Research On Methodology Of Landscape Ecology Applied In Eco-environmental Quality Assessment Of Lalu-marsh

Lalu-marsh, which is located at Lhasa, the capital of Tibet, is the highest, biggest urban wetland in the world. It is a habitat or a living-through-winter place of some cherish waterfowl and some waterfowl of be in severe danger, such as: Black-necked crane, Tadoma ferruginea, Anserindicus, some kind of golden eagle, etc.This wetland have 10 prominent actual or potential efficacies including: regulating the regional climate, maintaining water resource and regulating runoff, resorting sediment and nutrient, purifying the air, decontaminating the water, supplying oxygen, maintaining the biodiversity, providing biotic material, developing tourism, aiding scientific research and education, etc.Since 1960's, this wetland has continuously suffered from disturbance of human activities around the wetland, such as: draining from the wetland, agriculture development, excavating the turfs, pollution of urban sewage and urbanization... etc, and so, the wetland began to degrade, representing of decreasing of the area, deteriorating of the aquatic environment, declining of the ecosystem's productivity, losing of-the biodiversity... etc.To understand the bio-environmental quality of this wetland, promote the reasonable exploitation and protection, my dissertation bases upon theory and methodology of landscape ecology to develop an index-set for the bio-environmental quality assessment of Lalu-marsh, the result of assessment indicates that the naturalstate of the wetland has been altered in some great degree, that the structure of the landscape has been greatly destroyed, that the vitality of the ecosystem of the wetland has been diminished considerably, that the functions of the landscape of the wetland has began to degrade to different degrees and that the ability of recovery of this wetland has began to decline. On the other hand, the result also indicates that this wetland hasn't been destroyed completely and the wetland still has some potential ability of recovery. So, as long as the external disturbances are ceased, and the wetland is preserved, the landscape of the wetland, Lalu-marsh, will effectively restore to its original and natural state through a period of time.