攀枝花苏铁种群生态地理分布、分布格局及采挖历史的研究

 对攀枝花苏铁(Cycas panzhihuaensis)种群的地理分布、数量特征、空间分布格局和毁坏历史进行了野外调查和研究。结果表明：攀枝花苏铁种群的自然栖息地是相互隔离和片断化的。已发现的13个自然种群中，8个分布在金沙江河谷，5个种群分布在金沙江支流河谷；最大的种群位于攀枝花市郊，占有面积约3.80km2。79年以来的商业采挖使8个种群灭绝，种群分布区从30700km2减少到8800km2，种群占有面积从11.50km2减少到6.30km2。3个被研究种群的分布格局为集群分布，以幼苗聚集程度最大，随着年龄的增加，聚集程度逐渐下降。

THE ECOLOGICAL GEOGRAPHIC DISTRIBUTION, SPATIAL PATTERN AND COLLECTING HISTORY OF CYCAS PANZHIHUAENSIS POPULATIONS

The ecological geographic distribution,spatial distribution pattern,the history of commercial collecting and the size of Cycas panzhihuaensis populations were surveyed in the dry hot valley of Jinsha River.The results were showed as follows:The natural habitats of C.panzhihuaensis were fragmented and isolated.There were 13 populations in the region.Eight of them were distributed in Jinsha River Valley and the others in several tributaries of Jinsha River.The largest population existed in Xiqu of Panzhihua City,with occupancy area of 3.8km 2.Due to the rampant commercial collecting since 1979, eight populations have been destroyed.The extent of occurrence was reduced from 30700km 2 to 8800km 2 and the area of occupancy was decreased from 11 5km 2 to 6 30km 2.Three of five extant populations were still under the threat of destruction.The data of random plots in three populations have been used to analysis spatial pattern.The populations exhibited a clumped distribution.Their clumped degree reduced gradually along withthe increase in age of individuals.