Managing Endemic Species across the California Islands Archipelago in the Face of Climate Change

Southern California Bight and Channel Islands Map. (Image courtesy of NOAA)

STUDENT AUTHORSBrad Anderson Master’s Candidate, 2019 Bren School of Environmental Science & Management banderson@bren.ucsb.edu (805) 689-2815

Claire Powers Master’s Candidate, 2019 Bren School of Environmental Science & Management lcpowers@ucsb.edu (805) 905-1585

Laura Wolf Master’s Candidate, 2019 Bren School of Environmental Science & Management lwolf@bren.ucsb.edu (831) 206-0118 CLIENT AUTHORSThe Nature Conservancy John Knapp Island Ecologist jknapp@tnc.org

Santa Barbara Botanic Garden Denise Knapp Director of Conservation & Research DKnapp@sbbg.org (805) 682-4868

OBJECTIVES This project’s overall goal is to model species range shifts on the Channel Islands as average temperatures increase. Island managers could then use the information to identify and explore management and conservation techniques for various species. Oak woodland communities, comprised of Quercus tomentella and Lyonothamnus floribundus, are most at-risk on the islands. With a warming climate, researchers believe these communities will move upslope on north-facing slopes, following the relatively cool temperatures they rely on. In an island environment, viable habitat for plants adapted to cooler microclimates are very limited, and now shrinking as temperatures increase. Oak woodland communities are struggling on all of the islands except Santa Cruz Island, where they are thriving. This may be due to the presence of island scrub jays, which spread acorns across Santa Cruz Island. Our model would look at past and current distributions of Quercus tomentella, and project its likely future distribution as climate change drives range shifts. There is not sufficient data to do an analogous model for Lyonothamnus floribundus, but it follows parallel trends to Quercus tomentella. Similar methods could be used to model expansion of invasives due to climate change. Understanding where invasives are likely to expand would provide island managers with more robust information about which native plant communities are most at risk of invasive competition and therefore the highest priority in restoration efforts. Many invasive plants favor current climate change trends, whereas a multitude of native island plants are suffering due to the warmer and drier climate. We will model the spread of high profile invasives in a changing climate, and separately, where native plant alliances may shift with a changing climate—with that combination, we hope to determine which plant communities will be at the greatest risk of losing habitat from both a changing climate and competition with aggressive invasives. SIGNIFICANCE The Channel Islands are host to rich and diverse native plant communities, many endemic species, and fauna reliant on native plants for habitat. The health of native plant communities has been threatened for decades by a multitude of factors, including invasive plants and herbivores, recreation/visitor impacts, and changing climate. A significant amount of effort has been invested in the protection and restoration of native ecosystems across the Channel Islands by many different agencies, including The Nature Conservancy and Santa Barbara Botanic Garden. Climate change and invasive species in island ecosystems are particularly concerning, especially given the high density of endemic species. Even healthy endemic populations on the islands have limited habitat and resources, in addition to geographical boundaries that inhibit migration if those resources start to dwindle, or if competition with other species increases. Those combined factors make them very susceptible to extinction when environmental or competition pressures force sharp population declines. Our project will map where key plant communities are expected to shift with climate change. Such maps will help identify communities at greatest risk of extirpation due to climate change, and will inform where to prioritize native plant community conservation efforts. The maps and models we intend to produce would help advance efforts of the greater Channel Islands conservation community. Quercus tomentella is present on six of the islands and is an important species in the oak woodland community, so models and maps of its expansion could be used to inform conservation initiatives throughout the California Islands Archipelago. Additionally, many other island endemic species are expected to suffer from climate change, so the findings from this project have potential to help inform conservation actions for other species. BACKGROUND The project is located on the California Islands Archipelago which includes the Channel Islands and Isla de Guadalupe off the coast of Baja California, Mexico. The Channel Islands are a chain of eight islands located in the Pacific Ocean off the coast of southern California. The islands include Anacapa, San Miguel, Santa Cruz, Santa Rosa, San Clemente, San Nicolas, Santa Barbara and Santa Catalina. Isla de Guadalupe of Baja California, Mexico shares the California chaparral and woodlands ecoregion with the Channel Islands, so it is considered part of the archipelago. Five of the islands are part of Channel Islands National Park, and the waters surrounding these islands make up Channel Islands National Marine Sanctuary. Currently, the islands are used for research, U.S. Military training grounds, and recreation. The islands are managed mainly for the conservation of biodiversity―they are an excellent example of what can be accomplished with dedicated and sustained conservation effort.

