Abstract Lotic ecosystems in urban areas are severely impacted by anthropogenic environmental stressors, such as deforestation and nutrient pollution, due to socioeconomic activities in the catchment. To work out measures for identification and mitigation of concurrent multiple stressors to a stream system, it is necessary to assess the relative importance of impacts by the individual stressors. Here we aimed to discriminate the covarying effects of nutrient pollution and deforestation on benthic macroinvertebrate communities in an urbanised tropical stream system. In the Silang-Santa Rosa Subwatershed (SSRS) of Laguna de Bay, benthic macroinvertebrates and physicochemical environments were investigated at 13 sites varying in human population density, riparian canopy, and land-use pattern as indicated by geographic information systems in the catchment. Regression and multivariate analyses were performed to identify the drivers of the biodiversity loss and understand its underlying mechanisms. In the SSRS, where rapid economic growth took place without updating poorly installed wastewater treatment plants (WWTPs), domestic activity indicated by human population density in the catchment was the primary factor in generating heavy phosphorous loadings (mean total phosphorus = 0.91; range = 0–1.50 mg/l) that caused hypoxia (mean dissolved oxygen = 2.98; range = 0.13–6.27 mg/l) in stream waters and subsequently reduced macroinvertebrate diversity (mean H’ = 0.91; SD ± 0.61). Nutrient and organic pollution and riparian deforestation explained 53.5% and 9.7% of the variation of benthic macroinvertebrate communities in SSRS, respectively. Given such scenario, additional WWTPs servicing urban developments and improved riparian canopy cover in the SSRS can be both strategic and cost-effective in the initial steps of environmental mitigation in urbanised streams, especially in rapidly developing countries.

中文翻译：

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养分负荷和森林砍伐降低了城市化热带河流系统中底栖大型无脊椎动物的多样性

摘要 由于流域的社会经济活动，城市地区的陆域生态系统受到人为环境压力因素的严重影响，例如森林砍伐和养分污染。为了制定识别和减轻并发多个压力源对流系统的措施，有必要评估单个压力源影响的相对重要性。在这里，我们旨在区分养分污染和森林砍伐对城市化热带河流系统中底栖大型无脊椎动物群落的共变影响。在 Laguna de Bay 的 Silang-Santa Rosa Subwatershed (SSRS)，在 13 个不同人口密度、河岸冠层、流域内地理信息系统显示的土地利用模式。进行回归和多变量分析以确定生物多样性丧失的驱动因素并了解其潜在机制。在 SSRS 中，在没有更新安装不良的污水处理厂 (WWTP) 的情况下实现了快速经济增长，流域人口密度表明的家庭活动是产生重磷负荷的主要因素（平均总磷 = 0.91；范围 = 0 –1.50 毫克/升）导致溪水中缺氧（平均溶解氧 = 2.98；范围 = 0.13–6.27 毫克/升），随后减少大型无脊椎动物的多样性（平均 H' = 0.91；SD ± 0.61）。营养和有机污染以及河岸森林砍伐解释了 53.5% 和 9。SSRS 中底栖大型无脊椎动物群落的变异分别为 7%。鉴于这种情况，在 SSRS 中为城市发展服务的额外污水处理厂和改进的河岸树冠覆盖在城市化河流的环境缓解初始步骤中既具有战略意义又具有成本效益，尤其是在快速发展的国家。