Response of Fish Communities to Various Environmental Variables across Multiple Spatial Scales

Yong-Su Kwon,Myeong-Seop Byoen,Sang-Jung Park,Young-Seuk Park,Mi-Jung Bae,Soon-Jin Hwang,Fengqing Li,Namil Chung

doi:10.3390/ijerph9103629

Abstract

A better understanding of the relative importance of different spatial scale determinants on fish communities will eventually increase the accuracy and precision of their bioassessments. Many studies have described the influence of environmental variables on fish communities on multiple spatial scales. However, there is very limited information available on this topic for the East Asian monsoon region, including Korea. In this study, we evaluated the relationship between fish communities and environmental variables at multiple spatial scales using self-organizing map (SOM), random forest, and theoretical path models. The SOM explored differences among fish communities, reflecting environmental gradients, such as a longitudinal gradient from upstream to downstream, and differences in land cover types and water quality. The random forest model for predicting fish community patterns that used all 14 environmental variables was more powerful than a model using any single variable or other combination of environmental variables, and the random forest model was effective at predicting the occurrence of species and evaluating the contribution of environmental variables to that prediction. The theoretical path model described the responses of different species to their environment at multiple spatial scales, showing the importance of altitude, forest, and water quality factors to fish assemblages.

Highlights

The distribution and abundance of aquatic communities are governed by various environmental factors at different spatial scales [1,2,3,4]
We evaluated the relationship between fish communities and environmental variables at 691 sampling sites throughout South Korea
A total of 128 fish species in 32 families were collected from 691 sites (Table 2), including 49 endemic species and five exotic species

Summary

Introduction

The distribution and abundance of aquatic communities are governed by various environmental factors at different spatial scales [1,2,3,4]. Fish are relatively easy to identify, and are an important component of aquatic ecosystems through their regulatory effects on a variety of ecosystem-level properties and functions via their consumption of lower trophic levels [5,6,7] They are commonly recognized as sensitive keystone communities that can indicate habitat change, environmental degradation, and overall ecosystem health [8,9,10]. Diverse studies have explored the relationships between biotic and abiotic factors, including geological factors [11], land cover and land use types [12,13], hydrological factors [14], stream habitat characteristics [15], stream order [16,17,18,19], and water quality [20] These environmental factors are considered in a hierarchical structure ranging from large scale to small scale. Slightly different numbers of habitat levels and diversity of elements within levels have been reported [23,24]

Objectives

Methods

Results

Discussion

Conclusion