Biodiversity spillovers from terrestrial ecological restoration sites in southern California

Abstract Introduction There are numerous ecological restoration projects globally, but far fewer are within urbanized environments. One such project involves various community‐led restoration efforts across California under the auspices of the nonprofit group Test Plot. Objective Here we evaluate the effects on local biodiversity from 11 ecological restoration sites within Los Angeles County in southern California. Our goal was to test the outcomes of these restoration efforts on improving biodiversity within and adjacent to Test Plot's restoration sites. Methods Using archives of community science data on plant and animal occurrences, we were able to evaluate changes in biodiversity patterns within and adjacent to these restoration sites. We analyzed how the diversity of unique plant and animal species varied over time and space in response to local restoration efforts. Results Following restoration, we observed significant increases in plant diversity within and near the restoration sites. Additionally, we found increases in the diversity of both native and non‐native animal species at distances of up to 300 m from the restoration sites following restoration. Conclusion These results indicate that small, community‐led, ecological restoration efforts can have significant impacts on local biodiversity. These impacts also show that such efforts can, even in heavily urbanized environments, increase biodiversity outside of the immediate restoration site, potentially reflecting a spillover effect.