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A major challenge in the biological monitoring of stream ecosystems in protected wilderness areas is discerning whether temporal changes in community structure are significantly outside of a reference condition that represents natural or acceptable annual variation in population cycles. Otherwise sites could erroneously be classified as impaired. Long-term datasets are essential for understanding these trends, to ascertain whether any changes in community structure significantly beyond the reference condition are permanent shifts or with time move back to within previous limits. To this end, we searched for long-term (>8 years) quantitative data sets of macroinvertebrate communities in wadeable rivers collected...
Climate fluctuations are an environmental stress that must be factored into our designs for water resources, power, and other societal and environmental concerns. Under California's Mediterranean setting, winter and summer climate fluctuations both have important consequences. Winter climatic conditions determine the rates of water delivery to the state, and summer conditions determine most dem...
We compared the water balance among the earth's major terrestrial ecosystems. Potential evapotranspiration, actual evapotranspiration (AET) and deficit were derived for each month and year from 19-25-yr climate records at ninety-four sites around the world representing eleven biomes. For each variable, we determined mean annual values. Our focus, however, was to examine temporal variation in AET, which previously has been correlated with large-scale patterns of ecosystem structure and function. Standard deviation of annual AET, an absolute measure of interannual variability, was highest for grasslands and lowest for tundra and taiga. Coefficient of variation of annual AET, a relative measure of variability, was...
A major challenge in the biological monitoring of stream ecosystems in protected wilderness areas is discerning whether temporal changes in community structure are significantly outside of a reference condition that represents natural or acceptable annual variation in population cycles. Otherwise sites could erroneously be classified as impaired. Long-term datasets are essential for understanding these trends, to ascertain whether any changes in community structure significantly beyond the reference condition are permanent shifts or with time move back to within previous limits. To this end, we searched for long-term (>8 years) quantitative data sets of macroinvertebrate communities in wadeable rivers collected...