Exploring the nexus between human activities, ecosystem attributes, water quality, and ecological dynamics of macroinvertebrate functional community in Nigerian streams

Abstract

Understanding macroinvertebrate functional feeding groups (MFFGs) is essential for assessing the ecological health of freshwater ecosystems. Abirunmu, Awoosun, Mogimogi, Olumirin, and Aboto streams were investigated in Osun State Southwest ecoregion, to evaluate the ecological health of these water bodies by analyzing the interactions between human activities, ecosystem characteristics, physicochemical factors, and MFFG. Between December 2019 and October 2021, spanning early and peak wet and dry seasons, 2,077 macroinvertebrates were sampled, encompassing 16 orders, 40 families, and 80 species. Aquatic insects dominated the functional community, while other identified specimens were Mollusca, Crustacea, Arachnida, and Annelida. Predators consistently held the top position as the most common MFFG in all the streams, while collectorgatherers consistently ranked as the least abundant. The streams trophic status revealed Abirunmu and Aboto to be autotrophic, Awoosun and Olumirinheterotrophic, and Mogimogi was oligotrophic. All the streams except Aboto had functional riparian zones. Abirunmu, Awoosun, Olumirin, and Aboto had an ample supply of FPOM to support suspended feeders unlike Mogimogi. Also, all streams except Mogimogi had stable habitats with diverse substrates and none of the studied sites showed a balanced predator-to-prey ratio. Cluster analysis identified Olumirin as a unique site among the other streams. Physicochemical results showed notable spatial variations (p < 0.05) in channel width, dissolved oxygen (DO), total dissolved solids (TDS), and electrical conductivity (EC). Canonical correspondence analysis (CCA) did not show significant ecological correlations between MFFGs and physicochemical parameters, but regression analysis revealed ecological relationships between physicochemical variables, MFFGs, and ecosystem attributes. This study thus explores the use of MFFGs for assessing lotic ecosystem health and water quality, providing insights into their role as biological condition indicators.