西双版纳兰科植物海拔分布格局

根据实地调查和相关文献资料整理,确定西双版纳野生兰科植物428种。将研究区按200 m海拔段划分为10个海拔梯度,分析兰科植物垂直分布格局。结果表明:①西双版纳兰科植物的垂直分布格局呈"中间膨胀型",峰值出现在1 000~1 200 m海拔段;②相邻海拔段的兰科植物种类相似系数较高(0.31~0.79),海拔段相隔越远相似性系数越小;③随海拔升高各海拔段的兰科植物生活型及区系成分的种类数量也呈现出先升高后下降的垂直分布格局;④地生兰和附生兰的种数在海拔600 m左右达到平衡,600 m以上附生兰占优势;⑤各海拔段兰科植物均以热带种类占主导地位(72%~87.8%),其中又以热带亚洲分布型的种类占优势。

Altitudinal Distribution of Orchids in Xishuangbanna

Based on field survey and review to literature related, 428 species from Orchidaeeae were ascertained to occur in Xishuangbanna, Yunnan Province. Vertical distribution of the orchids was analyzed based on a 10-range altitudinal gradient of 200 m interval. The study shows： 1 ） the vertical distribution of the orchids in the prefecture is represented by ＂ Mid-dominant＂ pattern, with the peak in the elevation range from 1000m to 1200m; 2） there is a higher similarity coefficient between adjacent ranges （0. 31 0.79） , and the farther is the elevation ranges in distance, the smaller is the similarity coefficient ; 3 ） along with rise the elevation, species of varied life form and bio-geographieal affinity increase to almost the same rhythm of the total ; 4） proportion of the terrestrial and epiphytic orchid reach a balance around the elevation of 600m; 5） the species with tropical affinity prevail for all elevation ranges （72% - 87.8% ） , with the species of Tropical Asia ranking the top.