On a warm North Carolina spring night, after a refreshing rain, you are likely to be serenaded by the most boisterous of symphonies. Northern and southern cricket frogs make up the percussion section, and Cope’s gray treefrogs add their melodic, soprano trills. Green frogs pluck banjo strings while Fowler’s toads add their rhythmic singsong. It is a wildlife chorus unequaled outside of the southeastern United States, which boasts more than half of the country’s reptile and amphibian species. Indeed, more than 100 species of reptiles and amphibians found in this region occur nowhere else in the world.
Amphibians and reptiles are an important part of the rich ecological heritage of North Carolina, and they play important roles in North Carolina’s ecosystems. As urban development continues to expand across the state, it is important that North Carolina’s citizens recognize the value of reptile and amphibian populations and learn how to conserve their habitats.
Scientists combine amphibians and reptiles in a group called herpetofauna, or herps for short. This name comes from the word herpetology, which is the scientific study of reptiles and amphibians. Why combine reptiles and amphibians in the same group? Because they share some common characteristics. Unlike mammals and birds, many herps (along with fish) are ectotherms. Ectotherms (commonly called “cold-blooded animals”) do not rely on their metabolism or other physiological processes (such as sweating and shivering) to maintain a constant body temperature. Instead, ectotherms use behavior and the environment to regulate body heat. For instance, some of the more easily seen herps are pond turtles basking on logs and lizards sunning on fence posts or porch railings to raise their body temperatures. Conversely, a reptile or amphibian might slip into a shady pond to cool down.
Although basking turtles and lizards are fairly common sights, some behaviors associated with ectothermy can make herps more difficult to locate. Some hibernate during cold weather, drastically slowing down their body processes and remaining dormant and hidden until temperatures rise. Some herps aestivate (a behavior much like hibernation) during hot, dry times when moving about might cause them to overheat.
Even when temperatures are favorable, reptiles and amphibians often remain hidden from view. Frogs like the American bullfrog (Figure 1) spend much time in the water, where they quickly submerge when startled. Many snakes, such as the eastern hognose snake (Figure 2), box turtles, and toads are well camouflaged and blend easily into the colors of the forest floor. Salamanders dwell under logs, leaves, and rocks. And because ectothermic animals do not expend energy to regulate their body temperatures, they eat less often than endotherms, so they are less likely to be seen foraging for food.
Herps play important roles in the ecosystems where they live. Some are predators that keep numbers of their prey in check. Examples include salamanders that eat insect larvae or snakes that eat mice and other rodents. Herps are found on the other end of the food chain as well; frogs are important prey for many species of fishes, birds, mammals, and reptiles.
Herps can serve as good indicators of environmental health. A healthy, diverse herp community indicates that an area can support the plants and insects herps need for food and that the area has a habitat available for a variety of wildlife. Herp absence from an area where one would expect to find them can indicate that there is an environmental problem.
Amphibians and reptiles have many similarities, but they also have some big differences. Let’s explore those now.
Amphibians include salamanders, frogs, and toads. Typically, amphibians eat insects and other small invertebrates. Some larger species can eat small vertebrates, including fish, other amphibians, and small birds. Many tadpoles (the fully aquatic larval form of frogs and toads) eat mostly plants.
Amphibians’ skin is permeable, which means it is not a solid barrier between the environment and the insides of their bodies. Permeable skin allows amphibians to absorb oxygen and release carbon dioxide (in other words, respire) through their skin. The skin must remain moist for this process to work. Permeable skin is not the only way that amphibians breathe. They might have lungs similar to those of mammals or birds, gills similar to those of fish, or a combination of permeable skin, lungs, or gills for breathing. Many amphibians use different methods of breathing throughout their lives, depending on their stage of development.
The drawback of having permeable skin is that toxins and pollutants from the environment can pass through the skin and into an animal’s body. These toxins and pollutants might disrupt development or reproduction, or even kill the animal. This is one reason the presence of amphibians is an important indicator of environmental health—many species cannot survive and reproduce in polluted water.
As a group, amphibians have complex and varied life histories. Frogs and some salamanders, like the spotted salamander (Figure 3), lay eggs in water, and their young hatch as aquatic larvae but live their adult lives on land or a combination of land and water. Some amphibians (especially some salamander species) lay eggs on land in moist places. Amphibians’ eggs do not have shells, and, like adult amphibians, they are vulnerable to pollutants.
