Mesic Forests
The 2015 North Carolina Wildlife Action Plan defines 41 priority habitats for the state. More information about this habitat can be found in Section 4.4.9.
Contents
Habitat Priorities
Surveys
- Direct initial efforts toward surveys to determine the current baseline distribution and status of species mainly associated with mesic forests (especially those that are state-listed or believed to be declining) for which that information is lacking. (Surveys Priority)
- Focus secondary efforts on conducting surveys to understand current status, from which we can measure future population changes over time. (Surveys Priority)
Monitoring
- Enhance current monitoring systems and protocols (e.g., MAPS and BBS) to better cover certain species not well covered by current monitoring efforts.
- Establish long-term monitoring for small mammals and bats following initial surveys.
- Conduct general long-term herpetofauna monitoring to track the effects of the loss of old growth characteristics in this habitat type.
Research
- Collect demographic information on all bat species; investigate specific habitat needs and conduct life history studies.
Management Practices
- Create transportation facilities that utilize longer bridges at streams and wetlands to minimize impacts (and thereby reduce mitigation requirements) and provide crossing options for wildlife that often travel riparian corridors and disperse to upland communities.
- Maintain connections between habitat blocks, not only to allow adjustments in range in response to climate change, but to maintain population resilience and adaptability more generally.
Conservation Programs and Partnerships
Description
Mesic forests occur on sites that are moist but not wet. Mesic sites are among the most favorable environments for plant growth. They tend to support dense forests dominated by moisture-loving non-wetland trees such as beech, Tulip Poplar, and Northern Red Oak. They usually have well-developed understory, shrub, and herb layers. They often contain species that are common in the mountain parts of the state or farther north but are rare in the southern Piedmont and Coastal Plain. Some species may be disjunct long distances from cooler areas. At least some of these disjuncts are remnants of wider distributions in the past, such as during the cooler, moister climate of the Ice Age.
- Mesic mixed hardwood forests in the Piedmont are generally on north-facing slopes, sheltered ravines, or high terraces on the edges of floodplains. In the Coastal Plain, mesic forests occur in similar sites and also on moist portions of broad upland flats and on small island ridges surrounded by swamps. These sites are naturally sheltered from the fires that are a major natural shaper of vegetation in the Coastal Plain.
- Basic mesic forests are much rarer than the mesic type and occur on soils that are neutral to slightly basic in pH. They are more diverse than the mesic mixed hardwood forests and they have species that require high pH. The basic mesic forest subtype often has rare and disjunct plant species and both variants of basic mesic forest (marl outcrop and terrace slope) are rare because of the scarcity of basic substrates on the Coastal Plain (Schafale and Weakley 1990).
The 2005 WAP describes the Piedmont ecoregion and Mid-Atlantic Coastal Plain ecoregion Mesic Forest as a priority habitat (see Chapter 5) (NCWRC 2005).
Location of Habitat
The Coastal Plain and Piedmont subtypes cannot be separated by any particular species, but differ in their overall flora. In the Piedmont, mesic mixed hardwood forest communities occur on mesic sites that have typically acidic soils. Good examples can be found at Umstead State Park, Duke Forest, Hill Demonstration Forest, Raven Rock State Park, and Eno River State Park in the central Piedmont and also examples in parts of Uwharrie National Forest. Basic mesic forest communities are scattered across the Piedmont; good examples are found in Caswell Game Land, Uwharrie National Forest, and Raven Rock State Park.
Several distinctive variants of these subtypes are recognized in the Coastal Plain, including the swamp island, mesic flat, and bluff/slope variants of mesic mixed hardwood forest, and the terrace slope and marl outcrop variants of basic mesic forests. Examples of the mesic mixed hardwood forest bluff/slope variant are found in Croatan National Forest, Merchant’s Millpond State Park, and Cliffs of the Neuse State Park. Examples of the swamp island variant are found in the Great Dismal Swamp National Wildlife Refuge and along the Waccamaw River in Columbus County, and examples of the upland flat variant are found in Perquimans and Bertie counties.
Problems Affecting Habitats
There may be an increase in natural fires (due to increased drought and higher average temperatures), but landscape fragmentation and fire suppression practices will likely continue to prevent most fires from spreading very far in the Piedmont and in the dissected lands in the Coastal Plain where mesic forests occur. Mesic forests occur in sites sheltered from most fires, but wildfire during drought may increase the likelihood or severity of fires in them.
The importance of drought and hot spells in mesic sites is unclear. Most of these sites are mesic because of topographic sheltering such as north-facing slopes or deep ravines. These sites are buffered from extremes of weather. However, because they contain many species that are not adapted to hot and dry conditions, they may suffer stress from even slightly drier conditions. Although we are not aware of any identified problems from phenological disruption, there may be higher potential for it in these communities than others, because they have many spring ephemeral plants.
An increase in hurricanes or other severe storms likely would increase wind damage in forests. Increased storm disturbance will increase the potential for exotic plant invasion, especially if a seed source is present in nearby developed or disturbed areas, or has already entered the community. Wind damage is often more severe in forests if there are adjacent openings such as logged or developed areas. If more intense storms increase flood heights, this will affect lower lying mesic forests. If wind throw stimulates salvage logging, this will further increase the damage to natural areas.
Climate Change Compared to Other Threats
Comparing climate change to other ecosystem threats can help define shortand long-term conservation actions and recommendations. The greatest threats to Piedmont and Coastal Plain Mesic Forests are those from development and logging which are ongoing land uses. Climate change is less of a threat than ongoing concerns, but will exacerbate some of them. Although expected threats associated with climate change are the least significant to these forests, increased wind damage, droughts, and warmer temperatures may alter their structure and size.
Impacts to Wildlife
Fragmentation of mesic forests into smaller or narrower contiguous blocks is a concern for forest interior birds (like the Wood Thrush, Hooded Warbler, and Worm-eating Warbler), which may occur in lower densities or suffer lower productivity or survival in small habitat patches. Fragmentation by roads and development can be problematic for reptiles (especially Timber Rattlesnakes and Eastern Box Turtles), amphibians, and small mammals (particularly Eastern Mole) that suffer high mortality on roads when traveling between forest patches or between mesic forest and other habitats.
A lack of canopy gaps in this habitat type has probably lead to a reduced number of some avifauna such as the Eastern Wood-pewee, Hooded Warbler, and Kentucky Warbler. This reduction in canopy gaps has also caused a decline in midstory and understory vegetation, which has impacted species such as the Swainson's, Kentucky, and Hooded Warblers, and Wood Thrush. The reduction in standing snags negatively impacts primary and secondary cavity nesting species and the lack of dead wood on the forest floor impacts herpetofauna and small mammals.