两种百合种群空间分布格局对高温干旱气候的响应

Responses of Population Distribution Patterns in Two Species of Lilium to Hot and Drought Climate

将分形分析与方差均值比率及聚集强度指数相结合,比较分析了南川百合与泸定百合种群在高温干旱影响下的空间分布格局及其分形特征。研究表明:分形分析同方差均值比率及聚集强度指数测定得到的结果基本一致,说明分形维数不仅可以很好地反映种群的空间分布格局,也能很好地反映种群动态;两种百合种群的聚集强度均受到2006年高温干旱的影响,但南川百合种群所受影响比泸定百合大;两种百合的平均计盒维数和平均信息维数与2005年相比均减少,但南川百合种群平均计盒维数的减少比例(13.00%)约为泸定百合(9.04%)的1.44倍,平均信息维数的减少比例(22.71%)约为泸定百合(3.43%)的6.63倍,高温干旱天气对这两种百合的生长均有影响,泸定百合的抗热抗旱能力要高于南川百合,南川百合更易受高温干旱天气的伤害。与泸定百合相比,南川百合是一个比较脆弱的物种,在高温干旱等异常气候的影响下更易导致濒危,应尽快加以保护。

Population pattern and its fractal properties were compared for Lilium rosthornii and Lilium sargentiae under the hot and drought climate in Chongqing and Guizhou by the combined uses of fractal theory analysis and the classical analyses of indexes of variance/mean ratio, negative binomial parameter, mean crowding, and patchiness The results obtained from the analysis of the fractal theory and the classical methods were relatively consistent, suggesting that the fractal dimension could represent not only the population spatial patterns but also their dynamics. Although the assembling intensity of populations of both species was influenced by the hot and dry conditions in 2006, the influence on L. rosthoraii populations was bigger than that on L. sargentiae populations. As compared with that in 2005, the populations of both the species had lower mean box-counting dimensions and mean information dimensions in 2006. This may be due to the particularly dry climate they experienced in 2006. The percentage by which the mean box-counting dimension decreased was 1.4g times higher in L. rosthornii （ 13.00% ） than in L. sargentiae populations （9. 04% ）. On the other hand, the percentage by which mean information dimension decreased was much higher in L. rosthornii （22.71%）than in L. sargentiae populations（3.43% ）. These data indicated that the increment of both species was influenced by the hot and dry conditions and that L. sargentiae had stronger resistance to high temperature and drought as compared to L. rosthornii. It can be concluded that L. rosthornii, compared with L. sargentiae, is a species more vulnerable to the exceptional climatic events. More urgent procedures need to be taken for the conservation of L. rosthornii.