California is home to a number of ungulates, including mule deer, elk, pronghorn, and bighorn sheep. Many ungulate herds in California are migratory and inherently need large landscapes to persist, making them particularly vulnerable to habitat loss and fragmentation. Transportation infrastructure, such as highways and railways, is a key source of fragmentation, inhibiting ungulate migratory animal movements. Preserving connectivity between habitat patches is therefore crucial to conserve these charismatic species and to facilitate their movement across the landscape. California Department of Fish and Wildlife has engaged in planning efforts in recent years to identify and improve the quality of ungulate winter range habitats and migration corridors. GPS collars are deployed on ungulate herds to gather fine-scale movement data. Data is collected over years and Brownian bridge movement models are computed using GPS locations, date, time, and average location error to identify individual movement patterns per migratory season. These models are then combined at the population level to ascertain high-use corridors, stopover sites, and winter range for a herd. Mapping ungulate corridors aids managers in the identification of potential movement barriers and bottlenecks, which may prevent an individual from safely moving between habitat patches. Moreover, models help to inform conservation strategies, such as road crossing structures, to maintain connectivity. In ungulates, migration is a learned behavior, meaning it may be difficult to re-establish population level migration routes once they are lost, resulting in dramatic population declines. It is especially vital therefore, with California’s growing human population and heavily used transportation infrastructure, that further decline due to habitat loss and fragmentation along movement corridors is prevented where possible.
Link to the story map that is referenced in this presentation:
https://storymaps.arcgis.com/stories/96f0d5f05d7845b8bed3f05664655d64