Spatial variation of macroinvertebrate community structure and associated environmental conditions in a subtropical river system of southeastern China

Knowledge and Management of Aquatic Ecosystems (2015) 416, 17 c L. Fu et al., published by EDP Sciences, 2015  DOI: 10.1051/kmae/2015013 Knowledge & Management of Aquatic Ecosystems www.kmae-journal.org Journal fully supported by Onema Spatial variation of macroinvertebrate community structure and associated environmental conditions in a subtropical river system of southeastern China L. Fu(1),(2) , Y. Jiang(1),(2), , J. Ding(2) , Q. Liu(2) , Q.Z. Peng(3) , M.Y. Kang(1),(2) , L.Z. Wang(4) Received December 20, 2014 Revised April 5, 2015 Accepted May 18, 2015 ABSTRACT Key-words: Knowledge of macroinvertebrate distributions and associated environBiomonitoring, mental drivers in subtropical Asian rivers is relatively scarce. To fill this macroinvertebrate knowledge gap, we examined the spatial variation of macroinvertebrate communities, community structure and associated environmental conditions in a subspatial tropical river system, the Dongjiang River Basin, in southeastern China. differentiation, A total of 70 families and 9 classes of macroinvertebrates were identified Dongjiang River from 74 sites sampled in January 2013. Our study has the following findings: (1) a distinct spatial differentiation of macroinvertebrate communities basin, indicators was present in the Dongjiang River Basin indicated by non-metric multidimensional scaling (NMDS), which corresponded to the northern region (NR), middle region (MR), and southern region (SR) gradient; (2) ANOVAs showed that diversity indices (total taxa, Margalef index and the Shannon diversity index), biotic indices (richness of EPT, percentage of EPT, and family biotic index) and most of the studied environmental conditions (elevation, slope, steam order, water temperature, electrical conductivity, dissolved oxygen, pH, substrates, ammoniacal nitrogen, total phosphorus, percentage of urban land, percentage of rural land, and percentage of forest land) differed significantly among the three regions and a degradation gradient was observed in the NR–MR–SR direction; (3) Canonical correspondence analysis (CCA) revealed that NR sites were characterized by steep slope and coarse substrate, MR sites were characterized by high water temperatures and shallow slopes, and SR sites were primarily characterized by high total phosphorus and ammoniacal nitrogen concentrations; and (4) the Indicator Species Analysis, in conjunction with CCA analysis indicated that the most representative indicator taxon is Tipulidae for NR, Semisulcospira sp. for MR, and Branchiura sp. for SR. (1) State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, P.R. China (2) College of Resources Science and Technology, Beijing Normal University, No. 19 Xinjiekouwai Street, Beijing 100875, P.R. China (3) Faculty of Land Resource Engineering of KUST, Kunming University of Science and Technology, No. 68 Wenchang road, Kunming 650093, P.R. China (4) International Joint Commission, PO Box 32869, Detroit, MI 48105, USA  Corresponding author: This is an Open Access article distributed under the terms of the Creative Commons Attribution License CC-BY-ND (http://creativecommons.org/licenses/by-nd/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. If you remix, transform, or build upon the material, you may not distribute the modified material. L. Fu et al.: Knowl. Manag. Aquat. Ecosyst. (2015) 416, 17 RÉSUMÉ La variation spatiale de la structure de la communauté des macroinvertébrés et les conditions environnementales associées dans un système fluvial subtropical du sud-est de la Chine Mots-clés : biosurveillance, communautés de macroinvertébrés, différenciation spatiale, bassin de la rivière Dongjiang, Indicateurs La connaissance des distributions de macroinvertébrés et des facteurs environnementaux associés dans les rivières asiatiques subtropicales est relativement limitée. Pour combler cette lacune, nous avons examiné la variation spatiale de la structure de la communauté de macroinvertébrés et les conditions environnementales associées dans un système fluvial subtropical, le bassin de la rivière Dongjiang, dans le sud-est de la Chine. Au total 70 familles et 9 classes de macroinvertébrés ont été identifiées à partir de 74 sites échantillonnés en janvier 2013. Notre étude a tiré les conclusions suivantes : (1) une différenciation spatiale nette des communautés de macroinvertébrés dans le bassin de la rivière Dongjiang mise en évidence par « non-metric multidimensional scaling » (NMDS), ce qui correspond à un gradient de la région du nord (NR), à la zone médiane (MR), puis la région sud (SR) ; (2) des analyses de variance ont montré que les indices de diversité (total des taxons, indice de Margalef, de diversité de Shannon), les indices biotiques (richesse de l’EPT, pourcentage en EPT, et indice biotique), et la plupart des conditions environnementales étudiées (altitude, pente, ordre de Strahler, température de l’eau, conductivité, oxygène dissous, pH, substrat, azote ammoniacal, phosphore total, pourcentage de terres urbaines, pourcentage de terres rurales, et pourcentage de terres forestières) différaient sensiblement entre les trois régions et un gradient de dégradation était observé dans le sens NR-MR-SR ; (3) l’analyse canonique des correspondances (ACC) a révélé que les sites NR ont été caractérisés par la pente raide et un substrat grossier, les sites MR ont été caractérisés par des températures élevées de l’eau et des pentes faibles, et les sites de RS ont été principalement caractérisés par le phosphore total élevé et les concentrations d’azote ammoniacal ; et (4) l’analyse des indicateurs spécifiques, en conjonction avec l’analyse CCA, a indiqué que le taxon indicateur le plus représentatif est Tipulidae pour NR, Semisulcospira sp. MR et Branchiura sp. pour SR. INTRODUCTION Biomonitoring is one of the most valuable tools for making management policies and practices for aquatic ecosystems (Barbour et al., 1996; Friberg et al., 2011). Macroinvertebrate assemblage measures are considered as effective and reliable indicators for environmental degradation and overall river health (e.g. Thorne and Williams, 1997; Smith et al., 1999; Bieger et al., 2010). Relative to European and American river systems, subtropical Asian rivers support rich but poorly known macroinvertebrate communities (Morse et al., 2007). In addition, research on linkages between macroinvertebrates and their environment are lacking at the watershed scale in this region, resulting in poor river management practices, especially in China (Jiang et al., 2010). In many rivers, water is severely polluted as a result of untreated agricultural, urban, and industrial discharges with high concentrations of nutrients, organic materials, toxicants, and sediments (Pan et al., 2013). Several studies have suggested that nutrient pollutants (e.g. nitrogen a (...truncated)