Changes of biomass and species richness of grassland community along an altitude gradient in Hongchiba,Chongqing | 重庆红池坝地区草地群落生物量及物种丰富度沿海拔梯度格局变化

Chinese. 以重庆红池坝地区草地群落为研究对象,沿海拔梯度设置了14个样地,利用收获法和土钻法分别测定地上生物量和地下生物量,同时记录各样方内的物种数,研究了群落生物量及物种丰富度沿海拔梯度的变化特征。结果表明：草地群落地上生物量沿海拔梯度呈降低趋势,地下生物量和根冠比呈增加趋势;禾本科与杂类草植物的地上生物量与海拔梯度呈显著负相关（P〈0.05）,菊科植物地上生物量与海拔梯度相关性较小;物种丰富度与海拔梯度呈负相关关系,分布格局呈单峰曲线;物种丰富度与地上生物量呈正相关关系,与地下生物量和总生物量呈显著负相关关系（P〈0.05）,物种丰富度与生物量的关系呈单峰曲线。[著者文摘]

English. It is one of hot researches to study the characteristics and function of ecological systems along different altitude gradients because the altitude gradient provides the perfect experimental conditions for studying the response of ecological systems to different environmental factors.Recently,many scholars carried out plenty of experiments to clarify the relationship between the species diversity and ecosystem function according to the dynamics of the species richness and biomass along altitude gradient.However,the results were not consistent from the experiments in different areas and more experiments should be employed at different scales to discuss the characteristics of species richness and community biomass.The Hongchiba area of Chongqing was chosen as the investigated subject and 14 sampling plots were selected along the altitude gradient.The dynamic characteristics of species richness and biomass along the altitude gradient were clarified based on the measurements of aboveground biomass and belowground biomass using harvest method and soil auger method and the numbers of the species in each plot.The results show that the aboveground biomass decreased but underground biomass and root to shoot ratio increased along with the increasing altitude gradient.Biomass of Gramineae species and forbs showed extremely negative correlations with altitude gradients but no significant correlation for Compositae species.Species richness was negatively correlated with altitude gradient in a pattern of unimodal curve and positively correlated with aboveground biomass but extremely negatively with underground biomass and total biomass.A unimodal curve relationship was detected between species richness and biomass.[著者文摘]