Threats to the endemic species and native plant communities arose with the arrival of farmers and ranchers to the islands in the 1800s. During this time many invasive terrestrial plants and animals were introduced to the islands. Many of the invasive plant populations were kept in check by the herbivores raised on the ranches. When ranching ceased, the animals were left behind. Recent restoration efforts have removed these animals from the islands, but now the spread of invasive plants has increased. It is thought that climate change is affecting both the spread of invasives as well as the depletion of endemic species, as suitable habitat for various plants has changed over the years. Oak woodland communities on the islands are suffering. Quercus tomentella is the dominant species in these communities and is present on six of the islands. Quercus tomentella populations are declining on all of the islands except for Santa Cruz Island, where populations are thriving. Santa Cruz Island is the only island with island scrub jays. While it is unclear what is causing this differential success, one hypothesis is that the island scrub jays on Santa Cruz Island are assisting the maintenance of island oak populations by spreading their acorns throughout the island. In the past, each island was treated as a separate entity and managed individually with little communication among the various management agencies. As common issues arose on the different islands, island managers began to realize the benefits of collaboration. The agencies and organizations that manage the California Islands have conducted inter-island meetings since 1965 in order to address common challenges, goals and solutions (http://www.californiaislands.net/). This began with the California Island Symposium (1965-present), and continued with the Islands Research Collaborative (1990-2002), the Island Fox Meetings (1998-present), and the Islands BioSecurity and Plant quarterly meetings (2012-present). The Islands of the Californias Botanical Collaborative was formed in 2012, in an effort to combine management information for all islands, and to treat them as an archipelago rather than isolated individual landscapes. This proposal has established committed partnership with members of this collaborative, including Peter Dixon, the Plant Conservation Manager with the Catalina Island Conservancy; Dirk Rodriguez, a botanist with Channel Islands National Park; William Hoyer, the Natural Resources Manager for San Nicolas Island with the US Navy; and Scott Sillett, a Research Wildlife Biologist with the Migratory Bird Center at the Smithsonian Conservation Biology Institute. AVAILABLE DATA A powerful suite of GIS data is publicly available. All island managers have been contacted and have agreed to data collaboration. Available data includes:

● Complete vegetation maps are available for all of the islands down to the alliance level. ○ Most islands have invasive species distribution maps as well. Santa Cruz Island’s is particularly

detailed with location information down to single individuals in some cases. ○ US Navy and National Park Service will allow access to data that is not yet published.

● Maps of Quercus tomentella distribution across the entire archipelago, including Guadalupe, are available. ● Genetics for Quercus tomentella populations for all islands except on Guadalupe. We know which stands

are rare and related and which island had founding parent populations. ● Current and past climate data is available from land and marine weather stations ● Island Scrub Jay distribution and nesting data provided by T. Scott Sillett from the Smithsonian Migratory

Bird Center POSSIBLE APPROACHES The general approach will synthesize existing resources into a model to inform management strategy that meets the conservation goals and objectives identified by The Nature Conservancy and the managers of the other islands. This approach will include:

● A thorough review of current island management plans, GIS assessments, and relevant literature. ● Interviews with various island managers from the National Park Service, the Nature Conservancy, US

Navy, Catalina Island Conservancy, and Mexico. ● Research of existing management programs for island endemics to determine feasibility for the Channel

Islands.

● Use of extensive vegetation maps of the islands to model the potential distribution shifts of Quercus tomentella on the islands using available modeling programs like Maximum Entropy (Maxent) with bioclim climate variables.

● Analysis of conservation approaches such as translocations, biocontrol, and genome editing from other locations to assess feasibility of implementation for the California Islands.

Ultimately, the approach will focus on:

● Inputting existing climate information, species distributions, and remote sensing data into climate envelope models to develop a strategy for Quercus tomentella.

● Analyzing the ecological, economic, and infrastructure data to develop recommendations about prioritizing conservation resources to address oak woodland communities.

We plan to focus on Quercus tomentella as it is the rarest oak species in North America, and it is the dominant species in the oak woodland community on the islands. There is not enough data on Lyonothamnus floribundus to model its distribution changes with climate change, but it expected to behave similarly to Quercus tomentella. DELIVERABLES The main deliverable will be models projecting range shifts, due to climate change, of Quercus tomentella and high-profile invasives on the California Islands, at progressive temperature increments and time steps. The findings of these models can then be used to inform and analyze different management decisions for the oak woodland communities on the Islands.

● Once range shifts have been mapped, we will work to identify and assess conservation strategies and priorities. Options currently under consideration include, but are not limited to:

○ Preservation of genetic diversity ○ Translocation to other islands or mainland ○ Reintroduction of other oaks to maintain community structure ○ Maintenance of status quo

● We will create a geospatial framework to identify oak woodland hotspot areas to prioritize conservation efforts.

● This information will contribute to the recently created “Island Information System” database, used collaboratively by various island management agencies and organizations.

