The California Department of Transportation (Caltrans) Division of Environmental Analysis with support from Caltrans district staff and technical experts have developed the Wildlife Connectivity Assessment Tool (“WildCAT”). This tool has been developed for internal use by transportation planners, biologists, and other staff to determine if existing natural resources datasets highlight potential areas of interest for wildlife movement or habitat connectivity around and across the State Highway System (SHS). Caltrans has already completed construction of over 200 individual structures along the SHS as either focused wildlife crossings or multi-purpose structures with wildlife crossing enhancements. The goal of WildCAT is to inform transportation planners and biologists at all stages of project development and delivery to improve advanced planning efforts, transportation concept reports, Planning and Environmental Linkages efforts, and project-specific environmental assessments. The WildCAT output is a visual representation of the additive sum of the overlap of several GIS datasets, with a focus on habitat integrity datasets. The GIS dataset layers include mapped wildlife corridors and linkages, wildlife-vehicle collision hotspots, designated open space areas, federally designated critical habitat, areas of high biodiversity, and more. Caltrans applied a weighted scoring system of 1-4 to the individual GIS layers within the program based on organizational priorities that focus on protected species conservation, threatened and endangered species recovery, and enhancing motorist safety. For example, the GIS layers for modeled high-confidence terrestrial wildlife habitat corridors and long-term wildlife-vehicle collision hotspots each have a score of 4; the layer for federally designated critical habitat for terrestrial wildlife species has a score of 3; and the layer for mapped freshwater wetlands has a score of 1. For any area or segment on the SHS, users can easily view opportunities for planned improvements, areas that may warrant further study, or locations were wildlife connectivity should be included in projects. The WildCAT program generates an output of hexagon polygon features, symbolized in a choropleth map, along the SHS and surrounding areas. WildCAT will be used internally by Caltrans staff and updated annually as GIS layers are updated or as new data become available, ensuring the tool utilizes the best scientific data.
Mainstreaming ecology in transportation planning and program delivery