Macroinvertebrate functional feeding group assemblages in Nigerian streams draining a forested landscape: do environmental shifts in forested streams affect functional feeding group distribution?

Abstract

Hydrobiological studies often use macroinvertebrates as bioindicators to assess river health, employing methods such as diversity assessments, species richness analyses, functional trait evaluations and biotic or multimetric indices. This study focuses on macroinvertebrate functional feeding group (FFG) assemblages in selected streams in the South-South region of Nigeria, examining their ecological roles in relation to environmental conditions. Sampling was conducted at 18 sites along 11 streams in forested areas of Delta and Edo States over a five-year period (2008–2012). A total of 52 families of benthic macroinvertebrates were identified, with notable variations in functional assemblages. Predators were particularly abundant in environments with high dissolved oxygen levels, while other FFGs, including shredders, collector-filterers, scrapers and collector-gatherers, were influenced by factors such as conductivity, phosphate levels and pH. These results underscore the significant role of environmental conditions in shaping macroinvertebrate functional structure and their potential as ecological indicators. Integrating this knowledge into biomonitoring efforts will enhance stream health assessments and inform management strategies for the conservation of forested aquatic ecosystems in southern Nigeria.