Developing a Benthic Index of Biological Integrity and Some Relationships to Environmental Factors in the Subtropical Xiangxi River, China

Abstract

The aim of this study is to develop a benthic index of biotic integrity (B-IBI) to help understand how the increasing anthropogenic pressure may impact the subtropical Xiangxi River in China. Benthic macroinvertebrate and environmental surveys were conducted at 77 sites in early summer 2004. Each collection site was categorized as reference or impaired based on physical, chemical, biological, and land-use information. Six non-redundant metrics from 35 metrics were used to differentiate between reference and impaired sites. We selected six metrics for the final IBI. The scoring criteria of each metric were normalized based on the quadrisection and 0-10 scaling systems. Both scaling methods were used to assess the aquatic health of each site in the Xiangxi River watershed. The results showed that most sites were in fairly poor condition. Furthermore, we identified the relationship between B-IBI metrics, water-quality, and land-use variables with a principal component analysis. A composite of nutrients and land-use intensity explained most variances. These results suggest that the B-IBI may be a suitable method for assessing river conditions within the subtropical Xiangxi River in central China. IntroductionAquatic ecosystems, and their biological assemblages, continued to be degraded globally from anthropogenic activities in their watersheds (GANASAN and HUGHES, 1998;KARR, 1999). Part of the decline in water resources stems from insufficient consideration of their biological structure and function (KARR, 1999;STODDARD et al., 2006). Some factors have been reported which are linked to river degradation. Physical and chemical factors may be related to biological changes (MULLINS, 1999). Water quality may only partially reflect environmental impact (BOZZETTI and SCHULZ, 2004). Researchers increasingly include quantitative biological indicators (JOY and DEATH, 2004;ROSET et al., 2007). Biological indicators may reflect the intensity of anthropogenic stress and have been used as a tool in risk assessment and evaluation of human induced changes in freshwater ecosystem (KAMDEN-TOHAM and TEUGELS, 1999

Inter-annual patterns in the stability and persistence of stream macroinvertebrate communities: relationship with water physicochemical parameters

“…Its watershed has an area of 3099 km 2 and a natural fall of 1540 m from its headwaters to its confluence with the Yangtze River (Tang et al 2002;Jiang et al 2005;Qu et al 2005). The average annual precipitation within this watershed is 988 mm (Li et al 2010). …”

Evaluation of spatial and temporal variation in stream water quality by multivariate statistical techniques: A case study of the Xiangxi River basin, China

“…Xiangxi River watershed has an area of 3099 km 2 and a natural fall of 1540 m from its headwaters to its confluence with the Yangtze River (Jiang et al, 2005;Tang et al, 2006). The average annual precipitation within this watershed is 988 mm Li et al, 2010). Approximately 70.9% of this catchment is covered by forests, 6.5% is farmland and 5.3% is water area, 4.4% is wasteland whilst the remainder is residential land and transportation (Xu et al, 2010).…”

Altitudinal pattern of stream periphyton biomass in tributaries of the Lancang–Mekong River: An indicator of anthropogenic impact?

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