Overview
Habitat connectivity is critical for maintaining viable populations of wildlife species, particularly in the face of anthropogenic pressures and a changing climate. Barriers created by linear infrastructure such as roads, railways, and canals can influence wildlife movement, impede genetic exchange among populations, cause direct mortality, and ultimately reduce resilience of populations. Historically, efforts to identify and maintain important movement corridors (and conversely, remediate significant barriers to movement) have been somewhat limited and executed in a piecemeal fashion, but in recent years increased interest in a systematic approach to restoring, maintaining, and enhancing habitat connectivity for wildlife has emerged. Among other efforts, in 2018 the U.S. Secretary of the Interior issued Secretarial Order No. 3362 (SO 3362) directing the Bureau of Land Management (BLM), U.S. Fish and Wildlife Service (USFWS), and National Park Service (NPS) to work with western state wildlife agencies to enhance the quality of big-game winter habitat and migration corridors on and adjacent to federal lands
The California Department of Fish and Wildlife (CDFW) and The California Department of Transportation (Caltrans) are committed to meaningfully addressing wildlife connectivity across the state. This webpage and future updates will highlight how and where we will do more together. Further, the State of California continues to lead in this space with the passage of AB 2344 which, among other things, added a requirement to the Streets and Highway Code Section 158 that Caltrans consider wildlife connectivity areas identified by CDFW. This dataset identifies and provides a roadmap on where we will solve these challenges together.
Terrestrial Wildlife Connectivity Barriers Map. Open full-screen
In 2020, CDFW conducted an initial assessment of priority barriers to wildlife movement throughout the state. In 2022, CDFW reviewed and re-evaluated each 2020 wildlife barrier segment, updated the list of priority wildlife barriers in each region, identified additional wildlife barriers across the state, and identified the two top priority barriers in each region. In 2024, CDFW further refined and expanded the dataset to include additional information about each segment, modify existing segments as necessary (including merging, splitting, and/or extending segments as appropriate), and identify additional segments.
The dataset currently includes 204 segments of linear infrastructure that have been identified as wildlife barriers, or locations where wildlife movement is known to be negatively impacted. Of those barrier segments, 60 are classified as priority barriers; 12 of these are further identified as statewide top priorities. Collectively, all barrier segments comprise a total of 4914.7 kilometers of linear infrastructure; priority segments account for 1069.3 kilometers of this total and top priority segments account for 503.7 kilometers. Nearly all the known barriers are associated with the State Highway System, but railroads, canals, high-speed rail alignments, and local roads are also represented.
Some segments may be impacted by more than one infrastructure type (e.g., a high-speed rail alignment along a highway). Twenty of the identified priority wildlife barrier segments occur within SO 3362 priority areas. Outside these areas, CDFW identified additional priority barriers to ungulates including deer, elk, pronghorn, and bighorn sheep. Other species associated with barrier segments include large carnivores (mountain lion, black bear, gray wolf), mesocarnivores (e.g., bobcat, fox, kit fox, fisher, badger, ringtail), small mammals (e.g., Tipton kangaroo rat, San Joaquin antelope squirrel), birds (California gnatcatcher, sage grouse), reptiles (e.g., Alameda striped racer, western pond turtle, giant garter snake, blunt-nosed leopard lizard), amphibians (e.g., California tiger salamander, Santa Cruz long-toed salamander, California red-legged frog, arroyo toad), and one invertebrate (Quino checkerspot butterfly).
Bringing back these critically important movement pathways is part of CDFW’s mission. Achieving meaningful progress will take time, funding, and effort. We look forward to working in close partnership with our colleagues at the federal, state, local levels, as well as tribal nations, and interested stakeholders to restore wildlife connectivity throughout the state. Together, we can make meaningful progress to restore wildlife connectivity throughout the state.
Statewide Top Priority Wildlife Connectivity Barriers
The Barriers Database includes a comprehensive list of all terrestrial barriers information including the top priority barriers. Each of the six terrestrial CDFW Regions identified two wildlife barriers that are top priorities for remediation based on impacts to wildlife populations, for a total of twelve top priorities statewide; six of these segments are identified as a top priority by more than one region. Each top priority barrier was associated with at least one ungulate species (deer, elk, pronghorn and/or bighorn sheep) and ten of the 12 top priority barriers were associated with mountain lions. Five top priorities coincided with SO 3362 ungulate priority areas. Each of the top priority barriers was associated with the State Highway System, and two were also associated with high-speed rail.