Bayou-Diversity (11 February 2018) Biologists often just call them herps, an abbreviated version of the term herpetofauna, meaning the reptiles and amphibians of a specific region. The herpetofauna of Louisiana is diverse because of our mild climate that is conducive to the well-being of cold-blooded animals, and because of our great variety of habitat types, from upland forests to brackish marshes.
Reptiles include turtles, snakes, lizards, and the alligator. Amphibians comprise frogs, toads and salamanders. The two groups differ in significant ways. The skin of reptiles is covered in scales, and if they have feet they are tipped with claws. All Louisiana reptiles lay eggs with shells or give live birth on land. Amphibians don’t have scales or claws. Their skin is porous for breathing, and they need to be constantly moist. Except for woodland salamanders, all amphibians deposit eggs in water. Some go through metamorphosis like frogs and toads.
Eighty-seven native species of reptiles are found in Louisiana including 27 kinds of turtles, 47 snakes, 12 lizards, and the American alligator. Native amphibians include 30 frogs and toads, and 23 types of salamanders. Several species not native to the state have become established here. Herps are found throughout Louisiana, but those parishes east of the Mississippi River have the greatest diversity. Thirty-one species found in this region occur nowhere else in the state.
Within the groups of herps, diversity is amazing. Turtles vary from the five inch long mud turtle to the leatherback sea turtle that weighs more than 2,000 pounds. Flat-headed snakes are less than 10 inches long, and coachwhips reach eight and a half feet in length. A cricket frog is barely more than an inch long, and a large bullfrog will cover our dinner plate on a Louisiana Saturday night.
Like coal mine canaries, the well-being of Louisiana herps can reflect the overall health of our ecosystems including those components necessary to our own welfare. Many species are very susceptible to the menaces of environmental contaminants such as heavy metals and pesticides. Amphibians have moist, porous skin that easily absorbs toxins. Alligators are apex predators at the top of the food web. As such, they are especially at risk to contaminants that increasingly accumulate in those organisms below their level in the web. As shown in numerous scientific studies, it is no stretch of the imagination to state that the health of Louisiana herps as it pertains to environmental pollution reflects the same of humans. Likewise, diminishing numbers of herps that are adapted to a particular ecosystem, such as upland hardwood/pine forest, often indicate broad landscape alterations. In this example, it could be the widespread conversion of diverse upland forests to pine plantations.
Herps are more than interesting ornaments in the catalog of Louisiana fauna for those who pay attention. To learn more about them, check out the new book from LSU Press by Jeff Boundy and John Carr titled Amphibians & Reptiles of Louisiana. ©KO