海南龙血树种群生境及自然更新能力调查

Investigation on the Habitat and Natural Regeneration Capacity of Dracaena cambodiana Population

对海南岛海南龙血树(Dracaena cambodiana Pierre ex Gagnep)生境、人为破坏情况和自然更新能力进行了调查与分析,探讨了其濒危原因。结果表明,海南龙血树属典型的岩石伴生型植物,主要分布在高温少雨地区,常生长在陡峭且裸露的花岗岩或石灰岩的石缝残积土中,或紧贴石壁生长于砂壤土中,其伴生树种以小乔木或灌木为主;由于无节制采挖和生境破坏,海南龙血树野生资源数量已十分有限。自然条件下海南龙血树的更新方式有种子更新、根蘖更新和桩蘖更新,但现有生境条件下无论何种更新方式均无法有效地实现种群的扩大和更新。可见,原生境破坏和无节制采挖是海南龙血树濒危的外因,"濒危生境"造成种子无法萌发或幼苗生长失败,导致种群无法实现自然更新是内因和主要原因。

The habitat and natural regeneration capacity of Dracaena cambodiana Pierre ex Gagnep in Hainan Island and the extent of human damage to its wild population were investigated and analyzed,and its endangered reasons were also discussed.The results showed that D.cambodiana was a typical rock-associated plant species and mainly distributed in the high-temperature and less-rainfall regions.D.cambodiana usually grew in the gap of steep and bare limestone or granite,or in sandy loam soil alongside the rock,and its associated species were often some small trees and shrubs.Due to the unrestricted exploitation of the wild plants and the destruction of its habitats,the wild resources of D.cambodiana have been very limited.In natural conditions,there were three ways for the regeneration of D.cambodiana,including the reproduction through seeds and the sprouts from roots and stumps.However,under the existing habitats,all of them were unable to effectively enlarge their wild population.It was concluded that the original habitat destruction and the unrestricted exploitation were the external factors for the endangerment of D.cambodiana,and the failure of seed germination or seedling growth under the poor habitats was the internal and major factor causing its endangerment,both of which made the species in an endangered status.