岷山北坡高海拔区草本植物群落特征及主要植物功能群C、N、P含量分析

海拔是影响物种多样性格局的决定性因素之一,对生态系统格局与过程起着重要作用。运用回归分析、相关分析、Duncan多重比较和Pearson相关系数检验对岷山北坡高海拔2300—2900 m草本群落特征、群落初级生产力及不同植物功能群进行分析。结果表明:样地共调查出草本植物20科35属44种,菊科、百合科和蔷薇科的物种数分别占总物种数的比例为25%,14%和11%,表现出明显的优势性。草本群落的生物量均与海拔梯度的相关性不显著(P>0.05),且随海拔升高均表现出先增后减的总体趋势;植物盖度、物种丰富度、密度均与海拔表现出极显著负相关关系(P<0.001),而植物高度与海拔表现出极显著正相关关系(P<0.01)。从功能群的角度分析,随着海拔梯度的不断升高,禾本科、菊科以及杂类草3个植物功能群的叶碳含量(LCC)和根碳含量(RCC)整体呈上升趋势;叶磷含量(LPC)整体都呈下降趋势,而禾本科的根磷含量(RPC)呈上升趋势,菊科和杂类草表现出先升后降的趋势;叶氮含量(LNC)禾本科呈下降趋势,菊科呈上升趋势,杂类草呈先上升后下降的变化趋势,根氮含量(RNC)禾本科和杂类草的呈上升趋势,而菊科表现出先上升后下降的趋势。研究结果初步揭示了岷山北坡不同海拔梯度草本植物群落特征及其生物量的变化特征,以及物种多样性和主要植物功能群碳、氮、磷元素在海拔梯度上的分布差异,为今后岷山北坡草本群落分布格局和生物地球化学循环的研究提供科学依据。

Community Characteristics of Herbaceous Plants and Analysis of C,N and P Contents of Main Plant Functional Groups in High Altitude Area on the Northern Slope of Minshan Mountains

Altitude is one of the decisive factors affecting species diversity pattern and plays an important role in ecosystem pattern and process.In this paper,regression analysis,correlation analysis,Duncan multiple comparison and Pearson correlation coefficient test were used to analyze the characteristics of herbaceous community,primary productivity and different plant functional groups on the northern slope of Minshan Mountains at high altitude of 2300?2900 m.The results showed that:44 species of herbaceous plants belonging to 35 genera and 20 families were investigated in the sample plot.The number of species of Compositae,Liliaceae and Rosaceae accounted for 25%,14%and 11%respectively,and had obvious dominance.There was no significant correlation between biomass of herbaceous communities and elevation gradient(P>0.05),and the biomass showed a general trend of first increasing and then decreasing from low altitude to high one.Plant coverage,species richness and density showed a extremely significant negative correlation with elevation(P<0.001),while vegetation height showed a extremely significant positive correlation with elevation(P<0.01).According to the functional groups,the leaf carbon content(LCC)and root carbon content(RCC)of three functional groups of Gramineae,Compositae and miscellaneous grasses presented upward trends with the increase of altitude gradient;the leaf phosphorus content(LPC)had decrease trend for all herbaceous communities,while the root phosphorus content(RPC)of Gramineae showed increase trend and Compositae and miscellaneous grasses presented the trend of increasing first and then decreasing for leaf nitrogen Content(LNC).Gramineae decreased and Compositae increased,while miscellaneous grasses showed the trend of increasing first and then decreasing for RNC.Gramineae and miscellaneous grasses had increasing trend,and Compositae presented the trend of increasing first and then decreasing.The results preliminarily revealed the characteristics of herbaceous communities and their biomass changes in different altitude gradients on the northern slope of Minshan Mountains.On the other hand,there were differences of species diversity and the distribution of carbon,nitrogen and phosphorus elements for main plant functional groups along the altitude gradients,which provided scientific basis for the future study of the distribution pattern and biogeochemical cycle of herbaceous communities on the northern slope of Minshan Mountains.