INTERNSHIPS The Nature Conservancy in Ventura can provide an internship with a $2000 stipend to one student to work on this project for the summer. The intern will attend a workshop with the Islands of the Californias Botanical Collaborative around June 8th on San Nicolas Island. Transportation and lodging will be covered. The intern can use this opportunity to address conservation questions, how island managers might approach these problems, and what policy issues might arise with various conservation strategies.

RESOURCES John Randall, Lead Scientist for The Nature Conservancy’s California Chapter, Invasive Plant Expert jrandall@tnc.org Santa Rosa Island Cloud Forest Restoration Project SUPPORTING MATERIALS Ashley, Mary V., Saji Abraham, Laura C. Kindsvater, D. Knapp, and Kathleen Craft. "Population structure and genetic variation of Island Oak, Quercus tomentella Engelmann on Santa Catalina Island." Oak Ecosystem Restoration Research on Catalina Island, California. Denise A. Knapp, ed. Catalina Island Conservancy, Avalon, CA (2010): 125-135. Donlan, C. Josh, Donald A. Croll, and Bernie R. Tershy. "Islands, exotic herbivores, and invasive plants: their roles in coastal California restoration." Restoration Ecology 11, no. 4 (2003): 524-530. Kindsvater, L. C. “Conservation and restoration of the endemic island oak, Quercus tomentella.” Channel Islands National Park Using a Habitat Approach. PhD dissertation. University of California, Davis. 2006. Knapp, D.A., ed. 2009. “Oak ecosystem restoration on Santa Catalina Island, California.” Proceedings of an on-island workshop, February 2-4, 2007. Catalina Island Conservancy, Avalon, CA. Knapp, D.A. 2007. “Changes in Oak Distribution and Density by Decade on Santa Catalina Island, 1943 to 2005.” Oak ecosystem restoration on Santa Catalina Island, California: Proceedings of an on-island workshop, February 2-4, 2007.(2009):47-52 Knapp, John. Phone conversation. 24 January 2018. McCune, Jenny. “Report on the Census and Survey of Island Oak (Quercus tomentella Engelm.) and Canyon Live Oak (Quercus chrysolepis Liebm.) groves on Catalina Island, 2004 and 2005.” Catalina Island Conservancy. December 2005. "Restoring Anacapa Island: Native Plants." National Parks Service. June 24, 2016. Accessed January 21, 2018. https://www.nps.gov/chis/learn/nature/restoring-anacapa-island-native-plants.htm. “Terrestrial Invasive Plants.” National Park Service. Accessed January 21, 2018. https://www.nps.gov/chis/learn/nature/terrestrial-invasive.htm. BUDGET We do not expect our budget to exceed the available $1,300. Transportation (flights) to San Nicolas Island would be covered by U.S Navy. Vehicles and rooms are at interns’ cost.

The Santa Barbara Botanic Garden’s mission is to conserve

California’s native plants and habitats 1212 Mission Canyon Road

Santa Barbara, California 93105-2126 (805) 682-4726 FAX (805) 563-0352

26 January 2018 Group Project Committee Bren School of Environmental Science and Management Bren Hall, 2400 University of California, Santa Barbara, CA 93117 I am writing to confirm the Santa Barbara Botanic Garden’s support of Bren students’ Brad Anderson, Claire Powers, and Laura Wolf’s proposal, entitled "Managing Endemic Species across the California Islands Archipelago in the Face of Climate Change." Quercus tomentella and Lyonothamnus floribundus are iconic endemic species found only on the California Islands archipelago. They occupy north-facing slopes and other moist locations, which will be under increasing drought stress in a changing climate. Spatial models predicting how their populations will be affected by these changes, and the threat of invasive species, along with a review of management options, will be important conservation planning tools for the islands’ owner-managers. The Santa Barbara Botanic Garden is well poised to help, as we have been working to study and protect the California Islands’ flora since the 1920’s. Our extensive Channel Island herbarium specimen collection, rare plant seed bank, genetic tissue bank, and reference library are critical resources for their continued protection and restoration. Further, we are spearheading the development of an integrated California Islands Biodiversity Information System (Cal-IBIS), which will integrate species distribution information with data on rare and invasive plant management, habitat restoration projects, and more. If the proposal is accepted by the Group Project Committee of the Bren School of Environmental Science & Management at the University of California, Santa Barbara, our personnel will cooperate with you, and support the student group and the student intern by:

x Providing existing data, archives, and background materials x Mentoring the student group and the summer student intern x Providing on-site opportunities for the TNC summer student intern

We look forward to supporting the students, and this important project, through data and other materials, mentorship, and career-building experiences at the Santa Barbara Botanic Garden. Sincerely, Denise Knapp, Ph.D. Director of Conservation and Research Santa Barbara Botanic Garden 1212 Mission Canyon Road Santa Barbara, CA 93105 dknapp@sbbg.org