The Carolina madtom Potential Habitat dataset is a polygon layer depicting high, moderate and low potential habitat locations for Carolina madtom in NC counties.

Carolina madtom (Noturus furiosus) is a freshwater fish species endemic to the Tar-Pamlico, and Neuse River (including the Trent) drainages in North Carolina. The species occurs in riffles, runs, and pools in medium to large streams and rivers. Ideally, it inhabits fresh waters with continuous, year-round flow and moderate gradient in both the Piedmont and Coastal Plain physiographic regions. Optimal substrate for the Carolina madtom is predominantly siltfree, stable, gravel and cobble bottom habitat, and it must have cover for nest sites, including under rocks, bark, relic mussel shells, and even cans and bottles. The Carolina Madtom faces a variety of threats from declines in water quality, loss of stream flow, riparian and instream fragmentation, deterioration of instream habitats, and expansion of the invasive predator Flathead catfish. These threats are expected to be exacerbated by urbanization and climate change.

The three levels are: Low, Moderate, and High Probability of Potential Habitat (based on similarity of environmental conditions to those found at known occurrence locations). The category thresholds were set based on the distribution of predicted values for known habitat. The High-Moderate threshold is set at the level where 90% of the observed potential habitat (species presence and reviewer judgments) falls within the High category (Presence Percent Correctly Classified). The Moderate-Low threshold were set at the level where 8% of the observed potential habitat (species presence and reviewer judgments) falls within the Moderate category and 2% within the Low category. The final thresholds for this species are 0.526 and 0.767 for the Low-Moderate and Moderate-High thresholds, respectively. Lower thresholds result in more of the range labelled as High probability of habitat and greater misclassification of known non-habitat locations. Higher thresholds result in more of the range labelled as Low probability of habitat and greater misclassification of known habitat locations.

Given the larger spatial unit of ecological models and ecological characteristics of aquatic species, the landscape scale environmental attributes of potential habitat varied greatly among sites and could closely resembled non-habitat sites. It is important to remember that potential habitat (and non-habitat) can occur at any classification level within a catchment and must be verified by a qualified biologist.

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Datasets developed under Project ATLAS do not replace any NRTR work for future projects and may not be used as a replacement for site visits / field surveys by qualified professionals and hence should be used only as a supporting platform for decision making. Use of this dataset for project scoping or screening is merely pre-decisional.