伏牛山自然保护区森林生态系统草本植物功能群的分类

伏牛山国家级自然保护区是中国东部森林样带中的亚热带和暖温带的结合点,随着环境梯度(海拔)的变化,林下植物优势种变化明显.草本植物对环境的反应较为敏感,能较好的反映出植被与环境的动态关系.采用群落学调查方法,对伏牛山南北坡的植被进行调查.以X2检验为基础,结合联结系数AC和共同出现百分率PC来测定草本层优势种间的联结性,根据优势种间的联系性及其在海拔梯度上的变化异同,以优势种为主体划分伏牛山自然保护区林下草本植物功能群.研究结果表明,以优势种为主体对森林生态系统草本植物进行功能群划分可行性高,有较强的代表性.对草本优势种共划分了7组植物功能群:Ⅰ"伴人型",Ⅱ"高山型",Ⅲ"阴湿型",Ⅳ"耐旱型",Ⅴ"林隙型",Ⅵ"基础型",Ⅶ"原始型".每一组都有其特定的分布区域和形态特征,较好了反应出环境与植被的动态关系,为今后森林生态系统研究和植物功能群划分寻找新的思路.

The classification of plant functional types based on the dominant herbaceous species in forest ecosystem at FuNiu Mountain National Natural Reserve

Straddling the subtropical and warm-temperate zones of East China, the FuNiu Mountain National Natural Reserve is representative of north-south climatic transition zones. The vegetation in this natural reserve is well protected. Highly species rich, the understory layer is nonetheless mainly composed of a small number of dominant species whose abundances clearly vary along environmental (altitudinal) gradients. The shrubs appear to be greatly influenced by the trees. This may indicate that trees exert a certain degree of control over the renewal of the arboreal layer. Highly responsive to changes in environmental conditions, herbaceous plants are very useful to the study of vegetation-environment dynamics. Using community ecology techniques, we investigated plant assemblages on both the north and south slopes of the FuNiu Mountain. Results of this investigation were used to calculate species importance values, which in turn were used to identify dominant species. X2 test, together with association coefficient (AC) and percentage co-occurrence (PC), were used to measure interspecific associations of the dominant herbaceous species. PFTs were defined according to interspecific associations and altitudinal distributions of the dominant herbaceous species of the understory layer. Dynamics of these PFTs along moisture and temperature gradients were analyzed. The results of this study show that, in studies of forest understory plant assemblages, designating PFTs according to dominant herbaceous species is feasible, and PFTs thus defined are representative. Seven PFTs, each with its unique spatial distribution and morphological characteristics, are identified: campanion, alpine, dank, drought-resistant, forest gap, basic, primeval. These PFTs appear to reflect vegetation-environment dynamics well. This study may contribute to future studies on forest ecosystems and PFTs classification methods.