不同放牧强度下高寒灌丛植物的生长特点

 不同放牧强度下高寒灌丛植物在生长发育、生理生态，物质生产和群落结构等方面主要有以下变化：1．在高寒灌丛草场，禾草类、莎草类和灌丛类植物的叶面积指数和平均生长速率随着放牧强度的减轻而增大；随着放牧强度的增加而减小。植株平均高度，植被盖度水平也与放牧强度呈负相关(p<0.01)。2．各项生长分析参数中：叶面积比率(LAR)、叶面积干重比(SLA)和叶干重比(LWR)与放牧强度之间存在负相关。叶面积指数(LAI)与地上生物量呈正相关(p<0.5)，地上部现存在量与放牧强度呈负相关(p<0.01)。3．不同放牧强度条件下，高寒灌丛中的禾草类、莎草类、灌丛类和杂类草植物的种类组成和数量变化明显。其中禾草类和莎草类、灌丛类植物的生物量和种类组成比例在重度放牧下减少，在轻度放牧下增大。反之，重度放牧下杂类草的组成和数量明显增加，而轻度放牧下其比例降低。

STUDY ON SOME PLANT GROWTH CHARACTERISTICS UNDER DIFFERENT GRAZING INTENSITIES IN ALPINE BUSHLAND

This paper deals with some ecophysiological characteristies of plant gro- wth, parameters of physiology, material accumulation and community compo- sition in apline bushland. The results are as follows: 1. Leaf area index and average rate of growth of some species of Gramineae, Cyperaceae in Dasiphora fruticosa alpine shrub are increased with decreaded grazing intensity. The height and coverage of the community were negatively correlated with grazing intensity (P<0.001). 2. Changes of the aralytical growth parameters: LAR, SLA, LWR and LAI were negatively correlated with grazing intensity. Leaf area index was positively correlated with biomass (P>0.005); Aboveground biomass was ne- gatively correlated with grazing intensity(P<0.001). 3. The species numbers of Gramineae, Cyperaceae in Datiphora fruticosa shrub community were decreased in heavily grazed area and increased in lightly grazed area. But the proportion of Forb was increased with heavy grazing and decreased with light grazing. Thus light grzaing in alpine scrub showed profitable for plant growth and regeusration.