退化湿地生态系统的生态恢复与管理——以美国Hackensack湿地保护区为例

受城市化、工业化和地球温室效应等人类活动与自然因素的影响,美国Hackensack湿地保护区正面临着面积不断减少、景观破碎化、外来物种入侵、河水污染增加、盐碱化程度增加和范围扩大等生态胁迫。稳定湿地面积,重建湿地的复合景观,丰富生物多样性,恢复潮水的正常规律,减少水体污染,控制外来种的入侵与扩张,促进湿地原有植物的定居与扩增及原有植被的恢复是Hackensack湿地恢复的关键,也是恢复工程设计与实施的核心。退化湿地生态恢复的管理则以植被的生长、芦苇的扩散方式及动态、鱼类和蟹类的种群动态、鸟类的种类及其对生境地的利用情况对生态系统功能恢复状况进行生物检验,有效监控退化湿地生态系统的恢复动态,研究其恢复规律,进而采取相应的管理措施,科学调控生态恢复进程。

The ecological restoration and management of degraded wetland ecosystem--A case study of Hackensack Meadowlands in America

Influenced by human and natural disturbance,such as industrialization,urbanization and earth greenhouse effect,Hackensack Meadows,a wetland locating at the Northeast New Jersey,is facing many ecological stresses.Wetland area has shrunk two thirds in recent centuries. Landscape was fractured into12by roads,city and industrial zone.And the composition and structure of ecosystems became simple.At the same time,water contamination is becoming serious.Foreign species have been dominating more and more native wetland vegetation,and many native species disappeared.The wetland ecosystem had degraded sharply.In order to enhance the wetlands,conserve biodiversity and improve the environmental condition in this area,the New Jersey Wetland Commission and three other organizations in America set up a project(the special district management)to save the rest wetlands.The ecological restoration and management projects of Harrier meadow,Mill Creek marsh and Skeetill Creek marsh,a part of the project,were supported by the New Jersey Commission and had been finished in1998.Goal of the projects was to restore its original ecosystem,including ecological environment and biome.And the restoration engineering included rebuilding complex landscape,transplanting native plant,transporting substrates,restoring tidal pattern,reconstructing mitigating and nesting habitats for bird etc.And our research group conducted the management of their ecological restoration process.Growth of vegetation,control of foreign species and restora-tions of ecosystem biodiversity were chosen by us as the bioassays to indicate restoration trend of ecosystem function and sampled in the three restoration sites every season.Then database was set up and analyzed.Restoration process was evaluated two times every year for further management.The management of vegetation included investigation of composition and structure of vegetation,analyses of factors affecting restoration process and application of corresponding technology.The management of foreign species focused on mechanism of their population spread and methods to control the invaders.In the aspect of biodiversity,the enhancement of animal species and relati-onship between vegetation and animal biodiversity were studied especially.It was shown that the primary restoration on the three sites followed the restoration design on the whole.But the vegetation in Harrier meadow restored faster than other two sites due to the rich biodiversity surrounding the restoration site.The animal biodiversity in Mill Creek and Skeetkill Creek restored slowly as their vegetation was dominated by foreign species Phragmites australis and Solidago sempervirens.Restoring tidal pattern in restoration sites,harvesting overground parts and cleaning seedling could effectively control the spread of Phragmites and facilitate the growth of native plant species.