Benthic macroinvertebrate assemblages are used to assess anthropogenic stressors and pressures globally—although considerable spatial and temporal variability in those assemblages occur naturally and in their sampling. We evaluated the effects of an untreated domestic sewage spill on the spatial–temporal occurrence, structure and dynamics of benthic macroinvertebrate assemblages, through use of occupancy probability and time series modelling. Our study produced three key results: (1) Site colonization, extirpation, and occupancy probabilities of resistant and sensitive assemblages were not influenced by the predictor variables measured before and after the spill nor between sites. (2) Over time, site occupancy for the proportion of sensitive taxa increased while the proportion of resistant taxa decreased. (3) Artificial substrates reduced natural variability more than Surber sampling of natural substrates, but macroinvertebrate family richness differed over time regardless of sampling device. We conclude that rigorous monitoring and data analyses of benthic bioindicators can be a cost-effective approach for assessing the biotic effects of sewage discharges on neotropical urban streams.

底栖大型无脊椎动物组合被用于评估全球人为压力源和压力——尽管这些组合的相当大的空间和时间变化是自然发生的，并且在它们的采样中发生。我们通过占用概率和时间序列模型评估了未经处理的生活污水泄漏对底栖大型无脊椎动物组合的时空发生、结构和动力学的影响。我们的研究产生了三个关键结果：（1）抗性和敏感组合的场地定植、灭绝和占用概率不受泄漏前后或场地之间测量的预测变量的影响。(2) 随着时间的推移，敏感类群所占比例增加，而抗性类群所占比例下降。(3) 人工基质比天然基质的 Surber 采样减少了更多的自然变异，但无论采样设备如何，大型无脊椎动物家族的丰富度都会随着时间的推移而不同。我们得出的结论是，对底栖生物指标进行严格的监测和数据分析是评估污水排放对新热带城市河流的生物影响的一种具有成本效益的方法。