内蒙古温带典型草原围封十年草灌景观格局动态

通过样方调查和差分GPS法,研究内蒙古典型草原围封10年后灌木和草本盖度、生物量动态以及植被时空分布格局的变化。结果显示:草本盖度和生物量以2010年为拐点先减少后增加,灌木盖度和生物量呈现增加的趋势,样地整体植被生产力显著恢复。2010年以后,样地景观格局发生变化,小叶锦鸡儿灌丛斑块表现出破碎化程度和蔓延度先增加后减少的趋势。研究认为:(1)2012年之前为干旱期,草本生产力下降,且灌、草之间的竞争关系加剧了这一过程。(2)2012年之后降水增加,草本生产力先于灌木迅速恢复;景观尺度上小叶锦鸡儿灌丛斑块破碎化程度达到最高,是小叶锦鸡儿克隆生长的扩张过程所致。(3)2012年之后为湿润时期,小叶锦鸡儿对草本的生长存在促进作用,使生态系统逐渐恢复和重建。

The dynamics of landscape pattern within a ten-year exclosure in temperate typical grassland in Inner Mongolia

This study investigated the coverage and biomass dynamics of shrub and grass, the changing temporal-spatial pattern of vegetation (here refers to Caragana microphylla) in Inner Mongolia. Methods of field quadrat surveys and differential GPS have been conducted during ten-year exclosure. The results showed that: The coverage and biomass of grass increased firstly and then decreased with the inflection point in 2010, while shrub was gradually increasing, and the overall vegetation productivity restored significantly. After 2010, the fragmentation degree and contagion of the shrub patches increased firstly and then decreased too. Based on the study, we got summaries as follows: (1) The prolonged drought period before 2012 led to the reduction of grass productivity, and the competitive relationship between shrub and grass might contribute to the process. (2) With the increasing of precipitation in 2012, the grass recovered rapidly. At the landscape scale, the clonal growth of the young shrubs was responsible to the highest degree of fragmentation. (3) In the wetter period after 2012, the growth of the shrub was likely to promote the growth of the grass, which contributed to restoring and rebuilding the ecosystem.