Seepage Swamps



Headwater stream flowing from a seepage slope – Houston Chandler

On a recent trip to Georgia, I found myself exploring the mucky edges of a seepage swamp, searching for salamanders in a part of the Coastal Plain where they are often difficult to find. Compared to the rocky streams and deciduous forests of the Appalachian Mountains the Coastal Plain has relatively low salamander diversity, and many of the species that call this region home can be challenging to find, especially members of the genus Ambystoma. To reliably find salamanders in the Coastal Plain, the best approach is to search near small swamps and water bodies where frequently saturated soils provide critical habitat for salamanders.

Seepage swamps can be found throughout the Coastal Plain in areas where an impermeable soil layer forces groundwater to seep out near the base of a slope, often collecting into small headwater streams or swamps, which can then drain into larger wetlands. These wetlands are commonly found at the base of large sandhills where water moves laterally through sandy soils before being forced above ground. Seepage swamps can be seasonally or semi-permanently inundated depending on specific hydrologic characteristics, but these wetlands are typically inundated long enough to accumulate a thick layer of partially decomposed organic matter. Vegetation communities in seepage swamps are frequently dense, only opening up in larger wetted areas. These communities are characterized by bays and other trees and shrubs that prefer wetter soils and are also home to other interesting plant species, including the Greenfly Orchid (Epidendrum magnolia) – an epiphytic orchid that grows on a variety of tree species. Ultimately, seepage slopes and their associated wetlands support distinct floral and faunal communities and are a fascinating ecosystem to explore.

Greenfly Orchid (Epidendrum magnolia) from southern Georgia – Houston Chandler

Salamander communities inhabiting seepage swamps are generally composed of 3–5 terrestrial species and potentially 2–3 aquatic species, depending on the exact location and habitat characteristics. The most common members of these communities are members of the abundant and widespread Slimy Salamander Species Complex, the Dwarf Salamander Species Complex, and a member of the Dusky Salamanders. The specific species present from these groups will largely depend on location, although there is some suggestion that dwarf salamander species (Eurycea sp.) actually prefer different habitat types. New species of dwarf salamanders were recently described, and more information about the particular species can be found in Wray et al. (2017). Dusky salamanders (Genus Desmognathus) are another common member of the seepage swamp salamander community. The specific species will again depend on the exact location, although in most places across southern Georgia it will be the Southern Dusky Salamander (D. auriculatus). However, genetic analyses have recently indicated that there are multiple species contained within D. auriculatus as it was originally described (Means et al. 2017), and additional species descriptions are likely in the near future. In fact, a recent county record that I published for D. auriculatus was actually published as D. cf. auriculatus, the cf indicating that it is similar to D. auriculatus but might not actually be that species (Chandler et al. 2018). Regardless of the specific species, these groups are all easily recognizable and in most cases should be identifiable with a quick check of the range maps.

Southern Dusky Salamander from Candler County, Georgia – Houston Chandler

The other species of salamander commonly found in seepage swamps are members of the genus Pseudotriton, a personal favorite of mine. Both Red (P. ruber) and Mud (P. montanus) Salamanders can be found sharing the same cover objects in certain locations. As the name suggests, Mud Salamanders frequent areas with thick mucky habitats and are encountered less frequently than Red Salamanders. One of the striking things about Red Salamanders from the Coastal Plain is how drab older adults are, especially compared to individuals from the mountains. It is not uncommon to find Red Salamanders in Georgia that are a purplish, brown color instead of the bright red or orange that gives the species their common name.

The final component of seepage swamp salamander communities are the aquatic salamanders that frequent wetlands across the southeast. This includes the Greater (Siren lacertina) and Lesser Sirens (S. intermedia), along with the Two-toed Amphiuma (Amphiuma means). Sirens have also been the focus of recent species descriptions, and there are other species of amphiuma, especially outside of southern Georgia. If you have learned anything from reading this article, it should be to check the range maps carefully when trying to identify salamanders!

Examples of Red Salamanders (Pseudotriton ruber) found near seepage slopes in southern Georgia (top) and in southwestern Virginia (bottom). – Houston Chandler

Back to my recent trip exploring a seepage slope in search of salamanders. I was really interested in finding Mud Salamanders, which have escaped me over the many years that I lived within their range. However, it was not to be, and I will have to try again the next time I make the trip to Georgia. I did manage to find P. ruber, D. cf. auriculatus, P. ocmulgee, and a member of the dwarf salamander complex. Interestingly, this individual is one county east of the eastern-most specimen of the recently described Hillis’s Dwarf Salamander (E. hillisi). The appearance and habitat suggest this species over E. quadridigitata, but some genetic analysis may ultimately be needed to identify which species inhabits this seep. One of the key recommendations from the Wray et al. (2017) paper that described E. hillisi was to clarify the eastern boundary of the species’ range. While not a Mud Salamander, extending the range of this newly described species would certainly be an exciting find for a couple of hours wandering around in a seepage swamp.

Literature Cited

Chandler, H.C., B.S. Stegenga, D.J. Stevenson, and J.Y. Lamb. 2018. Desmognathus cf. auriculatus (First county record). Herpetological Review 49:68.

Means, D.B., J. Y. Lamb, and J. Bernardo. 2017. A new species of dusky salamander (Amphibia: Plethodontidae: Desmognathus) from the Eastern Gulf Coastal Plain of the United States and a redescription of D. auriculatus. Zootaxa 4263:467–506.

Wray, K.P., D.B. Means, S.J. Steppan. 2017. Revision of the Eurycea quadridigitata (Holbrook 1842) complex of Dwarf Salamanders (Caudata: Plethodontidae: Hemidactyliinae) with a description of two new species. Herpetological Monographs 31:18–46.