The intensification of agricultural practices is impacting on Piedmont streams in Patagonia and concern exists regarding the integrity of aquatic ecosystems. This study investigated changes in water quality, habitat and riparian condition, and macroinvertebrate community attributes at three small streams during high- and low-water periods. The upper reaches of streams consisted of well-conserved riparian forest where agricultural impact was minimal, while different production systems affected lower stream-reaches. Significant changes in water quality were indicated by increases in nutrient levels, conductivity, total suspended solids, and bacteria (E. coli) at spatial scale. These were mostly associated with livestock, pasture, and horticulture production, though the most severe impacts on in-stream habitat and riparian ecosystem occurred at sites with livestock productions. A gradient of disturbance was highlighted by Canonical Community Ordination and macroinvertebrates were grouped accordingly. Among the metrics measured, EPT richness, number of insect families, density of tolerant taxa, abundance of collector-gatherers, and total invertebrate density displayed significant responses to water quality. The overriding stressor explaining community changes with regard to intolerant taxa (EPT) was ammonium. Mitigation measures should be directed towards reducing livestock intrusion on streams and riparian areas, maintenance and restoration of buffer zones, and regulation of application of fertilizers.

中文翻译：

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农业实践改变了巴塔哥尼亚山麓溪流中大型无脊椎动物群落的功能和结构

农业实践的强化正在影响巴塔哥尼亚的皮埃蒙特溪流，人们对水生生态系统的完整性表示担忧。本研究调查了高水位和低水位期间三个小溪流的水质、栖息地和河岸条件以及大型无脊椎动物群落属性的变化。河流上游由保护良好的河岸森林组成，对农业的影响最小，而不同的生产系统影响了下游。营养水平、电导率、总悬浮固体和细菌（大肠杆菌）在空间尺度上的增加表明水质发生了显着变化。这些主要与牲畜、牧场和园艺生产有关，尽管对河内栖息地和河岸生态系统的影响最严重的是发生在畜牧业生产地点。规范群落排序突出了干扰梯度，并相应地对大型无脊椎动物进行了分组。在测量的指标中，EPT 丰富度、昆虫科的数量、耐受分类群的密度、采集者-采集者的丰度和无脊椎动物总密度对水质显示出显着的响应。解释关于不耐受分类群 (EPT) 的社区变化的压倒一切的压力源是铵。缓解措施应旨在减少牲畜对溪流和河岸地区的入侵，维护和恢复缓冲区，以及规范化肥的施用。规范群落排序突出了干扰梯度，并相应地对大型无脊椎动物进行了分组。在测量的指标中，EPT 丰富度、昆虫科的数量、耐受分类群的密度、采集者-采集者的丰度和无脊椎动物总密度对水质显示出显着的响应。解释关于不耐受分类群 (EPT) 的社区变化的压倒一切的压力源是铵。缓解措施应旨在减少牲畜对溪流和河岸地区的入侵，维护和恢复缓冲区，以及规范化肥的施用。规范群落排序突出了干扰梯度，并相应地对大型无脊椎动物进行了分组。在测量的指标中，EPT 丰富度、昆虫科的数量、耐受分类群的密度、采集者-采集者的丰度和无脊椎动物总密度对水质显示出显着的响应。解释关于不耐受分类群 (EPT) 的社区变化的压倒一切的压力源是铵。缓解措施应旨在减少牲畜对溪流和河岸地区的入侵，维护和恢复缓冲区，以及规范化肥的施用。和总无脊椎动物密度对水质表现出显着的响应。解释关于不耐受分类群 (EPT) 的社区变化的压倒一切的压力源是铵。缓解措施应旨在减少牲畜对溪流和河岸地区的入侵，维护和恢复缓冲区，以及规范化肥的施用。和总无脊椎动物密度对水质表现出显着的响应。解释关于不耐受分类群 (EPT) 的社区变化的压倒一切的压力源是铵。缓解措施应旨在减少牲畜对溪流和河岸地区的入侵，维护和恢复缓冲区，以及规范化肥的施用。