How Has Climate Change Affected Yellowstone Amphibians?


A new study published in the science journal Ecology Indicators highlights how environmental changes in Yellowstone National Park are leading to habitat loss for some amphibian species. As Yellowstone continues to heat up and dry out under the influence of climate change, certain amphibians that move across the park are expected to experience a loss of habitable zones. Authors of the study predict that continued climate change will “reduce snowpack, soil moisture, and forest cover” and diminish wetland habitats throughout Yellowstone National Park.

Will Amphibians Survive Climate Change?

Amphibians are ectothermic, meaning that they absorb heat from external sources in their environment to regulate their body temperatures. That being the case, hotter temperatures are potentially beneficial to amphibians in certain microclimates. Microclimates are small, restricted sections of an area that have different climatic states relative to the surrounding space. Warmer microclimates can help amphibians survive through the winter or forage for provisions during the day. However, warming temperatures that also drive dryer air and soils can limit amphibians’ ability to rehydrate while traveling cross stretches of land.

Amphibian hydroregulation is likewise dependent on factors in their environment, as they are unable to control water evaporation from their bodies. Amphibians require humidity and sufficient water availability to avoid dehydration. Terrestrial habitats that lack moist soils and forest cover from direct sun exposure can impede amphibians’ thermo-hydroregulation abilities.



How Has Climate Change Affected Yellowstone National Park Amphibians?

Researchers of the amphibian-Yellowstone study mechanistically modeled the movement of amphibians within the park for the years 2000, 2050, and 2090 to gauge the “costs” (disadvantages) to amphibians under the influence of climate change. Model simulations included data relating to Yellowstone’s vegetation, weather, and details about animals’ morphology and physiology. Western Toads (Anaxyrus boreas) were used as the subject species for the model. Inferences were then made about other amphibians native to the park.

How Did Amphibians Adapt to Their Changing Environment?

The results were mixed across the three “test areas” which were modeled; in one of the test areas, physiological movement costs increased, decreased in the second, and was mixed in the last. Authors of the study “predict that climate change will reduce the physiological costs for toads in some regions of YNP but increase them in others”. Snowpack loss and drying conditions throughout portions of Yellowstone may shrink wetlands, which could limit breeding sites for toads and make travel between breeding sites more costly. Other amphibian species are expected to experience worse consequences from warming and drying climates than toads. For example, Boreal Chorus Frogs (Pseudacris maculata), are less resistant to desiccation than toads because they are more dependent on wetlands for water and moisture.

Are Amphibians Sensitive to Climate Change?

Strictly speaking, warming conditions do not affect all amphibians in Yellowstone National Park the same. Variations in weather and vegetation cover brought on by climate change may make moving across the stretches of land that surround wetlands more costly for some amphibian species, particularly those less tolerant to dry habitats.


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