Vonesh James R, Kraus Johanna M
Tyson Research Center, Washington University in Saint Louis, One Brookings Drive, Campus Box 1229, St. Louis, MO 63130-4899, USA.
Oecologia. 2009 May;160(2):379-85. doi: 10.1007/s00442-009-1301-5. Epub 2009 Feb 28.
Anthropogenic chemical contamination is an important issue for conservation of aquatic ecosystems. While recent research highlights that community context can mediate the consequences of contaminant exposure, little is known about how contaminants themselves might determine this context by altering habitat selection and thus initial community composition. Here we show that the insecticide carbaryl and its commercial counterpart Sevin can affect aquatic community composition by differentially altering oviposition and colonization of experimental pools by amphibians and insects. On average, contaminated pools received 20-fold more adult beetle and heteropteran colonists and 12-fold more Culex mosquito and chironomid midge egg masses. On the other hand, ovipositing Anopheles mosquitoes and cricket frogs showed no preference and we have shown previously that gray treefrogs strongly avoid contaminated pools. Overall, initial richness doubled in contaminated pools compared with controls. By affecting colonizing taxa differently and increasing richness, the contaminant may alter the ecological context under which subsequent effects of exposure will unfold. Given that community context is important for evaluating toxicity effects, understanding the net effects of contaminants in natural systems requires an understanding of their effects on community assembly via shifts in habitat selection.
人为化学污染是水生生态系统保护的一个重要问题。虽然最近的研究强调群落背景可以调节污染物暴露的后果，但对于污染物本身如何通过改变栖息地选择从而决定初始群落组成进而影响这种背景，我们却知之甚少。在此我们表明，杀虫剂西维因及其商业产品Sevin可通过不同程度地改变两栖动物和昆虫在实验水池中的产卵和定殖情况来影响水生群落组成。平均而言，受污染的水池吸引的成年甲虫和异翅目定殖者数量多出20倍，库蚊和摇蚊的卵块数量多出12倍。另一方面，产卵的按蚊和姬蛙没有表现出偏好，而且我们之前已经表明灰树蛙强烈避开受污染的水池。总体而言，与对照相比，受污染水池的初始物种丰富度增加了一倍。通过对定殖类群产生不同影响并增加物种丰富度，污染物可能会改变后续暴露影响得以显现的生态背景。鉴于群落背景对于评估毒性效应很重要，了解污染物在自然系统中的净效应需要了解它们通过栖息地选择的变化对群落组装的影响。
