Estimation of ecological water requirements based on habitat response to water level in Huanghe River Delta, China

Abstract

In recent years, wetland ecological water requirements (EWRs) have been estimated by using hydrological and functional approaches, but those approaches have not yet been integrated for a whole ecosystem. This paper presents a new method for calculating wetland EWRs, which is based on the response of habitats to water level, and determines water level threshold through the functional integrity of habitats. Results show that in the Huanghe (Yellow) River Delta water levels between 5.0 m and 5.5 m are required to maintain the functional integrity of the wetland at a value higher than 0.7. One of the dominant plants in the delta, Phragmites australis, tolerates water level fluctuation of about ± 0.25 m without the change in wetland functional integrity. The minimum, optimum and maximum EWRs for the Huanghe River Delta are 9.42×10 6 m 3 , 15.56×10 6 m 3 and 24.12×10 6 m 3 with water levels of 5.0 m, 5.2 m and 5.5 m, corresponding to functional integrity indices of 0.70, 0.84 and 0.72, respectively. A wetland restoration program has been performed, which aims to meet these EWRs in attempt to recover from losses of up to 98% in the delta′s former wetland area.

Biological Flora of the British Isles:Phragmites australis

“…Bud density and diameter can also be a useful indicator of productivity in the next season (Haslam ), and there is a strong relationship between stem height and density as indicators of productivity within a single season (Cui et al . ; Zhang et al . ).…”

“…The ecological amplitude of P. australis extends from a soil water content of 2Á5-47% or a soil osmotic potential of 30-1000 kPa (Elhaak, El-Din & Sammour 1993). The optimum water level for growth of mature stems ranges from À30 to 70 cm above-ground level (Engloner & Papp 2006;Cui et al 2010;Zhang et al 2013). In Britain, it is most competitive in water c. 1 m below-ground level to c. 1-m above-ground level (Haslam 1971a).…”

“…In the Huanghe River Delta, China, the Phragmites australis-dominated plant Table S1 for a compilation of distribution data and sources. [Colour figure can be viewed at wileyonlinelibrary.com] community was most diverse in À30 cm deep water, while % cover of P. australis was greatest in 0 cm of water (Cui et al 2010). High biomass (5093 g m À2 ) was recorded in 22 cm of water in the temperate Zhalong wetland, China (Zhang et al 2013), and the tallest reported reeds (see V) grew in 10-cm-deep water in central Australia (mean water level within the stand was À4Á3 cm, 95% CI 17Á9-9Á2; Packer et al 2017a).…”

Ecological water demand of regional vegetation: The example of the 2010 severe drought in Southwest China

“…dintanensis forestland in the typical Karst areas of Guizhou Province ; the aquatic plants in the Baiyangdian Lake ; and others reported in the literature (Su & Kang 2005;Pan et al 2007;Cui et al 2009Cui et al , 2010Hu et al 2009;Du et al 2010;Jia et al 2011). These investigations, which were conducted on different scales and involved various ecological systems, illustrate the great progress that has been made in research on EWD of vegetation.…”

Ecological hydrograph based on Schizothorax chongi habitat conservation in the dewatered river channel between Jinping cascaded dams

“…Integrated methods [36,37] are based on entire river functions, which are more specific with complicated factors, furthermore, more human impacts are introduced into evaluation through experts experience on flow diversion. Habitat methods [38][39][40][41][42][43][44][45][46][47][48] consider both flow environment and biological process, and define ecological water requirement by aquatic organism reacting to water environmental factors. Although they require more data on monitoring, this would no longer be a problem with the development of advanced survey technology.…”