COS 127-6 - State of the Preserve: Regional preserve indicators and metrics after 25 years of multiple species conservation in a changing environment

Abstract: San Diego County is biologically diverse. Rapid urbanization in the 1980s led to federal and state listing of many plant and animal species. Multiple species conservation planning was initiated in the early 1990s. San Diego Association of Governments (SANDAG) was involved in this planning and funds regional monitoring and management of species and natural communities for 15 years. SANDAG established the San Diego Management and Monitoring Program (SDMMP) in 2008 to coordinate regional monitoring and management activities guided by a Strategic Management and Monitoring Plan (MSP Roadmap) with goals and objectives. SANDAG recommended SDMMP prepare a “State of the Preserve” report detailing progress implementing objectives of the MSP Roadmap and assessing health of the regional preserve system in San Diego County.

SDMMP, working with SANDAG and collaborators, identified 19 indicators evaluating the state of the preserve. These indicators include species, vegetation communities, and landscape-scale threats. Metrics for indicators focus on levels of conservation, status of species populations, ecological integrity of vegetation communities and level of threats. Most indicators (12 of 19) fall within an overall condition of Concern or Significant Concern. This is due largely to high levels of landscape-scale threats emerging over the last 20 years (e.g., altered fire regime, invasive species, and drought).

Overall, conservation of species and vegetation communities is progressing well except for mountain lions (which need larger blocks of conserved, contiguous habitat) and southwestern pond turtle (with few reproducing populations remaining in conserved habitat). Metrics for species status (8 of 13) fall within a condition of Concern or Significant Concern due to a high level of threats. Landscape-scale threat indicators include hydrology, connectivity, fire, and invasive nonnative Plants. All but two of the 11 metrics for these four threats fall within Concern and Significant Concern categories.

This evaluation was valuable, as it showed landscape-scale threats are affecting the preserve system and impacting the status of species and vegetation communities. Since the initiation of conservation planning there have been major changes in environmental conditions from human activities. The fire regime has changed dramatically over the last 30 years, with large catastrophic wildfires facilitating invasion by nonnative annual grasses and slowing down recovery of shrubland habitat for many species. Drought has contributed to habitat degradation and decline in species populations. Our evaluation focused on species and vegetation communities of highest conservation concern. In the future we will include additional indicators, including more common species to assess biodiversity.