贵州特有植物贵州槭的种群结构及动态研究

贵州槭(Acer guizhouense)属常绿阔叶乔木,仅分布于贵州省黄平县新州镇海拔770~1 000 m有山峰屏障的常绿阔叶落叶混交林中,颇具科研和经济价值,研究其种群结构特征和数量动态变化对于探索特有植物保护生物学具有重要意义。该研究对贵州槭疑似分布区开展普查,并在密集分布区设置样地进行详查,分析其种群结构与数量动态的变化规律。结果表明:(1)贵州槭的自然分布区极为狭窄,雷坪分布区约0.3 km~2,总计约2 600株,其中密集分布区0.03 km~2,平均种群密度78 800株/km~2,稀疏分布区0.27 km~2,平均种群密度≤1 500株/km~2;在东坡村飞云崖风景区有约0.05 km~2的稀疏分布,且在雷坪至东坡两分布区之间没有发现自然分布;采用SAFE指数和IUCN的标准评价,贵州槭属于濒危物种(EN)。(2)贵州槭幼树占种群的比重达63.23%,种群密度大小为幼树中龄树成年树,种群结构为增长型;种群死亡率曲线和消失率曲线分别在Ⅰ龄期和Ⅸ龄期出现2个高峰,在Ⅲ-Ⅷ龄期间和Ⅹ-Ⅺ龄期间出现2个低谷,种群存活曲线趋于Deevey-Ⅲ型特征;(3)人为采伐和生境遭破坏造成的植株死亡或者丧失增加是导致贵州槭种群数量稀少的主要原因,在加强就地保护的同时,开展人工育苗迁地应用栽培是现实而有效的合理保护措施。

Population structure and dynamics of the endemic plant Acer guizhouense in Guizhou Province

Acer guizhouense is a kind of evergreen broad-leaved tree with scientific and economic value, which only dis-tributed at 770-1 000 m in evergreen and deciduous broad-leaved mixed forest with mountain barrier in Xinzhou Town of Huangping County in Guizhou Province. So, it has significant value to explore conservation biology of endemic plants by studying its population structure and dynamic change. We took general survey in suspected distribution area, set up plots in dense area for full investigation, and analyzed the population structure and quantity dynamics pattern. The results were as follows:(1) The natural distribution region of A. guizhouense was very narrow, covered about 0.3 km2 in Leiping with a total of 2 600 trees. The dense area was 0.03 km2 , average population density 78 800 trees/km2 . The sporadic distribu-tion was 0.27 km2 , average population density≤1 500 trees/km2 . The species occasionally distributed in about 0.05 km2 Feiyunya of Dongpo Village. But there was no natural distribution between Leiping and Dongpo. According to the SAFE index and evaluation standard of IUCN, A. guizhouense was EN species. (2) The structure of A. guizhouense population was increasing and the proportion of young tree in population was 63.23%. The size of population density was young trees>middle-aged trees>adult trees. There were 2 peaks in theⅠand Ⅸ age-classes on the mortality rate curve and disap-pearance rate curve respectively, then there were 2 troughs inⅢ-ⅧandⅩ-Ⅺage-classes. So the survival curve of pop-ulation was more in line with the characteristics of Deevey-Ⅲmodel. (3) The main reason of few population individuals of A. guizhouense was the plant death or loss caused by human deforestation and habitat destruction. It is a practical and effective reasonable protection measure to carry out artificial breeding and ex situ cultivation when we strengthen the in situ conservation.