Increasing synchrony of high temperature and low flow in western North American streams: double trouble for coldwater biota?
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Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (T max_w) and stream flow minima (Q 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 max_w and Q min. We also examined if years with extreme low Q min were associated with years of extreme high T 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 max_w and Q 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.
KeywordsClimate change Freshwater ecosystems Hydrology Temperature Hydroclimatology
Brooke Penaluna, Tim D. Mayer, two anonymous referees, and the associated editor provided comments on the manuscript. Financial support was provided by US Geological Survey, the US Forest Service Pacific Northwest Research Station and Oregon State University. Use of firm or trade names is for reader information only and does not imply endorsement of any product or service by the U.S. Government.
- Arismendi, I., S. Johnson, J. Dunham, R. Haggerty & D. Hockman-Wert, 2012. The paradox of cooling streams in a warming world: regional climate trends do not parallel variable local trends in stream temperature in the Pacific continental United States. Geophysical Research Letters 39: L10401.CrossRefGoogle Scholar
- Fry, F. E. J., 1947. Effects of the environment on animal activity. University of Toronto Studies, Biological Series 55. Publication of the Ontario Fisheries Research Laboratory 68: 1–62.Google Scholar
- Kundzewicz, Z. W., & A. Robson (eds), 2000. Detecting trend and other changes in hydrological data. World climate programme data and monitoring. United Nations Educational World Meteorological Scientific and Cultural Organization. WCDMP-45. Geneva, Italy.Google Scholar
- Magnuson, J. J., L. B. Crowder & P. A. Medvick, 1979. Temperature as an ecological resource. American Zoologist 19: 331–343.Google Scholar
- McCullough, D. A., J. M. Bartholow, H. I. Jager, R. L. Beschta, E. F. Cheslak, M. L. Deas, J. L. Ebersole, J. S. Foott, S. L. Johnson, K. R. Marine, M. G. Mesa, J. H. Petersen, Y. Souchon, K. F. Tiffan & W. A. Wurtsbaugh, 2009. Research in thermal biology: burning questions for coldwater stream fishes. Reviews in Fisheries Science 17(1): 90–115.CrossRefGoogle Scholar
- Noormets, A., (ed.) 2009. Phenology of ecosystem processes applications in global change research. Springer, New York. doi: 10.1007/978-1-4419-0026-5.
- van Vliet, M. T. H., F. Ludwig, J. J. G. Zwolsman, G. P. Weedon & P. Kabat, 2011. Global river temperatures and sensitivity to atmospheric warming and changes in river flow. Water Resources Research 47: W02544.Google Scholar
- Wahl, K. L. & T. L. Wahl, 1995. Determining the flow of Comal Springs at New Braunfels, Texas, Texas Water ‘95, American Society of Civil Engineers, 16–17 August, 1995, San Antonio, Texas: 77–86.Google Scholar