Biological Health Assessments of Lotic Waters by Biotic Integrity Indices and their Relations to Water Chemistry

Kwang-Guk An,Usman Atique,Byungjin Lim,Johee Yoon

doi:10.3390/w11030436

Kwang-Guk An, Usman Atique + Show 2 more

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https://doi.org/10.3390/w11030436

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Abstract

Biological health assessment (BHA) has developed as an imperative gauge in efficient management of freshwater resources and fish assemblages. The principal objective of this research is directed at the development and application of a new index under the umbrella of the famous index of biological integrity (IBI). Further, we intended to carry out comparative assessments of the new index with two existing indices and testified to their rational in Geum River watershed, which is the third largest river water basin in South Korea. We analyzed the biotic integrity of 149 different study sites in the streams and rivers of Geum River watershed, perusing fish assemblages and water quality data. The results revealed the newer index, i.e., multi-metric (mm) IBI 06 (mmIBI 06 metrics), as comparatively more efficient than previously used indices, i.e., mmIBI 08 and mmIBI 11. Furthermore, the linear regression and correlational analyses indicated harmonic relation of mmIBI 06 with mmIBI 08 (R2 = 0.85) and mmIBI 11 (R2 = 0.87). Nonetheless, linear regression modeling discovered a very strong positive relation between mmIBI 08 and mmIBI 11 (R2 = 0.91), thereby implying previously used indices demonstrate better approximation. In significant contrast to both old indices, the newer index exhibited improved facility to better classify the study sites between the assortments of ‘excellent to very poor’ compared to old indices elucidated one-step lower, i.e., from ‘excellent to poor’. For instance, the newer index categorized 60 sites as ‘very poor’, requiring immediate attention owing to biological degradation. Additionally, the newer index endures grander ability to indicate sites requiring immediate management or restoration attention with a plausible site classification, especially in relation to the invasive alien species (IAS). The water chemistry was mainly influenced by rampant anthropogenic actions compounded by intensive monsoon precipitation that may relinquish highly suitable grounds for invasive alien fish species. This may eventually lead to severe biological degradation and successive deterioration of habitat by the IAS. In conclusion, the newer index endures ample capacity to indicate the fish community disturbances in rivers and streams. Further, correlation, linear regression, as well as principal component analysis (PCA) analyses on biotic indices and water chemistry showed higher approximations. Therefore, our newer index would be a valuable BHA tool to classify and elucidate the streams and rivers by indicating sites necessitating preferred attention and restoration measures.

Highlights

The biological health assessment (BHA) has evolved as an essential measure for effective management of freshwater resources [1,2] such as rivers, streams, and lakes
The variation in different water chemistry parameters was directly contingent to the distinct watershed types in Geum river watershed (Table 4)
The total nitrogen (TN) level (4.99 ± 0.22, mg/L) in whole Geum River watershed clearly suggested that the watershed was nitrogen rich

Summary

Introduction

The biological health assessment (BHA) has evolved as an essential measure for effective management of freshwater resources [1,2] such as rivers, streams, and lakes. Rivers, streams, and connected water basins are heterogeneous ecosystems subjected to a plethora of human activities and natural interactions at play that develop complex relationships within the lotic ecosystems [4,5]. Those activities, their effects, and consequential events collectively disrupt the aquatic environments in general and fish assemblages in particular. In the wake of sustainable management of freshwater resources across the globe, several indices of biotic integrity were explored to evaluate biological health of lotic ecosystems, mainly perusing fish assemblages and have been extensively used to assess the fish and other aquatic organism populations [10,11,12,13,14,15]. The study sites with none or the least disturbance would be labeled as ecologically integrated or biologically healthy and vice versa [14]

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