By Dr. Nathaniel Seavy and Tom Gardali, PRBO Conservation Science
PRBO Conservation Science is a non-profit organization with a mission to conserve birds, other wildlife, and ecosystems through innovative scientific research and outreach. PRBO’s highest priority is to develop and promote conservation practices that address the challenges of rapid environmental change. Since the early 1980’s, we have focused a large amount of our work on riparian areas of California because relative to other habitats, these areas are disproportionately important for migratory birds, but also disproportionately degraded.
After initially working to describe the bird use of existing riparian areas, we quickly began working with restoration practitioners to document the recolonization of restored riparian areas by migratory birds. Subsequently, we have helped develop and test new restoration strategies that can generate higher quality habitat in the shortest amount of time. As a result, our work has expanded to include collaborations with hydrologists, geomorphologists, landscape ecologists, and vegetation ecologists.
Climate change means that the field of restoration is no longer simply concerned with regenerating what has been lost, but also with preparing for what is to come. We are now frequently asked if restoration can remain relevant in a future with warmer temperatures, more frequent extreme events, and novel species assemblages. As a result, it has become impossible for us not to ask, “What will climate change mean for riparian restoration?” We addressed this question by assembling a team of partners who have been involved with restoration projects from several different perspectives (hydrology, vegetation science, and wildlife management) and organizations (The Nature Conservancy, Environmental Defense Fund, University of California Davis, Bureau of Land Management, River Partners, and Audubon California).
Working with this team we considered 1) the challenges that climate change might present for riparian ecosystems (e.g., warmer air and water temperatures, more frequent droughts, more severe flooding events), 2) how riparian restoration might help address some of these challenges, and 3) how we might modify riparian restoration to enhance performance under a rapidly changing climate. Our general impression after this review was reflected in the title of our work “Why climate change makes riparian restoration more important than ever.”
The paper resonated with restoration professionals, and we have had the opportunity to present our ideas at local and national restoration workshops. Our take-home message for these audiences is that restoration in general is one way to prepare for climate change, but that we must also be thinking of creative ways to adapt our restoration practices to climate change. While we emphasize that there are guiding principles for adapting to climate change (such as reducing existing stressors, promoting ecological redundancy, and preparing for a greater range of variability), we also stress that just as successful restoration meshes restoration science with local ecological knowledge, successful adaptation will require a similar approach. More than once, members of our audience have come up to us afterwards with exciting ideas about how they might make small changes to their restoration design to improve their ability to perform in a warmer and more variable climate. It has been our observation that simply discussing restoration in the context of climate change can catalyze practical, locally appropriate, and creative ideas for adaptation.
Today, we have a new and exciting opportunity to put this process to the test. We have been funded by a local foundation to help develop novel riparian restoration designs that we believe will perform better under a future of climatic uncertainty. For example, we are proposing to alter traditional planting palettes to include more species that are fire adapted and drought tolerant to increase the survival of vegetation under increasingly extreme conditions. Because we know that climate change may disrupt the timing of wildlife migration and reproduction, we are also proposing to plant a mix of shrubs and forbs that are chosen because together they will provide flowers, fruit, and seeds throughout the year. This will help ensure that even as the climate changes, resources will still be available to wildlife when they need them. Collaborating with a local restoration group, we will put these designs to the test by implementing them together with traditional restoration designs and monitoring their side-by-side performance into the future. In the short-term we will describe differences in cost between the two designs and identify barriers to implementing the novel restoration plans. In the mediumterm we will compare plant survival and wildlife response. And in the long-term we will evaluate whether the novel designs have better survival and provide more resources for wildlife under more variable and extreme climatic conditions.
Adapting restoration practices to address the challenges of climate change is not without risk. At its most extreme, this could mean risking the introduction of novel pathogens or new genes by using new species or genetic stock in restoration plantings. To date, we’ve avoided recommending such dramatic actions, but we encourage restoration practitioners to consider the utility of such extreme shifts. Less dramatically, but just as challenging, directing limited resources away from tried and true methods to novel restoration designs, some of which may fail, is also a risk. We are willing to wager that the risks are worth it – for faced with the challenges of a rapidly changing climate, business-as-usual is also a risk, potentially a very big one.