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

Atlantic pigtoe's (Fusconaia masoni) preferred habitat is coarse sand and gravel, and rarely in silt and detritus. Historically, the best populations existed in small creeks to larger rivers with excellent water quality, where flows were sufficient to maintain clean, silt-free substrates. This species originally ranged from the James and Chowan River basins in Virginia, the Roanoke, Tar, Neuse, Cape Fear, Pee Dee, and Catawba River basins in North Carolina, the Edisto River Basin in South Carolina, and the Savannah, Ogeechee, and Altamaha River basins in Georgia.

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 0.262 and 0.679 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.

For more information please click here https://xfer.services.ncdot.gov/gisdot/Metadata/Atlas/TechDocs/

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.