杨属物种多样性在中国的地理分布格局

利用地理信息系统技术与空间统计相结合的方法,研究了杨属物种多样性在中国区域尺度上的空间分布格局,并且采用线性回归分析方法研究了杨属物种多样性与经纬度的关系。结果表明:(1)杨属物种在中国呈带状分布,东西分布幅度大于南北分布幅度;(2)纬度梯度上杨属物种集中分布区位于30—40°N,经度梯度上位于110—120°E,说明杨属物种多样性格局在经、纬度梯度上并非单调递增或递减,而是在某一最适区域具有最高的物种多样性;(3)中国杨属物种多样性的分布中心集中于东北—西南方向的黑河-腾冲线两侧,从黑腾线向西北和东南方向延伸过程中,物种多样性逐渐降低;沿黑腾线从东北向西南方向物种多样性呈增加趋势;(4)从分组、分种检索上看,白杨组和青杨组物种在中国分布范围最广,山杨、小叶杨、响叶杨和青杨4种物种分布范围最广,可见同一类群中不同分类等级的植物多样性地理分布格局存在差异。

Geographical distribution pattern of species diversity of the genus Populus L. in China

The geographical distribution of the species diversity of the genus Populus in China was studied using the geographical information system and spatial statistics. The relationship between the Populus species diversity and longitudinal and latitudinal bands was analyzed using linear regression analysis. The results showed that:(1) In China, the genus Populus exhibited a zonal distribution that was in an east-west direction, which was wider than that in the north-south direction; (2) The greatest species diversity of the Populus distribution on the latitudinal and longitude gradient was located in the latitudinal and longitudinal bands of 30-40°N and 110-120°E, respectively, indicating that species richness was the greatest where the longitude and latitude were optimized and decreased as the longitude and latitude moved above or below the optimal range; (3) The distribution center of the Populus species biodiversity in China was located on both sides of the Heihe-Tengchong line in the northeast-southwest direction, and species diversity increased from the northeast to southwest of China along the line, but decreased from this line to the northwest and the southeast; (4) In terms of the level of taxonomy, the sections of Populus with the most extensive distribution range were sect. Populus and sect. Tacamahaca Spach in China and the four species with the most extensive distribution ranges were Populus davidiana Dode, Populus simonii Carr, Populus adenopoda Maxim, and Populus cathayana Rehd, which revealed that the differing levels of taxonomy within the same taxa resulted in a varied species diversity pattern on the same scale.