Hunt L, Marrochi N, Bonetto C, Liess M, Buss D F, Vieira da Silva C, Chiu M-C, Resh V H
Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, 94720-3114, USA.
ILPLA (CONICET-CCT La Plata)-UNLP Instituto de Limnología "Dr. Raúl. A. Ringuelet", Boulevard 120 y 62, La Plata 1900, Buenos Aires, Argentina.
Environ Manage. 2017 Dec;60(6):1155-1170. doi: 10.1007/s00267-017-0938-9. Epub 2017 Oct 4.
We investigated the influence and relative importance of insecticides and other agricultural stressors in determining variability in invertebrate communities in small streams in intensive soy-production regions of Brazil and Paraguay. In Paraguay we sampled 17 sites on tributaries of the Pirapó River in the state of Itapúa and in Brazil we sampled 18 sites on tributaries of the San Francisco River in the state of Paraná. The riparian buffer zones generally contained native Atlantic forest remnants and/or introduced tree species at various stages of growth. In Brazil the stream buffer width was negatively correlated with sediment insecticide concentrations and buffer width was found to have moderate importance in mitigating effects on some sensitive taxa such as mayflies. However, in both regions insecticides had low relative importance in explaining variability in invertebrate communities, while various habitat parameters were more important. In Brazil, the percent coverage of soft depositional sediment in streams was the most important agriculture-related explanatory variable, and the overall stream-habitat score was the most important variable in Paraguay streams. Paraguay and Brazil both have laws requiring forested riparian buffers. The ample forested riparian buffer zones typical of streams in these regions are likely to have mitigated the effects of pesticides on stream invertebrate communities. This study provides evidence that riparian buffer regulations in the Atlantic Forest region are protecting stream ecosystems from pesticides and other agricultural stressors. Further studies are needed to determine the minimum buffer widths necessary to achieve optimal protection.
我们调查了杀虫剂和其他农业压力源对巴西和巴拉圭集约化大豆产区小河流中无脊椎动物群落变异性的影响及相对重要性。在巴拉圭，我们在伊塔普阿州皮拉波河的支流上选取了17个采样点；在巴西，我们在巴拉那州圣弗朗西斯科河的支流上选取了18个采样点。河岸缓冲带通常包含处于不同生长阶段的原生大西洋森林残余和/或引进树种。在巴西，溪流缓冲带宽度与沉积物中杀虫剂浓度呈负相关，且发现缓冲带宽度在减轻对某些敏感类群（如蜉蝣）的影响方面具有中等重要性。然而，在这两个地区，杀虫剂在解释无脊椎动物群落变异性方面的相对重要性较低，而各种栖息地参数更为重要。在巴西，溪流中软沉积沉积物的覆盖百分比是与农业相关的最重要解释变量，而总体溪流栖息地得分是巴拉圭溪流中最重要的变量。巴拉圭和巴西都有要求设置有林河岸缓冲带的法律。这些地区溪流典型的充足有林河岸缓冲带可能减轻了农药对溪流无脊椎动物群落的影响。本研究提供了证据，表明大西洋森林地区的河岸缓冲带规定正在保护溪流生态系统免受农药和其他农业压力源的影响。需要进一步研究以确定实现最佳保护所需的最小缓冲带宽度。
