东莞低效荔枝林林下植被结构和多样性

Understory vegetation community structure and diversity in low-value lichee (Litchi chinensis Sonn.) plantation in Dongguan of South China

对东莞大岭山撂荒的荔枝林(品种为"妃子笑")林下植被进行样方调查,分析了荔枝林林下植物群落的结构、多样性及生态位特征,并提出撂荒荔枝林未来发展的对策。共记录到林下植被102种,隶属于50科85属。其中,蕨类植物13种,隶属于9科9属;双子叶植物65种,隶属于31科52属;单子叶植物24种,隶属于10科24属。林下植被以灌木和乔木(幼苗)为优势生活型。灌木层与草本层物种多度分布差异不显著,其物种丰富度、均匀度、Shannon-Wiener指数、Simpson指数差异亦均不显著。林下层优势物种中有春花(Raphiolepis indica)等8种灌木,芒萁(Dicranopteris dichotoma)等7种草本,玉叶金花(Mussaenda pubescens)等5种藤本。灌木层主要种群的生态位宽度与生态位重叠值变化范围分别为0.909～1.450、0.567～0.955,草本层分别为0.945～1.566、0.270～0.984。所调查的荔枝林林下自然演替的植被物种丰富,区系成分为亚热带地带性种类,结构亦较为复杂。因此,在荔枝产业面临转型的阶段,对于立地条件或荔枝品质较差不再经营的林分,可维持植被现状,或向生态公益林方向改造,以利于东莞荔枝产业的可持续发展。

Using field survey from an abandoned lichee（Litchi chinensis Sonn.） plantation in Dalingshan,Dongguan City,the community structure,diversity and niche characteristics of understory vegetation were analyzed.The field survey recorded 102 understory plant species,which belonged to 50 families and 85 genera.Thirteen ferns species of the vegetation mosaic belonged to 9 families and 9 genera;65 dicotyledons belonged to 31 families and 52 genera;and 24 monocots belonged to 10 families and 24 genera.Shrubs and tree seedlings dominated the understory vegetation.There was no significant difference in species abundance between the shrub and herbaceous layers.No significant difference was also noted in the indices of species richness,evenness,Shannon-Wiener,and Simpson between the shrub and herbaceous layers.The dominant plant species included 8 shrubs（e.g.,Raphiolepis indica）,7 herbs（e.g.,Dicranopteris dichotoma） and 5 vines（e.g.,Mussaunda pubescens）.Niches breadth and niche overlaps were 0.909～1.450 and 0.567～0.955 for the main shrub layer,and 0.945～1.566 and 0.270～0.984 for the main herbaceous layer,respectively.The study revealed rich species of natural recruitment in the understory vegetation of lichee plantation.This was characterized by subtropical floristic elements with a complex structure.In view of the findings,it was suggested that in the transitional stage of Dongguan lichee industry,lichee plantation ceased to operate due to adverse stand conditions.Hence understory vegetation should be maintained or transformed into an ecological forest,which could help sustain the development of Dongguan lichee industry.