瑶山苣苔群落优势种群生态位研究

Niches of Dominant Species in Dayaoshania cotinifolia Communities

根据野外180个样方的调查数据,应用Levins、Hurlbert生态位宽度指数及Pianka生态位重叠指数,分析了瑶山苣苔（Dayaoshania cotinifolia W.T.Wang）生存群落20个优势种群植物的生态位宽度和生态位重叠特征。结果表明,戟叶圣蕨（Dictyocline sagittifolia Ching）、翠云草[Selaginella uncinata（Desv.）Spring]、球子复叶耳蕨[Arachniodes sphaerosora（Tagawa）Ching]和镰叶瘤足蕨（Plagiogyria distinctissima Ching）的生态位宽度较大,其Levins值和Hurlbert值分别为1.752 3和0.759 8、1.604 5和1.035 5、1.627 2和1.158 7、1.771 4和0.601 6;瑶山苣苔的生态位宽度较小,其Levins值和Hurlbert值分别为1.324 6和0.456 5。瑶山苣苔群落中20个优势种群之间生态位重叠值大部分在0.10~0.25,大于0.20的只有18对,占总对数的9.47%,表明瑶山苣苔群落优势种群的生态位分化程度较高,种间的竞争关系较弱。瑶山苣苔多生长在林下石壁上,在空间上易发生生态位分离,从而确保了与其他物种的共存。

Based on the data of 180 plots obtained from investigation, the niche breath and niche overlapping of 20 dominant herbage populations in concomitant communities of rare and endangered plant Dayaoshania cotinifolia W. T. Wang were studied by using Levins and Hurlbert niche breadth index and Pianka niche overlapping index. The results showed that the niche breadth of Dictyocline sagittifolia Ching, Selaginella uncinata （Desv.） Spring, Arachniodes sphaerosora （Tagawa） Ching and Plagiogyria distinctissima Ching was larger than that of other species, with the Levins and Hurlbert＇s values of 1.752 3 and 0.759 8, 1.604 5 and 1.035 5, 1.627 2 and 1.158 7, 1.771 4 and 0.601 6, respectively. The niche breadth of D. cotinifolia was smaller when Levins and Hurlbevt value of 324 6 and 0.456 5. Among the 20 dominant populations, the niche overlap ranged from 0.10 to 0.25, of which only 18 pairs （9.47%） having niche overlapping indice over 0.20, indicating that high niche polarization of dominant populations and weak competition in community of D. cotinifolia. D. cotinifolia often grew on understory cliff where niches separation took place among the space to ensure its coexist with other species was ensured.