ATTACHMENT  7. Documentation for the UDL Overlap Tool
The UDL Overlap tool supports the assessment of threatened and endangered species by summarizing the co-occurrence between potential pesticide use sites and species location. This tool uses GIS based datasets when considering co-occurrence and compiles results as a percent overlap (i.e., the area of potential use and off-site movement found within the species location divided by the total area for the species). Generated using a number of publicly available land cover datasets, the EPA Use Data Layers (UDLs) delineate the potential pesticide use locations and areas where off-site movement could occur following application. The datasets delineating species range and designated critical habitat are provided by the U.S Fish and Wildlife Service (USFWS) and National Marine Fisheries Services (NMFS) of NOAA. This tool generates outputs for species ranges and designated critical habitats separately, with the resulting percent overlaps summarized by use and off-site distance. When assessing impacts to threatened and endangered species, the outputs from this tool are utilized to set the overlap category, as low (<5%), medium (<10% but >5%) or high (>10%).

The full methods and documentation are available with the tool at: 
https://www.epa.gov/endangered-species/provisional-models-and-tools-used-epas-pesticide-endangered-species-biological

