Habitat characteristics and anthropogenic activities infuence the distribution of macroinvertebrate traits and ecological preferences in Nigerian streams: a case study of Osun State, Nigeria

Abstract

Impact of habitat characteristics and anthropogenic activities on the distribution of macroinvertebrate traits and ecological preferences was assessed in Osun State, Nigerian. Physicochemical parameters involving water depth (WD), channel width (CW), fow rate, discharge, water temperature (W.T), dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), pH, biological oxygen demand (BOD), turbidity, nitrate, phosphate and organic matter (OM), were appraised, alongside macroinvertebrates from 5 streams in diferent geographical locations. Sampling spanned from December 2019 to October 2021, covering early and late dry seasons, as well as earlyand late rainy seasons. Principal component analysis classifed the sites into three impact categories: least impacted (LIS), moderately impacted (MIS), and highly impacted (HIS). Nine traits and ecological preferences displayed signifcant variations alongside nine physicochemical variables, such as phosphate, OM, WD, discharge, CW, TDS, EC, W.T, and nitrate, within the Fourth-corner fgure. Furthermore, these traits and ecological preferences exhibited notable correlations with site impact categories, including–no turbidity preference, spherical body shape, climbers to LIS, preference for transparent water, crawlers, climbers, burrowers, small body size to MIS, and highly tolerant to ocxygen depletion to MIS.This study underscores the efectiveness of macroinvertebrate trait-based approach as a freshwater biomonitoring tool in Osun State, Nigeria, providing essential insights into how environmental factors infuence macroinvertebrate traits in lotic systems in the region, with implications not only locally but also for broader eclogical studies.