Recovery of Stream Ecosystems from Insecticide Treatment andDrought

将在北卡罗来纳州西部的考韦塔水文实验室研究小山溪流中的有机质和营养动态。控制这些动态的两个因素将被考虑--无脊椎动物的消费活动(即撕叶的水生昆虫)活动和干旱。撕碎树叶的水生昆虫被认为是小溪中有机物和营养物质的主要加工者。这一假设将通过比较未经处理的溪流和用杀虫剂清除水生昆虫的溪流中的有机物和营养动态来检验。在研究期间的中途，将停止杀虫剂处理，并将跟踪无脊椎动物消费者群落的恢复与这些溪流中有机质和营养动态变化之间的关系。Coweeta水文实验室自1984年以来一直处于干旱状态，并在此期间采集了有关河流有机质和养分动态的数据。对这些动态的继续研究将进一步记录小溪生态系统对干旱条件的反应；如果水文状况恢复到“正常”，研究将记录这些系统从干旱中恢复的情况。这项研究很重要，因为关于干旱对溪流中有机质和营养动态的影响的信息很少。这些研究将使用经过充分验证的实验室和现场技术进行。华莱士博士和他的同事韦伯斯特博士和苏伯克罗普博士有着良好的研究记录，为这项工作提供了高质量的机构支持。

Organic matter and nutrient dynamics in small mountain streams at the Coweeta Hydrologic Laboratory in western North Carolina, will be studied. Two factors controlling these dynamics will be considered - invertebrate consumer (i.e. leafshredding aquatic insects) activity and drought. Leaf-shredding aquatic insects are hypothesized to be major processors of organic matter and nutrients in small streams. This hypothesis will be tested by comparing organic matter and nutrient dynamics in unmanipulated streams with those in streams from which aquatic insects have been removed with insecticides. Part-way through the study period the insecticide treatment will be halted and the relationship between the recovery of the invertebrate consumer community and changes in organic matter and nutrient dynamics in these streams will be followed. Drought conditions have prevailed at the Coweeta Hydrologic Laboratory since 1984, and data have been taken over this period on stream organic matter and nutrient dynamics. Continued studies of these dynamics will further document the small-stream ecosystem responses to drought conditions; and if the hydrologic regime should return to "normal," the studies would document recovery of these systems from drought. This research is important since very little information exists on the effects of drought on organic matter and nutrient dynamics in streams. The studies will be conducted using well-proven laboratory and field techniques. Dr. Wallace and his colleagues, Drs. Webster and Suberkropp, have good research records and the institutional support for the work is of high quality.