Assessing Aquatic Ecological Health for Lake Poyang, China: Part I Index Development

Abstract

Abstract:The development of an ecosystem health index to assess health status in freshwater lakes is urgently needed in China, especially in polluted lakes. This study developed a specific Ecosystem Health Index (LP-EHI) for Lake Poyang in China. LP-EHI quantified lake health from the perspectives of physical, chemical, biological integrity and social service. Physical integrity indices included hydrological conditions (water level and runoff), basic morphometric characteristics (lake area and shoreline), and tributary connectivity. Chemical integrity indices used water quality, nutrition, and toxicity to quantify chemical impairment. Biological integrity indicators covered six major components of the aquatic food chain, namely, phytoplankton, zooplankton, benthic macroinvertebrates, wetland plants, fish, and wintering birds. Social service indices included drinking water, pathogenic potential, flood storage capacity, sand mining, and dish-shaped sub-lake areas under management to measure whether the lake fulfilled the needs of human society. Reference and impaired conditions for each metric were defined by "historical" conditions, "least disturbed" conditions, national standards and expert opinions. The value of LP-EHI ranging from 0 to 1 was divided into five health conditions: excellent (≥0.8), good (0.6-0.8), fair (0.4-0.6), poor (0.2-0.4) and bad (<0.2). The metrics' reliability was further validated using a box-and-whisker plot test. The developed index (LP-EHI) is so far the most comprehensive index to evaluate ecosystem health for Lake Poyang, and is well reflected in the unique characteristics of Lake Poyang. It can enhance our understanding of lake health conditions and thus guide lake management to achieve better health conditions.

Assessing Aquatic Ecological Health for Lake Poyang, China: Part II Index Application

“…In Part I, the meteorological, hydrological, and bathymetry conditions of Lake Poyang have been described [17]. Sample sites were selected via a randomized systematic design with a spatial component [18].…”

“…In Part I, LP-EHI was developed to quantify lake health from the perspectives of physical, chemical, biological, and social service [17]. This index can be an alternative method of estimating the health status of lake ecosystems and guide lake management to achieve better health conditions.…”

“…This index can be an alternative method of estimating the health status of lake ecosystems and guide lake management to achieve better health conditions. Further implementation details about LP-EHI, including metric selection, weight estimation, reference condition definition, metric standardization, and categorization can be found in Qi et al [17].…”

Modelling the Impacts of Bathymetric Changes on Water Level in China’s Largest Freshwater Lake

“…Dramatic water level and velocity changes are a threat to ecosystem stability [58] and water resource management, including irrigation and farming [59]. Previous investigations focused on the cause of the lower water level during the dry seasons of Lake Poyang and proved that the declining lake levels can be caused by changes in climate, increased water use or changed regulation patterns [60,61].…”

Research on Ecosystem Health Assessment Indices and Thresholds of a Large Yangtze-Connected Lake, Poyang Lake

“…(Ludovisi, 2006;Ludovisi and Poletti, 2003;Kane et al, 2009). The primary assessment approaches include the comprehensive health indices (Xu, 2005;Shuai and Li, 2014) generated by index system weighting or algorithmic derivation and the water quality model-based method (Xu et al, 2013;Zhang et al, 2010;Banerjee et al, 2017;Qi et al, 2018). Poyang Lake is one of the only two remaining large Yangtzeconnected lakes in the middle reaches of Yangtze River in China.…”