Dickinson Ch28: Reptiles and Amphibians

Reptiles and Amphibians (Herpetofauna) in the Southern United States

The Southern United States (SUS) contains forest habitats with great diversity, including uplands, bottomland hardwoods, pine flatwoods, and swamps.
Reptiles and amphibians (herpetofauna) are permanent residents and rival all other vertebrate groups in biodiversity in the region.
Historically, wildlife management emphasized game species, resulting in herpetofauna receiving minimal attention.
The perspective has shifted, and herpetofauna are now recognized as meaningful components of forest wildlife management.

The SUS region has the richest herpetofaunal biodiversity in the U.S.. Of the over 460 species in the U.S. and Canada, roughly 272 occur in this area.
Most amphibians (salamanders, frogs, toads) exhibit their highest species diversity in the southern region.
Herpetofauna are vital for environmental welfare and are important links in the food web. Snakes help control rodent populations. Aquatic turtles act as scavengers, reducing decaying organic material.

Herpetofauna species are classified into four groups based on their reliance on forest habitats:

Group 1: Permanent residents of forested terrestrial habitats, such as the great diversity of salamanders in the genus Plethodon.
Group 2: Semi-aquatic species that use forests primarily as corridors or pathways to non-forest wetlands (e.g., Ambystoma salamanders, narrow-mouthed toads).
Group 3: Species spending most of their life in water but requiring forests for nesting or winter dormancy (e.g., chicken turtles, mud turtles).
Group 4: Species whose primary habitat is peripheral to the forest but influenced by it (e.g., Tennessee cave salamander, which needs shaded, cool microhabitats).

Southern Appalachians: Known for extraordinary high diversity of salamanders, primarily the family Plethodontidae. Specific endemic species include Weller's salamander and the Cow Knob salamander.
Piedmont: Contains many reptiles and amphibians. Forest-dwelling reptiles and amphibians often experience habitat degradation here.
Coastal Plain: Shows the greatest overall diversity. Key habitats include longleaf-wiregrass communities and mixed hardwood-pine habitats. Examples include the gopher tortoise and flatwoods salamanders.

Historical Habitat Loss: The original extent of southern bottomland hardwood forests has been reduced by 69% (estimated loss of 17.7 million acres). Longleaf pine-wiregrass communities are reduced to less than 10% of their original area.
Modern Land Use Impacts: Forestry, agriculture, and urban expansion are key threats. Short-rotation forestry reduces herpetofauna populations.
Habitat Fragmentation: The road network and development lead to fragmentation, impeding dispersal. Direct road mortality is a major cause of death, especially for long-lived species like turtles.
Pollution: Industrial effluents and heavy metals (cadmium, arsenic, selenium) released into the environment can lead to declines, particularly in amphibian fauna.

Habitat Recommendations: Conservation efforts should preserve breeding wetlands and maintain extensive riparian buffer zones to protect adjacent terrestrial habitats. Maintaining habitat connectivity is essential for dispersal and migration.
Research Challenges: A lack of comprehensive data exists on the life history and ecology of most herpetofauna. Many species are highly secretive and difficult to capture.
Increased Research Efforts: More intensive research is necessary to understand ecology, life history, and geographic distribution.
Public Education: Positive public attitudes are crucial for effective conservation. Public support and education concerning herpetofauna should be increased.