Additive Effects of Sediment and Nutrient on Leaf Litter Decomposition and Macroinvertebrates in Hyporheic Zone

摘要: Despite the fact that leaf decomposition constitutes an important function in rivers, how multiple environmental stressors simultaneously affect it remains largely unknown. This study investigated interactive effects of fine sediments (particle size: <2 mm; experimentally manipulated) and a specific nutrient (i.e., nitrate) on subsurface (hyporheic) litter rate macroinvertebrates gravel-bed river its tributary eastern Hokkaido, Japan. The experiment was conducted by measuring dried Alnus japonica leaves (3 ± 0.05 g) benthic hyporheic zones with without sediment treatments at four sites had gradient nitrate concentration. comparable between two but slowed down addition zone. functional responses were highly predictable for individual stressors. Detritivore invertebrates main driving component decreased under higher condition, whereas accelerated stimulated microbe-driven as well detritivore feeding. Overall, negative effect could be offset presence while considering gross responses. We demonstrated additive