|
| General Description |
This habitat consists of shallow, wetlands dominated by graminoids. Ooften called beaver meadows in the past, rhey were once major features of stream and river valleys, forming hummocks and larger wet meadows as beaver ponds gradually filled in with sediments. With the near extinction of beavers across North America at the beginning of the 20th Century, these habitats became greatly reduced and fragmented. Many of their distinctive species -- most prominently, Mitchell's Satyr -- were left as rare relicts, scattered across their once vast geographic range.
The plants in this habitat grow in wet, mucky soils and experience frequent, shallow flooding. Some species, such as Carex stricta, form hummocks that rise up to a foot above the surface of the waters. Most grow in full sun but are capable of surviving in narrow galleries along streams as shrub and tree cover develop due to succession. Some are even capable of persisting for at least a while under full shade. In some areas along the lower Roanoke and other brownwater river floodplains, extensive meadows of Carex occur under a closed hardwood canopy.
The Lepidoptera belonging to this habitat all occur in association with wetland graminoids, with many known to have larvae that are obligate feeders on Carex or the other species of graminoids. The Orthoptera probably feed more generally on both sedges and wetland grasses. The one predatory member of this habitat, Libellula flavida, is associated with sedgy bogs, seeps, and beaver sedge meadows. Adults perch in open, sunny areas; larvae have also been found with the same, shallow, graminoid-choked waters.
Unlike bogs, fens, hillside seepage bogs, and sandhill seeps, all of which have significant amounts of sphagnum and thick deposits of peat, this habitat is more marsh-like in character, lacking these deposits. The openness characteristic of this habitat is maintained by frequent flooding and -- at least historically -- beaver activity, rather than occasional fire or the build up of peat too deep to allow tree growth.
|
| Abiotic Factors |
Geographic Regions: High Mountins to the Lower Coastal Plain. USDA Hardiness Zones: 6-8. Landform: restricted to floodplains and wet flats. Soil Moisture: hydric. Soil Texture: mucky. Soil pH: usually acidic due to the build-up of humic acids. Soil Nutrients: generally poor with nutrient-rich examples found only in a few fens. Mucky soils are also typically anoxic. Microclimate: warm to cool, humid. Flood Frequency: several times per year to permanent. Flood Duration: weeks to months or permanent. Presence of Pools: common; both permanent and ephemeral ponds and pools may imbedded withing this habitat. Fire Frequency: uncommon in bottomlands but frequent when adjoining fire-maintained habitats. Drought Frequency: rare. Insolation: partial to full sun.
|
| Biotic Structure |
Key Species species of graminoids are the dominant plant species in this habitat. Vegetation Type: herbland. Strata: canopy, subcanopy, and shrub layers are absent, although individual trees or small shrubs may be present. Organic Shelter, Foraging, and Nesting Structures: woody debris can be essentially absent; the thick growth of graminoids provides the main shelter, foraging and mating sites in this habitat; in some cases, the dead leaves of the graminoids accumulate to form hummocks that are well-elevated above the normal water levels, providing additional shelter and nesting sites.
|
| Co-evolved Species Groups |
Phagic and Competitory Symbioses:
Sedge species // Amolita fessa-Amolita obliqua-Amplicephalus osborni-Cosmopterix clemensella-Deltote bellicula-Euphyes dion-Meropleon diversicolor
Carex species // Lethe appalachia-Neonympha mitchellii
|
| Determining Species |
|
| Estimated Risk to the Determining Species |
One sedge species in this habitat is ranked as S1 and five others are ranked as S2. The Average PE is equivalent to a State Rank of S3, indicating a moderate level of conservation concern.
|
| Estimated Risk to the Co-evolved Species Groups |
|
| Estimated Security of the Habitat |
Fifteen species in this habitat are considered secure in North Carolina. The Proportion of Secure Species, however, is moderately low at 25%.
|
| Index of Habitat Imperilment |
The combination of a moderately high value of ENE, a moderately low value of PSS, and no identified SH or SX species results in a moderately high value of HRI. Although not given much attention for conservation in the past, this habitat merits at least a stronger monitoring effort to determine whether it is declining or actually increasing.
|
| Identified Risks |
|
| Observed Trends |
Sedge and wetland graminoid meadows may actually be increasing due the restoration of beavers to the North Carolina landscape and also to the impacts of deer grazing in the bottomlands, which may be opening up more areas for this habitat type at the expense of the thick shrub layers that once existed in our forested floodplains. In many bottomlands, now, the understory is very open and very expansive graminoid meadows are now prominent features.
|
| Distribution Map | |
| Distribution |
|
| Major Conservation Reserves |
|
| Priority Areas for Surveys and Conservation Protection |
|
| Stewardship and Management Recommendations |
|
| References |
|
| Updated on |
2022-06-05 17:33:07 |
»