RESEARCH ARTICLE Consequences of Warming and Resource Quality on the Stoichiometry and Nutrient Cycling of a Stream Shredder

As a result of climate change, streams are warming and their runoff has been decreasing in most temperate areas. These changes can affect consumers directly by increasing their met-abolic rates and modifying their physiology and indirectly by changing the quality of the re-sources on which organisms depend. In this study, a common stream detritivore (Echinogammarus berilloniCatta) was reared at two temperatures (15 and 20°C) and fed Po-pulus nigra L. leaves that had been conditioned either in an intermittent or permanent reach to evaluate the effects of resource quality and increased temperatures on detritivore perfor-mance, stoichiometry and nutrient cycling. The lower quality (i.e., lower protein, soluble car-bohydrates and higher C:P and N:P ratios) of leaves conditioned in pools resulted in compensatory feeding and lower nutrient retention capacity by E. berilloni. This effect was es-pecially marked for phosphorus, which was unexpected based on predictions of ecological stoichiometry. When individuals were fed pool-conditioned leaves at warmer temperatures, their growth rates were higher, but consumers exhibited less efficient assimilation and higher mortality. Furthermore, the shifts to lower C:P ratios and higher lipid concentrations in shred