Wildlife Corridors: A Last, Best Chance for Key Local Species?
The Big Sur Land Trust (BSLT) is collaborating with Connectivity for Wildlife LLC to study and identify local lands and waterways that provide important connectivity between core habitat areas for wildlife. When animal populations are unable to travel through a highly fragmented landscape to find mates they may become locally extinct. Wildlife corridors can reduce the negative effects of habitat fragmentation by facilitating the movement of wildlife species through habitat patches, helping key carnivore species such as mountain lions and bobcats establish their own home ranges. Connectivity for Wildlife LLC (CFW) is finalizing a report detailing the importance of wildlife corridors to animal populations in Marks Ranch, Toro Park, and Fort Ord. Mountain lions, gray foxes, bobcats, coyotes, deer, and North American badgers (a federally listed species of concern), were among the animal populations found to depend on key wildlife corridors for their habitat. Drawing on both high-tech satellite imagery and on-the-ground field work, this collaborative study graphically identifies a last remaining undeveloped connection between the protected upland habitats within Marks Ranch and Toro Park to the lowland and coastal habitats of the Fort Ord Natural Reserve.
In May 2007, BSLT purchased the 816-acre Marks Ranch in Salinas. A key goal has been to protect the Ranch’s natural characteristics, which offer important habitat for wildlife. Soon after the purchase, BSLT was contacted by Jesse Quinn, a UC Davis graduate student studying American badger populations at Fort Ord with support from the California Department of Fish and Game. Using radio-telemetry tracking, her team determined that a young badger was crossing Highway 68 several times during the mating season, from Fort Ord into Marks Ranch and back to Fort Ord, an area that is a high conservation priority in danger of becoming an isolated habitat patch due to development and roads. Hoping to build upon this research and to develop a better understanding of wildlife activity and movement on Marks Ranch and surrounding areas, BSLT contacted Tanya Diamond of CFW to begin documenting wildlife sightings and signs on the Ranch.
BSLT began a collaboration with CFW to study vegetation, habitat and wildlife sightings and signs on Marks Ranch, in order to determine likely movement patterns for wildlife based on habitat preference. The research team documented wildlife movement on the Ranch through track and sign identification and the use of photographic “trap” stations. Road kill data was also acquired, evaluated and incorporated into the study. CFW used data collected from field observations to “ground-truth” habitat suitability models used to predict likely movement patterns of focal species. Information gathered through this process determined that Marks Ranch provides important habitat for wildlife, serving as both home range and corridor habitat for large-ranging species, including mountain lions, gray foxes, bobcats, coyotes, deer, and North American badgers.
In August of 2008, BSLT moved to expand this study beyond Marks Ranch. The resulting ongoing regional connectivity study has two goals: to document species richness and relative abundance, habitat preference and movement patterns in the area; and to use the gathered data to prioritize and design land protection strategies that protect critical habitat for species while recognizing local development pressures and needs.
To date, the study has focused on the north end of the Sierra de Salinas Mountains and the area around Marks Ranch, Toro Park and the protected lands of Fort Ord Natural Reserve. Grassland, oak woodland, oak savannah and riparian habitats typify these two adjacent properties. On both sides of Highway 68, these protected lands are home to several state and federally listed plant and wildlife species, and provide critical habitat for sensitive species such as tiger salamander, dusky footed woodrat, North American badger and burrowing owl, as well as home range habitat for numerous wide-ranging species, including mountain lion, gray fox, bobcat, coyote, and deer. Equally important, these protected areas are part of a larger matrix of habitat that form critical linkages for these large-ranging species, allowing them to move between the upland habitats of the coast ranges and the lowland and coastal habitats fringing the Monterey Bay National Marine Sanctuary.
The eight focal species of this study consist of the North American badger, mountain lion, gray fox, Tule elk, kit fox, bobcat, mule deer, and Dusky-footed woodrat. These focal species represent the diversity of ecological interactions that can be sustained by successful linkage design and were selected on the basis of representing a diversity of habitat requirements and movement needs. This “focal species” approach recognizes that species move through and utilize habitat in a variety of ways.
Field data, collected by wildlife tracking techniques, were integrated into habitat suitability models and connectivity analysis. Wildlife tracking methods incorporating camera stations and tracking transects were used to detect species, and in some cases individuals. For example, bobcats have distinct pelage patterns that can identify individuals; this data can also be used to calculate species’ relative densities.
Data collection was primarily done using remote camera, augmented with wildlife tracking when applicable. The advantage of using these cameras is that movement patterns, such as an animal traveling back and forth through the highway culverts, can be captured. The cameras are digital infrared, which were selected in favor of using the most noninvasive cameras possible.
Results of this portion of the study indicate that this entire region exhibits a high degree of wildlife activity. Aerial imagery, habitat suitability models and other Geographic Information System (GIS) tools graphically identify a last remaining undeveloped connection between the protected upland habitats within Marks Ranch and Toro Park to the lowland and coastal habitats of the Fort Ord Natural Reserve. This narrow, roughly half-mile wide, undeveloped gap sits between the relatively dense housing along San Benancio Road and Toro Park Estates. Additionally, Toro Creek passes under Highway 68 in this unique and important area for wildlife movement. A large underpass for El Toro Creek allows for safe passage for animals moving between these areas.
Between November 2008 and July 2009, 296 individual animal detections were recorded via remote sensor cameras at a single location within this gap. This is a highly significant amount of passages by wildlife within this linkage. Previous connectivity studies have established that this high volume of passages is an indicator that this habitat is indeed providing connectivity for multiple species. This habitat and the safe passage afforded by the Toro Creek/Highway 68 underpass is facilitating movement of wildlife species between Fort Ord, Toro County Park and Marks Ranch. This movement between habitats is critical for wildlife to find viable mates and resources, and provides habitat for the dispersal of juveniles to travel out of their parental home ranges to establish their own.
The eastern side of the Toro Creek underpass leads directly into areas proposed for development. Currently, when wildlife leave Fort Ord via the Toro Creek underpass they cross proposed development areas as they disperse into the Sierra de Salinas mountains. As currently designed, the proposed development would effectively close off this important corridor, threatening to disconnect otherwise viable habitat within the Fort Ord Reserve from the Sierra de Salinas Mountains and ultimately the rest of the state. Policy makers and planners seeking to sustain connectivity and minimize negative impacts on wildlife populations in this area should consider development configurations that accommodate existing movement paths for wildlife.
BSLT will continue to work with policy makers and planners in order to seek ways to sustain connectivity and minimize negative impacts on wildlife populations in this area. It is vital that stakeholders consider development configurations that accommodate existing movement paths for wildlife.
