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Vulnerability of an endangered amphibian to climate-change induced hydrologic change

Published Article

California

Publication date: May 23, 2025

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Climate change is reshaping hydrologic regimes, yet its effects on riparian species remain understudied. Using species distribution models, researchers assessed how climate‑driven flow alterations affect the endangered arroyo toad (Anaxyrus californicus). Current habitat predictions were compared with future flow scenarios generated from stochastic temperature and precipitation changes. Key flow metrics showed mostly negative relationships with toad occurrence, consistent with breeding requirements. Vulnerability analyses revealed potential range contractions, reduced protected habitat and elevational shifts under altered flows. These findings emphasize the importance of managing hydrologic change to support freshwater ecosystems and guide conservation priorities, while recognizing that geomorphology and human activities also shape long‑term outcomes.

Subject Tags

  • Climate impacts
  • Habitat restoration
  • Wildlife

Abstract

Climate change significantly affects precipitation patterns at multiple scales, which influences river and other hydrologic flow regimes. However, the impacts of climate-driven changes to hydrologic regimes on the vulnerability of species associated with riparian areas remain largely unexplored. Not considering the effect of flow alteration compromises the ability to identify and protect critical habitat areas. We developed a species distribution model to predict the distribution of an endangered amphibian (arroyo toad, Anaxyrus californicus ) under current and future climate-impacted flow scenarios to better understand its vulnerability to altered conditions. The current modeled distribution of the arroyo toad was compared to models that estimated flows altered through stochastic changes in air temperature and precipitation associated with climate change. To analyze vulnerability, we investigated disparities in elevation, range size, range overlap, protected range, and predicted probability of occurrence. The study identified key flow metrics associated with toad habitats, emphasizing a negative relationship with most, aligning with arroyo toad breeding requirements. Vulnerability assessments demonstrated a potential reduction in toad range and shifts in elevational range potentially due to climate-induced flow alterations. Our study underscores the importance of managing altered flow to support freshwater ecosystems, allowing managers to prioritize conservation efforts, protect vulnerable streams and address problematic areas. However, additional factors like geomorphology and human activities also play significant roles, suggesting the need for diverse management strategies.

Citation

Irving, K., Taniguchi‐Quan, K. T., Santana, A., Treglia, M. L., Fisher, R. N., Haas, J., ... & Stein, E. D. (2025). Vulnerability of an Endangered Amphibian to Climate‐Change Induced Hydrologic Change. River Research and Applications, 41(7), 1438-1455. https://doi.org/10.1002/rra.4455

TNC Authors