Chin J Plan Ecolo ›› 1999, Vol. 23 ›› Issue (1): 23-30.

• Research Articles • Previous Articles     Next Articles

The Ecological Geographic Distribution, Spatial Pattern and Collecting History of Cycas panzhihuaensis Populations

He Yonghua and Li Chaoluan   

  • Published:1999-01-10
  • Contact: Zhang Wenhui

Abstract: 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 3.8km2. Due to the rampant commercial collecting since 1979, eight populations have been destroyed. The extent of occurrence was reduced from 30700km2 to 8800km2 and the area of occupancy was decreased from 11.5km2 to 6.30km2. 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 with the increase in age of individuals.