海南岛霸王岭国家重点保护植物的生态位研究

A study on the niches of the state's key protected plants in Bawangling, Hainan Island

为进一步了解国家重点野生保护植物的生存群落及不同种群利用资源和占据生态空间的能力,为制定国家重点保护植物种群的保护措施提供依据,2009–2011年,对霸王岭有国家重点保护植物分布的70个样地进行群落调查,研究了霸王岭保护区内12种国家重点保护植物的生态位宽度以及物种间的生态位重叠。结果表明:(1)生态位宽度值从大到小依次为:土沉香(Aquilaria sinensis)、海南韶子(Nephelium topengii)、普洱茶(Camellia sinensis var.assamica)、油丹(Alseodaphne hainanensis)、海南油杉(Keteleeria hainanensis)、鸡毛松(Podocarpus imbricatus)、海南梧桐(Firmiana hainanensis)、乐东拟单性木兰(Parakmeria lotungensis)、海南粗榧(Cephalotaxus mannii)、香子含笑(Michelia hedyosperma)、粘木(Ixonanthes reticulata)和陆均松(Dacrydium pierrei);(2)物种生态位宽度值的大小与其自身的地理分布范围密切相关,如:陆均松、乐东拟单性木兰等生态位宽度较小的原因与其分布的海拔范围狭窄有关。生态位宽度较大的种群对资源的利用能力较强,与其他物种的生态位重叠一般较大,如:生态位宽度较大的普洱茶与海南油杉的生态位重叠值最大,为0.872,而一些生态位宽度较小的物种生态位重叠值较高,如:香子含笑的生态位宽度较小,但与海南梧桐的生态位重叠较大,为0.693。因此,种群间的生态位重叠值与它们对环境资源利用的相似程度以及物种自身的生物学特性密切相关;(3)香子含笑、粘木等的生态位宽度较小,而且个体数量较少,适宜其生存的群落和生境极少,应该给予更多的关注和优先保护;(4)未来对濒危植物的保护不仅要考虑各物种自身的生物学特性,还应从植物群落的角度考虑。只有保护好这些濒危植物的生存群落,如山地雨林等,才能实现对濒危植物的有效保护。

Aims An understanding on the living communities of the state＇s key protected wild plants and the ability in utilizing resources and occupying ecological spaces by different populations is essential to the protection and propagation of rare and endangered plant species. We use our findings to highlight the knowledge gaps in the conservation strategies for the endangered species. Methods Field investigations were conducted during 2009-2011. Based on the survey data on 70 forest plots in the Bawangling protected area, the niche breadths and overlaps of 12 species listed as the state＇s key protected plants were calculated and analyzed. Important findings The 12 species, by their niche breadth values in descending order, include Aquilaria sinen- sis, Nephelium topengiL Camellia sinensis var. assamica, Alseodaphne hainanensis, Keteleeria hainanensis, Po- docarpus imbricatus, Firmiana hainanensis, Parakmeria lotungensis, Cephalotaxus manniL Michelia he- dyosperma, Ixonanthes reticulata, Dacrydium pierrei. The niche breadth value of a species is closely related to its range of geographical distribution; both Dacrydium pierrei and Parakmeria lotungensis had a narrow niche breadth corresponding to their narrow ranges of altitudinal distribution. In general, the niche overlap value is higher between species with greater niche breadth; the highest niche overlap value of 0.872 was found between Camellia sinensis var. assamica and Keteleeria hainanensis. However, the niche overlap value between species with smaller niche breadth could also be high; e.g. the niche overlap value was relatively high （0.693） between two species with smaller niche breadth, Michelia hedyosperma and Firmiana hainanensis, indicating that niche overlap value is dependent upon the biological characteristics and requirements for environmental resources of the species of comparison. Some species with low niche breadth values （e.g. Michelia hedyosperma and Ixonanthes reticulata） were found to have smaller populations. Due to lack of suitable community and habitats, these plant species are in dire need of more attention and prioritization for conservation. In conclusion, for the better protection and propagation of these endangered plants in the future, we should combine knowledge of their biological characteristics with that of their living communities such as the montane rainforests, etc.