Different species of amphibians need specific habitat conditions based on their own life histories. Generally speaking, for amphibians to survive in an area they need:
- Access to aquatic or wet sites (pools, ponds, streams, seeps, or marshes) to lay eggs, and in some cases, to live as adults.
- Access to terrestrial sites (dry land) for adult life, breeding, and movement between aquatic environments.
- Access to shelter (damp, rotting logs and stump holes) to protect them from predators and weather and to keep their skin moist.
Amphibians Common to Urban/Suburban Areas
Frogs and Toads
American toad Bufo [Anaxyrus] americanus
Fowler’s toad Bufo [Anaxyrus] fowleri
Southern toad Bufo [Anaxyrus] terrestris
Northern cricket frog Acris crepitans
Southern cricket frog Acris gryllus
Cope’s gray treefrog Hyla chrysoscelis
Green treefrog Hyla cinerea (Figure 5)
Squirrel treefrog Hyla squirella
Spring peeper Pseudacris crucifer
Upland chorus frog Pseudacris feriarum
Eastern narrowmouth toad Gastrophryne carolinensis
American bullfrog Rana catesbeiana [Lithobates catesbeianus]
Green frog Rana [Lithobates] clamitans
Pickerel frog Rana [Lithobates] palustris
Southern leopard frog Rana sphenocephala [Lithobates sphenocephalus]
Marbled salamander Ambystoma opacum
Spotted salamander Ambystoma maculatum
Eastern newt Notophthalmus viridescens (Figure 6)
Southern two-lined salamander Eurycea cirrigera
Blue Ridge two-lined salamander Eurycea wilderae
Northern dusky salamander Desmognathus fuscus
White-spotted slimy salamander Plethodon cylindraceus
Atlantic Coast slimy salamander Plethodon chlorobryonis
Reptiles include snakes, lizards, turtles, and crocodilians. Unlike amphibians, reptiles have scaly, impermeable skin that does not need to stay moist. All reptiles use lungs to breathe.
Reptilian diet varies widely among groups and species and can include small vertebrates (such as birds, mice, and frogs), invertebrates (insects and crustaceans), and plants. Most reptiles lay leathery-shelled eggs on dry land, while some snakes (especially aquatic and semi-aquatic species) give birth to live young.
In general, for reptiles to survive in an area, they need:
- Access to basking sites to warm in the sun or absorb heat from a surface that has been warmed by the sun (such as a log) (Figure 4).
- Access to shelter, such as trees, leaf litter, shrubs, downed logs, or snags (standing dead trees) to cool off, to hide from predators, and to ambush prey.
- Access to hibernacula, often stump holes or crevices under rocks or logs, to hibernate through the winter.
- For aquatic turtles, alligators, and some aquatic snakes: access to a safe, dry, land buffer along the water’s edge to lay eggs.
Reptiles Common to Urban/Suburban Areas
Worm snake Carphophis amoenus
Black racer Coluber constrictor
Ringneck snake Diadophis punctatus
Corn snake Elaphe guttata [Pantherophis guttatus]
Rat snake Elaphe obsoleta [Pantherophis alleghaniensis]
Eastern hognose snake Heterodon platirhinos
Eastern kingsnake Lampropeltis getula
Rough green snake Opheodrys aestivus (Figure 7)
Eastern garter snake Thamnophis sirtalis
Copperhead Agkistrodon contortrix
Rough earth snake Virginia [Haldea] striatula
Common snapping turtle Chelydra serpentina
Painted turtle Chrysemys picta
Eastern box turtle Terrapene carolina (Figure 8)
Yellowbelly slider Trachemys scripta
Green anole Anolis carolinensis
Eastern fence lizard Sceloporus undulatus
Five-lined skink Eumeces [Plestiodon] fasciatus
Broadhead skink Eumeces [Plestiodon] laticeps
Southeastern five-lined skink Eumeces [Plestiodon] inexpectatus (Figure 9)
Before considering how to share our land with reptiles and amphibians and protect them, we must understand how human activities might threaten their populations. Once armed with this information, we can manage and use the land in harmony with wildlife’s needs.
