Ecology

Reports on Conservation Research Findings from S.J. Kupferberg and Co-Researchers Provide New Insights

  2012 JUN 22 (VerticalNews) -- By a News Reporter-Staff News Editor at Ecology, Environment & Conservation -- Fresh data on Conservation Research are presented in a new report. According to news reporting originating from San Francisco, California, by VerticalNews correspondents, researchers stated "Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood-drought cycles; thus, their likelihood of persistence may decrease in response to disruption of the seasonal synchrony between stable low-flow conditions and reproduction."

  Our news editors obtained a quote from the research by the authors, "We evaluated whether altered flow regimes affected 2 native frogs in California and Oregon (U.S.A.) at 4 spatial and temporal extents. We examined changes in species distribution over approximately 50 years, current population density in 11 regulated and 16 unregulated rivers, temporal trends in abundance among populations occupying rivers with different hydrologic histories, and within-year patterns of survival relative to seasonal hydrology. The foothill yellow-legged frog (Rana boylii), which breeds only in flowing water, is more likely to be absent downstream of large dams than in free-flowing rivers, and breeding populations are on average 5 times smaller in regulated rivers than in unregulated rivers. Time series data (range = 8 - 19 years) from 5 populations of yellow-legged frogs and 2 populations of California red-legged frogs (R. draytonii) across a gradient of natural to highly artificial timing and magnitude of flooding indicate that variability of flows in spring and summer is strongly correlated with high mortality of early life stages and subsequent decreases in densities of adult females."

  According to the news editors, the researchers concluded: "Flow management that better mimics natural flow timing is likely to promote persistence of these species and others with similar phenology."

  For more information on this research see: Effects of Flow Regimes Altered by Dams on Survival, Population Declines, and Range-Wide Losses of California River-Breeding Frogs. Conservation Biology, 2012;26(3):513-524. Conservation Biology can be contacted at: Wiley-Blackwell, Commerce Place, 350 Main St, Malden 02148, MA, USA. (Wiley-Blackwell - www.wiley.com/; Conservation Biology - onlinelibrary.wiley.com/journal/10.1111/(ISSN)1523-1739)

  The news editors report that additional information may be obtained by contacting S.J. Kupferberg, Garcia & Associates, San Francisco, CA 94110, United States.

  Keywords for this news article include: California, San Francisco, United States, Conservation Research, North and Central America

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