宁夏珍稀濒危植物半日花种群结构和点格局分析

半日花是国家二级珍稀濒危植物,其种群数量日益减少,分布区破碎化。以宁夏新记录物种半日花为研究对象,分析在沙地和砾石质两种生境下半日花种群结构、各龄级的空间分布格局及关联性。结果表明: 宁夏青铜峡地区半日花个体主要集中在龄级Ⅲ,种群年龄结构呈倒三角形,种群正在衰退。种群空间分布格局与不同龄级间空间关联性受生境条件的影响较大,并且对空间尺度表现出很强的依赖性,与沙地生境相比,砾石质生境中半日花种群更趋向于聚集分布,各个龄级之间的正相关性也更明显,这种差别与两种生境的环境条件和群落结构有关。半日花种群中幼龄个体(龄级Ⅰ和龄级Ⅱ)具有相互依赖的生态关系。

Population structure and point pattern analysis of rare and endangered plant Helianthemum soongoricum in Ningxia,China

Helianthemum songaricum is a second-class protected plant in China, threatened by decreased population size and fragmentation of distribution area. It is a new record species in Ningxia. We analyzed population structure, spatial distribution, and relationship of different age classes of H. songaricum living in sandy and gravel habitats. The results showed that majority of H. songaricum individuals were belonged to age-class Ⅲ. The age structure of the population was inverted triangle. The population was at a declining stage. The spatial pattern and spatial association between different age class of H. songaricum were greatly affected by habitat condition, with strong dependence on spatial scale. Compared with sandy habitat, H. songaricum population in gravel habitat tended to be clustered distribution, with a more obvious positive correlation among different age classes. The difference between two habitats was related to environmental condition and plant community structure. H. songaricum from age-class Ⅰ and Ⅱ had mutually dependent ecological relationships.