Prioritizing Riparian Conservation: A Methodology Developed for the Santa Clara River, California

Abstract

Riparian ecosystems perform many important ecological functions, but human activities have seriously altered and degraded these systems. To avoid continued habitat loss and associated losses in biodiversity, lands that contain intact riparian habitat can be acquired and managed for conservation values and degraded riparian areas can be restored. The Nature Conservancy (the Conservancy) is implementing a riparian conservation project on the Santa Clara River in Ventura County, California that includes both approaches. Because larger restoration projects have faster recovery rates and are more self-sustaining, the Conservancy is protecting and restoring as much contiguous riparian habitat as possible using a “conservation nodes” approach. To this end, we have begun acquisition of high-value parcels, and have developed a methodology for prioritizing additional land acquisition and restoration actions on the river. The methodology is based on quantitative measures of five criteria for 68 discrete parcels of real property contained within five nodes designated as high priority for conservation. The criteria were combined into a score for each parcel. We found that the five nodes varied in terms of their average parcel score, and in terms of the completeness of parcel acquisition. Nine of the top 20 scoring parcels have yet to be acquired by a conservation entity. We also found that the potential conservation value to be gained by restoring all of the parcels within a node varies by node. Conservation entities using this prioritization approach can phase implementation of large-scale projects by allowing restoration work to begin while acquisition efforts continue.