SOME INVASIVE SPECIES ARE HERE TO STAY
In southern Alabama or southern Georgia, seeing an American alligator gobble up a beaver amid white water lilies would be a memorable sight, and an entirely natural one. To see a Nile crocodile chomp down on a nutria (another large aquatic rodent) swimming through water hyacinths in Florida would also be a memorable sight. Either scenario is possible, but the second would be an unnatural event. Why? Because neither the plant nor the animals in the second scene are native to the United States.
An invasive species is defined as one brought to a region, usually from another continent, that successfully establishes itself in its new environment. The most nefarious invasive species are those we cannot control as they eat, compete with and even eliminate native species; destroy habitats; or otherwise become a nuisance. Invasive animals typically have no natural predators to control their spread in their new home. Invasive plants have no native herbivores to keep them in check. Pleas are made constantly to federal and state authorities asking them to set controls on one invasive threat or another. Unfortunately, by the time a species is recognized as a problem, it has often become too entrenched to eliminate. Take for example, kudzu, Burmese pythons and fire ants. Are they native to these shores? No. Are they fully established as U.S. flora and fauna? Yes.
Water hyacinth is a floating aquatic plant native to South America that was introduced into the United States at the 1884 world’s fair in New Orleans. A visitor to the fair brought some of the exotic plants back to a fishpond near the St. Johns River in Palatka, Florida. The rapidly reproducing water hyacinths have been clogging semitropical waterways in the Sunshine State for more than 130 years. The State of Florida considers them an invasive species. Programs to control them have been under way for many years. The U.S. government classifies water hyacinth throughout the country as a “noxious weed.” As with so many other nonnative life-forms people have introduced onto the North American continent, these plants have found a home.
Nutria, meanwhile, were intentionally introduced into Louisiana from South America in 1889 to enhance the fur trade. Nutria (also called river rats or Cajun groundhogs) are enormous rodents, bigger than native muskrats but smaller than beavers. Nutria are recognized as an invasive species capable of destroying native vegetation and agricultural crops. Over the years, they spread from Louisiana into other coastal states, including parts of Florida. Despite bounties and other eradication programs, nutria are abundant in some areas and considered by some people to be a nuisance.
Nile crocodiles (which, based on reliable documentation, have no qualms about eating humans in Africa) arrived on the scene in southern Florida more recently than water hyacinths and nutria. A few individuals were documented by researchers during the 2000s, then removed from the wild. Presumably these had escaped from captivity. Environmental conditions around the Everglades are not unlike places they live in Africa. I am not aware of any confirmed sightings since 2016, but no one can say for sure that a few Nile crocodiles are not cruising around Florida’s waterways. We may eventually hear about them eating animals other than nutria. One fact is true of all invasive species: Few generalizations can be made about what will determine their success or failure.
In addition to American alligators, North America has a native crocodile, the American crocodile. These typically inoffensive creatures are restricted to mostly brackish habitats in the Miami area. Many intriguing animals, native and invasive, can be found in southern Florida. The beaver is not one of them. If a Nile crocodile eats a beaver, it will be noteworthy. It means this nonnative predator has made its way to Georgia or Alabama. Let’s hope that if any Nile crocodiles remain in the wild, they’re satisfied eating nutria swimming through water hyacinths in southern Florida and do not decide to migrate northward.
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