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

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.

Establishment of native seedlings species as an indicator of ecological restoration of riparian forest, Cerrado, DF, Brazil

“…Even if native species are expected to have good establishment and growth when introduced into degraded areas of similar environments, Kimball et al (2019) stated that there are certain interactions with the environment, like herbivory, that may influence the establishment and growth of the introduced plants.…”

“…Good seedlings quality is necessary for a higher survival rate after transplantation, which is critical to the success of any restoration program. Furthermore, the transplanted plant species should compete successfully with exotic plants (Prach et al, 2019) as well as with herbivores (Kimball et al, 2019). For this reason, there should be silvicultural management actions before and after planting and seedlings ought to be planted in the rainy season.…”

Native and non‐native mulch resulted in increased soil moisture and reduced plant recruitment in container plant restoration of coastal sage scrub

“…Malosma laurina is also a drought‐tolerant and dominant coastal sage scrub species (Kirkpatrick & Hutchinson 1977; Westman 1981b). Increased water can increase the prominence of non‐native species that out‐compete native shrub seedlings (Goldstein & Suding 2014; Kimball et al 2019). Survival of M. laurina was lowest in the control plots that contained more non‐native species than in mulch treatment plots.…”

“…Trained interns and educators were present with students to ensure data quality. In previous community science efforts at Crystal Cove, the data collected by trained students were comparable to data collected by professional ecologists (Kimball et al 2019). Data were collected from January through June of 2019 and only in January and June of 2020.…”