Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (T [subscript max_w]) and stream flow minima (Q[subscript min]) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and decreases in low flow during summer/fall have been reported. We hypothesized that an earlier peak flow could be shifting the timing of low flow and leading to a decrease in the interval between T [subscript max_w] and Q [subscript min]. We also examined if years with extreme low Q [subscript min] were associated with years of extreme high T [subscript max_w]. We tested these hypotheses using long-term data from 22 minimally human-influenced streams for the period 1950-2010. We found trends toward a shorter time lag between (T [subscript max_w] and Q [subscript min] over time and a strong negative association between their magnitudes. Our findings show that aquatic biota may be increasingly experiencing narrower time windows to recover or adapt between these extreme events of low flow and high temperature. This study highlights the importance of evaluating multiple environmental drivers to better gage the effects of the recent climate variability in freshwaters.Keywords: Freshwater ecosystems, Hydrology, Hydroclimatology, Temperature, Climate chang
