双台子河口植被“红退绿进”演替的淤积驱动机理研究

Red beach，consisted of dense Suaeda salsa, was a typical coastal wetland in the coast of north China. It provides not only valuable economic resources, but also ecosystem services in improving coastal soil quality, purifying the estuary water and providing food and breeding habitat for endangered birds. However, in recent years, the red beach has degraded greatly on a large scale in Shuangtaizi estuary, which exhibited that a large area of Suaeda salsa was quickly replaced by Phragmites spp within only a few years. Studies have been carried out on the cause of red beach degradation, few have focused on the mechanism lies in the quick succession between different plant communities and the interactions between vegetation succession and environment changes. In our present project, we will focus on spatio-temporal dynamics of the quick succession by analyzing the satellite images in a relatively long time, and we will try to reveal the role of environment change in the succession of the two plant communities by using the Surface Elevation Table and Marker Horizon (SET-MH) technique. By these two means mentioned above, we hope to be able to explain the mechanism which controls the quick vegetation succession and the plant adaptation strategy when facing the environmental changes. We believe this study will be useful for policy makers and coastal wetland researchers to develop appropriate strategies for coastal wetlands’ management and protection, especially for coastal wetlands in the north coast of China.

由翅碱蓬密集生长而成的红海滩作为中国北方典型滨海湿地类型，除具有重要景观效果外，还具有改良滨海土壤、净化河口污水、为珍稀濒危鸟类提供觅食和繁育场所等重要生态功能。近年来，双台子河口翅碱蓬群落大规模急剧退化，芦苇群落在红海滩快速扩张，短短几年时间红海滩植物优势种由翅碱蓬转变为芦苇，呈现明显的“红退绿进”演替趋势。以往研究多集中对翅碱蓬退化原因进行探究，忽略了植物群落演替的自然属性及演替过程对环境的反馈。本项目拟围绕植物群落快速演替，通过遥感影像解译掌握红海滩“红退绿进”演替过程及时空动态，结合沉积速率测定系统定点长期监测土壤剖面变化，进而探究沉积环境变化与植物演替的相互作用机理，阐明植物群落演替的淤积驱动机理，揭示滨海湿地植被演替发生的原因。研究结果不仅对揭示植物群落演替具有理论意义，还能指导滨海湿地修复工作，为建立滨海湿地植物修复体系提供理论依据。

红海滩由翅碱蓬密集生长而成，除具有重要景观效果外，还具有改良滨海土壤、净化河口污水、为珍稀濒危鸟类提供觅食和繁育场所等重要生态功能。近年来，双台子河口翅碱蓬群落大规模急剧退化，芦苇群落在红海滩快速扩张，短短几年时间红海滩植物优势种由翅碱蓬转变为芦苇，呈现明显的“红退绿进”演替趋势。本项目首先利用遥感手段结合野外踏查，根据其分布区域与退化类型，将辽河口红海滩分为“岛屿型”与“海岸型”两种类型。采用生态学中的上行效应和下行效应的控制理论，从沉积物淤积与动植物相互关系等方面入手对红海滩退化进行了研究。研究结果表明：1）“岛屿型”红海滩主要受上行效应环境要素的调控，表现为沉积物的快速淤积影响翅碱蓬的萌发，进而抑制翅碱蓬扩散，最终导致其退化；2）“海岸型”红海滩主要受下行效应的调控，即水鸟-天津厚蟹-翅碱蓬这一食物链受到破坏，使得天津厚蟹对翅碱蓬大量摄食，直接导致“海岸型”红海滩退化；3）近年来持续增强的人类活动是影响红海滩退化的根本原因。本研究通过探究红海滩退化的机理，构建了辽河口红海滩退化的理论框架，为红海滩的保护、管理与恢复提供了理论指导，可为我国滨海湿地的保护与管理提供参考。