濒危物种杏黄兜兰的保育生态学

杏黄兜兰(Paphiopedilum armeniacum)是中国特有的兰科濒危物种。自2000年4月1日至2005年10月10日,在云南省怒山的落砂坡山选取66个调查点进行杏黄兜兰保育生态学研究:对443基株共1302分株进行了繁殖式样、物候和生命周期等主要生物学特性,以及对该物种的生境要求、群落结构特征等生态学习性进行了观察研究,并在广东省深圳进行迁地保护和迁地繁殖后重返原产地的试验,研究了原产地的气候、植被和其他环境因素与杏黄兜兰之间的关系以及杏黄兜兰迁地栽培和繁殖的无性后代重返原生长地的生物学特性。研究结果表明:落砂坡山的杏黄兜兰在石灰岩上的次生灌木丛或草丛内生长良好;它兼具有性和无性繁殖,无性繁殖的目的就是实现有性繁殖和延长基株的寿命;无性繁殖有二种形式:产生分蘖或根茎;灌木丛或草丛的落叶为杏黄兜兰生长提供腐殖质,杏黄兜兰根茎繁殖是它对落叶等覆盖的一种适应;分株的开花率为7.39%±1.02%,开花分株的结果率为32.23%±12.08%;杏黄兜兰具有入侵适度破坏和正处于恢复初期的森林环境的能力,而在茂密连片的大树森林内不能生长。杏黄兜兰在深圳人工疏林下生长良好并繁殖许多无性的克隆分株,将繁殖的克隆分株重返原产地能正常开花和结实。试验结果显示,杏黄兜兰可以进行迁地保护以保存种质资源和迁地繁殖的植株回归原产地。基于杏黄兜兰濒危机制的分析,认为,杏黄兜兰生存所面临的威胁是生长空间被完全剥夺和人为灭绝性采集而不是其自身存在的生物学缺陷,为此,提出了相应的保育对策。

Conservation ecology of endangered species Paphiopedilum armeniacum(Orchid-aceae)

Paphiopedilum armeniacum is an endangered orchid species endemic to China. From April 2000 to October 2005, we selected 66 observation sites in Luoshapo of Nushan Mountains in Yunnan to carry out the conservation ecological research on P. armeniacum. We sampled 443 genets (total 1302 ramets) of P. armeniacum, observed their biological characteristics such as reproductive pattern, phenology and life cycle, and studied the ecological habits of the species such as the habitat and the structure of communities. And we conducted experiments of ex-situ conservation and replanting the cloned ramets to the original habitat after ex-situ reproduction in Shenzhen, Guangdong. We investigated the relationships between P. armeniacum and climate, vegetation and other environmental factors in the original habitat, and the biological characteristics of P. armeniacum asexual offsprings which were replanted to original habitat after ex-situ cultivation and reproduction. The studies show that P. armeniacum in Luoshapo grows very well in secondary shrub boskets or in tussocks on limestone hills; it has both sexual and asexual reproduction, asexual reproduction serves to fulfill the sexual reproduction and to extend the lifetime of genets, and does not reduce sexual reproduction; there are two modes of asexual reproductionby tillering or by rhizoming; the litter of shrub boskets or tussocks provides P. armeniacum with humus, and the rhizome reproduction of P. armeniacum is an adaptation to the litter-covered condition, i.e. to escape from the unfavorable environment; blooming rate of ramets is 7.39%±1.02%, fruit set rate from the blooming ramets is 32.23%±12.08%; P. armeniacum is able to invade the moderately destroyed forests and those in early restoring, but unable to grow in large dense forests. P. armeniacum also grows very well in artificial spare woods in Shenzhen and can reproduce many cloned ramets which can normally bloom and fruit after being replanted to the original habitat. Our results show that P. armeniacum can be conserved by ex-situ conservation and replanting the ex-situ reproduced ramets to original habitat. Based on the analysis of endangered mechanisms of P. armeniacum, we conclude that P. armeniacum has strong capability of both asexual and sexual reproductions, and an emergency mechanism consisted of massive production of rhizomes to cope with damage; since highly effective pollinating insects are present in the habitat, flowering ramets produce fruits with large quantity of seeds, many of which in turn grow into new genets that can reproduce many cloned ramets; and P. armeniacum makes highly effective use of its environment, and has distinct characteristics of enduring harsh environmental conditions, therefore, the main threats which this species faces with are destruction of its survival space and the wipe-out collecting of the plants for trading, rather than its own inherent biological defects. Based on these, we propose some appropriate strategies for the conservati
on of P. armeniacum.