祁连山区草原退化原因分析及管理对策

CAUSE AND EFFECT ANALYSIS AND MANAGEMENT STRATEGY OF THE GRASSLAND RETROGRESSION IN QILIAN MOUNTAINS

本文以祁连山东段松山草原为研究对象,探讨了该草原的退化机理,组建了多层次权重分析模型及最优管理对策模型,提出了优化利用草地资源的相应的管理对策。权重分析结果表明,超载放牧是导致草原退化的主要动因;围栏封育、轮牧是控制放牧强度的最有效的措施,其组合权重为0.4876。该草原优势种群短花针茅的最优水平为x1=94.72（重要值）,相应的最优放牧策略为:u*（t）=0（当x【94.72时）u*（t）=17.01（当x=94.72时）和u*（t）=21.88（当x】94.72时）。

This paper explores the mechanism of the grassland retrogression of east Qilian Mountains and establishes a multi-level weight analysis model and an optimum management model. The managing strategy is accordingly proposed. The main results ineludes:1. Results of weight analysis indicate that overgraziug is the most important cue among many causing factors. Fencing and rotated grazing are most effective.2. The calculation of the optimum management model suggests that the dominant, Stipa breviflora, population has an optimum level, x~*=94.72 (importance value) , the corresponding optimum tactics of grazing are:Five management strategies of utilizing grassland resources are accordingly proposed.