Hydrologic variability contributes to reduced survival through metamorphosis in a stream salamander

Winsor H. Lowe, Leah K. Swartz, Brett R. Addis, Gene E. Likens

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17 Scopus citations


Changes in the amount, intensity, and timing of precipitation are increasing hydrologic variability in many regions, but we have little understanding of how these changes are affecting freshwater species. Stream-breeding amphibians-a diverse group in North America-may be particularly sensitive to hydrologic variability during aquatic larval and metamorphic stages. Here, we tested the prediction that hydrologic variability in streams decreases survival through metamorphosis in the salamander Gyrinophilus porphyriticus, reducing recruitment to the adult stage. Using a 20-y dataset from Merrill Brook, a stream in northern New Hampshire, we show that abundance of G. porphyriticus adults has declined by ∼50% since 1999, but there has been no trend in larval abundance. We then tested whether hydrologic variability during summers influences survival through metamorphosis, using capture-mark-recapture data from Merrill Brook (1999 to 2004) and from 4 streams in the Hubbard Brook Experimental Forest (2012 to 2014), also in New Hampshire. At both sites, survival through metamorphosis declined with increasing variability of stream discharge. These results suggest that hydrologic variability reduces the demographic resilience and adaptive capacity of G. porphyriticus populations by decreasing recruitment of breeding adults. They also provide insight on how increasing hydrologic variability is affecting freshwater species, and on the broader effects of environmental variability on species with vulnerable metamorphic stages.

Original languageEnglish
Pages (from-to)19563-19570
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number39
StatePublished - Sep 24 2019


  • Climate change
  • Demography
  • Headwater streams
  • Long-term monitoring
  • Plethodontidae


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