Habitats of North Carolina
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Lentic Habitats
General Pond Shorelines
General Description This habitat consists of open, shallow ponds located along stream and river channels; unlike depression ponds -- the other major type of natural pond habitats in North Carolina -- they do not occur in isolation from stream flow. Instead, they occur as the result of dams, originally made by beavers but now frequently man-made as farm ponds. A major difference between these two types of ponds is that beaver dams are relatively permeable -- the loose construction and frequent breaches allow aquatic species to more through them, whereas man-made dams constituted nearly impenetrable barriers to movements. For the same reason, silt and pollutants can pass through the dams made by beavers but cannot do so in artificial ponds. During times of drought, beaver ponds also continue to allow some degree of water flow downstream, helping to preserve water availability in entire watersheds. Artificial impoundments, on the other hand, preserve water only in their small, isolated localities. As a result of these differences, beaver ponds are highly important in maintaining native species not only within their own limits but across entire river and stream basins.

Artificial ponds are included in this habitat only where they have not been subject to heavy agricultural runoff, intensive use by livestock, or overstocking of game or farm fish. Where allowed to exist under semi-natural and unpolluted conditions, these ponds often support species that were originally associated with beaver ponds. In fact, the proliferation of farm ponds that followed the massive extirpation of beavers may have been an important factor allowing these species to survive within our region.

The Determining Species of this habitat include only aquatic or amphibious species associated with open, shallow ponds. Species associated with "beaver meadows", marshes, shoreline shrub-thickets and other habitats often found as part of the larger complex of habitats created by beaver activities are treated separately. The same is true for species that make use of deep water lakes and reservoirs, coastal marshes, forested wetlands or ephemeral pools.

Currently, this group is mainly composed of Odonates that are associated with small, shallow, open ponds. The nymphs of these species dwell within the ponds themselves and the adults forage over the ponds or along their shorelines, where mating also takes place. Since dispersal is done mainly by flying adults, the barrier effect of artificial dams is not a major factor for this group of species, many of which are common sights along the edges of semi-natural farm ponds. While frogs, toads, and pond-dwelling salamanders also have adults capable of overland dispersal, most also make use of other types of wetlands, especially those that are intolerant of the presence of fish species.

Abiotic Factors Geographic Regions: Low Mountains to Lower Coastal Plain. USDA Hardiness Zones: 6-8. Landform: restricted to the floodplains of perennial streams and rivers. Soil Moisture: hydric. Soil Texture: alluvial/loamy/silty/mucky. Soil pH: acidic to circumneutral -- includes blackwater as well as brownwater floodplains. Soil Nutrients: poor to rich. Microclimate: warm to cool, humid. Flood Frequency: permanently flooded. Flood Duration: year-round. Presence of Pools: a key factor for this habitat. Fire Frequency: generally not a factor except around the margins of a pond. Drought Frequency: extremely rare. Insolation: full sun; in addition to the limiting effects on tree species of permanent inundation, woody species located along the margins of the ponds are felled by beaver for food.

Biotic Structure Vegetation Type: open ponds that may or may not have significant floating vegetation. Organic Shelter, Foraging, and Nesting Structures: standing snags and fallen logs are a common feature of beaver ponds, especially in their earlier successional stages; beavers also actively harvest trees and shrubs in the vicinity of the ponds and haul them into the ponds themselves for storage

Co-evolved Species Groups Competitor Guilds:
Dragonfly nymphs and adults show interspecific aggression related to competition and/or interspecific predation (see Moore, 1964; Pezalla, 1979; Wissinger, 1989). Species that are similar in size, phenology, and range and that use similar habitats and foraging techniques fall into the classic structure of competitory guilds as described by Root (1967). Pond-dwelling Odonates can be placed in the following guilds:
Pond Edge Percher/Salliers: Dythemis velox-Libellula auripennis-Libellula cyanea-Libellula luctuosa-Libellula pulchella-Lestes australis-Lestes inaequalis
Pond Edge Hoverer/Gleaners: Enallagma doubledayi-Enallagma geminatum-Enallagma traviatum
Pond Littoral Libellula Nymphs: Libellula auripennis-Libellula cyanea-Libellula luctuosa-Libellula pulchella

