Upper reaches of temperate streams and oligotrophic lakes depend trophically on the organic matter coming from the surrounding watershed. These aquatic ecosystems accumulate particulate and dissolved organic matter, and chemical compounds liberated from decomposing leaves or from the leachates of leaf litter. These materials supply a wide range of chemical compounds, which may serve as food, but also cause ecotoxicological effects on aquatic organisms. However, this ecotoxicological risk has been amply ignored, especially for freshwater invertebrates. The aims of our study are: (1) to assess the direct toxicity of aqueous extracts of leaf litter from two native (Populus alba, Fraxinus angustifolia) and two tree species exotic to Europe (Robinia pseudoacacia, Ailanthus altissima) on a pelagic and a benthic species of model aquatic invertebrates: Daphnia magna (Cladocera) and Potamopyrgus antipodarum (Mollusca) and (2) to estimate the ecotoxicological risk of the leaf litter extracts to lacustrine ecosystems using different simulated scenarios of shallow lakes. For both invertebrate species, we assessed the effective concentration of leaf extract causing an effect on 50% of the population (EC50) by means of laboratory bioassays. Our results show that the extracts of leaf litter from all the tested trees have a potential ecotoxicological risk in some scenarios, which is independent from the geographic origin of the tree species.

温带河流和贫营养湖泊的上游在营养上依赖于来自周围流域的有机物。这些水生生态系统会积聚颗粒和溶解的有机物，以及从分解叶片或凋落物沥出物中释放出的化学化合物。这些材料提供了各种各样的化合物，这些化合物可以充当食物，但也对水生生物造成生态毒理学影响。但是，这种生态毒理风险已被完全忽略，尤其是对于淡水无脊椎动物。我们研究的目的是：（1）评估来自两种本土（杨（Populus alba），白蜡树（Fraxinus angustifolia）和两种对欧洲具有异国情调的树种（Robinia pseudoacacia，在模式水生无脊椎动物的浮游和底栖物种上的臭椿（Ailanthus altissima）（Daphnia magna（Cladocera）和Potamopyrgus antipodarum（Mollusca））和（2）使用不同的浅湖模拟情景估算叶子凋落物提取物对湖泊生态系统的生态毒理风险。对于这两种无脊椎动物，我们通过实验室生物测定法评估了对50％的种群造成影响的叶提取物的有效浓度（EC50）。我们的结果表明，在某些情况下，所有被测树木的凋落物提取物均具有潜在的生态毒理风险，而与树木物种的地理起源无关。