowning them. Caution should be taken, however, to ensure eggs are from non-native snails before destroying them. Information on identifying apple snails and reporting non-natives you encounter can be found online using FWC’s Nonnative Apple Snail Reporting page.

Article by Dr. Shawn Liston.

Corkscrew Swamp: Winter cold fronts put small dent in South Florida’s non-native fish population

posted on January 26, 2011 in Corkscrew Swamp,Invasive Species

Even our pristine Corkscrew Swamp Sanctuary isn’t immune to the influx of non-native fishes that have moved into South Florida in recent decades. Currently, Southwest Florida is home to at least 17 species of non-native freshwater fishes. Most of these species have entered Florida as aquarium pets, while others were brought here to farm as exotic delicacies.

Often released (either accidentally or intentionally) into neighborhood canals or ponds, the localized flooding we experience during heavy summer rains coupled with South Florida’s extensive canal system allow these opportunistic fish to move long distances relatively easily. Our interconnected waterways have allowed (and continue to allow) non-native fish to reach Southwest Florida from the large port cities north and east of us. Unfortunately, Tampa and Miami/Ft. Lauderdale are currently home to at least 23 additional non-native freshwater species that, in time, can potentially move into our area.

The non-native fish species that do especially well here are from tropical areas of Asia, Africa and Central and South America. These species (many of which are from the family of ‘cichlids’) are so well-adapted to our harsh aquatic environment that studies have shown some of them are better able to survive our dry-season, low oxygen conditions than our native fishes. Many of the non-natives are also larger and notably more aggressive than our native fishes. Studies conducted by Audubon biologists and others have shown marked decreases in native fish populations as non-native fish spread.

The proverbial chink in their armor, however, appears to be our winter cold spells. In addition to the manatees and snook that made news headlines, the record-breaking cold temperatures we experienced last January were responsible for killing a disproportionate number of non-native freshwater fish. In fact, Audubon’s monitoring efforts in Big Cypress National Preserve have noted a marked absence of non-native fishes at several study sites since the January 2010 cold snap. Unfortunately, scientists anticipate the non-native fish population will quickly recover – perhaps even evolving more cold tolerance through time.

Because there are currently no effective methods of controlling the spread of non-native fishes once they become established, our native ecosystem is relying on us to stop the introduction and spread of these, and all non-native animals. As we learn from the consequences of Burmese pythons in the Everglades and Nile monitor lizards in Cape Coral, the importance of responsible pet ownership has never been more apparent here in Southwest Florida.

Article by Dr. Shawn Liston.

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