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Wetland Wildlife of Arkansas

Arkansas Natural Heritage Commission - Friday, November 16, 2018
by Dustin Lynch

Wetlands are among the most important and imperiled of all ecosystems. Not only are they home to many remarkable species of plants and animals found nowhere else, but they also provide vital ecological services such as protecting and improving water quality, storing floodwaters, maintaining surface flow during dry periods, and providing recreational opportunities for sportsmen and women.

Wetland species in Arkansas exhibit a fascinating assortment of special adaptations that allow them to survive in these environments. From mammals and birds to amphibians and reptiles to tiny invertebrates that most people have never heard of, wetlands are home to some of our most fascinating species.

Amphibians are undoubtedly one of the first groups that come to mind when one thinks of wetland animals. Although Arkansas’s amphibian species live in a wide variety of habitats, most species are found relatively close to water. Most, but not all, amphibians must lay their eggs in the water and spend the first part of their life cycles as aquatic larvae. The striking Ringed Salamander (Ambystoma annulatum) is one of our most attractive species and is primarily endemic to the Ozark and Ouachita Highlands. Ringed Salamanders spend much of the year living underground beneath the forest floor in moist woodlands. In the fall (mid-September through early November), the cool autumn rains stimulate the adults to emerge and migrate to the shallow ponds where large numbers congregate to court and lay their eggs. Wetland-breeding species such as the Ringed Salamander are often dependent on the conservation of very specific types of wetlands – in this case, small, fishless ponds within large tracts of surrounding forest habitat – for their survival. Photo above right — Ringed Salamander (Amystoma annulatum), photo by Dustin Lynch.

The Sora (Porzana carolina) is a secretive marsh bird belonging to the family Rallidae (commonly known as Rails). These small, secretive marsh birds prefer to live in shallow wetlands with dense emergent vegetation such as sedges, rushes, and cattails. In Arkansas, they can primarily be seen during spring and fall migration. Soras are about 8-10 inches in length and resemble small chickens with stubby bright yellow bills, black masks, and short tails that they often hold cocked up. Due to their secretive nature, these birds are more often heard than seen. They give a variety of calls, the most distinctive of which is a loud descending whinny that lasts 2-3 seconds. Soras are omnivores that eat animals such as snails, crustaceans, insects, and spiders, but also the seeds of many plant species. Photo at right — Sora (Porzana carolina), photo by Nick Seeger, Arkansas Cooperative Fish and Wildlife Research Unit.

Graham’s Crayfish Snake (Regina grahamii) is a semi-aquatic species that inhabits marshes, sloughs, oxbows, and backwaters of slow-moving streams. This snake is a crayfish-feeding specialist that prefers recently molted individuals, although it may also consume other aquatic prey such as fish and amphibians. Graham’s Crayfish Snake is a secretive, nocturnal species that typically utilizes crayfish burrows as retreats, although it will also hide under rocks or logs at the water’s edge. During the daytime, this snake is most often observed basking just above the water. However, it is a wary animal and will often drop quickly into the water when seen. Photo at right — Graham's Crayfish Snake (Regina grahamii), photo by Dustin Lynch.

The Pirate Perch (Aphredoderus sayanus) is a unique species that inhabits lowland waters in Arkansas, ranging from bottomland lakes and oxbows to sluggish bayous, ditches, and Cypress-Tupelo swamps. This small fish is the only living member of its family (Aphredoderidae) and feeds on aquatic invertebrates and occasionally small fishes, primarily at dusk and dawn. A unique adaptation of the Pirate Perch is the position of its anus, which begins in the typical location near the anal fin in juveniles and gradually moves forward as the fish grows until it resides in the fish’s throat upon maturity. There has been some debate about the evolutionary significance of this unique anatomical trait – scientists once believed that this facilitated gill brooding of eggs, although now it is thought that the fish use their forward facing urogenital pores to deposit eggs into the underwater root masses used for nesting. Male Pirate Perches are territorial and exhibit nest-guarding behavior. Photo at left — Pirate Perch (Aphredoderus sayanus), photo by Dustin Lynch.

The Osage Burrowing Crayfish (Procambarus liberorum) is a regional endemic primarily known from a few counties in northwest Arkansas. While there are other species of crayfish found in wetlands, this species is a primary burrower, i.e. one that lives most of its life in tunnels below the ground excavated down to the water table. However, the need for proximity to a relatively high water table means that these species are often found in poorly drained soils such as those near wetlands, seepages, roadside ditches, or near streams. While burrowing crayfish are seldom seen at the surface, their occurrence is often indicated by the presence of “chimneys” consisting of soft mud pushed up above the surface of the soil during the excavation of their burrows. Networks of crayfish burrows can be very important habitat for other wetland species such as the previously mentioned Graham’s Crayfish Snake as well as the Crawfish Frog (Lithobates areolatus) which depend on them as homes, retreats from predators or fire, places to overwinter below the frost, and important sources of water. Photo above left — Osage Burrowing Crayfish (Procambarus liberorum) and a crayfish chimney, photo by Dustin Lynch.

The Six-spotted Fishing Spider (Dolomedes triton) is a distinctively marked semi-aquatic species that hunts by waiting patiently at the water’s edge, where it detects ripples from prey (including insects, tadpoles, and small fish) and then rapidly scampers across the water’s surface to capture it. These spiders are covered in short, velvety hairs that are hydrophobic, i.e. “unwettable,” allowing them to move along the surface of the water utilizing surface tension. They can even climb beneath the surface of the water by trapping air in these hairs, allowing them to breathe underwater and remain buoyant. This is one of several species of fishing spiders found in Arkansas. Photo at left — Six-spotted Fishing Spider (Dolomedes triton), photo by Dustin Lynch.

These are just a handful of the species that call Arkansas’s wetlands home. Next time you find yourself walking along the edge of a swamp, marsh, bayou, oxbow, or wet prairie, keep your eyes open and you might be lucky enough to see some amazing creatures.

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