宁夏香山荒漠草原区植物群落多样性时空特征

采用多个多样性指数对宁夏香山荒漠草原区植物群落多样性时间、空间动态进行分析。结果表明，该地区群落时、空动态特征不明显。长期过度放牧导致环境恶化，生境碎化，这些作用的长期性、循环性是造成物种、群落格局与原有时、空动态规律相悖的主要因素，这些因素消除了物种或群落在时间梯度上应有的变化规律。干旱山地物种在长期进化过程中成功的发展了对环境的适应机制，环境的波动性强烈导致了群落多样性在原来消长动态基础上的复杂化，也使多样性动态机制复杂化。应用多种指数数学模型对研究对象进行综合评价，能够真实地反映群落多样性动态。

Spatio-temporal Characteristics of Plant Community Diversity in Desert-grassland of Xiangshan Mountainous,Ningxia

Several diversity indices were used to analyze community diversity in different times and spaces.The results showed that,the dynamic characteristics of communities were not evidenced.Long-time disturbance of grazing severely abated the pattern and dynamics of species,population and community at different gradients of environment and time,furthermore the chronicity and circularity of this sequel aggravated the non-completeness of ecosystem of desert grassland.Those therefore led to more degradation of the ecosystem,and the habitat more fragmentation,and the maladjustment of functions(including the bastard pasture increasing,the loss of species,the degradation of quality of Zhongwei Goat).The sequence of the communities'diversity at different times and spaces were no long existed after heavier and long time grazing.In addition, most species had formed the adapting mechanism(including ecological actions and shapes)to the flucuating environments,and which was an important factor leading to the dynamics of diversity and its mechanism more complex.Because there are many limitations of all diversity indices,the communities'diversity was evaluated and analyzed should by several indices of diversity synthetically.