The 2015 North Carolina Wildlife Action Plan defines 41 priority habitats for the state. More information about this habitat can be found in Section 4.4.8.

Habitat Priorities

Surveys

Map these sites in a GIS format to facilitate tracking changes over time in both the habitat and the associated species, and to facilitate landscape scale management of this rare habitat. (Surveys Priority)
Obtain baseline data on amphibian, small mammal, and reptile communities and habitat use (e.g., identify Timber Rattlesnake den sites). (Surveys Priority)

Monitoring

Continue monitoring the Peregrine Falcon population.
Continue monitoring Green Salamander populations, as well as other salamanders of this habitat type (e.g., Crevice and Southern Zigzag salamanders).

Research

Study Timber Rattlesnake movements, use of hibernacula, and reproductive success at gestation sites.
Study the impact of various management scenarios on the habitat and associated species.
Initiate genetic and morphological studies to clarify taxonomic status of plethodontid salamanders.
Study habitat use by rock outcrop salamander communities, including movements in and among rock outcrop habitats (e.g., Green Salamander metapopulations).

Management Practices

Protect these habitats through active management to remove invasive species.
Burn around open, dry outcrops that naturally burned to restore more natural structure around the margins, and favor species that will tolerate drought and wildfire better.
Maintain biologically significant areas, including Peregrine Falcon nesting areas, reptile den sites, and significant salamander occurrences.
Assign appropriate management schemes to rock outcrops on conservation lands to minimize negative impacts from human activities, including recreational use and development.

Conservation Programs and Partnerships

Description

This broad ecosystem group encompasses many, though not all, of the community types at low to mid-elevations that are too steep or rocky to support a closed tree canopy. The vegetation of these communities is generally very patchy, reflecting extreme variability in the depth and composition of soil and of available moisture. Plants include forest species with broad site tolerances, species characteristic of a wide range of open habitats, and species specialized for rock outcrops. Rock outcrops typically are very dry, but seepage zones are often present and may support wetland vegetation. This community type generally occurs below 2,000 feet in elevation. In contrast, mid-elevations range from 2,000 to 4,000 feet and high elevations are above 4,000 feet.

The nine natural cliff and rock outcrop community types are separated based on rock chemistry, topographic location, and geographic region, and the latter is an important factor in determining flora. The community types are: Piedmont/Coastal Plain heath bluffs and acidic cliffs; Piedmont mafic and calcareous cliffs; montane mafic, calcareous, and acidic cliffs; and low-elevation granitic domes and rocky summits.

Low-elevation rocky summit communities occur in exposed positions on peaks, ridgetops, and upper slopes in the Mountain ecoregion. Low-elevation rocky summits have fractured rock which allows growth of deep-rooted woody plants in places. Soil accumulates in pockets of varying depth and produces heterogeneous vegetation. Many variants potentially occur, but are not well known.
Low-elevation granitic domes occur on exfoliated outcrops of granitic rock, where peeling of sheets of rock parallel to the surface produces a dome-shaped outcrop of solid rock. Soil mats that begin as moss clumps gradually thicken over time and follow a characteristic vegetational succession from herbs to shrubs and stunted trees. The unanchored mats are periodically destroyed by falling off or by being pulled up by falling trees, leaving the rock bare and beginning the succession anew.
Cliff communities occur on lower, more sheltered topographic sites. They are generally created by streams undercutting a bluff, but may occur somewhat above a stream. Like rocky summits, the rock is usually fractured and supports very patchy vegetation that includes woody plants rooted in crevices, as well as herbs in soil pockets, and mosses and lichens on bare rock. The Mountain and Piedmont/Coastal Plain types have flora typical of their regions, often combining plants from adjacent communities with typical outcrop plants.
North-facing cliffs have a cooler microclimate than the surrounding areas and sometimes harbor disjunct or regionally rare species characteristic of cooler, moister regions. In some cases these species are believed to be remnants from more widespread populations that existed in the Ice Ages. In the Mountain ecoregion, south-facing cliffs may support species more typical of the warmer Piedmont or even Coastal Plain.
The acidic, mafic, and calcareous types support different flora that reflect the rock chemistry. Mafic and calcareous cliffs contain calcium-loving species that do not occur on the more common Acidic cliffs. The floristic differences between calcareous and mafic cliffs are more subtle, and reflect differences in the balance of basic elements.
Piedmont/Coastal Plain heath bluffs differ somewhat from the other community types in that they have little bare rock. They do, however, lack a closed tree canopy, apparently because of steepness. They are characterized by a dense shrub layer of Mountain Laurel or Catawba Rhododendron, which are otherwise essentially absent in the Piedmont and Coastal Plain. These communities occur on north-facing bluffs, and the cool microclimate is believed to be important to these species.
Granitic flatrock communities occur on flat to gently sloping exfoliated outcrops of granitic rocks and are scattered throughout the Piedmont region, from Virginia to Alabama. The rock outcrop is generally flush with the surrounding soil and has only minor irregularities. These communities are somewhat related to the granitic dome communities of the upper Piedmont and Mountains in that vegetation is sparse and very patchy. On bare rock, soil mats that accumulate in moss clumps undergo a gradual development, deepening and being invaded by a succession of plants.

