黄土高原不同气象因子对中国沙棘亚居群遗传多样性的影响

顶生金花茶(Camellia terminalis)是一种濒危植物,主要分布在广西天等县石灰岩山钙质土上的常绿阔叶林内.采用样地调查、统计分析和回归模型预测等方法,对顶生金花茶种群的分布环境、资源量现状、大小和高度结构等进行了研究.结果表明:该种群主要依存于天等县小山乡的蚬木-石山樟林(P1)和任豆-蚬木林(P2)、福新乡的枝花李榄-石山楠林(P3)和齿叶大风子-闭花木林(P4)4种群落,构成灌木层的优势种和共优种;P1、P3和P4种群处于群落较稳定的典型常绿季雨林中,结构较完整,属于稳定或增长型;P2种群由于恶劣环境和频繁人为干扰的共同胁迫,有衰退的趋势;与小山乡生境相比,福新乡相对冷凉湿润的气候条件、丰厚肥沃的土层以及较轻度的人为干扰有利于顶生金花茶种群的发展.目前顶生金花茶种群的资源量有限,建议列为"严重濒临灭绝"(CR)等级.

Population structure of endangered species Camellia terminalis

Camellia terminalis is an endangered species only distributed in the evergreen monsoon rain forest in limestone hills of Tiandeng County,Guangxi of China.In this paper,the environmental conditions,resources status,and size-and height structure of C.terminalis populations were studied by field investigation and statistical analysis,and the population dynamics was predicted by cubic regression equation.The results showed that C.terminalis mainly existed in the communities of Burretiodendron hsienmu-Cinnamomum saxatile(P1),Zenia insignis-B.hsienmu(P2),Linociera ramiflora-Phoebe calcarea(P3) and Hydnocarpus serratus-Cleistanthus saichikii(P4) in Xiaoshan Town,Tiandeng County,and constituted a dominant species or one of the co-dominant species in shrub layer.The C.terminalis population in P2 showed an obviously declining trend under the stress of bad environment and human disturbance,while that in P1,P3 and P4 with stable structure showed a stable or growing tendency.Compared with the habitat in Xiaoshan Town,the environmental conditions with cold and humid climate,fertile soil,and slight human disturbance in Fuxin Town were more favorable to the development of C.terminalis.Owing to the limited resources of C.terminalis,this species should be ranked as a critically endangered species.