scholarly journals Ecological drought and its state assessment: a case study in the Yellow River estuary

2021 ◽  
Author(s):  
Jinliang Zhang ◽  
Bojun Liu ◽  
Libin Yang ◽  
Liyuan He ◽  
Xinyi Cao ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Water Cycle ◽  
Yellow River ◽  
River Estuary ◽  
Water Shortage ◽  
Yellow River Estuary ◽  
Vegetation Coverage ◽  
The Yellow River ◽  
Extreme Climate ◽  
Four Levels

Abstract Water cycle has been intensified by global warming, leading to frequent extreme climate events. Drought is an extreme climate phenomenon. Runoff decrease and human water demand increase aggravate the water shortage of regional ecosystems, affecting regional water and land ecosystems and causing ecological drought, river cutoff and water pollution. Finally, the reverse succession and the imbalance of regional ecological structures take place. The clarification of the concept of ecological drought for effective evaluation of regional ecological drought degree has become an urgent important scientific issue to be resolved. Therefore, in this paper, the typical region of the Yellow River estuary was studied for the analysis of characteristics of regional ecological changes and the definition of the concept and connotation of ecological drought. Based on the representative monitoring and early warning indices to ecological drought, the evaluation method and the classification standard of regional ecological drought were proposed. The regional ecological drought includes four levels: I (Severe), II (General), III (Weak) and IV (None). The indicator thresholds of river runoff, biodiversity and vegetation coverage on different ecological drought levels were quantified. The research results can be technically beneficial for the improvement of global ecological drought emergent support capacity and reducing loss due to drought.

Effects of interactions between macroalgae and seagrass on the distribution of macrobenthic invertebrate communities at the Yellow River Estuary, China

2021 ◽  
Author(s):  
Xinyan Wang ◽  
Jiaguo Yan ◽  
Junhong Bai ◽  
Dongdong Shao ◽  
Baoshan Cui
Keyword(s):  
Yellow River ◽  
River Estuary ◽  
Yellow River Estuary ◽  
The Yellow River ◽  
Negative Effects ◽  
Primary Producers ◽  
Biomass Density ◽  
Invertebrate Communities ◽  
Seagrass Ecosystem ◽  
Hydrodynamic Disturbance

<p>Algae-dominance in seagrass beds has been well recognized, however, the competitive relationship between seagrass and macroalgae along land-sea gradients and their ecological effects has received little attention. In this study, a field survey was conducted at the Yellow River Estuary to investigate the effects of macroalgal proliferation on seagrass and macrobenthic invertebrate communities. Our results suggested that strong competitive interaction existed between the two primary producers, and the positive or negative effects of macroalgae on seagrass growth varied along land-sea gradient. Furthermore, the dominant controlling factors on the biomass, density and diversity of macrobenthic invertebrate communities were found to vary accordingly, i.e., from features of the primary producers in the nearshore where macroalgae suppressed seagrass growth to hydrodynamic disturbance in the offshore where macroalgae facilitated seagrass growth. Our study emphasizes the importance to integrate interspecific competition into ecosystem-based management of seagrass ecosystem, and provides references for additional ecological indicators.</p>

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