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| General Description |
This habitat is composed of open, forb-dominated fields that invade lands opened up by disturbances; in our area, these fields follow clearing of forests, or the abandonment of cultivated fields which themselves occupy lands once covered with forests. If left to natural processes, these habitats are transitory and will eventually be replaced by the return of forests. This habitat includes the most generalized examples, with its species occurring in at least two of the state's physiographic provinces. Soils typically have some loammy content; fields growing on sandy substrates are treated separately. Both upland and lowland examples are included.
The Determining Plant Species of this habitat type mainly consist of dicot forbs and vines; the grasses that typically occur in successional fields are treated separately in the General Successional and Semi-Natural Grasslands habitat, which strongly intersects the one considered here but has a somewhat different ecological trajectory. Similarly, the trees associated with successional or semi-natural grasslands are covered in the Forest-Field Ecotones and Groves habitat.
Animal members of this habitat group are in some cases obligate herbivores on the plant members of the group but most are associated more generally with areas of dense herbaceous vegetation. Like the plant species, these animals are well-adapted for dispersal, allowing them to keep up with a constantly changing environment. Several of the insects belonging to this group -- especially the butterflies -- lead a nomadic, migratory lifestyle, reproducing opportunistically whenever they find suitable populations of their host plants.
Although now associated with human-disturbed landscapes, the native species that we include as members of this habitat were originally adapted to rapidly colonizing lands where forest cover was destroyed by floods, fire, or storms. Some are found in other, more persistent types of open habitats but the majority of the occurrences of these species are believed to associated with sites undergoing succession back to forest. Under natural conditions, these habitats are fairly ephemeral, with the species needing to be well-adapted to dispersal in order to keep up with shifting landscape conditions.
Following conversion of much of the former forest lands in eastern North America to croplands, these species became much more common and widespread than their original condition. They are now so associated with abandoned farm lands that they are now described as "old field" species. Although many exotic "weeds" are now major components of successional habitats, these are left out of consideration in determining the conservation needs of this habitat.
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| 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
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| Biotic Structure |
Vegetation Type: open forblands, including those associated with natural succession and those consisting of native forbs that are maintained by mowing or fire. Strata: only the herb layer is well-developed in these habitats, although both trees and shrubs soon invade. Organic Shelter, Foraging, and Nesting Structures: the herb layer provides virtually all of the shelter, foraging, and nesting sites within this habitat; viney tangles created by Rubus species are particularly important as shelter for many species of birds and mammals.
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| Co-evolved Species Groups |
Phagic and Competitory Symbioses:
Ambrosia species // Chionodes mediofuscella-Ponometia candefacta-Ponometia erastrioides-Schinia rivulosa-Schinia thoreaui-Spragueia leo
Apiaceae species // Papilio polyxenes
Asteraceae species // Astrotischeria heliopsisella-Condica sutor-Condica videns-Dichomeris flavocostella-Leuconycta diphteroides-Ogdoconta cinereola-Perigea xanthioides-Vanessa virginiensis
Bidens species // Cirrhophanus triangulifer
Brassicaceae species // Pontia protodice
Chamaecrista species // Abaeis nicippe-Phoebis sennae-Pyrisitia lisa
Eupatorium species // Schinia trifascia
Helianthus species // Mesamia nigridorsum
Polygonaceae species // Timandra amaturaria
Rubus species // Coptotriche aenea
Rumex species // Lycaena phlaeas
Solanum carolinense // Synanthedon rileyana
Solidago species // Astrotischeria solidagonifoliella-Epiblema scudderiana-Gnorimoschema gallaesolidaginis-Limotettix anthracinus-Pelochrista similiana-Schinia nundina
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| Determining Species |
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| Estimated Risk to the Determining Species |
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| Estimated Risk to the Co-evolved Species Groups |
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| Estimated Security of the Habitat |
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| Index of Habitat Imperilment |
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| Identified Risks |
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| Observed Trends |
This habitat massively expanded during Colonial times, when European settlers cleared vast areas of previously forested lands to create farm lands. Traditional farming practices that involved letting fields go fallow periodically allowed natural old-field succession to take place, at least as a patchy, shifting mosaic similar to other disturbance-maintained habitats. Decline of this habitat began in the 1930's, due to the widespread soil erosion and loss of farming population due to the Great Depression; much former farmlands were restored to forests during that period. In the Post-war Period, increased use of mechanized farm equipment and agricultural chemicals greatly transformed the nature of farming, as did the replacement of small, family farms with vast expanses of industrialized farms owned by big agribusinesses. Extensive use of pesticides, including both herbicides and insecticides, along with "clean farming" practices -- removing hedgerows, shade trees, and any other obstacles to mechanized farm equipment -- have led to a great decline in the old-field successional habitats that were once a natural, although artificially expanded occurrence across much of the country.
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| Distribution Map | |
| Distribution |
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| Major Conservation Reserves |
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| Priority Areas for Surveys and Conservation Protection |
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| Stewardship and Management Recommendations |
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| References |
Oosting, H.J., 1942. An ecological analysis of the plant communities of Piedmont, North Carolina. American Midland Naturalist 28:1-126.
Sharpe, T., 2010. Idle-Area 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 |
2022-02-06 12:33:36 |
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