祁连山北坡5类天然草地地上部数量特征及其与环境因子的关系

摘要

We analyzed the aboveground numerical characteristics of natural grasslands and their relationships to environmental factors by means of the aboveground survey data of five natural grasslands and synchronous meteorological data in the northern slopes of the Qilian Mountain.The results indicated that the difference of the aboveground biomass and vegetation coverage among five kinds grasslands was significant (P＜0.05).Sequence for the aboveground biomass and vegetation ranked as follows : mountainous meadow, mountainous meadow rangeland, mountainous pastureland, alpine pastureland, and mountainous desert rangeland;The seasonal dynamic of aboveground biomass, community height and vegetation coverage all appear to be single apex type and their values came to the peak in late August;The growth of the aboveground biomass was significantly correlated with the vegetation coverage (P＜0.05), and more prominently with the community height (except for mountainous meadow) (P＜0.01).It implied that the aboveground biomass significantly increased with the increase of the vegetation coverage and the community height; The growth of plant community height basically accorded with Logistic models before it reached to the maximum (P＞ 0.01); (5)The aboveground biomass were not significantly correlated with synchronous climate factors (P＞0.05).The sensitivities of vegetation coverage and community height to climate factors were different in five grassland types.%利用祁连山北坡5类天然草地调查数据和同期的气象资料,分析其地上部数量特征及其与环境因子的关系.结果表明,5类草地的地上生物量、植被盖度均存在显著差异(P＜0.05),表现为山地草甸＞山地草甸草原＞山地草原＞高寒草原＞山地荒漠草原;各草地群落地上生物量、高度和盖度的季节变化均呈单峰型,且峰值均出现在8月下旬;地上生物量与植被盖度显著相关(P＜0.05),与群落高度(除山地草甸外)极显著相关(P＜0.01),说明地上生物量随植被盖度和高度的增加而增大;各草地群落高度在达到最大值之前,均基本符合Logistic生长模型(P＞0.01);地上生物量与同期水热因子的相关性均不显著(P＞0.05),各草地群落高度和植被盖度对水热因子的敏感性存在差异.