Impacts of low-level pollution by pesticides on freshwater ecosystem.

由于人为影响，水生生态系统存在许多现实问题。农药的化学污染是造成这些问题的一个因素。生物种群动态受生物相互作用和非生物环境因素的复杂组合控制。每个物种对农药的易损性不同，因此化学物质应诱导不同的群落结构。此外，这些化学物质不仅影响个体的生存或繁殖，而且在很低的浓度下也会干扰猎物-捕食者的相互作用。本文通过个体、种群和群落水平的实验，研究了杀虫剂、除草剂和杀菌剂三种农药低水平暴露对淡水生态系统的影响。结果表明，农药浓度较低时对食物网结构和生态系统功能的影响显著高于PNEC和HC5。

Aquatic ecosystems have many real problems due to anthropogenic impacts. Chemical pollution by pesticides is one contributing factor to these problems.Population dynamics of the organisms are controlled by complex combinations of biotic interactions and abiotic environmental factors. Vulnerability to the pesticides differs between each species, so the chemicals should induce different community structures. Moreover, the chemicals not only affect the individual survival or the reproduction, but also disturb the prey-predator interactions at very low concentrations.Here, we have examined the impacts of low level exposure of three pesticides (insecticide, herbicide and bactericide) on freshwater ecosystem by conducting individual-, population- and community level experiments. Our results suggest that pesticides affect significantly on food web structure and ecosystem functions at lower concentrations than PNEC or HC5.