Araújo Cristiano V M, Shinn Cândida, Vasconcelos Ana M, Ribeiro Rui, Espíndola Evaldo L G
IMAR-Instituto do Mar, Department of Life Sciences, University of Coimbra, Apartado 3046, 3001-401, Coimbra, Portugal,
Ecotoxicology. 2014 Jul;23(5):851-60. doi: 10.1007/s10646-014-1225-7. Epub 2014 Mar 21.
Tadpoles of two amphibian species, the neotropical anuran Leptodactylus latrans and the North American bullfrog Lithobates catesbeianus, were used in experiments to assess their preferred spatial distribution along habitat gradients and, thus, to what extent contamination by the fungicide pyrimethanil could trigger active spatial avoidance. The tadpoles were tested in a non-confined multi-compartment static system with a pyrimethanil contamination gradient through which organisms could move freely. Two samples, with and without (reference) pyrimethanil contamination, taken from outdoor mesocosms, were assayed. Tadpoles showed to be able to detect and move to the most favorable environment by preferring compartments containing reference mesocosm water. Pyrimethanil concentrations from 0.2 to 1.4 mg L(-1) were below lethal levels, but acted as habitat disturber since spatial avoidance was triggered. Avoiders of L. latrans reached almost 50 % at 1.4 mg L(-1). The present data reinforces the hypothesis regarding the risk of plant protection products to act, not only as toxicants, but also as habitat disturber, potentially leading to avoidance-driven population decline of amphibians.
两种两栖动物的蝌蚪，即新热带区无尾目动物南美牛蛙（Leptodactylus latrans）和北美牛蛙（Lithobates catesbeianus），被用于实验，以评估它们沿栖息地梯度的偏好空间分布，从而确定杀菌剂嘧霉胺的污染在多大程度上会引发主动的空间回避行为。蝌蚪在一个无限制的多隔层静态系统中进行测试，该系统存在嘧霉胺污染梯度，生物可以自由移动。对取自室外中型生态箱的两个样本进行了分析，一个有嘧霉胺污染，另一个没有（作为对照）。蝌蚪表现出能够通过偏好含有对照中型生态箱水的隔层，检测并移动到最适宜的环境中。0.2至1.4毫克/升的嘧霉胺浓度低于致死水平，但由于引发了空间回避行为，所以起到了栖息地干扰物的作用。在1.4毫克/升时，南美牛蛙的回避者比例几乎达到50%。目前的数据强化了关于植物保护产品风险的假设，即它们不仅作为有毒物质起作用，还作为栖息地干扰物，可能导致两栖动物因回避行为而种群数量下降。
