Studies investigating the effects of human activities on the functional organization of macroinvertebrate communities in tropical streams and rivers are very limited, despite these areas witnessing the greatest loss of natural forests globally. We investigated changes in taxon richness, numerical abundance and biomass of macroinvertebrate functional feeding groups (FFGs) in streams draining different land-use types in the Sosiani-Kipkaren River in western Kenya. Twenty-one sites in river reaches categorized as forested, mixed, urban or agricultural were sampled during the dry and wet seasons. Collected macroinvertebrates were identified to the lowest taxon possible (mainly genus) and classified into five major FFGs; collector-gatherers, collector-filterers, scrapers, predators and shredders. There were significant (p < 0.05) spatial variation in habitat quality, organic matter standing stocks, total suspended solids, electrical conductivity, dissolved oxygen, temperature and nutrient concentrations across land-uses, with forested sites recording lowest values in mean water temperature, electrical conductivity and nutrients while recording highest levels in dissolved oxygen concentrations. Responses in macroinvertebrates to changes in land-use varied with richness, abundance and biomass showing differences within FFGs. Biomass-based metrics responded more strongly to change in land-use while taxon richness was the least predictive, indicating replacement of taxa within FFGs across land-use types. Higher shredder abundance, biomass and richness were recorded in forested streams which were cooler with protected riparian areas and high biomass of coarse particulate organic matter. Collector-gatherers dominated agricultural and urban streams owing to an abundance of particulate organic matter and nutrients, while scrapers responded positively to increased nutrient levels and open canopy in mixed and agricultural streams where primary production and algal biomass was likely increased. Overall, this study provides further evidence of the effects of agricultural and urban land-uses on tropical streams and rivers and contributes to the use of macroinvertebrate FFGs as indicators of ecological health.

尽管人类活动对全球天然林的损失最大，但研究人类活动对热带小河和河流中无脊椎动物群落功能组织的影响的研究非常有限。我们调查了肯尼亚西部Sosiani-Kipkaren河中流失不同土地利用类型的溪流中大型无脊椎动物功能性饲喂组（FFG）的分类单元丰富度，数量丰度和生物量的变化。在干旱和潮湿季节对河段的21个地点进行了采样，这些地点被分类为森林，混合，城市或农业。收集到的大型无脊椎动物被确定为可能的最低分类群（主要是属），并被分类为五个主要的无脊椎动物。集尘器，集尘器，刮板，掠食者和切碎机。有显着性（p <0.05）栖息地质量，有机质存量，总悬浮固体，电导率，溶解氧，温度和养分浓度在不同土地利用中的空间变化，其中森林林地记录的最低水温，电导率和养分均最低，同时记录溶解氧浓度最高。大型无脊椎动物对土地利用变化的反应随丰富度，丰度和生物量的变化而变化，这表明实地调查组内部存在差异。基于生物量的指标对土地利用的变化反应更强烈，而分类单元丰富度的预测性最差，这表明不同土地利用类型的实地调查组内的分类单元已被替换。更高的碎纸机容量，在森林溪流中记录了生物量和丰富度，森林溪流较凉爽，河岸保护区和粗颗粒有机物的生物量较高。由于大量的颗粒有机物和养分，收集者集中在农业和城市河流中，而刮板对混合水和农业河流中养分水平的提高做出了积极的反应，在这些地方，初级生产和藻类生物量可能会增加。总体而言，这项研究提供了农业和城市土地利用对热带河流和河流的影响的进一步证据，并有助于使用大型无脊椎动物FFG作为生态健康的指标。刮土机对混合和农业流中养分含量增加和树冠开阔做出了积极的反应，在这些流中，初级生产和藻类生物量可能会增加。总体而言，这项研究提供了农业和城市土地利用对热带河流和河流的影响的进一步证据，并有助于使用大型无脊椎动物FFG作为生态健康的指标。刮土机对混合和农业流中养分含量增加和树冠开阔做出了积极的反应，在这些流中，初级生产和藻类生物量可能会增加。总体而言，这项研究提供了农业和城市土地利用对热带河流和河流的影响的进一步证据，并有助于使用大型无脊椎动物FFG作为生态健康的指标。