Aquatic ecosystem health assessment of a typical sub-basin of the Liao River based on entropy weights and a fuzzy comprehensive evaluation method

Jiabo Chen,Yanjie Wang,Fayun Li,Zicheng Liu

doi:10.1038/s41598-019-50499-0

Abstract

River ecosystem health assessments provide the foundation for river ecological protection and integrated management. To evaluate the aquatic ecosystem health of the Fan River basin, benthic macroinvertebrate indices (the Multimeric Macroinvertebrates Index Flanders (MMIF) and Family Biotic Index (FBI)), a habitat index (the river habitat quality Index (RHQI)) and a water quality index (the Improved Water Pollution Index (IWPI)) were selected. The entropy weighting method was used to calculate the RHQI and IWPI. A fuzzy comprehensive evaluation method was used to evaluate the aquatic ecosystem health. The evaluation results indicated that the aquatic ecosystem health of the Fan River basin was better in 2018 than in 2011, which respectively belonged to the ends of the 11th and 12th Five-Year Plans of the Major Science and Technology Programs for Water Pollution Control and Treatment in China. The proportions of sampling stations with good, moderate and poor grades in 2011 were 50.0%, 40.0% and 10.0%, respectively, and in 2018, the proportions of stations with excellent, good and moderate grades were 20.0%, 50.0% and 30.0%, respectively. A correlation analysis showed that the RHQI was significantly correlated with the MMIF, FBI and IWPI. The riparian land use pattern was an important factor that influenced changes in the aquatic ecosystem health grade. Of the water quality parameters, total phosphorous (TP) and potassium bichromate index (COD) were the main factors that affected the characteristics of benthic macroinvertebrates and the aquatic ecosystem health.

Highlights

In recent years, the utilization of water resources has increased, and aquatic ecosystems have been seriously degraded or destroyed
Because the characteristics of benthic macroinvertebrates can reflect the extent of damage to aquatic ecosystems at different scales in a basin, macroinvertebrates are among the most important biological indicators of watershed and aquatic ecosystem health[6]
Ephemeroptera, Plecoptera and Trichoptera among benthic macroinvertebrates are greatly influenced by dissolved oxygen and sediment types

Summary

Introduction

The utilization of water resources has increased, and aquatic ecosystems have been seriously degraded or destroyed. The health of aquatic ecosystems comprehensively reflects the physical, chemical and biological integrity and spatial differentiation characteristics of river ecosystems and can effectively reflect the structure and function of the ecosystems[6]. River ecosystem health assessments include the habitat characteristics of the river sediment, hydrological conditions[15], water quantity and flow velocity, vegetation structure and coverage, riparian type[2], erosion degree, land use patterns[16], and other factors. Human activities, such as water conservation and engineering projects, mining, reclamation, riverside agriculture, urbanization and others, can significantly impact the river environment[17]. Pollution problems in rivers can greatly reduce habitat heterogeneity and water quality and directly and indirectly affect aquatic organisms in the catchment[23], leading to adverse impacts on the river ecosystem[24]

Objectives

Methods

Results