UC Davis

This dissertation is a three-part study of the practice of systematic conservation planning (SCP) on a regional scale in California, necessary for protecting the more than 2,000 plant species and more than 900 animal species considered to be at risk. Natural Community Conservation Plans (NCCPs) pursuant to California Endangered Species Act represent the most powerful tool in statute for such planning, with the highest standards for conserving species. Study results are intended to improve practice in the explicit use of species conceptual models (SCMs) and management-oriented species distribution models (SDMs). Chapter 1 analyzes 18 NCCPs to determine if or how explicit connections were made between both types of models for a covered species and key components of its conservation strategy. Results indicate plans were strong in the use of SDMs, however, each deferred preparing or using SCMs to later management and monitoring phases. A more effective best practice for developing a conservation strategy is to explicitly integrate SCMs and SDMs during plan preparation. Chapter 2 acknowledges the central role scientists play in systematic conservation planning and the decisions they must make regarding management and monitoring in the face of many biological and ecological uncertainties. SCMs are a way for species experts and other stakeholders to share knowledge and document these uncertainties as they determine the most effective conservation strategy for a species. Using San Diego County, California, as a case study, this chapter examines when, how, and by whom SCMs are created and later refined. Keyword searches of planning documents and interviews with scientists revealed that many SCMs have been created but have not yet been formally refined based on monitoring data and stakeholder input. A grounded theory analysis of SCM workshop proceedings and interviews with scientists to determine how and by whom yielded the emergent theory “A Collaborative Ideal: Personalities and Attitudes of Individuals Affect Outcomes and Consensus is Reported.” The chapter concludes with a discussion of best practices for ensuring useful SCMs that reflect species expertise and the input of other stakeholders. Chapter 3 is built on the premise that habitat connectivity is key when designing reserve networks for species conservation. However, acquiring land over time to achieve connectivity for multiple species in a conservation plan can pose a data challenge because of limited species occurrence data and complexity in using multiple species models together. Using an NCCP for Yolo County, California, as a case study, four land acquisition strategies were evaluated in their ability to meet each of three objectives: 1) meet conservation targets, 2) maximize structural habitat connectivity, and 3) maximize connectivity for multiple focal species. The efficiency of each strategy to meet conservation targets was assessed using MARXAN. Structural habitat connectivity of MARXAN solutions for each strategy was analyzed using ‘Contiguity Index’ and ‘Perimeter-Area Ratio’ in FRAGSTATS, and ‘Nearest Neighbor’ in ArcGIS. Focal species connectivity was evaluated by using ‘Cost Connectivity’ in ArcGIS to define species-specific least cost networks and then assessing each network’s conformity with MARXAN solutions. The strategy of acquiring Priority 1 parcels and corridor parcels together provides the best combination for attaining all three objectives. The chapter demonstrates how to use several measures of connectivity in decision-making and recommends using spatial prioritization software often, especially because land acquisition patterns are time sensitive and data may be limited.