Ecosystem health assessment of urban rivers and lakes — Case study of “the six lakes” in Beijing, China

Abstract

The assessment of the ecosystem health of urban rivers and lakes is the scientific basis for their management and ecological restoration. This study developed a three-level indicator system for its assessment. The results indicated that: Zhonghai and Nanhai are in the state of transition from unhealthy to critical state and all the other lakes are in unhealthy states. Water environmental quality, structure and function of the aquatic ecosystem, and the structure of waterfront areas were the constraints. Nanhai was ranked as poor and the others were all ranked as very poor. However, the ecological environment of Zhonghai and Nanhai were better than the others, the sums of the degree of membership to the healthy state and critical state were all close to 0.6. and the restorations of these lakes were moderate. The sums of the degree of membership to the healthy state and critical state of the other lakes were under 0.3, as it was difficult to restore these lakes. Some suggestions on scientific management and ecological restoration of the six lakes were proposed: ①To control non-point pollution and to improve the water quality of six lakes and the water entering into these lakes; ②To improve the hydrological conditions of six lakes; ③To rehabilitate the aquatic ecosystem and waterfront areas.

The ecohealth assessment and ecological restoration division of urban water system in Beijing

“…Weights of the elements and indicator layers see Zhang et al 2008a. The indicator weight of rivers is the same as the lakes here, that is there are so many gates in the urban rivers, so the rivers are separated and have similar traits with lakes.…”

“…The indicator system consisted of hydrological characteristics, water quality, structure and functions of aquatic ecosystem, riparian zone structure, landscape effect and stress factor six major elements and 16 indicators. The details see Zhang et al (2008a). For the rivers, FV is expressed by velocity changes caused by sluice gate operation, …”

Community–environment relationships of riverine invertebrate communities in central Chinese streams

“…For instance, point source chemical and organic contaminants remain prevalent in developing countries, whereas diffuse pollution associated with land use tends to be the main stressor for freshwater systems in developed countries. For some regions, this has already led to very sophisticated assessment systems based on invertebrate and other organism groups including fish or algae in Europe, Australia, North America, Japan and South Korea, for instance (Clarke et al 2003;Hering et al 2004;Jun et al 2012;Komori et al 2013), while for other populated regions such as China and many other Asian countries, few studies are available (Azrina et al 2006;Dudgeon 2006;Korte 2010;Meng et al 2009;Zhang et al 2008;Zhao and Yang 2009). It is widely acknowledged that using univariate metrics (reflecting biodiversity, community composition or functional aspects) are useful to reduce complexity, mirror environmental stressors and enhance comparability across systems, but it has been shown that such metrics may vary in their response and sensitivity (Sundermann et al 2013;Tachamo Shah and Shah 2012) or capability to respond to local-scale variability underlying the gradients in which they were designed to reflect (Tonkin 2014).…”

Multi-scale evaluation of river health in Liao River Basin, China

“…Meanwhile, based on the consideration of impacts of abiotic factors such as the physical structure of a river and hydrologic regime on river ecosystems, index systems such as the riparian, channel environmental inventory (RCE) in Sweden [14] and index of stream condition (ISC) in Australia [15] have been applied to river health characterization. Simultaneously, specific index systems have been proposed for river health assessment according to the characteristics of Yellow River Basin [16], Liao River Basin [17] and urban rivers [18,19] in China, respectively. However, most previous studies were based on the indices selected to represent the water quality, hydrology, organisms, and riparian environment on a river-corridor scale and only a few case studies used assessment indicators on both river-corridor and habitat scales, which ignored the complex relationships among the river, the associated socioeconomic systems of the basin, and the associated habitats.…”