Impacts of land use and environmental factors on macroinvertebrate functional feeding groups in the Dongjiang River basin, southeast China

Abstract

The aim of this study was to assess the impacts of different land use practices on physicochemical characteristics and macroinvertebrate functional feeding groups (FFGs) in the Dongjiang River basin, southeast China and also to evaluate if macroinvertebrate FFGs match the river continuum concept (RCC) predictions. For this aim, a total of 30 sampling sites were selected that comprised three different land use types (10 forest, 10 agricultural, and 10 urban sites) and sampled during the dry season in January 2013. Analysis of variance results showed evident differences in the environmental factors among the three land use types, particularly between the forest and urban sites. The forest sites had significantly lower water temperature, lower stream order, higher pH, higher dissolved oxygen, higher elevation, and coarser substrates than the other land use sites. Conversely, the urban sites showed significantly higher mean values for electrical conductivity, nitrogen and phosphorus compounds. Significant differences in the shredder and predator richness and density were observed among land uses with more shredders and predators found in forest sites. Redundancy analysis showed a clear separation of forest sites from riparian modified areas (agriculture and urban use sites). Our results were broadly in accordance with the central RCC theme. However, the longitudinal distribution of predators and collectors did not completely match the prediction of the RCC. These results confirm that macroinvertebrate FFG structure has been altered by agricultural and urbanization practices in the Dongjiang River basin. Moreover, shredders and predators could be potential candidates for monitoring and assessing land use impacts on water quality in this basin to improve future watershed management.