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| General Description |
This habitat includes permanent ponds and sloughs in the Coastal Plain that support dense masses of floating and submerged aquatic plants. Many of the sites occupied by this habitat represent natural depression ponds, including Carolina Bays, limesink ponds, and interdune ponds. Also included are beaver ponds, old mill ponds, borrow pits, and other shallow man-made ponds. This particular habitat is limited to the Coastal Plain, with the Determining Species found only or predominately in that region. The General Herbaceous Ponds habitat intersects with this habitat but also extends across the Piedmont and into the Mountains.
All of these habitats are open and very sunny, a critical factor for the high diversity of aquatic plants that are the Determining Species of this habitat. Swamp forests generally do not have enough insolation to support a high biomass of aquatic plants and are therefore not included. The Coastal Plain Sluggish Waters habitat intersects this habitat but also intersects swamp forests and is likewise treated separately.
Animal members of this habitat include herbivores such as the turtles and several moth species that have aquatic larvae that specialize on the plant members of this habitat. Also included are amphibious predators, such as the Dragonflies and Damselflies, that are adapted as nymphs to foraging within the submerged vegetation and as adults to hunting from perches on the emerged portions.
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| Abiotic Factors |
Geographic Regions: Sandhills to Lower Coastal Plain. USDA Hardiness Zones: 8. Landform: Open ponds located in stream and river floodplains and isolated ponds in poorly drained flats. Soil Moisture: hydric. Soil Texture: alluvial/loamy/silty/mucky. Soil pH: strongly acidic. Soil Nutrients: poor. Microclimate: warm and humid. Flood Frequency: permanently flooded. Flood Duration: year-round. Fire Frequency: generally not a factor except around the margins of the ponds; fires in depressional wetlands may be important for nutrient recycling. Drought Frequency: extremely rare. Insolation: full sun
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| Biotic Structure |
Vegetation Type: floating vegetation covering large areas of a pond's surface; trees and shrubs are very sparse or absent. Organic Shelter, Foraging, and Nesting Structures: standing snags and fallen logs are a common feature of beaver ponds, especially in their earlier successional stages; woody debris may be nearly absent, however in depressional wetlands that are burned during pond drawdowns. The floating mass of plants provides the main structural features of this habitat, providing shelter for both the specialist animal members of this habitat, as well as many other more generalized species. The adults of the Odonates that belong to this habitat, as well as other more generalized species use the plants as both hunting sites and as platforms for mating displays.
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| Co-evolved Species Groups |
Phagic and Competitory Symbioses:
Myriophyllum species/Parapoynx allionealis
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).
Bluets associated with this habitat can be placed in the following guild:
Pond Edge Hoverer/Gleaners: Enallagma concisum-Enallagma dubium-Enallagma minusculum-Enallagma sulcatum
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| Determining Species |
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| Estimated Risk to the Determining Species |
Under our model, the Average Probability of Extirpation, 0.06365, is equivalent to a state rank of S2. This reflects the large number of rare species -- six S1s and six S2s -- that belong to this habitat. Additionally, one species is considered Historic within the state.
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| Estimated Risk to the Co-evolved Species Groups |
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| Estimated Security of the Habitat |
Two species -- both animals -- are considered Secure within the state. For these species, both of which are capable of overland movements between ponds, there is sufficient connectedness between habitat units to support stable, long-lasting populations. The Proportion of Secure Species, 6%, is otherwise very low, indicating that most of the species belonging to this habitat do not disperse easily and become permanently extirpated during severe droughts that cause their pool habitats to completely dry out.
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| Index of Habitat Imperilment |
The large number of Species at Risk, coupled with the high Average PE, produce a large value for the Expected Number of Extirpations. With only a small counter-balancing influence due to PSS and with the additional influence of a single Vanished Species, the resulting value of HRI gives this habitat a high priority for conservation.
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| Identified Risks |
Drainage and conversion of depressional wetlands, including large, clay-based Carolina Bays has been a major source of loss of this habitat type. The near extinction of beavers at the end of the 19th Century must also have played a significant, although almost completely unnoticed source of loss of pond habitats in the Coastal Plain. The decline of millponds as a mainstay of flour production has had a similar impact, although some of these ponds were so extensive -- e.g., Merchants Millpond -- that they still support large numbers of the species belonging to this habitat.
In addition to the loss of the pools themselves, invasion of these habitats by a large and growing list of exotic aquatic weeds represents a significant threat. The rare plants belonging to this habitat are likely to suffer the most from competition with these invasive species, but there may also be impacts to the herbivores that are specialized on those species. Moreover, the large volume of decaying matter produced by the invasives may lead to severe anoxic events affecting the entire ecosystem of the ponds and lakes of which this habitat is a component.
For the aquatic insects belonging to this habitat, spraying to control mosquitos may have significant impacts. Use of BTI (Bacillus thuringiensis israelensis) is fairly specific in its effects on larvae of mosquitos and black flies, but the use of broad-spectrum insecticides may cause extirpation of the Odonate and moth species of this habitat.
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| Observed Trends |
Beavers were extirpated from North Carolina by the early 1900s and conversion of Carolina Bays and other depressional wetlands accelerated in the second half of the 20th Century. Changes in the population sizes and distributions of the species belonging to these habitats appears to be largely unrecorded.
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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 |
NC State University Cooperative Extension Service. 2021. Aquatic Weeds: A Pocket Identification Guide for the Carolinas, Second Edition. Univ. of NC Press; Chapel Hill.
NC State University Cooperative Extension Service. 2022. Aquatic, Wetland, and Invasive Plants. Website available online at: https://onslow.ces.ncsu.edu/aquaticweeds/
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| Updated on |
2022-05-20 23:22:49 |
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