Determining Species
Lindernia dubiaFalse pimpernelG5S4S40.00041
Celithemis vernaDouble-ringed PennantG5S3S4S3S40.00132
Enallagma vesperumVesper BluetG5S3S4S3S40.00132
Anax longipesComet DarnerG5S4S40.00041
Epitheca costalisStripe-winged BaskettailG5S4S40.00041
Lestes inaequalisElegant SpreadwingG5S4S40.00041
Libellula pulchellaTwelve-spotted SkimmerG5S4S40.00041
Nehalennia integricollisSouthern SpriteG5S4S40.00041
Dythemis veloxSwift SetwingG5S4S5S4S50.00010
Celithemis elisaCalico PennantG5S5S50.00000
Celithemis fasciataBanded PennantG5S5S50.00000
Celithemis ornataFaded PennantG5S5S50.00000
Enallagma doubledayiAtlantic BluetG5S5S50.00000
Enallagma geminatumSkimming BluetG5S5S50.00000
Enallagma traviatumSlender BluetG5S5S50.00000
Epitheca cynosuraCommon BaskettailG5S5S50.00000
Ladona deplanataBlue CorporalG5S5S50.00000
Lestes australisSouthern SpreadwingG5S5S50.00000
Libellula auripennisGolden-winged SkimmerG5S5S50.00000
Libellula cyaneaSpangled SkimmerG5S5S50.00000
Libellula luctuosaWidow SkimmerG5S5S50.00000
Perithemis teneraEastern AmberwingG5S5S50.00000
Nr = Number of Ranked Species = 22
Ner = Number of Extant, Ranked Species = 22
Nv = Number of Historic and Extirpated Species = 0
Nar = Number of Species at Risk of Extirpation (State rank > S5) = 9
Nss = Number of Secure Species (State Rank = S5) = 13
Pss = Proportion of Secure Species (Nss/Ner) = 0.59091
ENE = Expected Number of Extirpations (Sum of PE) = 0.00520
Average PE (ENE/Ner) = 0.00024
Habitat Risk Index = (Nar+Nv) x Average PE = 9 x 0.00024 = 0.00216

Estimated Risk to the Determining Species No species in this habitat has a higher State Rank than S3S4. The Average PE value is equivalent to a State Rank of S4.

Estimated Risk to the Co-evolved Species Groups
Estimated Security of the Habitat Thirteen species in this habitat are considered secure in North Carolina. The Proportion of Secure Species of 59% is relatively high. These values reflect the fact that this habitat is still widespread in the state and most occurrences are reachable by the dispersal abilities of the Determining Species, all but one of which are capable of flight.

Index of Habitat Imperilment The combination of a very low value of ENE, a high value of PSS, and no identified Historic or Extirpated Species, results in a value of HRI that falls with our Tier 5 Level of Conservation Concern (0.005 ≥ HRI > 0). That level indicates a negligible priority for conservation efforts.

Identified Risks
Observed Trends
Distribution Map
Major Conservation Reserves
Priority Areas for Surveys and Conservation Protection
Stewardship and Management Recommendations
References Moore, N.W., 1964. Intra-and interspecific competition among dragonflies (Odonata). The Journal of Animal Ecology, pp.49-71.

Pezalla, V.M., 1979. Behavioral ecology of the dragonfly Libellula pulchella Drury (Odonata: Anisoptera). American Midland Naturalist, pp.1-22.

Wissinger, S.A., 1989. Seasonal variation in the intensity of competition and predation among dragonfly larvae. Ecology, 70(4), pp.1017-1027. Available online at: http://links.jstor.org/sici?sici=0012-9658%28198908%2970%3A4%3C1017%3ASVITIO%3E2.0.CO%3B2-9

Updated on 2022-10-02 19:40:39