Conservation planning for climate change vulnerability across the islands of the Californias

Published Article

California, Mexico

Publication date: May 27, 2025

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Island ecosystems face acute climate threats, yet comprehensive adaptation planning remains rare. A climate‑vulnerability workshop for the islands of California (USA) and Baja California (Mexico) brought together scientists and managers to assess climate sensitivities using the Resist‑Accept‑Direct (RAD) framework. Participants identified widespread risks including habitat loss, population declines, invasive species impacts, phenological mismatches and range contractions. They proposed resilience‑building actions such as bolstering populations, translocations, invasive‑species control, fire‑risk reduction and creating refugia. While resistance strategies inspired the most confidence, the workshop also opened space to consider accepting or directing ecological change. The process produced a suite of “no‑regrets” actions and highlighted the value of cross‑boundary collaboration for managing this globally significant archipelago.

Subject Tags

  • Climate resilience
  • Conservation Planning
  • Invasive Species

Abstract

Climate change poses threats to island ecosystems worldwide. Despite widespread recognition of the significance of islands in the global biodiversity extinction crisis, comprehensive climate vulnerability assessments and adaptation strategies for islands remain limited. Here, we present the outcomes of a climate vulnerability planning workshop for the loose archipelago of islands of California (USA) and Baja California (Mexico). Scientists and resource managers engaged in discussions to identify climate sensitivities and suggest management actions using the ResistAcceptDirect (RAD) framework. Breakout sessions identified widespread climatedriven impacts on the islands of the Californias, including habitat loss, population declines, invasive species impacts, impaired ecosystem function, phenological mismatch and range shifts/contractions. Participants proposed a suite of management actions that could improve climate resilience, including bolstering existing populations and habitats, translocating species, reducing risk of fire, controlling invasive species and creating refugia. Although participants expressed more confidence in actions designed to resist the effects of climate change, the workshop provided a venue to discuss implications of directing ecosystems along new trajectories and accepting changes that managers are unwilling or unable to prevent. The workshop facilitated discussions that transcended individual islands, scientific disciplines and land management entities, and contributors produced a suite of “no regrets” actions that managers can implement immediately, even in the face of uncertainties. We highlight the value of collaboration in planning and implementing responses to climate change and discuss next steps in the adaptive management of this globally significant archipelago.

Citation

Brenner, L. J., Wallingford, P. D., Holmes, N. D., Knapp, J. J., Randall, J. M., & Morrison, S. A. (2025). Conservation planning for climate change vulnerability across the islands of the Californias. Western North American Naturalist, 85(2), 323-340. https://doi.org/10.3398/064.085.0217

TNC Authors

  • Lara J. Brenner
    Senior Island Scientist, California
    The Nature Conservancy
    Email: lara.brenner@tnc.org

  • Piper D. Wallingford
    Climate Resilience Scientist, California
    The Nature Conservancy
    Email: piper.wallingford@tnc.org

  • Nick D. Holmes
    Associate Director, Oceans Program, California
    The Nature Conservancy
    Email: nick.holmes@tnc.org

  • Scott A. Morrison
    Director of Conservation Science & Programs, California
    The Nature Conservancy
    Email: smorrison@tnc.org