Winter severity affects occupancy of spring- and summer-breeding anurans across the eastern United States

Diversity and Distributions
By: , and 




Climate change is an increasingly important driver of biodiversity loss. The ectothermic nature of amphibians may make them particularly sensitive to changes in temperature and precipitation regimes, adding to declines from other threats. While active season environmental conditions can influence growth and survival, effects of variation in winter conditions on population dynamics are less well-studied. Given that extreme winter temperatures can influence amphibian survival and fitness, we expected that increased winter severity—as measured by variability in winter temperatures and snow cover—would be associated with decreased occupancy, and that populations that experience more severe winters would have the largest sensitivities and show the greatest declines.


Eastern United States.

Time period


Major taxa studied



We used large-scale citizen science data from the eastern half of the United States, a diverse biogeographic and climatic region, to assess how variation in winter severity influenced occupancy dynamics (i.e. presence or absence of species across sites and years) of 11 spring and summer breeding anuran species.


Most species had increased occupancy in years with greater than average snow cover and warmer than average mean winter temperatures. Surprisingly, climatic conditions in winter affected occupancy dynamics of species with varying life history characteristics, including both spring and summer breeding species, those that overwinter under the soil, and those that overwinter in ponds and stream beds. For two wide-ranging species (Lithobates catesbeianus and Lithobates clamitans), colder winter temperatures reduced occupancy more at northern latitudes, while the association between days of snow cover and latitude was equivocal.

Main conclusions

As the climate continues to change, expected reductions in snowpack may reduce occupancy of already declining anuran populations, while milder winters may improve overwinter survival for some species. The contradictory impacts of temperature and snow cover illustrate the importance of considering multi-dimensional impacts of climate change on anuran populations.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Winter severity affects occupancy of spring- and summer-breeding anurans across the eastern United States
Series title Diversity and Distributions
DOI 10.1111/ddi.13620
Volume 28
Issue 10
Year Published 2022
Language English
Publisher Wiley
Contributing office(s) Patuxent Wildlife Research Center, National Climate Adaptation Science Center
Description 13 p.
First page 2187
Last page 2199
Country United States
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