关键词: 榉树, 种群, 物种保护, 地理分布格局

Abstract:

Natural population distribution status,population characteristics and population distribution pattern of natural 〖WTBX〗Zelkova schneideriana〖WTBZ〗 in Hubei province were investigated in the present study.The results showed that 〖WTBX〗Zelkova schneideriana〖WTBZ〗 resources in Hubei province mainly distributed in the altitude condition of 500~1 000 m,being divided or being surrounded in the bottom of valley and mountainside,and their geographical distribution showed a shrinking group pattern,with relatively small populations.Variance method and mean value method were employed to analyze the geographical distribution pattern of 〖WTBX〗Zelkova schneideriana〖WTBZ〗,and the results indicated that its value was equal to 1.66 and larger than 1,which demonstrated that its geographical distribution appeared to be a grouping distribution.The scattered geographical distribution pattern of 〖WTBX〗Zelkova schneideriana〖WTBZ〗 resulted in spatial interval distribution,which was a barrier for the gene crossing,while smaller populations increased the chances for genetic drift,leading to an increase in the heredity instability,and affecting the population viability.All these were the major reasons resulting in the species endangerment.The causes responsible for the distribution status of Hubei 〖WTBX〗Zelkova schneideriana〖WTBZ〗 were,on the one hand,biological characteristics of species themself and its specific requirements for habitat,on the other hand,overexploitation of 〖WTBX〗Zelkova schneideriana〖WTBZ〗 resources by human beings and the habitat fragmentation resulted from human economic activities.Based on the evidences provided in the present study,the authors suggested that ecological environment should be improved,and populations enlarged so as to promote the gene intercourse among different population and thus to protect the species.

Key words: Zelkova schneideriana〖WTBZ〗, population, species conservation, geographical distribution pattern