南亚热带人工杉木林灌木层物种组成及主要木本种间联结性

Species composition and correlation of understorey woody plants in chinese fir plantation in the lower subtropical area

南亚热带杉木人工林经过13a自然更新过程,林下灌木层植物种有71种,灌木层出现小乔木。通过重要值分析,判别了各物种在群落中的地位和作用。用x2统计和r检验研究了该杉木林下灌木层25种主要木本种种间关系,测定它们的种间联结性和相关性,结果清楚地反映了木本植物种间关系以及它们在资源利用和生态特性上的差异。依据分析结果将灌木层25种主要木本植物分成4个种组:.对叶榕(Ficushispida)+五月茶(Antidesmabunius)+毛桐(Mallotusbarbatus)+耳叶榕(Ficuscunia)+水东哥(Saurauiatristyla)+粗糠柴(Mallotusphilippinensis)+杜茎山(Maesajaponica)+粗叶榕(Ficushirta)+山麻杆(Alchornearugosa)+黄毛榕(Ficusfulva)+白背叶(Mallotusapelta);.拓树(Cudraniatricuspidata)+鸭脚木(Scheffleraoctophylla);.杉木(Cunninghamialanceolata)+大青(Clerodendroncytophyllum)+相思子(Millettiasemicastrata)+山石榴(Randiaspinosa)+山苍子(Litseacubeba)+木姜子(Litseapungens);.紫金牛(Ardisiajaponica)+九节(Psychotriarubra)+山牡荆(Vitexquinata)+风箱树(Cephalanthusoccidentalis)+亮叶围涎树(Pithecellobiumlucidum)+华腺萼木(Mycetiasinensis)。种组划分的生态指示表明:如果杉木群落中灌木层以种组或的种为优势种,则认为该群落是一个不稳定的过渡类型,最终可能会变化为以这些种为优势的稀疏阔叶林;若以种组为优势种,该群落则是在本地区气候条件下的相对稳定的针叶林群落;以种组I为优势的群落则是乔木层从以针叶树为主、针叶林向针阔混交林的过渡类型。种组划分将为该区域同类型人工林生态功能评价以及林分近自然恢复改造提供理论依据。

Cunninghamia lanceolata is the main timber tree in the low subtropical area. Because of the simple stand structure and the traditional management focusing only on wood production, the potential consequences of biodiversity loss for ecosystem function and services have received considerable attention in recent years. It is necessary to change stand structure and species composition of Chinese fir plantation in order to increase its species diversity and ecosystem services. The understorey woody plant is beneficial to maintaining site productivity, species diversity and stability of community. Study on the species richeness, interspecific association and correlation can direct the sound practice of vegetation restoration. There are 71 species in shrub layer in Cunninghamia lanceolata plantation after 13 years natural succession. The species richness and diversity have increased with slight anthropogenic disturbance. The status and function of understorey woody species are judged by analysis of important Value. Ficus hispida, Cudrania tricuspidata,Mallotus apelta, Millettia semicastrata etc. are the constructive species; Periploca forrestii,Alangium chinese,Pueraria thunbergiana,Mallotus barbatus etc. are the subdominant species, Clerodendron cytophyllum, Maesa japonica ,Randia spinosa ,Litsea cubeba etc. are the companion species ; Viburnum dilatatum, Cayratia japonica,Rubus palmatus etc. are the rare species. X^2 statistics and r test are used for testing significance of interspecific association and correlation among 25 main understorey woody plants selecting from the woody population. The results clearly show their interspecific relationships and their differences in resource utilization. Species-pairs of positive association are in the majority. The most species have accommodated the shady habitat. There is a positive correlation between the important value of species and the interspecific association. The higher important value of the species is, the more close and significant interspecific association is. Based on analytical results of interspecific association and correlation, 25 woody plants in shrub layer could be divided into 4 ecological species groups ： Ⅰ. Ficus hispida ＋ Antidesma bunius ＋ Mallotus barbatus ＋ Ficus cunia ＋ Saurauia tristyla ＋ Mallotus philippinensis ＋ Maesa japonica ＋ Ficus hirta ＋ Alchornea rugosa ＋ Ficus fulva ＋ Mallotus apelta ; Ⅱ. Cudrania tricuspidata ＋ Sche ff lera octophylla ; Ⅲ. Cunninghamia lanceolata ＋ Clerodendron cytophyllum ＋Millettia semicastrata ＋ Randia spinosa ＋Litsea cubeba ＋ Litsea pungens ; Ⅳ. Ardisia japonica ＋ Psychotria rubra ＋ Vitex quinata ＋ Cephalanthus occidentalis ＋ Pithecellobium lucidum＋Mycetia sinensis. If species group Ⅲ or Ⅱ are advantaged species in shrub layer, the community would change from coniferous forest to sparse evergreen broad-leaved forest; For group Ⅳ , the community would be relatively stable; For group Ⅰ,the coniferous forest would be mixed coniferous broad leaved forest. The classification of ecological species groups would provide a theoretical basis on judging its ecological function, adjusting the stand structure of plantation and directing the suitable natural vegetation type through the close-natural restoration process.