茂兰喀斯特常绿落叶阔叶混交林群落组成和优势种更新类型

Community Composition and Regeneration Types of Dominant Species in Evergreen and Deciduous Broad-leaved Mixed Karst Forest in Maolan National Nature Reserve, Guizhou Province

为探讨茂兰喀斯特森林群落结构和优势种更新机制,对茂兰自然保护区常绿落叶阔叶混交林群落进行了调查。结果表明,群落中有木本植物37科58属70种,以樟科、蔷薇科、无患子科和漆树科为主。常绿树种41种,占总种数的58.6%;落叶树种29种,占总种数的41.4%,这体现了喀斯特常绿落叶阔叶混交林的群落学性质。群落的优势乔木树种有轮叶木姜子(Litseaverticillata)、青冈栎(Cyclobalanopsisglauca)、狭叶润楠(Machilusrehderi)和翅荚香槐(Cladrastisplatycarpa)等。灌木优势种有皱叶海桐(Pittosporumcrispulum)、裂果卫矛(Euonymusdielsianus)、革叶铁榄(Sinosideroxylonwightianum)和南天竹(Nandina domestica)等。优势种种群结构有5种类型:单峰型,如樱桃(Cerasus pseudocerasus)、南酸枣(Choerospondias axillaris)等阳性乔木,为林窗更新种,随林窗的郁闭将衰退消失;逆J字型,如轮叶木姜子、香港四照花(Dendrobenthamia hongkongensis)、皱叶海桐等耐荫性强的常绿阔叶树种,更新能力较强,为顶极群落优势种;间歇型,如青冈栎、狭叶润楠、齿叶黄皮(Clausena dunniana)等树种,群落中的个体多集中在小径级阶段,能长期存在于群落中;L字型,如桂皮(Cinnamomumtamala)、梓叶槭(Acer catalpifolium)、革叶铁榄等;单柱型,如石岩枫(Mallotus repandus)、南天竹等常绿灌木树种,个体集中于幼苗、幼树阶段,为顶极群落亚乔木层和灌木层的主要组成种。因此,这表明调查区域的植物群落处于相对稳定的顶极阶段。

In order to understand the structure and regeneration mechanism of dominant species in community, the evergreen and deciduous broad-leaved mixed karst forests in Maolan National Nature Reserve, Guizhou Province, were investigated. The results showed that there were 70 woody species, belonging to 37 families and 58 genera in the community. The dominant families were Lauraceae, Rosaceae, Sapindaceae and Aceraceae. There were 41 evergreen trees and 29 deciduous trees, accounting for 58.6% and 41.4% of the total species, respectively, which indicated the character of evergreen and deciduous broad-leaved mixed karst forests. The dominant trees in community were Litsea verticillata, Cyclobalanopsis glauca, Machilus rehderi and Cladrastis platycarpa, etc., while dominant shrub were Pittosporum crispulum, Euonymus dielsianus, Sinosideroxylon wightianum and Nandina domestica, etc. Based on DBH class distribution pattern, the dominant species community structure could be divided into five types. The unimodal type species, such as heliophyte Cerasus pseudocerasus and Choerospondias axillaris, regenerate in gap, which would disappear finally with the gap closing. The inverse-J type species, such as evergreen broad-leaved trees Litsea verticillata, Dendrobenthamia hongkongensis, Pittosporum crispulum, were dominant species in climax community with strong shade tolerance and renewability. The sporadic type species, such as Cyclobalanopsis glauca, Machilus rehderi, Clausena dunniana, main in small DBH class, can exist in the community for a long time. The L type species, such as Cinnamomum tamala, Acer catalpifolium, Sinosideroxylon wightianum, and the unibar type species, such as Mallotus repandus, Nandina domestica, were the dominant species in subtree layer and shrub layer of the climax community. Therefore, the karst forest community in Maolan is in a relatively stable climax stage.