Balancing Active and Passive Restoration in a Nonchemical, Research-Based Approach to Coastal Sage Scrub Restoration in Southern California

Abstract

Coastal sage scrub restoration at Audubon’s Starr Ranch Sanctuary commences with nonchemical control of a high-priority non-native in degraded (and native) grasslands, artichoke thistle (Cynara cardunculus). Scrub restoration begins the second year of artichoke thistle control. Here I report on how our approach combines active and passive restoration. We use experiments, when time and funding allow, to help guide the active restoration process by answering questions on technique: the effectiveness of soil tamping, differing seed rates, and timing of planting on restoration success. As a result of past experiments, our field crews tamp seeds into soil after hand broadcasting both early (October) and late ( January) each season. Passive processes are compatible with coastal sage scrub restoration since shrub dominants are proficient natural grassland colonizers. We monitor both active and passive restoration sites quantitatively and qualitatively and have demonstrated success that is highly dependent on levels of annual precipitation. We at Starr Ranch believe that our nonchemical, research-based project can serve as a model of a rigorous, sustainable approach to land management in southern California.