Page 133 - 《广西植物》2023年第5期
P. 133

5 期                   李晨笛等: 吊罗山热带天然林物种多样性的海拔分布格局                                            9 1 3

                 altitude of Diaoluo Mountain were analyzed from the aspects of species compositionꎬ species diversityꎬ flora composition
                 and leaf characteristics. The results were as follows: (1)With the increase of altitudeꎬ the temperature decreasedꎬ the
                 humidity increased and the human disturbance decreased. The species composition of tropical natural forest in Diaoluo
                 Mountain and the diversity indexes of Margalefꎬ Shannon ̄Wienerꎬ Simpsonꎬ and Pielou all showed a pattern of first
                 increase and then decrease. The middle ̄altitude community had the most suitable hydrothermal conditions and moderate
                 human disturbanceꎬ and the α species diversity was the highest. (2) With the increase of altitudeꎬ the proportion of
                 important value (IV) of dominant species decreased first and then increasedꎬ and the dominant species had obvious
                 replacement phenomenon. The middle altitude community showed the transition nature of lowland rain forest and
                 mountain rain forest. ( 3) The Sørensen community similarity coefficient between communities was significantly
                 negatively correlated with altitude difference (P<0.05). (4)The floristic composition was dominated by tropical elements
                 and mainly distributed in tropical Asia ( India ̄Malaysia). The proportion of tropical distribution was significantly
                 negatively correlated with altitude (P<0.01)ꎬ and the proportion of temperate distribution was significantly positively
                 correlated with altitude (P<0.01). (5)The leaf characteristics showed the obvious indigenous characteristics in tropical
                 regions mainly with mesophyll leavesꎬ single leavesꎬ leathery leaves and entire leaves. The proportion of microphyll
                 leaves and single leaves was significantly positively correlated with altitude (P<0.01)ꎬ while the proportion of leathery
                 leaves and non ̄entire leaves was not significantly correlated with altitude (P> 0.05). To sum upꎬ the hydrothermal
                 conditions and human disturbance degree of low altitude community in Diaoluo Mountain are quite different from those of
                 high altitude communityꎬ which leads to the difference of species distribution and community characteristicsꎬ and reflects
                 the characteristics of tropical plants adapting to their habitat conditions.
                 Key words: altitudeꎬ tropical natural forestꎬ species compositionꎬ species diversityꎬ floraꎬ leaf characteristics



                物种多样性对反映群落物种的丰富程度、群                            升高后降低的物种分布格局( 龙文兴ꎬ2016)ꎮ 因
            落结构的复杂程度和生态系统的稳定性具有重要                              此ꎬ受水热、光照、群落特性、外部干扰等多重因素

            意 义 ( Legendre et al.ꎬ 2009ꎻ Ghaley & Porterꎬ      影响ꎬ沿山体海拔ꎬ物种分布具有差异性( 龙文兴ꎬ
            2014)ꎮ 不同生境条件下ꎬ植物群落物种组成各不                          2016)ꎮ 而不同的生境条件亦使群落区系组成和
            相同ꎬ海拔梯度不仅改变了群落中光照、温度、湿                             外貌特征各不相同ꎮ 受温度变化影响ꎬ随海拔升

            度 等 环 境 因 子 ( Gastonꎬ 2000ꎻ Simsim et al.ꎬ         高ꎬ群落区系呈现出热带成分减少、温带成分增加
            2015)ꎬ甚至影响树木受人为干扰的程度ꎬ是影响                           的特点(朱华ꎬ2008)ꎻ较少的人为干扰ꎬ使高海拔

            物种多样性格局的关键因素之一( Brownꎬ 2001)ꎮ                      群落中国特有分布增加(苏文苹ꎬ2007)ꎬ区系地理
            一般而言ꎬ温度随海拔升高而降低ꎬ湿度随海拔升                             成分更加复杂(巫翠华等ꎬ2021)ꎮ 随海拔升高ꎬ川
            高而升高ꎬ树木受人为干扰的影响随海拔上升呈                              滇高山栎(Quercus aquifolioides)群落叶性质呈现出
            下降趋势( 龙文兴ꎬ2016)ꎮ 前人将物种多样性在                         细微型叶比例升高、纸质叶比例降低的特点( 刘兴
            海拔层面的分布格局一般分为 5 种( 贺金生和陈                           良等ꎬ2013)ꎬ体现了植物与其生境紧密适应的特
            伟烈ꎬ1997)ꎬ分别是与海拔呈负相关的单调降低                           征(吕晓波ꎬ2012)ꎮ 因此ꎬ研究物种多样性的海拔
            格局、与海拔呈正相关的单调升高格局、随海拔梯                             分布格局ꎬ分析随海拔梯度群落特征变化规律ꎬ对
            度先升高后降低的格局、随海拔梯度先降低后升                              揭示树木与海拔的内在联系具有重要意义ꎮ
            高的格局以及与海拔相关性不显著的格局ꎮ 如在                                 海南省吊罗山国家森林公园是我国重要的热
            人为干扰小的湿润地区ꎬ温度是影响群落物种垂                              带森林分布区之一ꎬ具有我国热带地区发育最盛、
            直分布的第一要素ꎬ随海拔升高ꎬ温度降低ꎬ物种                             最接近赤道热带雨林的热带森林( 江海声ꎬ2006)ꎬ
            多样性也随之下降( 唐志尧和方精云ꎬ2004)ꎮ 在                         沿山体海拔分布着热带低地雨林、热带山地雨林
            干旱地区ꎬ随海拔升高ꎬ虽温度下降ꎬ但雨水增多ꎬ                            等植被类型ꎮ 前人对吊罗山热带天然林的物种多
            有利于物种多样性的提高ꎬ然而山顶高寒且风巨                              样性、区系组成、群落特征进行了大量研究( 安树
            的严峻生境又导致物种多样性降低ꎬ故呈现出先                              青等ꎬ1999ꎻ丁 坦 等ꎬ2002ꎻ 王 帅 等ꎬ2015ꎻ 韩 天 宇
   128   129   130   131   132   133   134   135   136   137   138