PREDICTING CLIMATE CHANGE EFFECTS ON NEOTROPICAL STREAM PHYSICOCHEMISTRY: COMPARING IMPACTS OF PRECIPITATION REGIME AND TEMPERATURE VIA WAVELET ANALYSIS
Increasing temperature and shifting precipitation regimes due to climate change are likely to impact stream physicochemistry. However, comparisons of predicted impacts of temperature vs. precipitation (especially from the tropics) are lacking. We used longterm datasets from La Selva Biological Station, Costa Rica, to examine how precipitation vs. air temperature impact the physicochemistry of streams receiving two distinct groundwater types (low-solute, poorly-buffered local groundwater vs. high-solute, well-buffered regional groundwater). Stream and air temperatures were positively correlated, but neither increased significantly during our study period (1997-2013). Water temperature was lower, more variable, and more strongly related to air temperature in the local-groundwater stream than in the regional-groundwater stream. We used wavelet analysis to show that precipitation drove pH declines in both stream types and that air temperature determined stream temperature but did not otherwise strongly affect physicochemistry. Our data and previous studies suggest that precipitation may have a stronger impact than temperature on stream biota, principally because precipitation drives pH declines that may override effects of more slowly changing temperatures. Our results also indicate that streams receiving regional groundwater are naturally buffered against shifts in temperature.
Carissa Ganong (Primary Presenter/Author), Missouri Western State University, firstname.lastname@example.org;
Thomas Barnum (Co-Presenter/Co-Author), USAID, email@example.com;
John Duff (Co-Presenter/Co-Author), United States Geological Survey, firstname.lastname@example.org;
Catherine Pringle (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, email@example.com;