Background Mining, agriculture and cattle production are activities that threaten the quality and quantity of water resources in the Colombian Andes. However, many drainage basins in this region have not been subjected to simultaneous evaluation of the impact these activities have on the density, diversity and composition of aquatic macroinvertebrates (AMI). The first two of these ecological variables are expected to decrease drastically from zones with no apparent impact towards areas with anthropogenic activity, which areas with mining will present the most impoverished AMI community. Methods We evaluated the density, diversity and composition dissimilarity of AMI in streams impacted by gold mining, agriculture and cattle production. Two reference streams were also studied. Six benthic samplings were conducted bimonthly (Feb 2014–Feb 2015) using a Surber net. Water samples were taken in order to make environmental evaluation among the aforementioned streams, including hydrological, physicochemical and bacteriological parameters (HPCB). Diversity was evaluated as the effective number of RTUs—recognizable taxonomic units—by comparing the richness, typical diversity, and effective number of the most abundant RTUs. Compositional dissimilarity was examined with nMDS and CCA analysis. Results A total of 7,483 organisms were collected: 14 orders, 42 families and 71 RTUs. Our prediction regarding the density and diversity of AMI (Reference > Cattle production > Agriculture > Mining) was partially fulfilled, since the agriculture-dominated stream presented a more impoverished AMI community than that of the gold mining stream. However, these streams presented lower diversity than the cattle production and reference streams, and the AMI density only differed significantly between one reference stream and the agriculture stream. The AMI composition in the agriculture-dominated stream clearly differed from that of the other streams. Discussion The observation of a more impoverished AMI community in agricultural production areas compared to those with mining or cattle production may reflect the importance of the remaining riparian vegetation, which was scarce at the stream with agricultural activity. Moreover, the low diversity, and mainly the reduced AMI richness, in the agriculture stream coincided with the absence of insect genera are intolerant to deterioration of the biological and physicochemical conditions of the water (e.g. Anacroneuria). Conclusions The results suggest that the local impact of agricultural activities may be of equal or greater magnitude than that of mining in terms of AMI density, diversity and composition, in the Colombian Andean riverscape. Future studies should systematically evaluate, throughout the annual cycle, the relative effects of the productive land use, the remaining native vegetation cover and the consequent changes in the HPCB parameters of the water on AMI communities in Colombian Andean basins.

中文翻译：

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受采矿、农业和养牛业影响的哥伦比亚安第斯河流中大型无脊椎动物的密度和多样性

背景 采矿、农业和养牛业是威胁哥伦比亚安第斯山脉水资源质量和数量的活动。然而，该地区的许多流域尚未同时评估这些活动对水生大型无脊椎动物 (AMI) 的密度、多样性和组成的影响。预计这些生态变量中的前两个将从对人为活动区域没有明显影响的区域急剧减少，其中采矿区域将呈现最贫困的 AMI 社区。方法 我们评估了受金矿开采、农业和养牛生产影响的溪流中 AMI 的密度、多样性和组成差异。还研究了两个参考流。使用 Surber 网络每两个月（2014 年 2 月至 2015 年 2 月）进行六次底栖采样。采集水样以对上述河流进行环境评估，包括水文、物理化学和细菌学参数（HPCB）。通过比较最丰富的 RTU 的丰富度、典型多样性和有效数量，将多样性评估为 RTU 的有效数量（可识别的分类单位）。用 nMDS 和 CCA 分析检查了成分的差异。结果共收集到7483种生物：14目、42科、71个RTU。我们对 AMI 的密度和多样性的预测（参考 > 牛生产 > 农业 > 采矿）已部分实现，因为以农业为主的流比金矿流呈现出更贫困的 AMI 社区。然而，这些溪流的多样性低于牛生产和参考溪流，AMI 密度仅在一个参考溪流和农业溪流之间存在显着差异。以农业为主的溪流中的 AMI 组成明显不同于其他溪流。讨论 与采矿或养牛业相比，农业生产区的 AMI 社区更加贫困，这可能反映了剩余河岸植被的重要性，在农业活动的河流中，这些植被稀缺。此外，多样性低，主要是 AMI 丰富度降低，在农业流恰逢没有昆虫属不能容忍水的生物和物理化学条件恶化（例如Anacroneuria）。结论 结果表明，在哥伦比亚安第斯河景观中，就 AMI 密度、多样性和组成而言，农业活动对当地的影响可能与采矿相同或更大。未来的研究应在整个年度周期内系统地评估生产性土地利用、剩余的原生植被覆盖以及水的 HPCB 参数随之变化对哥伦比亚安第斯盆地 AMI 群落的相对影响。结论 结果表明，在哥伦比亚安第斯河景观中，就 AMI 密度、多样性和组成而言，农业活动对当地的影响可能与采矿相同或更大。未来的研究应在整个年度周期内系统地评估生产性土地利用、剩余的原生植被覆盖以及水的 HPCB 参数随之变化对哥伦比亚安第斯盆地 AMI 群落的相对影响。结论 结果表明，在哥伦比亚安第斯河景观中，就 AMI 密度、多样性和组成而言，农业活动对当地的影响可能与采矿相同或更大。未来的研究应在整个年度周期内系统地评估生产性土地利用、剩余的原生植被覆盖以及水的 HPCB 参数随之变化对哥伦比亚安第斯盆地 AMI 群落的相对影响。