黄河河口湿地景观变化影响丹顶鹤生境的评价分析

Wetland Landscape Dynamics in the Yellow River Mouth:Implications for Conservation

上世纪90年代以来,在全球气候变化及人类活动的影响下,黄河河口湿地景观发生了显著变化,对河口湿地生态系统及生物多样性保护带来深远影响。本文以景观生态学理论为指导,利用遥感技术和GIS空间分析方法,在对河口湿地景观变化过程分析的基础上,以丹顶鹤为指示物种,重点探讨了湿地景观变化对物种生境的影响,进而为河口退化湿地生态系统恢复和重建,以及湿地生境保护提供理论依据和决策支持。本文研究表明,1992-1999年,黄河三角洲河口湿地干旱化趋势明显,芦苇沼泽和翅碱蓬滩涂萎缩严重,丹顶鹤适宜生境面积大幅度减少,近30%的栖息地生境发生退化,严重退化的生境占11%。1999-2006年,在水量调控及湿地恢复措施的影响下,芦苇沼泽、翅碱蓬滩涂,以及水面湿地面积都有显著增加,占栖息地总面积28.7%的生境,得到一定程度的改善。但受不断加剧的景观破碎化影响,生境得到较好恢复的栖息地面积只占12%。研究认为,对于退化湿地的修复,在改善湿地景观的同时,加强生境管理,减轻人为活动引起的生境破碎化影响,是一重要的措施。

Since 1990＇ s, a sharp decrease of water Yellow River caused by climate change and rapid leads to deficiency of suitable water needed by the quantity and frequent discontinuous flow happened in the lower increase of water consumption in the Yellow River basin. This ecological system of the estuarine wetlands. As a result, fresh water wetlands in the river mouth are diminishing and facing the danger of disappearance. There is a growing awareness that evaluating consequences of landscape dynamics on habitat conditions became a central issue in wet- land management and protection in the Yellow River Delta. In this paper, landscape bined with RS and GIS techniques were used to study the spatial-temporal variations and its impact on biodiversity conservation in the Yellow River Delta. To do so, we first ecological approaches corn- in landscape pattern change analyze the river mouth wet- land landscape dynamics from 1992 when the Reserve was built to the present. Two landscape metrics are used for assessing the characteristics and fragmentation process in the river mouth wetlands. Then the Red-Crowned Crane is selected as an indicator species for evaluating the ecological effect and habitat suitability variations under different landscape processes. The research shows that landscape degradation and habitat fragmentations are major threats to biodiversity conservation in the Yellow River mouth wetlands. From 1992 to 1999, the reed marsh wetland de- creased almost as much as 50 per cent. The southeast spit formed before 1996 has experienced much erosion,with large area of tidal flat disappeared. As a result,30 per cent of the red crowned crane habitat degraded. Since 2000, the wetland restoration project has greatly increased the area of reed marsh, tidal flat and water body. However, oil exploration has caused the landscape more fragmented, which resulted in only 12 per cent of the red crowned crane habitat getting some improvement. Understanding the process of landscape change is thus crucial for determination of the driving factors for species conservation in wetland and for elaboration of restoration plans.