Dear All,

I would like to share some new research that was just published from a survey of long-term outcomes I conducted from 2019-2021 of restored coastal grasslands ranging from 3-30 years post-implementation ranging from Santa Barbara to Humboldt counties (37 projects total). I surveyed the vegetation at all of these projects, for some of them I surveyed multiple years, and I also compiled project documents when possible and conducted interviews with the responsible land managers. All the sites were coastal and at minimum were either actively planted or seeded. I prepared an audio file of the article in the supplementary material for those that may prefer to listen to it on the go or while working. The article is open access so you can use the link in the first sentence, but I've also attached the PDF. Here are some of the key findings and their implications.

1. Good news, coastal grassland restoration is very successful at reaching project-based goals (outlined by the specific project) and a standard performance metric of at least 25% native cover and five native species (many projects achieved higher). Native cover ranged up to about 80% for maximum cover at a site. So current practices work well, but invasive species management is consistently a problem for all projects. Our analyses using vegetation data and labor investment found that increased maintenance intensity helped improve native cover and richness and limited non-native cover. Another recent study of mine also found that periodic maintenance may be needed to limit woody (Baccharis) encroachment into areas recently restored with plantings. 

2. Thinking about species selection and diversification will be important going forward. Management interviews indicated that the same seven species are commonly selected for restoration across this 1000-km span, which is understandable given risk-aversion and the desire to achieve project goals and not fail but going forward it may be important to develop strategies or regional coordination to limit the risk of using too much of the same species and contributing to biotic homogenization as we continue to lose highly species-rich remnant habitat and only a small subset are restored. We did find that increased species use during restoration was associated with higher plant diversity at a given site, but that increased use was associated with increased cost. This follows a trend for restoration of many different ecosystem types outside of California.

3. Some statutory (legally mandated compliance/mitigation projects) projects (8) denied access for vegetation surveys, but no voluntary project denied access. I cannot speculate on what the status of those projects are but it may call into question the use of restoration as offset or mitigation in certain instances or with conflicts of interests. 

4. Some projects were able to adjust their target with the regulatory agency after implementation and targets were not met. In some instances it was because the statutory agency had a unreasonably high target (e.g. lowering original target 80% cover), but in other instances it was to help achieve compliance (e.g. lowering original target 25% cover).

I'm happy to take any questions or comments and also wanted to let you know I'm working to pilot coordination efforts through a statewide restoration network and would be happy to hear of any interest for participation.

Please note that if you do have questions, all data associating site/projects/managers with specific outcomes or results are confidential and cannot be shared.

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Justin Luong, PhD (he/his)

USDA Agriculture Food Research Initiative Postdoctoral Fellow: UC Davis - Plant Sciences - Funk Lab

Affiliate at Vernon and Mary Cheadle Center for Biodiversity and Ecological Restoration (CCBER)

Board Member of California Native Grassland Association

Coordinating Editor at Restoration Ecology

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Recent publications: 

2023. Lessons learned from an interdisciplinary evaluation of long-term restoration outcomes on 37 restored coastal grasslands in California. Biological Conservation

2023. Native and invasive bunchgrasses have different responses to trail disturbance on California coastal prairies. Plant Ecology

2022. Nonperiodic grassland restoration management can promote native woody shrub encroachment. Restoration Ecology

2022. Overcoming biotic homogenization in ecological restoration. Trends in Ecology and Evolution 

2022. Inclusive restoration: Ten recommendations to support LGBTQ+ researchers in restoration science. Restoration Ecology