Influences of water and sediment quality on benthic macroinvertebrates in a river with different land use types

Rivers are influenced by surrounding environmental factors, especially land use and occupation type in their watersheds, which affect the integrity of the communities. This study aimed to evaluate the benthic macroinvertebrate community (BMIC) in a river passing through rural (Rur) and urban (Urb) areas and its correlation with various physical–chemical parameters, nutrients, and heavy metals in the water and sediment. The BMIC samples from five sites (three Rur and two Urb) were collected bimonthly between July 2015 and July 2016. The physical–chemical parameters of water (electrical conductivity, biochemical oxygen demand, dissolved oxygen, pH, total solids turbidity, and temperature), heavy metal (Cd, Pb, Fe, Mn, and Zn), and nutrient (N and P) contents in the water and sediment were measured. We compared the BMIC in different areas using principal coordinate analysis and permutational multivariate analysis of variance. These analyses were performed considering the Euclidean distance to which the Hellinger transformation was applied for determining abundance. We performed partial canonical redundancy analysis using the forward selection method, followed by variance partitioning techniques to evaluate the effect of these factors on BMIC. The BMIC varied between Rur and Urb areas. Taxa tolerant to high N and P contents were predominant in the Urb area, which indicates a high degree of contamination by organic pollutants. In the Rur area, Zn contamination, possibly from agricultural activities, was evident. Thus, although BMIC complete part or all of their life cycle close to the substrate, the physicochemical parameters of water, mainly pH and total dissolved phosphorus, had the highest influence on its composition.