Analysis on Landscape Ecological Risk of the Qinghai-Tibet Plateaus:A Case Study on Niyang River Basin

Taking Niyang River Basin as an example,applying with the indices of landscape pattern,the indices of ecological risk of ecosystems are calculated in this paper,which takes the value of ecological loss of main ecosystem as the evaluation standard and takes into account the impacts of probability or the velocity of main hazards and event of the ecosystem.And the grades of ecological risk are assessed.According to the results of assessment,the ecological risk grades of the basin are divided into five classes.From the first grade risk to the fifth grade risk,the values of regional risk indices gradually reduce.The first grade risk areas mainly distribute in Niyang river and its branches downstream and the surrounding areas of main towns.And the basin area of non-valley region and the headstream regions of the branches are the fifth grades risk areas.This evaluation results provide the basis to the regional sustainable development.