2.2.3: Reptiles and Amphibians

Figure \(\PageIndex{1}\): Captive axolotl. Bernard Dupont, France, CC BY-SA 2.0, via Wikimedia Commons

Amphibians and reptiles are both groups that are managed by wildlife biologists. Amphibians include animals that must (for the most part) live in damp areas because of their unprotected skin, and rely on bodies of water to reproduce, because their eggs lack any shell.  Reptiles can live in a variety of terrestrial areas, because they have scales that protect them from water loss, and leathery shells on their eggs. Both groups are managed wildlife species for a variety of reasons. 

Amphibians

Amphibians include organisms such as frogs, toads, newts, and salamanders, which all live in bodies of fresh water. . Their thin skins allow them to absorb oxygen from the air around them (supplemented by their gills (young) or lungs (adult). This feature results in many species being considered as indicator species. Because they absorb through their skin, it makes them very susceptible to pollutants or infectious agents in the water bodies in which they live. If water quality is degraded, amphibians are often the first animals to disappear. Coupled with that, changes in temperature and precipitation caused by climate change also put a strain on amphibian populations. For example, the golden toad (Bufo periglenes disappeared between 1987 and 1989 from the Monteverde Cloud Forest of Costa Rica due to unusually dry conditions. Many other species of frogs are succumbing to a chytrid fungus called Batrachochytrium dendrobatidis, or BD. This fungus affects the thin skin of frogs and toads, which act as both a respiratory and excretory system. It spreads easily from frog to frog, and can decimate a population in a couple of years. BD is an invasive disease, and is thought to be spread by humans traveling between isolated populations. 

Another amphibian that faces extinction because of the pet trade is the axolotl, Ambystoma mexicanum. They are pale salamanders that never develop fully to adulthood. They have been taken from their native environments for decades because they are a popular pet species. That, coupled with the destruction of their native habitat as Mexico City expands, have resulted in them being classified as critically endangered, with only an estimated 50-1000 left in the wild. Management of an endangered species requires conservation efforts by governments and citizens to protect the habitat that is left, and not allow them to be sold as pets. 

 

Reptiles

Reptile species include turtles, crocodilians, snakes, and lizards. They face some of the same threats as amphibian species, including habitat destruction and the pet trade. Many species of turtles are collected from their ponds and shipped out of the U.S. for the pet trade, which is illegal for countries that have signed on to the CITES international treaty for the protection of wildlife. However, enforcement is lacking, and each year, hundreds of thousands of animals are sold. Turtles are long lived and slow to reproduce, and thus, cannot sustain a pet trade at that level. Turtles and tortoises are also closely adapted to their habitat, whether it be a bog, stream, pond, or the desert. Habitats around the world are being affected by climate change, with some areas becoming drier and hotter. Turtles that are adapted to a narrow range of conditions cannot adapt as climate change progresses, as quickly as it is happening, and they can't emigrate. They are stuck in a habitat that no longer serves their needs, and their numbers decrease. 

Some reptile species are considered nuisances, and must be managed by public education, or by relocation or removal. Rattlesnakes are an important part of the ecosystem as a mid-level predator, however, when found in someone's yard, they are often killed. Relocating a rattlesnake should only be carried out by a professional, and there is often not a professional on hand. Alligators are a protected species in Florida due to a decline in their populations due to habitat loss and overharvesting for meat and hides. However, alligators also frequent suburban ponds, and are responsible for the deaths of pets and the injury (and sometimes death) of people. An alligator in such a pond may need to be relocated, however, as that is prime alligator habitat, more will come. Signage alerting people to the presence of this apex predator is a necessary form of public edcuation. 

Sea turtles are reptile species that evolved from land turtles, but now are limited to ocean and bay habitats. They were managed as a fishery when people hunted them for their meat and shells, but now, their numbers are so depleted that they are listed as endangered and threatened species. Sea turtles haul out onto the beach, where they are on land, for two purposes only: to nest, and to escape their predators (mainly the tiger shark). In the U.S., while on land, they are managed by a completely different agency (the U.S. Fish and Wildlife Service) than they are when at sea (the National Marine Fisheries Service). Researching and managing these species requires intergovernmental cooperation, as its the same turtle individuals being managed.