Pieters Barry J, Liess Matthias
UFZ-Centre for Environmental Research, Department of System Ecotoxicology, Leipzig, Germany.
Environ Sci Technol. 2006 Oct 1;40(19):6157-62. doi: 10.1021/es052180o.
This study investigated the responses of Daphnia magna populations to pulsed exposures of the pyrethroid insecticide Fenvalerate applied during an early and a late stage of population development, and analyzed the dynamics of the subsequent recovery. A novel digital observation technique was used to describe the size and numbers of animals. High Fenvalerate concentrations caused high mortality rates during exponential population growth as well as during the food-limited stationary phase. However, recovery of populations took considerably longer in the stationary phase than in populations growing exponentially. The poor nutritional and reproductive state of food-deprived adults was indicated as the main cause of the slow recovery of populations. It is argued that populations operating at the carrying capacity of their environment are vulnerable to toxicant-induced disturbances to an extent not predictable from observations on exponentially growing populations such as are commonly used in ecotoxicology.
本研究调查了大型溞种群对在种群发育早期和晚期施加的拟除虫菊酯类杀虫剂氰戊菊酯脉冲暴露的反应，并分析了随后恢复的动态。采用一种新颖的数字观测技术来描述动物的大小和数量。高浓度氰戊菊酯在种群指数增长期以及食物受限的静止期均导致高死亡率。然而，静止期种群的恢复比指数增长种群花费的时间长得多。食物匮乏的成年个体营养和生殖状态不佳被认为是种群恢复缓慢的主要原因。有人认为，处于环境承载能力下的种群易受毒物诱导干扰的影响，其程度无法从对指数增长种群（如生态毒理学中常用的种群）的观察中预测。
