后河自然保护区珍稀濒危植物种群分布格局的分形特征：计盒维数

通过4种优势树种和7种珍稀树种种群的计盒维数来反映种群分布格局的分形特征．结果表明，4种优势种群的计盒维数在1．346-1．414之间，在历研究的整个常绿落叶阔叶混交林群落中占据了较大的生态空间；其中尖连蕊茶种群的计盒维数最大，占据最大的生态空间．而7种珍稀树种种群的计量续数除了金钱槭种群大于1之外，其余6个种群的计盒维数都小于1，说明它们占据生态空间的能力较小．并且这11个种群的拐点尺度都出现在5-12．5m之间．根据分形的自相似性，可以推断种群在大于拐点尺度的所有尺度上都为同一分布类型，并且在拐点前后种群的格局类型夏发生变化．种群分布格局的判定结果部分地验证了这一观点，11个物种中有5个物种的种群格局在拐点前后发生变化，另6种没有发生这种变化。

Fractal properties of the spatial pattern of rare and endangered plant populations in Houhe Nature Reserve in Hubei :Box-counting dimension

The fractal properties of the spatial distribution pattern of 4 dominant plant populations and 7 rare and endangered plant populations were reflected through the box counting dimensions. The results showed that the box counting dimensions of 4 dominant populations ranged between 1.346 and 1.414, and occupied relatively larger ecological spaces in the community. Camellia cuspidata population occupied the largest ecological space because of its biggest box counting dimensions. However, most of other populations occupied relatively smaller spaces due to their smaller values of the box counting dimensions. The box counting dimensions of 7 rare and endangered populations were smaller than 1 except Dipteronia sinensis population. The inflexion scales of 11 populations covered the range from 5 m to 12.5 m.According to the self similarity o f the fractal,the distribution pattern types under certain scales larger than the inflexion scale could be inferred as similar,and the results partly proved the ideas.The populations of Diospyros lotus, Pterostyrax psilophyllus, Davidia involucrata, Tetracentron sinense and Aesculus wilsonii were changed at the inflexion scale ,and other 6 populations had the same distribution pattern types despite of the scale changed.