Over two-thirds of Californians live in coastal counties. Californians love their coastline for good reasons—the mild weather, recreational opportunities, and of course their iconic beauty and natural diversity.
The California coastline hosts a variety of ecosystems ranging from sand dunes to rolling grasslands to mixed evergreen forests. These ecosystems not only are beautiful and provide habitat to many species of plants and animals, they also provide important services to people. Coastal wetlands, for example, help to improve water quality, reduce shoreline erosion, and buffer against sea level rise.
Mission Bay Wetlands in San Diego. Photo by Joanna Gilkeson/USFWS.
But the millions of Californians who live near the coast have had significant impacts on these ecosystems. Less than 10 percent of original wetland habitat remains. Likewise, the forces of urbanization and agriculture have made California’s coastal grassland and scrub ecosystems among the most endangered in the nation. The challenge is finding the balance between meeting the needs of people and conserving these ecosystems and the many species that depend on them, including humans.
Valuing, conserving, and restoring our coastlines
Example of sand dune ecosystem. Photo: K. Holl.
Fortunately, California has visionary leaders and a general population that has recognized the need to protect the coast for future generations. In 1972, voters passed an initiative to establish the California Coastal Commission, which was tasked with balancing development and protecting coastal resources. Californians continue to recognize the importance of coastal ecosystems, as we saw in the June 2016 election: 70 percent of voters in nine San Francisco Bay Area counties approved a $12 parcel tax that will provide an estimated $500 million to support wetland restoration efforts over the next 20 years.
Conserving remaining intact ecosystems must be the first priority. But ecological restoration is also an important component of conservation efforts, especially where there has been extensive habitat conversion and degradation, as in many areas of coastal California. The question is how to restore coastal ecosystems in an ecologically appropriate and cost-effective manner. This is where the work of my students, my collaborators, and me plays an important role.
Improving restoration success
Developing methods to restore ecosystems starts by documenting what is out there. How degraded are the hydrologic and soil conditions? Which species are missing entirely? If left alone for a few years, will the site recover on its own? If not, will changing the management regime favor native species?
For example, our coastal grasslands host approximately 250 native wildflower species, many of which are now threatened or endangered due to habitat loss and competition with tall-stature invasive grasses, primarily from Europe. My lab has studied how different management regimes, such as grazing and fire, can be used to help restore native wildflowers. Our results show that properly-managed cattle grazing can help to increase the density of a number of wildflower species.
Much of my research aims to develop restoration methods that are practical and safe for humans. To do this, I work with land managers at government agencies like California State Parks, private land trusts, and other groups to understand their challenges and identify research questions they need answered. For example, herbicides are widely used in many coastal restoration projects to control invasive plant species prior to planting native species. But, there is growing concern about the effects of herbicides on the health of those who apply them and on nearby communities. Hence, we have been testing various non-chemical methods of invasive control, measuring not only their ecological effectiveness but also costs, to evaluate whether alternative methods would be practical at a larger scale.
Training the next generation of environmental leaders
Students learning at the UC Natural Reserve System. Photo: K. Holl
As a professor at the University of California, one of my most important roles is training the next generation of environmental leaders. Therefore, both undergraduate and graduate students are an integral part of my research. Each year, the University of California Natural Reserves staff and I work with 50-60 students doing hands-on restoration research and implementation. This gives students an opportunity to develop both critical thinking and practical job skills. We aim to ensure that the students involved in these projects reflect the diversity of the state. We know that low-income and minority communities are disproportionately affected by negative environmental impacts, but they are generally under-represented in ecology. We offer introductory field courses for students who have not had ample opportunities to study outdoors, and we are raising funds for paid internships so they can gain these important job skills and contribute to the growing restoration economy.
My goals are to do research that improves how we restore coastal ecosystems and to provide educational opportunities for learners of all ages. My hope is that together we can conserve California’s amazing coastal ecosystems for future generations.