The 2005 WAP describes low-elevation cliffs/rock outcrops in the Southern Blue Ridge Mountains as a priority habitat (see Chapter 5) (NCWRC 2005).

Location of Habitat

Low-elevation cliff and rock outcrop habitat is spread throughout the Mountain and upper Piedmont ecoregions. Piedmont examples include Sauratown Mountains inclusive of Pilot Mountain, and the Crowders, Uwharrie, and South Mountains. Flatrock communities are found primarily in the eastern Piedmont. Other habitat types are present even into the Coastal Plain, such as heath bluffs.

Problems Affecting Habitats

Conditions vary considerably within this habitat type, with a significant number having been impacted and/or lost due to numerous factors, while others remain functional “natural sites” and still others are specifically managed to minimize human impacts.

Low-elevation cliffs and rock outcrops are diverse communities that are expected to have a variety of responses to climate change. While some are dependent on moisture and may be harmed, others may actually benefit from increased drought and fire. This benefit will only be realized if sites are protected from other forms of destruction, and for most, if fire is restored to them through prescribed burning. These communities are naturally rare in North Carolina, due to limited availability of suitable habitat. Examples need to be protected and managed appropriately.

As with high-elevation rock outcrops, two major problems most associated with the low-elevation rock outcrops include development and recreational impacts. However, low-elevation rock outcrops are subjected to short-term habitat alterations (e.g., forestry operations) more often than high-elevation rock outcrops due to land ownership patterns, proximity to markets, accessibility, and other factors. The extent and degree of impact associated with such temporary habitat alterations is unclear for most species. Regardless of the impacts or problems associated with short-term habitat modifications, the relative scarcity of low-elevation rock outcrop habitat across the landscape of North Carolina, and reliance upon it by numerous wildlife species lends greater significance to the need to identify and manage these habitats appropriately to conserve wildlife.

Some climate change models predict that rainfall will be concentrated during the fall, and there will be increased droughts in the spring and summer. Droughts could favor herbaceous species and grasses in open, dry outcrops, which tend to be rarer than the woody species associated with outcrops. Drought will kill trees on edges and soil islands. This already happens in current droughts, and is part of the mechanism keeping flatrocks open. Increased length or severity of droughts might cause flatrocks to expand at the expense of adjacent shallow-soil woodlands. Herb species associated with granitic flatrocks tolerate drought at present, or grow in the moist early growing season. It is unclear if they are at the margin of their tolerance, or whether they could withstand longer or more severe droughts. Drought in spring would be detrimental, while drought in other seasons might not be. A few additional flatrocks may be opened up by wind throw or drought mortality. Increased storms may blow down trees and pull up soil mats more frequently. Amount of bare outcrop and shallow soil mats may increase at the expense of deeper mats.

