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| General Description |
This habitat is defined by aquatic to semi-aquatic species that are associated with rivers that possess extensive areas of riffles: there must be at least a moderate current and plentiful rocks present. All species in this habitat must be able to cope with the scouring action of the rivers.
The Odonates included in this habitat perch as adults on exposed rocks located well out in the water. Foraging and mating take place in the vicinity of the riffles. Nymphs of Neurocordulia are rock-clingers (also clinging to roots and woody debris) (Tennessen, 2018) and may therefore also stick close to the riffles. So may the nymphs of the two damselflies, who live within aquatic vegetation (Schwiebert, 2007). The nymphs of the Gomphurus species, on the other hand, may reside in substrates located away from the rocks. Gomphurus nymphs are burrowers who live in substrates -- sometimes buried quite deeply -- ranging from sand, silt, gravel, and mud (Tennessen, 2018). All of these species generally require the well-oxygenated waters associated with riffle habitats and are usually found only in unpolluted rivers.
Virtually all examples of this habitat occur west of the Fall-line and include species that occur in both the Piedmont and Mountains or in the Piedmont alone. Species restricted to the cooler rivers of the mountains are treated in the Montane Rocky Rivers habitat.
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| Abiotic Factors |
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| Biotic Structure |
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| Co-evolved Species Groups |
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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 |
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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 |
Schwiebert, E., 2007. Nymphs, Stoneflies, Caddisflies, and Other Important Insects: Including The Lesser Mayflies (Vol. 2). Rowman & Littlefield.
Tennessen, K.J., 2018. Dragonfly Nymphs of North America: An Identification Guide. Springer. |
| Updated on |
2019-09-08 18:48:50 |
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