仙湖苏铁群落优势种群的生态位特征

采用生态位宽度和生态位重叠探讨仙湖苏铁群落优势种群的生态位特征。结果表明,群落中生态位宽度大的优势种群,对其它种群的生态位重叠大,而生态位宽度小的种群对生态位宽度大的种群的生态位重叠不一定大;如果2个种群生态位宽度相近,则存在着较大的生态位重叠。优势种之间生态位重叠大,由于存在资源竞争,导致群落组成和结构发生变化从而影响群落的演替发展。相同的物种对在不同层次其生态位重叠水平不一致,从林下层到立木层,物种对的生态位重叠程度降低。仙湖苏铁种群与立木层中生性树种的生态位重叠大,由于植株高度的差异,它们之间可能存在着促进而非竞争关系,因此调整群落林分组成,使群落向着以中生性树种为优势种的方向发展,也许是促进仙湖苏铁种群恢复和发展的有利措施。

Niche characteristics of dominant populations in Cycas fairylakea community

The analysis on the niche characteristics of dominant populations in Cycas fairylakea community by calculating niche breadth and niche overlap showed that the dominant populations with wide niche breadth had an entire niche overlap with other populations,whereas the populations with small niche breadth did not have a necessarily entire niche overlap with the populations of wide niche breadth.The populations with similar niche breadth had a large niche overlap,and the large niche overlap between dominant populations would cause the changes of community composition and structure,and thus,affect the development of the community because of resource competition.With the growth from understory to stand canopy,the niche overlap between two same populations changed from large to small.The larger niche overlap of C.fairylakea and mesophilous dominant populations indicated that there was a promotion between them,and no competition existed due to the difference of their plant height.Therefore,rebuilding the composition of C.fairylakea community to make the mesophilous populations be dominant ones may be helpful to recover and develop C.fairylakea population.