Upland Seepages and Spray Cliffs
The 2015 North Carolina Wildlife Action Plan defines 41 priority habitats for the state. More information about this habitat can be found in Section 4.3.10.
Contents
Habitat Priorities
Surveys
Monitoring
Research
- Perform genetic studies to determine the degree of gene flow or degree of isolation between populations and to assess overall population health for species restricted to this habitat.
- Document how priority species are utilizing the habitat and whether specific hydrological and biological requirements are being met under current management regimes.
Management Practices
- Specific management needs include the control of woody encroachment and succession, the maintenance (and where necessary, restoration) of natural surface water and groundwater hydrology (using ditch plugs, temporary dams, level spreaders, or other engineering devices), the restoration of herbaceous vegetation, and the prohibition of take of rare bog-related species (e.g., Bog Turtle).
Conservation Programs and Partnerships
Description
The communities included in upland seepages and spray cliffs are wetlands that occur on sloping uplands and can be found across the state. The soils are generally saturated permanently or for long periods. They are generally fairly small and contrast sharply with adjacent communities, though boundaries may be gradational. There are four communities in this ecosystem group: spray cliffs, hillside seepage bogs, low elevation seeps, and high-elevation seeps. Spray cliffs are areas kept wet by spray from waterfalls. The other three community types are fed by groundwater seepage and their soils are saturated for much or all of the year, but they are seldom, if ever, flooded.
- Most spray cliff areas are vertical cliffs, but gentle slopes, talus, and soil at the base of cliffs are also included. Vegetation is very patchy, reflecting the patchiness of soil accumulations. The microclimate is generally moderated by the flowing water and sheltered position of the cliffs. Though water flow may vary with rainfall, these are probably among the most stable environments in North Carolina. Trees rooted in crevices and between rocks often grow to large size and may shade the entire area. The bare wet rocks generally have a great diversity of mosses and liverworts. Herbs in small soil pockets include a wide variety of forbs, ferns, and sedges.
- The rarest type is the hillside seepage bog. These communities, in a few Piedmont locations, are wet enough to have boggy vegetation. The vegetation is generally a patchy mix of shrubs and herbs with an open tree canopy. Many species characteristic of the Coastal Plain occur in these communities. Fire may have played a role in keeping hillside seepage bogs open enough to allow persistence of light-requiring bog species.
- Low elevation seeps, occurring in uplands or edges of floodplain throughout much of the state, are also very wet but differ in vegetation. The factors which cause these differences are poorly known. Trees such as red maple may be present, or the seep may be shaded by canopy species from adjacent forests.
- High-elevation seeps occur in the higher Mountains, where they are surrounded by spruce–fir forests, northern hardwood forests, or grass and heath bald communities. High-elevation seeps are quite variable in vegetation and setting. Some are open and somewhat boggy, with peat moss, sundews, and even cranberries present. Others are shaded by canopy and more closely resemble a rich northern hardwood forest.
Location of Habitat
This group of communities covers a wide geographic range in the Mountains and Piedmont ecoregions. High-elevation mountain seepage communities are usually surrounded by spruce–fir forests, northern hardwood forests, or grass and heath bald communities. Low-elevation seeps tend to occur at the bases of slopes in the Piedmont and lower Mountains, just above a floodplain. Spray cliffs are more likely to occur in gorges and riverine areas. Examples of spray cliffs can be found in the Nantahala National Forest, Bonas Defeat Gorge on the Tuckasegee River in Jackson County, Reid Branch waterfalls in Transylvania County, Phillips Branch waterfalls in Caldwell County, and the Dismal Creek waterfalls in Transylvania County (Stevenson 2015).
Problems Affecting Habitats
Threats to individual seepages and spray cliffs are extremely variable and include: invasive plants; death of Canada hemlock trees due to the Hemlock Woolly Adelgid; development on or adjacent to the community; recreational trampling; stream flooding and scouring or downcutting; depletion of ground water pools that supply seepage; ditching or drainage; increased temperatures in sheltered refugia; and vegetational succession in the absence of fire or other natural disturbance. This ecosystem is highly threatened overall, with or without climate change.
The communities located at high elevations are the most likely to be affected by increased temperatures. Some distinctive high-elevation species may be lost, while some lower elevation species may be able to migrate into them. Warmer temperatures may allow exotic species to invade. Some seeps have increased in tree cover due to fire suppression or other alterations, and loss of tree cover may be positive in some examples.
Climate Change Compared to Other Threats
Comparing climate change to other ecosystem threats can help define shortand long-term conservation actions and recommendations. While climate change is not the most severe threat, a combination of synergistic effects with other existing conditions could stress these systems to the point where several species are unable to persist.
The effect of a changed climate is likely to vary widely among examples of these communities, depending on topographic sheltering, configuration of rocks, soil depth, size of groundwater pools, and amount of overland runoff. These systems are tied to specialized small environments and will be unable to migrate as the climate changes. Many may change very little, while a few will shrink, be disturbed by wind or flood, or change substantially because of temperature changes or drought. A small net loss of acreage may occur, but more seeps may be temporarily affected by drought.
Impacts to Wildlife
Seepage communities have very limited distribution and availability across the landscape and are one of the most significant habitat types of the state for rare plants and animals (TNC and SAFC 2000). Several animal species that are state-listed or rare are associated with seepage habitats, including the Bog Turtle, Mole Salamander, Four-toed Salamander, Long-tailed Salamander, Seepage Salamander, Alder Flycatcher, and the common Gray Treefrog.
The priority amphibian associated with mountain bogs are all salamander species, though there certainly are a much larger number of amphibians found in mountain bogs. These salamanders (e.g., Mole, Four-toed, Marbled, Three-lined, and Spotted Salamanders) for the most part require pools of water (preferably fishless) for breeding purposes. The community association is less related to the system being spring fed, muddy, or with specific plant associations than for many of the other priority species associated with the seepage habitats.
Some of these communities serve as refugia for species for which the current climate is not suitable. They are likely to continue to do so, but warming temperature and changed moisture regimes may make some of them less hospitable to some of these species. At the same time, these communities may become refugia for additional species that are currently common, if the regional climate becomes unsuitable for them. They may be crucial for the survival of some species in the state.
While moisture levels are probably the most important factor in these communities, some species may be directly affected by increased average or extreme temperatures. Warmer temperatures may cause some species to be lost at certain sites, and this may include some of the most unusual and rarest species in these communities. Warmer temperatures may also allow some more southern species to enter these communities, but the small and isolated nature of these distinctive environments will limit movement of species. The species that depend on cool, moist conditions are more likely to be extirpated if warmer temperatures (especially combined with drought) reduce the suitable habitat and/or allow other species to invade the habitat.