Can Macroinvertebrate Traits Be Explored and Applied in Biomonitoring Riverine Systems Draining Forested Catchments?

Augustine O Edegbene,Oghenekaro N Odume,Francis O Arimoro,Unique N Keke,Efe Ogidiaka

doi:10.3389/frwa.2021.607556

Abstract

Trait-based approach (TBA) in recent time has received tremendous attention as complementary tool over taxonomic-based approach in assessing ecological health of riverine systems in developed countries, but in the Afrotropical region the trait-based approach is still in its infancy. No trait-based approach has been developed for riverine systems draining forested catchment in the Afrotropical region. Hence, this study was conducted to explore and apply macroinvertebrates traits as potential biomonitoring tools in assessing ecological health of riverine systems draining forested catchments in the Niger Delta area of Nigeria. Selected physico-chemical variables were sampled together with macroinvertebrates in 18 stations of 10 riverine systems from 2008 to 2012. The 18 stations were classified into three ecological classes namely near natural stations (NNS), slightly disturbed stations (SDS), and moderately disturbed stations (MDS) using physico-chemical-based classification with the aid of principal component analysis (PCA). The results revealed traits such as possessions of hardshell body armouring, preferences for clear and transparent water and opaque water, climbing and crawling mobility mechanisms, large (&gt;20–40 mm) body size, preferences for scrapping, shredding, and grazing feeding habits to be associated with NNS and SDS based on RLQ (R, physico-chemical variables; L, taxa; Q, traits) analysis performed. Thus, these traits were deemed to be sensitive to human impact in forested systems. Also, traits such as tegument/cutaneous respiration, soft and exposed body armouring, burrowing mobility mechanism, spherical body shape, preference for detritus [fine particulate organic materials (FPOM)] food materials, small (&gt;5–10 mm) body size and preference for filter feeding mechanism were associated with MDS. Hence, they were deemed tolerant of human impact in forested systems. A fourth-corner test performed revealed tegumental/cutaneous respiration preference, soft and exposed body armouring and burrowing mobility mode, which were associated with the MDS on the RLQ ordination were also positively correlated to 5 day biochemical oxygen demand (BOD5); while preference for clear and transparent water, which were positively associated with MDS, were also positively correlated with pH and negatively correlated to dissolved oxygen (DO). Overall, this study affirmed that the TBA can be explored in biomonitoring riverine systems draining forested catchments. Nevertheless, we suggest the trait-based approach to be further explored, with a view to developing trait-informed indices for biomonitoring Afrotropical riverine systems.

Highlights

Trait-based approach has recently gained attention as complementary to taxonomy-based approach when assessing riverine water quality (Fierro et al, 2017; Krynak and Yates, 2018; Desrosiers et al, 2019)
Vannote et al (1980) in their popular river continuum concept postulated the proportional distribution of functional feeding groups from forested systems dominated by allochthonous production to open system dominated by autochthonous production, shredders adapted for breaking down coarse particulate organic matter (CPOM) are expected to be dominant in forested system, whereas collector-gatherers and filter-filter feeders, which are adapted for consuming fine particulate organic materials (FPOM) are expected to be dominant in large open river systems (Vannote et al, 1980; Edegbene, 2020)
BOD5, electrical conductivity (EC), and pH were positively correlated with Adofi River, Stations 2 of Eriora and Ogbonwen Rivers, Edor, Eriora, Utor Rivers, and Orogodo River, and they were positioned on Component 1

Summary

Introduction

Trait-based approach has recently gained attention as complementary to taxonomy-based approach when assessing riverine water quality (Fierro et al, 2017; Krynak and Yates, 2018; Desrosiers et al, 2019). With regard to forested riverine systems receiving allochthonous materials from surrounding riparian vegetation, functional feeding groups (FFGs) such as shredders would dominate such systems providing a non-taxonomy based approach for assessing functional changes along the river length (Vannote et al, 1980; Moares et al, 2014; Brand and Miserendino, 2015). Vannote et al (1980) in their popular river continuum concept postulated the proportional distribution of functional feeding groups from forested systems dominated by allochthonous production to open system dominated by autochthonous production, shredders adapted for breaking down coarse particulate organic matter (CPOM) are expected to be dominant in forested system, whereas collector-gatherers and filter-filter feeders, which are adapted for consuming fine particulate organic materials (FPOM) are expected to be dominant in large open river systems (Vannote et al, 1980; Edegbene, 2020)

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