澜沧江上游森林珍稀草本植物生态位研究

Niche of rare herbage plants in the upstream of Lancang River

20 0 2年和 2 0 0 3年 7— 8月 ,笔者采用常规调查方法对三江源自然保护区内澜沧江上游物种进行了调查研究 .以不同群落类型和海拔高度作为资源位 ,分别以物种重要值和个体多度为生态位计测的状态指标 ,对澜沧江上游桃儿七、星叶草和角盘兰及选取的几种对照草本植物进行生态位的计测和分析 .结果表明 :桃儿七、星叶草、角盘兰生态位宽度值小 ,充分显示了它们的稀有性 ,在该地区应优先保护 .桃儿七种群在海拔 36 0 0～ 36 5 0m分布最多 ,并且种群数量随海拔高度的增加逐渐减少 ;星叶草种群在海拔 36 5 0～ 375 0m分布最多 ,但种群数量不随海拔高度变化呈现规律性变化 .草本植物物种的生态位相似性比例值大于 0 5的占 5 0 % ,桃儿七、星叶草、角盘兰的生态位相似性比例大 ,说明它们在该地区的生态位相似程度大 .草本植物的生态位重叠值较小 ,大于 0 0 1的占 2 1 4 3% .桃儿七、星叶草、角盘兰之间生态位重叠程度小 ,它们分布的群落类型相似程度小 .

The niche characteristics of Sinopodophyllum hexandrum,Circaeaster agrestis,Herminium monorchis and a few herbage species are described and analyzed, with different community styles and altitudes as the resource state and with the importance value and the abundance as the resource state descriptor of the niche. The results indicate that Sinopodophyllum hexandrum,Circaeaster agrestis and Herminium monorchis have lower niche breadth values and have higher requirement of habitat, which shows their rarity, and the priority to be conserved. Most of Sinopodophyllum hexandrum populations are distributed at the altitude of 3?600～3?650 m, and their number reduce gradually with the increase of the altitude. Nearly all of Circaeaster agrestis populations are distributed at the altitude of 3 650～3 750 m with stochastic distribution. 50% of the population_links have a niche similarity over 0.5, and the niche similarity between Sinopodophyllum hexandrum and Circaeaster agrestis is higher, which shows that their niches are more similar. Niche overlap between a few herbage species is lower and only 21.43% of them have a niche overlap over 0.01. The niche overlap between Sinopodophyllum hexandrum,Circaeaster agrestis, and Herminium monorchis is lowest.