College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.
Sci Total Environ. 2021 May 10;768:144534. doi: 10.1016/j.scitotenv.2020.144534. Epub 2021 Jan 7.
Hydrology-climate changes and food availability are expected to be the primary drivers that result in a loss of waterbirds diversity. Non-biological factors are vital to food availability in interconnected river-lake systems, so in addition to identifying the ecological response to drivers, it is also important to analyze and quantify relationships between drivers. In order to explore the impacts of these drivers on the wintering waterbirds, we selected Dongting Lake (DTL) as a study area, which is a typical interconnected river-lake system in the middle and lower reaches of the Yangtze River Floodplain. The Anatidae species, most of which are herbivorous, were chosen as the representative waterfowl. The Pearson correlation coefficient was applied to select variables related to the timing of water recession and food availability, which have significant influences on the Anatidae. Then, the structural equation model (SEM) was carried out to quantify the relationships among the food availability, hydrological variables, and climatic variables. The results showed that unseasonably early or late water recession had a negative impact on the diversity of the Anatidae, and in particular affected population dynamics of the Lesser White-fronted goose Anser erythropus. Significant changes in Anatidae populations in DTL occurred in response to maximum NDVI (r = 0.53, p<0.01) and the interval time of water recession (r = -0.43, p<0.1). Water level, flow, and interval time of water recession explained 71% of maximum NDVI in DTL. In addition, hydraulic interactions between the mainstream and each lake jointly affected the inundation pattern and the vegetation growth stage of the lake after the flood season, thus affecting foraging suitability. Our findings suggest that water compensation should be carried out within an appropriate range of hydraulic gradient to optimize the time of water recession and improve the suitability of the habitat effectively.
水文学-气候变化和食物可获得性预计将成为导致水鸟多样性丧失的主要驱动因素。非生物因素对互联河湖系统中的食物可获得性至关重要，因此，除了识别对驱动因素的生态响应外，分析和量化驱动因素之间的关系也很重要。为了探讨这些驱动因素对越冬水鸟的影响，我们选择洞庭湖（DTL）作为研究区域，它是长江中下游典型的互联河湖系统。选择以雁形目物种（大部分为草食性）作为代表性水禽。应用 Pearson 相关系数选择与水位退去时间和食物可获得性相关的变量，这些变量对雁形目有显著影响。然后，采用结构方程模型（SEM）量化食物可获得性、水文变量和气候变量之间的关系。结果表明，水位过早或过晚退去对雁形目多样性有负面影响，特别是对白额雁 Anser erythropus 的种群动态有影响。DTL 雁形目种群的显著变化是对最大 NDVI（r=0.53，p<0.01）和水位退去间隔时间（r=-0.43，p<0.1）的响应。水位、流量和水位退去间隔时间解释了 DTL 中最大 NDVI 的 71%。此外，主流和每个湖泊之间的水力相互作用共同影响了洪季后的淹没模式和湖泊植被生长阶段，从而影响了觅食适宜性。我们的研究结果表明，应该在适当的水力梯度范围内进行水补偿，以优化水位退去时间，有效地提高栖息地的适宜性。
