中国壳斗科的地理分布及其与气候条件的关系

THE DISTRIBUTION OF FAGACEAE IN CHINA AND ITS RELATIONSHIP WITH CLIMATIC AND GEOGRAPHIC CHARACTERS

壳斗科是温带、亚热带最重要的森林树种之一，在我国有７属３５０多种和变种，呈北东东－南西西向分布，几乎遍及全国，在亚热带和温带森林中，常成为重要的建群种。壳斗科在我国总体上是北温带－亚热带分布类型。本文对壳斗科的物种丰富度分布、特有性分布及其与气候地理条件的关系进行了研究，并提出种类特有性的指数（ＥＩ，ＥｎｄｅｍｉｃＩｎｄｅｘ）：ＥＩ＝ＮＮｉ＝１Ｋｉ×１０研究发现，分布的物种丰富度中心在滇、桂、黔一带，而特有性中心则在滇、藏、琼等地。另外，通过逐步回归及比较分析，发现水热状况往往成为限制壳斗科物种丰富度分布格局的主导因子。而海峡等生态、地理隔离因子及空间异质性等对特有性指数的增加有明显的促进作用。影响物种丰富度与特有性指数分布的生态因子往往有较大的差异。

Fagaceae is one of the most important families in temperate and subtropical regions.There are 7 gena and about 352 species and variants in China.The distributions of species richness and species Endemic Index and their relationships with climatic and geographic characters of Chinese Fagaceae were studied.The Endemic Index is firstly defined in this paper to describe the speciality of species components in some flora.If there are N species in some flora,and the ith species has been found in another Ki-1 flora,then the species Endemic Index(EI) is defined as follow:EI=NNi=1Ki*10Through comparison and stepwize regression analysis,we found out that species richness center of Fagaceae was mostly at Yunnan,Guangxi and Guizhou provinces,but its endemic center was usually in Yunnan,Tibet and Hainan provinces.The results show that geographic isolations,such as gulf,large mountains,were important factors limiting the distribution of Fagaceae,and that the Endemic Index(EI)was more sensitive to these factors than species richness.