Impacts of competition and herbivory on native plants in a community‐engaged, adaptively managed restoration experiment

Abstract

Abstract Restoring biodiversity to degraded sites in the wildland–urban interface is challenging due to many factors, including competition with non‐native species and increased herbivore pressure. In a unique collaboration between land managers, environmental educators, students, and academic ecologists, we tested the effectiveness of multiple restoration techniques in an adaptive management framework, modifying methods each year based on results in the previous years. We evaluated the impact of non‐native species and rabbit herbivores on soil moisture and native plant growth. We added native seedlings to our site either immediately adjacent to existing native shrubs (potential nurse plants) or in the open. One native species, Artemisia californica, was significantly negatively influenced by the presence of an existing shrub and grew more in the open in both a wet and a dry year. Another native species, Eriogonum fasciculatum, experienced high mortality by rabbit herbivores when it was not protected by fencing. Fencing also increased abundance of non‐native plants, so a combination of fencing and non‐native removal without a nurse plant was optimal for restoration. Soil moisture was greater in the open than under existing native shrubs, indicating that existing shrubs decreased soil water available to seedlings. Data collected by trained students was indistinguishable from that collected by professional ecologists. Our use of community‐engaged science demonstrates how scientific adaptive management experiments can include a diversity of participants and allow for immediate dissemination and implementation of results.

Keywords

• citizen science
• coastal sage scrub
• facilitation
• inter‐annual variation
• Mediterranean‐climate system
• nurse plant