Optimum water supplement strategy to restore reed wetland in the Yellow River Delta

Abstract

In order to supply optimum water to restore reed wetlands used for bird habitats, a field investigation and greenhouse experiment were conducted. Three water supplementation stages (early stage at 20 May, middle stage at 20 July and later stage at 20 September, respectively) and five depths (0, 10, 15, 20 and 35 cm over the surface, respectively) were established, with three replicates for each treatment combination. Reed growth characteristics (survival rate, height, density and biomass) and soil properties of field investigation and experiment were recorded to determine the impacts of water supplementation on reed wetland restoration. The field investigation showed that reeds in natural wetlands grow better than those in degraded wetlands and soil properties in degraded wetlands were significantly different from soils in natural wetlands. With freshwater supplementation, reed growth characteristics and soil properties greatly improved. As water depth increased, reed growth decreased gradually. Reeds grew best in shallow water depth (≦10cm) than in the greater flooding depths. Saturated soils with no standing water at the early stage of reed growth increased reed survival and water depth can be increased as the reeds grow. During the process of water supplementation, soil salinity was reduced significantly. Soil salinity was reduced dramatically at early and middle stages of reed growth, but it increased slightly at the later stage. Soil pH increased greatly during the experiment. Soil total nitrogen (TN) and total organic carbon (TOC) showed contrasting changes, with soil TN decreasing and TOC increasing. To best manage reed wetlands restoration, we suggest saturating wetland in the spring to stimulate reed germination, increasing surface water depth up to 15cm at the stage of reed rapid growth, and then reducing water depth during the later growth stage.

Ecological Effects of Surface Water Evolution in the Yellow River Delta

“…The evolution of the surface water not only directly changed the overall landscape pattern of the Yellow River Delta but also influenced the changes in the other land-use types, thus leading to evolution of the ecosystem service value of the Yellow River Delta. Studies have found that different control schemes for sluices and dams lead to different water depth distributions, resulting in different soil water contents and soil salt contents, affecting the spatial distributions of the nutrients and pollution [57] and forming different vegetation cover types and land-use patterns [58]. Based on the results of this study, the single-factor response of the water evolution is the basis of the overall response of the ecosystem.…”

Spatial changes in a macrozoobenthic community depend on restoration methods in historically squeezed coasts in a brackish lagoon

“…dbRDA ordination further supported this inference; all plots in cluster B were plotted on the positive side of the first axis (Figure 5a), indicating associations with shallower depths and developed reed vegetation. Common reed is known to grow best and dominates in shallow water depth (Coops et al, 1996; Wang et al, 2017), and reed vegetation in the Kugushi‐ko lagoon develops only at sites where tidal zones are present (e.g., Figures S1c,f). Therefore, clusters A and B likely reflect changes in species composition along the water depth gradient and its associated environment (i.e., developed reed vegetation).…”

A threshold‐like effect on the interaction between hydrological connectivity and dominant plant population in tidal marsh wetlands

“…Several studies consider this species as the footstone or at least a key species for coastal wetland restoration (Huang, Zhang, et al, 2017;Huang, Zhao, et al, 2017). The wide range of salinity (Hurry, James, & Thompson, 2013) and inundation (Wang, Zhang, Guan, Qi, & Tong, 2017; tolerance help the population expand and connect habitat patches quickly. However, wide ranges of niche and clonal reproduction also make P. australis highly competitive; thus, it lowers plant diversity with its encroachment.…”