The importance of crayfish in the breakdown of rhododendron leaf litter at the Coweeta Hydrologic Laboratory in 1999

Rhododendron (Rhododendron maximum) is a common evergreen shrub in riparian areas of the southern Appalachians, where its leaves can comprise a large proportion of leaf litter in streams. However, they are relatively refractory and generally considered a low quality food resource for detritivores. Our objective was to assess whether macroconsumers (primarily crayfish (Cambarus bartonii)) influence rhododendron leaf breakdown in a forested southern Appalachian stream in both summer (when leaves other than rhododendron are relatively scarce) and autumn (when other leaves are relatively abundant). We conducted two leaf decay experiments, one in summer and one in autumn, using pre-conditioned leaves. Macroconsumers were excluded from the benthos of a fourth-order stream using electric fences; we predicted that excluding macroconsumers would reduce the decay rate of rhododendron leaves in both summer and autumn.大杜鹃花（Rhododendron maximum）是阿巴拉契亚南部河岸带的常见常绿灌木，其叶片可在溪流凋落物中占据较大比例。但该类叶片相对难降解，通常被视作腐食性动物的低品质食物资源。本研究旨在评估大型消费者（主要为巴氏螯虾（Cambarus bartonii））对阿巴拉契亚南部某森林溪流中大杜鹃花叶片降解过程的影响，实验分别设置于夏季（除大杜鹃花外其他叶片相对匮乏）与秋季（其他叶片相对充足）两个时段。我们采用预培育叶片开展了两项叶片降解实验，一项于夏季实施，另一项于秋季实施。实验通过电围栏排除了某四阶溪流底栖生境中的大型消费者；我们预测，排除大型消费者会同时降低夏季与秋季情境下大杜鹃花叶片的降解速率。