It is hypothesised that ecological restoration in grasslands can induce an alternative stable state shift in vegetation. The change in vegetation influences insect community assemblages and allows for greater functional redundancy in pollination and refuge for native insect species. 2. Insect community assemblages at eight coastal California grassland sites were evaluated. Half of these sites had undergone restoration through active revegetation of native grassland flora and half were non-restored. Insects were collected from Lupinus bicolor (Fabaceae) within 2 × 2-m2 plots in spring 2017. Lupinus bicolor is a common native species that is used in California restoration projects, and home and state landscaping projects. 3. Ordination demonstrated that insect community assemblages were different between restored and non-restored sites. These differences were seen in insect functional groups as well as taxa-specific differences and were found to be driven by environmental characteristics such as non-native forb cover. 4. Functional redundancy of herbivores decreased at restored sites, while pollinators became more redundant compared with non-restored sites. The assemblages of the common species found at restoration sites contained more native insects than those found at non-restored sites, including species such as Bombus vosnesenskii. 5. Local grassland restoration has the potential to induce an alternative stable state change and affect insect community assemblages. Additionally, it was found that grassland restoration can be a potential conservation tool to provide refugia for bumblebees (Bombus), but additional studies are required to fully understand its broader applicability.
In coastal California dune ecosystems protect coastal cities from damaging storms and provide habitat for native wildlife. Despite the economic and ecological importance of coastal dunes, habitat loss has continued and is predicted to accelerate with a changing climate. To combat the effects of climate change and ensure that coastal dunes will persist into the future, they need to be prioritized for conservation and restoration. However, for restoration to be successful, endemic plants, which are plant with specialized habitat requirements, need to be prioritized because they make up a significant portion of the biodiversity in California coastal dunes. Because endemic plants are rare and there is limited stock of plants available for transplant, we need to be more aggressive in using pilot studies. These can be used to evaluate the biotic and abiotic conditions that maximize growth and reproduction and to help guide effective reintroduction. To evaluate how exploratory pilot studies can enhance the restoration of rare and endemic plant species, we conducted a study restoring Lupinus nipomensis, a United States federally endangered species, on coastal dunes in San Luis Obispo County, California. We found that L. nipomensis had the highest seed production in plots that had a steep, north facing slope and were protected from herbivores. Our results suggest that restoration efforts should be focused on areas with these characteristics to maximize restoration success. Our pilot reintroduction of L. nipomensis highlights the importance of using pilot experiments to enhance reintroduction success and to quicken the recovery of coastal dune ecosystems.
