Regional Connectivity Management and Monitoring Program for San Diego County

Trish Smith, The Nature Conservancy

This presentation will highlight work by the San Diego Management Monitoring Program (SDMMP) and its partners in the development and implementation of a regional connectivity management and monitoring program for conserved lands in San Diego County.  

San Diego Association of Governments uses funds from a half-cent sales tax, collected for local transportation projects, to support regional monitoring and management of sensitive species covered in multiple species conservation plans. This funding supports SDMMP in its efforts to work with 115 federal, state and local government agencies, non-profit organizations, and research partners to coordinate regional monitoring and management on conserved lands.

The Management and Monitoring Strategic Plan for Conserved Lands in Western San Diego County includes goals and objectives for 113 species, 11 vegetation communities, and 13 threats. The Connectivity Element identifies threats to wildlife connectivity and measurable objectives to address these threats. Objectives include performance of connectivity research for over a dozen wildlife species, evaluating the functionality of identified linkages, identifying measures to protect or increase linkage functionality, developing wildlife crossing infrastructure improvements for major highways, and developing monitoring programs to document wildlife use of linkages and wildlife crossings.

The role of USGS is to provide scientific information to assist resource managers who are developing and implementing management approaches.  In that context, a number of studies have been conducted by USGS to determine the movement and genetic structure of a several wildlife species in San Diego County and across southern California, including American badger, mule deer, arroyo toad, and Blaineville’s horned lizard. Two focal bird species, Coastal California gnatcatcher and coastal cactus wren, have been determined to have very different genetic population structures even though they co-occur in coastal sage scrub. They differ in their ability to move through fragmented and urbanized landscapes and as a result require different management strategies.

USGS evaluated structural connectivity of linkages between core preserve areas and identified areas where wildlife movement is constrained or blocked by roads and development. USGS conducted a study of small vertebrate movement through wildlife underpasses and found that adding cover structures increased underpass use.  

Researchers from UC Davis conducted a multi-year study of mountain lion movement, genetic population structure, and causes of mortality. Currently UCD is evaluating mountain lion use of culverts for major highways in documented mountain lion movement areas in northern San Diego County, with the goal of informing the design and placement of future wildlife crossing structures to facilitate movement and gene flow of lions and other wildlife between the inland Peninsular Ranges and the Santa Ana Mountains.  Similar wildlife crossing infrastructure improvement plans have been developed for other highways in central and southern portions of the county.

The SDMMP, TNC and USGS are working with partners to develop a regional long-term connectivity monitoring plan.  The SDMMP and TNC are prioritizing and implementing management actions to improve wildlife movement across the preserve system in San Diego County, with counties to the north, and with Baja California, Mexico to the south.