North Carolina’s human population is rapidly expanding, especially in urban and suburban areas. The biggest threats to herps from development include traffic hazards, pollution, and habitat loss and fragmentation (Figure 10, Figure 11, and Figure 12).
Habitat Loss and Fragmentation
Habitat is lost when a natural area is converted into a developed area that herps no longer can use. Filling in low-lying areas to level the land eliminates pools used to breed, hide, or cool off. Clearing forests removes sheltering trees, leaves, shrubs, and access to hibernacula that protect animals and provide safe nesting and hibernation sites.
Habitat is fragmented when roads, neighborhoods, shopping centers, or other developments divide them, risking exposure to predators, vehicles, and the weather as herps move between the smaller habitat patches. If development isolates a lake, pond, or stream from drier areas or disturbs a particularly sensitive habitat, it will be especially likely to increase mortality rates for herps.
Nearly everyone has seen an eastern box turtle whose shell was crushed as it tried to cross a highway. Snakes basking on roads and frogs dispersing from their birth ponds also are frequent victims of vehicles. Herps have nearly no chance of surviving a trip across a heavily traveled (15,000 vehicles/day) road.
Sedimentation and Pollution
Sedimentation occurs when rain washes sediment such as dirt or silt into streams or other wetlands. Sedimentation increases during construction because exposed dirt erodes easily during rainstorms. After construction is complete, rainwater runs quickly across impervious surfaces such as concrete, asphalt, or buildings, carrying sediment and debris into nearby bodies of water. Sedimentation clouds the water and fills hiding places between rocks. Animals cannot get the oxygen and food they need from the muddy water, and the plants they eat cannot survive.
In addition to washing sediment into streams, rainwater washes toxins, including insecticides, herbicides, fertilizers, and petroleum products, into waterways and low-lying wetlands. Toxins poison amphibians directly through their permeable skin or eggs; herps that eat contaminated prey become sick. Fertilizers washed into ponds and streams can cause algal blooms that make laying eggs impossible for amphibians, reduce the amount of oxygen in the water, and kill the invertebrates that amphibians eat. Insecticides reduce herps’ food supply, as insects make up much of the prey for both reptiles and amphibians.
Creating a Backyard Habitat
People can do a lot to help conserve herp populations right in their own backyards. You can help by planning for wildlife when you decide how to manage your lawn and garden. Many of the same practices that will make your backyard attractive to herps also will attract other wildlife such as birds and butterflies.
Part of managing your yard for herps requires creating or improving habitat. To help provide for herps’ habitat needs, you can:
- Add a pool or pond (see Adding a Water Feature). Include native plants such as pickerelweed (Pontederia cordata), but do not add fish, as they will eat amphibian eggs and larvae. If you are concerned about mosquitoes, you can use treatments available at gardening stores that contain a chemical named Bt-israelensis (Bt-i) and marketed under the name Mosquito Dunks. These tablets are added to pools or other standing water and prevent mosquito larvae from surviving, but they do not harm other wildlife. Dragonflies are predators of mosquitoes, so planting underwater vegetation where dragonfly nymphs can hide and plants where adult dragonflies can perch and lay eggs will help attract them to your pool. Some salamander larvae also prey on mosquito larvae.
- Select native species for your garden. Native wildlife species survive best when surrounded by plants that are native to the region in which they live. Non-native plants, especially those that grow uncontrolled, can disrupt the natural ecosystem in your yard. For information on native plant species in the Southeast, visit the Going Native website.
- Provide shelter (see Providing Shelter for Herps). Providing shelter for herps can mean building a structure or simply not removing shelter that already is present. Dead trees, stumps, and taller grass all provide good protection for herps. Consider building rock piles or walls near a pond, pool, or wet area to provide both shelter and basking sites. Brush piles placed on dry land near a tree, bush, or thicket are readily used by herps—just be sure not to include chemically-treated wood.
Adding a Water Feature
A water feature like the one in Figure 13 is an excellent habitat for herps. It provides aquatic habitat and a rock wall for shelter. Keep in mind, however, that an elaborate water feature is not necessary. A large trashcan filled with rain water will attract treefrogs in the spring. If you do choose to build a minipond, keep these ideas in mind:
Good habitat is wasted if your yard is otherwise unsafe for herps. To reduce hazards to herps, you should:
- Limit chemical use. Remember that storm drains lead directly to streams. Apply herbicides, insecticides, and fertilizers only in the smallest amounts necessary and only when absolutely needed. Always follow the instructions on the labels. Avoid using any chemicals near water sources and storm drains, unless labeled for such use. Rinse excess or spilled fertilizer off your driveway onto the lawn so it does not wash into storm drains when it rains. If your car is leaking oil, repair it and clean up the spill so that the oil does not wash into streams.
