茂兰喀斯特森林不同演替阶段优势乔木种群生态位研究

Analysis of Ecological Niches of Dominant Arbor Populations in Different Succession Stages in the Karst Forest in Maolan Nature Reserve

以贵州茂兰国家级喀斯特森林自然保护区3个演替阶段的乔木层优势种群为研究对象,通过典型样方调査,运用Levins和Pianka公式计算各种群生态位宽度和生态位重叠值.结果表明:樟叶槭、革叶铁榄、翅荚香槐、石岩枫、齿叶黄皮、皱叶海桐、狭叶润楠7个种群生态位宽度较大,在3个演替阶段均有出现.樟叶槭、石岩枫和齿叶黄皮分别是演替早期、演替中期和演替晚期的优势种群,具有最大的生态位宽度.演替早期重叠值大于0.70的种对有55对,而演替晚期重叠值大于0.70的种对有98对,表明随着演替的进展,种群的生态位重叠增强.在演替过程中生态位宽度与生态位重叠之间的关系复杂,生态位宽度呈下降趋势而生态位重叠值呈上升趋势,二者间没有相关性.

The dominant populations of the tree layer in three succession stages of the Karst forest in Maolan Nature Reserve in Guizhou were studied, and the niche breadth and niche overlap of the arbor populations were calculated using the Levins formula and the Pianka formula based on a typical sample survey. The results showed that the niche breadth of seven species, i. e. Acercinn arnomifolium, Sinosiderozylon wightianum, Cladrastis platycarpa Makino, Mallotus repandus, Clausena dunniana, Pittosporum crispulum Gagnep and Machilus rehderi Allen was relatively large, and they appeared in all the three suecession stages. A. amomifolium, S. wightianum and C. platycarpa were the dominant species in early succession, mid-succession and late succession stages, respectively, and had the highest niche breadth among all species. Fifty-five species pairs had a niche ：overlap of greater than 0. 7 in the early succession stage, and 98 species pairs had a niche overlap of greater than 0.7 in the late succession stage, indicating that the niche overlap of the populations was intensified with community succession. The relation between niche breadth and niche overlap presented a complicated picture during the succession process. Niche breadth was on a declining curve but niche overlap was on the rise. There was no correlation between them.