广州市珍稀濒危植物水松的种群现状与保护策略

Population Status and Conservation Strategy of the Rare and Endangered Plant Glyptostrobus Pensilis in Guangzhou

水松[Glyptostrobus pensilis（Stanunt.）K.Koch]为我国I级重点保护野生植物之一,曾于珠江三角洲地区普遍生长。但由于近50 a来人类活动的强烈干扰,其野生种群和个体数量骤减,世界自然保护联盟（IUCN）已将水松评估为“极危”状态。文章以实测法进行野外调查,结果表明：广州市野生水松古树在近5 a间快速消亡,现仅存8个种群共14株个体,且半数处于生长不良或濒死状态;种群个体数量少,仅包括1~4株水松,无法进行自然更新;这些水松长期未得到科学合理的保护,如不采取有效保育措施,残酷的生存压力可能导致大部分种群的快速死亡。因此,在广州地区开展水松的就地和迁地保护、扩大种群的个体数量、开展水松的保护遗传学和监测人工林种群的遗传结构变化情况等研究,应成为目前保护和拯救本地区水松种群及其遗传多样性的必要策略。

Glyptostrobus pensilis is one of the state key protected wild plants listed in Class I, mainly distributed in South and Southeast China, and also found in Vietnam and Laos. It was very common in the Pearl River Delta Region previously but decreased quickly in the past 50 years because of serious disturbance from dramatic human activities, rapid habitat loss and its own physiological defects. It has been now evaluated as ＂Critically Endangered＂ category according to IUCN criteria. Our field investigation to the remaining populations of Glyptostrobus pensilis in Guangzhou has recorded the data of habitat types, community profiles, number of individuals, diameter at breast height, tree height, crown breadth, geographic coordinates, regeneration status and threat factors. The field investigation reveals that many wild individuals of G. pensilis died in recent five years and only 14 in eight populations were found in the field in Zengcheng and Conghua Districts, these individuals usually live near the ponds or ditches at village edge or downtown, each population include only 1-4 individuals and can＇t be effectively enlarged by natural regeneration. Of these extant plants, half are in bad conditions or at the edge of death. Most existing individuals can produce seeds normally, but the seeds are usually embryos dysplasia and hard to germinate, or hardly survive after sprout. And although some individuals have been protected for conservation by local forestry departments, the trees are still in worrying condition because of the improper conservation strategies. In addition, these plants have not been protected scientifically and reasonably for a very long time. And most of them will become extinct quickly in wild because of the heavy survival pressure, if no any prompt and reasonable conservation methods are provided. Therefore, we put forward the following suggestions for the protection of Glyptostrobus pensilis in Guangzhou： 1） launch in situ and ex situ conservation work, enlarge the quantity of each population, maximally maintain its normal growth to postpone their death and strive to get more time for the population propagation; 2） take the opportunities of urban wetland construction to carry out ex-situ conservation of Glyptostrobus pensilis; 3） develop the seedling propagation, disease and pest control technique; 4） construct germplasm repository of Glyptostrobus pensilis, expand population heterogeneity, enhance genetic exchange, and protect genetic diversity of the taxus; 5） strengthen the conservation genetics research, find out the branches of the pedigree of its genetic structure, so as to guide the scientific practice of conservation biology.