定量研究中国栎属广域种分布区特点

Quantitative Study on Geographic Range Characters ofWide-ranging Species in Quercus of China

通过研究中国栎属广域种分布区特点,探讨广域种与其属间关系,广域分布的标准、特点,分布区指标的空间含义,为空间分布、多样性等定量研究提供依据。采用地理信息系统技术,基于县制作中国栎属广域种的空间分布图,从图中提取分布区的经纬度、面积、周长,计算延伸的方向角、长轴及短轴,种间空间相似性系数等指标,定量研究中国栎属广域种分布区。中国栎属有7个广域种,面积均大于3.85×105km2,分布于中国东南半部,空间分布为聚集类型。广域种的空间分布特点能体现出其属分布区及多样性的主要特征,但广域种间空间分布差异较大。白栎、枹栎基本呈现东西向分布,其它种则呈现从中国西南向东北延伸分布,壳斗直径、高,坚果直径是区分广域种分布区走向的重要性状。白栎、枹栎主要分布在亚热带,比其它种分布更聚集,白栎的南北向扩展分布比枹栎的要窄,槲树从中国西南呈窄带分布到东北黑龙江,与其它种有所不同,麻栎和槲栎在聚集类型中较分散,麻栎聚集区比槲栎的更偏南,栓皮栎与锐齿槲栎空间分布最相似,尤其体现在其西南部的聚集分布,但前者比后者分布更偏西。广域分布的标准是广域分布的经、纬度范围占其上一级分类单位的1/3以上,少数广域种占据其属的绝大多数分布区,广域种多为单种分布。

After geographic range characters of wide-ranging species in Quercus of China are studied,relationship between wide-ranging species and its genera,standard and feature of wide-ranging distribution,meaning of indices in geographic range are discussed.It provides a basis for spatial distribution,diversity,et al in quantitative methods.Spatial distribution map of wide-ranging species in Quercus based on county of China was made in geographic information system software.Longitude,latitude,area and perimeter were gotten from the map.Direction angle,long axis,short axis,spatial similarity coefficient between species,and other indices were calculated.Geographic ranges of wide-ranging species in Quercus of China were studied in quantitative methods.There are 7 wide-ranging species in Quercus of China.The area of every species is over 3.85×105 km 2.They distribute in southeast part of China and cluster type of spatial distribution.Spatial distribution characters of wide-ranging species can express major information of geographic range and diversity in its genus.But differences between wide-ranging species are larger in spatial distribution.Q.fabri and Q.serrata appear approximately east-west distribution.Other species extend the distribution from southwest to northeast in China.Diameter and height of cupule and diameter of nut are important characters for distinguishing species distribution trend.Q.fabri and Q.serrata are largely in subtropics.They are more aggregated than other species.North-south spread of Q.fabri is narrower than that of Q.serrata.Narrow-band spread of Q.dentata which is different from other species is from southwest to northeast Heilongjiang in China.Q.acutissima and Q.aliena are more scattered in cluster type.Aggregated area of Q.acutissima is more south than that of Q.aliena.Spatial distribution between Q.variabilis and Q.aliena var.acuteserrata is most similar,especially aggregated area of southwest in China.The distribution of Q.variabilis is more west than that of Q.aliena var.acuteserrata.The standard of wide-ranging category is over one third in the extent of longitude and latitude of higher category.Minority wide-ranging species occupy majority distribution of its genus.The distribution is mainly formed by one species.