渐危植物浙江楠群落结构及叶片性状多样性

Community structure and leaf trait diversity in a vulnerable species,Phoebe chekiangensis(Lauraceae)

浙江楠为商品材"金丝楠木"的原植物之一,天然分布区窄,属国家二级保护渐危种,在全球气候变化背景下,研究其天然种群所在森林群落的结构特征及其多样性具有重要意义.本研究以浙江楠天然分布区内13个典型种群为对象,研究其所在群落的群落结构特征、物种多样性和叶片表型变异特征.结果表明:浙江楠天然种群所在群落的结构复杂,物种多样性较高,13个群落的16块样地内共有维管束植物87科162属235种,其中种子植物79科151属221种;重度干扰导致浙江开化、浙江临安等群落的乔木层物种多样性指数显著低于其他群落,而中度干扰提高了福建建宁群落灌木层物种多样性,轻度干扰则利于浙江楠种群自然更新.叶片表型作为楠木属植物重要的分类依据,叶片表型性状在种群间、种群内均存在丰富变异,平均变异系数为17.2%,变异幅度为10.4%~27.5%.种群间的变异(53.6%)大于种群内的变异(17.0%),平均表型分化系数为75.1%,种群间变异是浙江楠叶片表型变异的主要来源.基于欧式距离(10 cm)将13个天然种群划分为两大类群,但变异呈随机性.

Phoebe chekiangensis,as one original species of ‘Nanmu with golden tint＇,harbors limited natural distribution regions,which is recognized as a vulnerable species in China under nationwide protection. Under the background of global climate change,it is of scientific significance to study the community structure and diversity of the natural populations of P. chekiangensis. In this study,community structure,species diversity and the phenotypic variation leaf traits in the communities of thirteen residue natural populations were analyzed. A total of 235 vascular species from 162 genera and 87 families were found in 16 plots within 13 natural populations,including 221 seed plants from 151 genera and 79 families. The species diversity in tree layer of community in Kaihua,Zhejiang and Linan, Zhejiang was significantly lower than that of other communities due to severe disturbance,while intermediate disturbance promoted the species diversity of shrub layer in community in Jianning,Fujian,and slight disturbance was beneficial to natural regeneration of P. chekiangensis. Foliage phenotype was important for species identification within Phoebe genus. There existed substantial variation in foliage phenotypic diversity among and within populations. The mean coefficient of variation was 17.2%,ranging from 10.4% to 27.5%. The variation was greater among populations（ 53.6%） than within populations（ 17.0%）. Mean phenotypic differentiation coefficient was 75.1% among populations,indicating that the variance among populations was the main source for the phenotypic variation of the species. Results from the cluster analysis indicated that the 13 natural populations were divided into two distinct groups based on the Euclidean distance（ 10 cm）,with stochastic variation.