Aquatic Life: Amphibians

Amphibians are a class of vertebrates who spend at least part of their lives both in water and on land. The name amphibian comes from the Greek words amphi, meaning “both,” and bios, meaning “life.” In essence amphibians live a “double life” as they progress through their life cycle. For example:   a frog lays its eggs in a pool of water, which is the only place the eggs can remain viable. Outside of water they would dry up. As an egg develops and hatches it becomes a tadpole, which spends all of its time in water. The tadpole begins to change. Its gills become lungs; it grows legs, and loses its tail. It then emerges from the water and can carry on for the rest of its life on land. This does not mean that an amphibian is totally independent of water. An amphibian’s skin requires moisture and is one of the ways through which it breathes, therefore a certain degree of dampness is required for an amphibian to survive on land. Amphibians are totally dependent on water as part of their life cycle and water quality is an important issue to them.

We all are familiar with frogs and toads, as these are probably the most talked about amphibians. Most people are somewhat familiar with salamanders too (they’re the ones that look kind of like lizards), but most do not understand the importance of salamanders. Salamanders typically breathe in three ways: gills, lungs, or through their skin (with possible combinations). Probably the most unique are the lungless salamanders that are either totally skin breathers or have gills. These animals require high quality environmental conditions (clean air and clean water) to survive. Without it, these animals would surely die. There are 360 salamander species in the world, 90% of which are lungless. The southeastern U.S. has more of these salamanders than anywhere else in the world. While most of these are terrestrial through most of their adult life, many of them spend a great majority or all of their time in the water.

A great example of a salamander requiring high quality streams is the Hellbender. Hellbenders are large salamanders that breathe totally through their skin. They can grow up to 29 inches long. They are only found in high quality rivers and streams of the mountains. They are highly sensitive to all forms of pollution. Hellbenders probably occurred in our watershed at one time, but decades of sedimentation have probably wiped them out. None have been reported from this watershed in recent times. Other species that we often see in our streams are dusky salamanders and blackbelly salamanders, both of which are lungless and require highly oxygenated water.

Salamanders are important indicators of our environment. In an area with poor air and water quality, you won’t find many salamanders. Much research has been done to link salamander decline to air and water pollution, and the evidence is astounding. Even in streams where water quality is good, but there is a high rate of sedimentation; the numbers of salamanders are declining. Once again we can see a piece of the ecological puzzle being taken away because of our failure to reduce off-site sedimentation. While we don’t think about the impacts in terms of how salamanders affect humans directly, we should look at the bigger picture and what the affects may be on down the line. To learn more, visit www.herpsofnc.org/herps_of_NC/salamanders/salamanders.html.