Small-scale species richness and its spatial variation in an alpine meadow on the Qinghai-Tibet Plateau
Small-scale species richness and its spatial variation in an alpine meadow on the Qinghai-Tibet Plateau
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DOI：
10.1007/s11284-007-0423-7
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发表时间：
2008-07-01
影响因子：
2
通讯作者：
Tang, Yan-hong
中科院分区：
文献类型：
--
作者：
Chen, Jun;Yamamura, Yasuo;Tang, Yan-hong
我们调查了中国青藏高原高寒草甸高的小尺度物种丰富度是如何维持的。这个地区的特点是冬季漫长，风大，严寒。在冬季，大多数牲畜在农民住所附近的小牧场上吃枯叶，而在短暂的夏季，牲畜在远离农民住所的山区放牧。植物物种的数量和地上生物量进行了调查，为三个相邻的牧场不同的放牧管理：晚冬放牧牧场放牧温和2月1日至4月30日，早冬放牧牧场放牧轻轻9月20日至10月下旬，全年放牧牧场放牧全年密集。在每个样带中，我们采集了沿着80或100个0.01 m（2）样方的地上生物量，并按物种分类。每0.01m2有15.5-19.7种物种，在世界范围内属于高物种丰富度。两种冬季放牧草地的物种丰富度均高于全年放牧草地。物种丰富度和物种组成的空间变异在两个冬季放牧草地中，物种丰富度高，大于在全年放牧草地中，物种丰富度较低。夏季在冬季放牧牧场上保存的大部分叶子在冬季被强风吹走，剩余的叶子在冬季被牲畜放牧完全耗尽。一个高丰度的牧场伴随着物种丰富度和物种组成的高度空间变异。这种空间变异特征很可能也是由该地区传统的放牧方式造成的。
We investigated how the high small-scale species richness of an alpine meadow on the Qinghai-Tibet Plateau, China, is maintained. This area is characterized by strong wind and severe cold during long winters. In winter, most livestock is grazed on dead leaves in small pastures near farmers' residences, whereas in the short summer, livestock is grazed in mountainous areas far from farmers' residences. The number of plant species and the aboveground biomass were surveyed for three adjacent pastures differing in grazing management: a late-winter grazing pasture grazed moderately from 1 February to 30 April, an early-winter grazing pasture grazed lightly from 20 September to late October, and a whole-year grazing pasture grazed intensively throughout the entire year. In each pasture, we harvested the aboveground biomass from 80 or 100 quadrats of 0.01 m(2) along a transect and classified the contents by species. We observed 15.5-19.7 species per 0.01 m(2), which is high richness per 0.01 m(2) on a worldwide scale. The species richness in the two winter grazing pastures was higher than that in the whole-year grazing pasture. The spatial variation in species richness and species composition in the two winter grazing pastures in which species richness was high was greater than that in the whole-year grazing pasture in which species richness was lower. Most of the leaves that are preserved on the winter grazing pastures during summer are blown away by strong winds during winter, and the remaining leaves are completely exhausted in winter by livestock grazing. A pasture with a high richess is accompanied by a high spatial variation in species richness and species composition. There is a high possibility that the characteristic of spatial variation is also caused by traditional grazing practices in this area.