Low intensity fires could expand the open area and benefit some of the rare plants of outcrops. More mesic outcrops such as heath bluff communities are more likely to be harmed by fire. Landscape fragmentation and fire suppression practices likely will continue to prevent most fires from spreading very far. The central parts of granitic flatrocks are unlikely to burn even in droughts. Fire could affect the dry woodlands that form the edge zone of the flatrocks. However, most flatrocks occur in fragmented landscapes where fire is unlikely to spread. They are likely altered by lack of fire.

Increased temperatures could increase demand for water, a limited resource in these sites. Phenological shifts (earlier bloom periods, emergence from hibernation, nesting and breeding) in seasons may occur in a warmer climate. Exotic plants readily invade favorable microsites on many outcrops. Increased disruption of adjacent forests may bring seed sources closer to many outcrops.

Dense woody vegetation around edges may become more open. Increased drought or fire might produce beneficial structural changes. Some outcrops have been altered by fire suppression and these changes may help return to more natural composition. Others will lose characteristic mesophytic species. The effect may be severe in a small number of outcrops. Some dry outcrops may expand into adjacent forests, while heath bluffs may shrink.

Climate Change Compared to Other Threats

Comparing climate change to other ecosystem threats can help define shortand long-term conservation actions and recommendations. Granitic flatrocks are tied to specialized sites and cannot migrate. Communities will change in situ but it is uncertain how much. As with high-elevation rock outcrops, the two major problems most associated with the low-elevation rock outcrops include development and recreational impacts. For animals associated with cool, moist slopes or cliffs, particularly in relict situations, climate change represents the most significant threat, particularly in the Piedmont where their populations are typically small and highly isolated. For the plants associated with this theme, climate change is not expected to be a major threat. Development and changes caused by fire suppression are the most severe threats. In some areas, excessive deer browse is also a major threat.

Impacts to Wildlife

Many wildlife species utilize the rock outcrop habitat without regard to arbitrary elevational distinction (e.g., Peregrine Falcon), and others will utilize only high-elevation rock outcrop habitats, at least according to what we currently know (e.g., Rock Voles and Rock Shrews). However, many wildlife species and even more plant species (Schafale and Weakley 1990) are either associated with high-elevation rock communities or low-elevation rock communities. The elevation limits for each species, however, are quite variable. Many low-elevation rock outcrop species of plants and animals are restricted to ranges outside high-elevation areas (e.g., Crevice Salamanders are only found in and around the relatively low-elevation Hickorynut Gorge). Still other wildlife may occur in both high- and low-elevation rock communities, but for various reasons may reach higher densities or have wider distribution in low-elevation rock outcrops (e.g., Timber Rattlesnakes).

The extent of habitat that each rock outcrop provides is dependent upon the entire set of conditions in and surrounding the surface rock. Those conditions influence its use by plants and animals dependent upon the surface rock and may include significant amounts of adjacent ecological community types. Water seepage through rock crevices may provide moisture for amphibians, mosses, lichens, and wetland vegetation. Reptile species may use rocky areas exposed to direct sunlight for basking or use openings amongst rocks for dens.

No species belonging to these guilds appear to be vulnerable to complete extinction due to the effects of climate change. However, both the Hickory Nut Gorge population of Crevice Salamander and the Piedmont populations of Red-backed Salamander exist as isolated disjuncts and are likely to be highly vulnerable to the effects of climate change. In both cases, extirpation of these populations would constitute loss of significant ecological as well as genotypic variants of their species.

DeWan et al. (2010) suggest that habitat specialists and species with restricted ranges will likely be some of the greatest affected by the combined effects of habitat loss and climate change. They also note such populations are more vulnerable to extinction by rare events and susceptible to additional stressors such as climate change.

quoted from the 2015 North Carolina Wildlife Action Plan

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Low Elevation Flatrocks, Cliffs, and Rock Outcrops

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