- Control household pets that might harm herps or their habitats. Outdoor cats and dogs prey on lizards and a variety of other wildlife. Studies have shown that up to 90 percent of outdoor domestic cats’ diet can be wild animals. Dogs trample leaves and disturb garden pools. Keep your cat indoors and restrict your dog from wildlife habitats to maintain healthy herp populations in your yard.
Providing Shelter for Herps
Log and Brush Piles
Once you have created a habitat for amphibians and reptiles, wait for them to arrive naturally. Never move herps from the wild to your yard. It may take several months for them to start appearing—longer if you are farther away from other natural habitat.
You can view your new backyard inhabitants with binoculars, especially close-focusing binoculars, and you may notice signs of herps such as shed skins or eggshells. Most of the time you can learn a lot by viewing from a distance, but a close-up look is very interesting, especially for children. If you choose to handle herps you find in your yard, do so minimally and with great care. Handling an animal risks injuring it or, in the case of amphibians, exposing it to any chemicals you might have on your hands from soap, lotion, or insect repellant. Some species can inflict injuries from bites or scratches if carelessly handled.
A note about venomous snakes: North Carolina is home to six venomous snake species (Figure 14). Copperheads are the most commonly found backyard venomous snake in North Carolina. They are secretive and typically are not aggressive, and pose a threat only if provoked. If you find a venomous snake in your yard, keep pets and small children who might disturb the snake away from the area where it was seen and leave it alone.
You don’t have to limit your desire to share the land with herps to your own backyard. Encourage your neighborhood, community, or town to engage in responsible, wildlife-sensitive development. Urge developers to limit chemical use and landscape with native plants. Other wildlife-friendly practices developers can incorporate into their plans include:
• Protect seasonal wetlands during construction. Undisturbed, low-lying areas that are seasonally wet are particularly important for herps. These temporary, or ephemeral, pools often stay wet just long enough for aquatic larvae of many frogs, toads, and salamanders to hatch and metamorphose into terrestrial adults. There are no fish in them that might eat amphibian eggs, so they are relatively safe places to lay eggs. These pools provide a good prey base of insects and vegetation.
- Do not disturb buffer zones adjacent to wetlands. Protecting uplands is important so that many turtles and other pond-dwelling herps can safely lay their eggs out of the water. Many salamanders that lay their eggs in ephemeral pools live in the adjacent uplands during most of the year.
- Leave or create safe corridors between habitat patches. Amphibians need both wet and dry sites, and they need to be able to move back and forth between these areas freely. Reptiles need to be able to disperse to mate and breed. Corridors between habitat patches should not be intersected by roads, should have adequate cover, and are most effective if they are at least 300 feet wide.
- Reduce potential for road mortality. Community planners should reduce speed limits, install speed bumps, and put up signs alerting drivers where herps and other wildlife are likely to cross roads. Installing fences and culverts or amphibian tunnels can help route reptiles and amphibians safely under a roadway. Avoid new road construction around critical herp breeding wetlands.
- Minimize sedimentation. During development, construction workers should leave the soil as undisturbed as possible. Disturbed and compacted soil disrupts habitat for fossorial species (species that live underground) and increases erosion. If installed properly, sediment-catching silt fences can be helpful during construction.
- Protect streamside vegetation during development. Leaving streams intact and stream banks un-mowed provides cover and helps filter sediment and toxins out of the water before they enter streams and other wetlands.
The next time you hear the symphony of frogs greet you on a warm evening, you will have a better appreciation for the amazing lives of the diverse amphibians and reptiles that live in North Carolina. Even more importantly, you will know some simple, enjoyable, and effective steps that you can take to ensure the symphony continues year after year.
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Some animals in this document have recently been assigned new scientific names.
For animals that have had recent name changes, their scientific names are listed in the format, 'Previous name [new name]'.
Publication date: Aug. 23, 2017
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