|
| General Description |
This habitat includes species associated with the grass stage of secondary succession, as it occurs widely over the state. It also includes pastures, hayfields, and other managed grasslands that are composed of native species of grasses and associated forbs, along with their symbiotic herbivores and other native members of the grassland food web.
The grasslands included here are usually successional and hence transitory in our area. Under natural conditions, species found in these habitats are fugitive, colonizing species. Following Eurpean settlement, however, grasslands became managed for livestock production and became more persistent. Management practices originally involved periodic burning (as was done previously by Native Americans) or mowing, both of which were conducive to maintaining populations of native species. These species, however, are declining under current agricultural practices that are replacing native grasses with more intensively managed exotic species (see discussion of Threats and Trends below).
This particular habitat includes species that are found widely across the state, occurring extensively in at least two of the state's physiographic provinces. These successional and/or semi-natural grasslands intersect other, more naturally persistent grasslands, particularly those associated with glades, savannas, and beach dunes. Each of those habitats, however, have additional habitat factors, including those that keep the habitats open rather than closing in to forest. Their characteristic species are also, consequently, different and they are treated in separate habitat groups.
|
| Abiotic Factors |
Geographic Regions: Lower Coastal Plain to High Mountains. USDA Hardiness Zones: 6-8. Landform: ridges, slopes, bottomlands, and wet flats. Slope Aspect: occurs on all slopes aspects as well as on ridges and flats. Soil Moisture: Dry to wet. Soil texture: sandy to loamy to alluvial. Soil pH: circumneutral to acidic. Soil Nutrient Content: rich to poor. Microclimate: Warm to cool; humid to dry. Hydrological Features: surface waters are common to scarce. Flood Frequency: varies from occasionally to never flooded. Flood Duration: nonexistent to transitory. Fire Frequency: common to rare. Drought Frequency: frequent to rare. Insolation: full sun
|
| Biotic Structure |
Vegetation Type: open grasslands, including those associated with natural succession and those consisting of native grasses that are maintained by mowing or fire; examples that include "improved" pasture grasses or that are maintained by application of herbicides or pesticides
|
| Co-evolved Species Groups |
Phagic and Competitory Symbioses:
Andropogon and Schizachyrium species // Atrytonopsis hianna-Hesperia metea-Nastra lherminier
Digitaria ciliaris // Cosmopterix magophila
Tridens flavus // Heliocheilus lupatus-Polites origenes
|
| Determining Species |
|
| Estimated Risk to the Determining Species |
One species in this habitat is ranked as S1S2 and two are ranked as S2. The Average PE is equivalent to a State Rank of S3. |
| 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 is moderately high at 42%. Successional grasslands are still fairly well distributed across the state, but the management of pastures and hayfields is changing, with fewer examples now supporting the native species that once thrived in them.
|
| Index of Habitat Imperilment |
The combination of a moderately high Average PE with a relatively large number of species produces a relatively high value of ENE. That value is only moderately reduced by the PSS value. The resulting value for HRI is consequently moderately high, especially for a semi-natural habitat type.
|
| Identified Risks |
Changes in management of pastures and hayfields that replace native warm-season grasses with cultivated species that require heavy use of agricultural chemicals have been implicated in the decline of grassland birds in North Carolina (see Sharpe, 2010), as has the more intensive use of mechanized farm equipment. Although not often mentioned, the great reduction in grasshoppers and other grassland insects is likely also taking a toll on the vertebrates associated with our natural (or semi-natural) grasslands. That the insects themselves are key components of these habitats is generally completely overlooked.
|
| Observed Trends |
|
| Distribution Map | |
| Distribution |
|
| Major Conservation Reserves |
|
| Priority Areas for Surveys and Conservation Protection |
|
| Stewardship and Management Recommendations |
|
| References |
Askins, R.A., Chávez-Ramírez, F., Dale, B.C., Haas, C.A., Herkert, J.R., Knopf, F.L. and Vickery, P.D., 2007. Conservation of grassland birds in North America: understanding ecological processes in different regions. Accessible online at: https://digitalcommons.conncoll.edu/cgi/viewcontent.cgi?article=1004&context=biofacpub
Rosenberg, K.V., A.M. Dokter, P.J. Blancher, J.R. Sauer, A.C. Smith, P.A. Smith, J.C. Stanton, A. Panjabi, L. Helft, M. Parr, P.P. Marra. 2019. Decline of the North American avifauna. Science. Published Online19 Sep 2019. DOI: 10.1126/science.aaw1313
Sharpe, T., 2010. Grassland Management. In: Tarheel wildlife-A guide for managing wildlife on private lands in North Carolilna. North Carolina Wildlife Resources Commission, Raleigh, North Carolina. Available online at: https://www.ncwildlife.org/Portals/0/Hunting/Documents/Tarheel_Wildlife.pdf |
| Updated on |
2022-08-03 17:03:31 |
»