中国潜在植被空间分布格局

The potential vegetation spatial distributions and patterns in China

潜在植被作为一种与所处立地达到平衡的演替终态,反映的是无人类干扰情况下,立地所能发育形成的最稳定成熟的一种顶极植被类型,是一个地区现状植被的发展趋势。潜在植被的研究能够真实反映气候条件对植被形态变化的影响,是植被-环境分类与关系研究的起点,也是全球变化与陆地生态系统研究的关键。以综合顺序分类法为基本理论基础,在GIS研究方法支持下,利用我国2348个气象台站1961～1990年30a的气候资料,对我国潜在植被类型进行了划分,得出以下结论:(1)分布在我国的潜在植被类型有41类,表现出了我国潜在植被的多样性特征;从面积相对比例来看,我国潜在植被在分布面积上很不均匀,面积最大的寒冷潮湿多雨冻原、高山草甸类分布面积达到1526188km2,面积最小的炎热微干稀树草原类分布面积仅为13km2。(2)海拔0～6800m之间,是我国潜在植被主要分布的海拔界限,并且此海拔段植被多样性随海拔变化呈现出一定的规律性,即随海拔增加植被多样性显著下降。(3)我国潜在植被的空间分布很好的体现了三向地带性规律,而决定这种分布的主要原因是太阳辐射的纬度性变化、距离海洋的远近引起水分条件变化以及由海拔高度引起的从基带向上热量和干湿变化。(4)我国潜在植被空间格局在重心分布上,主要表现为空间聚集(P1、P2、P3、P4、P5、P6)和空间线型邻接(L1、L2、L3)两个主要特征。

The potential vegetation, as a final state of succession which achieves the balance with its site,is the most stable and mature climax vegetation type at the site without human interference, and is the trend of the regional vegetation development. The study of potential vegetation can substantially reveal the impact of climate on the changes of the vegetation patterns. It is the starting point of the vegetation-environmental classification and relationship study, as well as the key point of the global change and terrestrial ecosystem study. Based on the methodology of integrated sequence classification and the support of GIS methods, this paper analyzed meteorological data （ 〉 0℃ annual cumulative temperature and precipitation ） from 2,348 stations from 1961 to 1990, and classified the potential vegetation categories in China. The classification results show that： （1） There are 41 potential vegetation categories in China, which shows the diversity of potential vegetation in China. Comparatively, the distribution of China＇s potential vegetation is rather uneven in light of the different size that the potential vegetation covers; the largest one, which is the frigid perhumid rain tundra, alpine meadow, covers 1526188 km2, and the smallest one, which is the tropical-semiarid savanna, only covers 13 km^2. （2） The main altitude limits of the potential vegetation in China is between 0 - 6800m. Within this range, with the increase of the altitude the vegetation diversity decline significantly. （3）The spatial distribution of China＇ s potential vegetation reflects the three zonality very well, which is latitude zonality, longitude zonality and the vertical zonality. These three zonalities are mainly caused by the variation of the radiation along the change of latitude, changes of the humidity with the ehange of distances from the sea, and changes of the heat and humidity caused by the change of height respectively. （4） China＇s potential vegetation shows two main characteristics in the distribution of gravity center, which are space gathering（ P1, P2,P3, P4,PS, P6 ） and space linear adjacency （ L1, L2, L3 ）.