School of Nature Conservation, Beijing Forestry University, Beijing, China.
College of Forestry, Central South University of Forestry and Technology, Changsha, China.
Sci Rep. 2017 Feb 6;7:41761. doi: 10.1038/srep41761.
Wet meadows are one of the most important ecological components in floodplain, and are among the most dynamic ecosystems. Understanding the development of wet meadows and contributing environmental factors can provide better support for wetland management. Carex meadows in East Dongting Lake National Nature Reserve (EDLNNR) provide vital wintering ground for thousands of migratory waterbirds, and their ecological functions are under threated due to hydrological alternation. We measured wet meadow expansion in EDLNNR from 1989 to 2014, and explored its responses to hydrological and climatic factors within the generalised additive models (GAM) framework. We found an overall expansion of wet meadows over the study period. However, in contrast to many previous studies, our results showed that water level fluctuations at the hydrologic indicator site had only limited impacts on their development. Instead, sampling year, timing of water level recession, and local rainfall exerted significant effects. The effects of sampling year reflected the changes in sedimentation within Dongting Lake; and effects of timing of water withdrawal might be explained by the life history of the dominant sedge species. Our study suggested that the impacts of large scale hydrological alternation on vegetation may operate indirectly through its effects on sediment balance.
湿地是河流湿地生态系统的重要组成部分，也是最具活力的生态系统之一。了解湿地的发育和影响其发育的环境因素，可以为湿地管理提供更好的支持。东洞庭湖国家级自然保护区（EDLNNR）的苔草湿地为成千上万的候鸟提供了重要的越冬地，由于水文变化，其生态功能受到威胁。我们在 1989 年至 2014 年期间测量了 EDLNNR 湿地的扩张情况，并在广义加性模型（GAM）框架内探讨了其对水文和气候因素的响应。我们发现，在研究期间，湿地整体呈扩张趋势。然而，与许多先前的研究不同，我们的结果表明，水文指标点的水位波动对其发育的影响有限。相反，采样年份、水位退水时间和当地降雨量有显著影响。采样年份的影响反映了洞庭湖内部的泥沙淤积变化；而水位退水时间的影响可能可以用优势莎草物种的生活史来解释。我们的研究表明，大规模水文变化对植被的影响可能通过对泥沙平衡的影响而间接发生。
