Sunday, December 8, 2019

Florida’s Invasive Animal Species

Stepping Stones

Lush, tropical landscapes, grass prairies and warm, sandy beaches are the dream of dreams for many Florida visitors. They can’t wait to soak up the sun, enjoy the natural fruits and vegetables and bathe in the fresh water wetlands. Who needs a hotel when you have such a magnificent setting?

Wait! You thought I was talking about humans? No, no, my friends. There are other visitors here besides people and they are invasive to the area. In fact, more than 500 non-native plants and animals now call Florida home and they are taking a serious toll on the fine and fragile ecosystems that comprise our state. Let’s meet just a few.

Just about every human coming here has a question about one major invader and that is “Have you ever encountered a Burmese python?” Only a few weeks ago a 160-pounder was captured in Southwest Florida. These reptiles have been dominating the south-central portion of the state, eating anything it can take down. Although they are nonvenomous, they have the ability to constrict and strangle prey before swallowing them whole. For nearly three decades pythons have dwindled the bird and land mammal population, eliminating as much as 95% in some areas. They are a force to be reckoned with and will never be completely eradicated from our lands.



Cane toads get their name from the sugar cane fields. They were brought here, on purpose, in the 1930s, from Central and South America to help control (eat) the beetles that damaged the sugarcane crops. Also known as Bufo toads, they didn’t know that they were supposed to stay in the sugar crop area and have expanded their range considerably. The food supply of these invaders includes native frogs, fish and insects. Closer to home, they have acquired a taste for pet food and can be dangerous to dogs and cats because of a toxin they secrete which can be fatal to a pet.

Another invasive species to our state receiving a lot of attention lately are green iguanas. They were first reported in Florida in the 1960s on the coastline of Miami and Key Biscayne areas. They now range up to Palm Beach County on the oceanside and in Lee and Collier counties here on the west coast. Both residential and commercial landscape vegetation are being damaged by these invaders. Iguanas have been seen digging burrows below sidewalks, seawalls and other infrastructure that could cause a collapse of those manmade pieces.

When Spanish explorers arrived in Florida in the 1500s, they brought with them plants and animals to help sustain their journey and also provide food when land had been settled. One animal species not only survived to breed in America, it now resides in all 67 counties of Florida. Call it a swine, wild pig, feral hog or wild boar they multiply very quickly. Feral pigs root with their noses so much that an area could look like it was plowed when they are done. These non-natives can reach weights of 150 pounds and lengths up to six feet.

Our area waters are not exempt from invaders either. Native to the Red Sea and Indo-Pacific, the lionfish can be found year-round in Florida waterways, ranging from all estuary settings to depths up to 1,000 feet. They were first reported on the Atlantic coast in 1985 and have flourished along our coastline, feeding on native fish, reducing that population and eliminating species that help our reef systems survive.

Let’s talk about one more species before you go happily about your daily routine. Arriving from South America, specifically Argentina, beware of the black and white lizard known as the Tegu. In their native country they have occupied areas from sea level up to 4,000 feet in elevation. They rarely climb more than a few feet off the ground and are excellent swimmers. Tegus prey upon nests of native animals and have been seen devouring gator and croc eggs from their nests. The adults have few predators and females can give birth to large numbers of offspring each year. Breeding takes place in March.

There you have it! We’ve brought to light six of the more than 500 non-native and invasive species in our state. I feel that, by the time we discuss the other 494 invaders, we will have to go back and ask for a recount for, surely, there will be more!

Bob is a Naturalist on board the dolphin survey vessel Dolphin Explorer. He is the author of two books, “Beyond The Mangrove Trees” and “Beneath The Emerald Waves,” both available locally. He is an award-winning columnist for this newspaper and a popular speaker at events throughout South Florida. Bob loves his wife very much!

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