后河自然保护区珍稀植物群落主要种群结构及分布格局研究

利用方差均值比和修正的Clark-Evans最近邻体两种分布格局判定方法，对湖北省五峰县后河国家自然保护区1hmz固定样地中DBH≥5cm、重要值>2．5的26个树种的种群结构和分布格局类型进行了研究．结果表明，26个种群中有金钱槭、天师栗、白辛树、珙桐、领春木、水青树、连香树7种珍稀濒危植物种群和尖连蕊茶、君迁子、建始槭、曼青冈、鸡爪槭、桃叶黄杨、鹅耳枥等19种非珍稀濒危植物种群,7种珍稀植物种群中，除了2种个体较少的种群之外，1个种群为衰老型，其余4个种群均为增长型；3个种群呈随机分布类型，其余4个种群呈聚集分布类型,19个非珍稀植物种群中，1个种群为衰老型，6个种群为稳定型，其余12个种群为增长型；2个种群为随机分布类型，其余的17个种群为聚集分布类型．可见在26个种群中，以增长型种群居多(占66．7％)，稳定型种群次之(占25．0％)，衰老型种群最少(占8．3％)；两种分布格局判定方法所得的结果较为一致，表现为种群的分布格局类型以聚集分布居多(占80．77％)，随机分布和均匀分布较少。

Population structure and distribution pattern of rare plant communities in Houhe Nature reserve

An investigation on the size structure and spatial pattern of 26 major tree species with a diameter at breast height (DBH) > or = 5 cm was made on a 1 hm2 fixed plot in the mixed evergreen and deciduous broad-leaved forest in Houhe National Nature Reserve of Central China. The results showed that 7 populations of the 26 species, i.e., Dipteronia sinensi, Aesculus wilsonii, Pterostyrax psilophyllus, Davidia involucrate, Euptelea pleiosperma, Tetracentron sinense and Cercidiphyllum japonicum, were rare endangered, species, and two of the 7 populations, T. sinense and C. japonicum, were very limited in numbers. The population structure of P. psilophyllus was in declining, and that of the rest was in growing. The spatial distribution pattern of P. psilophyllus, A. wilsonii and T. sinense was in random, and that of the others was clumped. Among the other 19 non-rare populations, the population structure of P. wilsonii was in declining, that of D. lotus, A. palmatum, A. wilsonii, A. franchetii, M. cuneifolia and H. dulcis was stable, and the rest was in growing. The spatial distribution pattern of D. lotus and H. dulcis was in random, and that of the others was clumped. On the whole, the growing populations were dominant, amounting to 61.54%, and the stable and declining populations accounted for 6.92% and 11.54%, respectively. The results of the two judging methods were consistent, showing that the distribution pattern of clumping (80.77%) was dominant, while the random and even distribution patterns were infrequent.