黔北丹霞地貌桫椤群落优势种群生态位研究

Niche Characteristics of Dominant Plant Populations of Alsophila spinulosa Community of Danxia Landform in North Guizhou

为探讨黔北丹霞地貌桫椤群落优势种群在群落中的地位、对资源的利用状况以及种群间的相互关系,揭示该区植物群落的稳定性以及植物种群在特定环境下的生态适应性。对黔北丹霞地貌濒危植物桫椤群落进行样地调查,采用定量分析方法,用Levins、Shannon-wiener生态位宽度公式、Schoener生态位相似性比例等指数公式研究了桫椤群落中主要种群的生态位宽度、生态位相似比例以及生态位重叠。结果表明:(1)罗伞、杜茎山、桫椤生态位宽度较大,Shannon Wiener和Levins指数分别为7.6076、7.3449、6.9105和0.5314、0.5931、0.6515,表明它们广布于该群落内,对环境适应能力较强;(2)石岩枫和川桂生态位相似比例最大,Cih值为0.998 6;(3)裂叶榕与美脉琼楠生态位重叠最大,其值为0.3365;(4)生态位宽度较高的两个树种,其种间生态位相似比例值较高,生态位重叠也较大,但由于个别生态位宽度较大的物种本身的生物生态学特性不一定相同,对环境资源的要求不完全相同,导致其间的生态位重叠与相似系比例并不一定很高;(5)从生态位相似比例和生态位重叠分布格局来看,桫椤群落主要植物种群利用资源相似程度较高,生态位重叠较普遍,但主要集中在较低水平,表明群落内因利用相同资源或占有同一资源而产生的种间竞争并不激烈,均表明各种群对资源的共享趋势较为明显,显示桫椤群落相对稳定。

The objectives of the present study were to discuss the status and utilization of resources and the mutual relationship of dominant plant population,to reveal the stability of phytocoenosium and ecological adaptability of plant population under the specific environment,to accumulate theory data for further research on Alsophila spinulosa competion with other species,meanwhile,to provide reference of the protection,utilization and related research for China Danxia world natural heritage. Based on the sample investigation of A. spinulosa community of Danxia Landform in North Area,Guizhou,with the method of quantitative analysis,the niche breadths proportional similarity and overlaps of main dominant species were measured using a series of indices proposed. The results showed that the niche breadth values of Brassaiopsis glomerulata,Maesa japonica and A. spinulosa are the biggest,Shannon Wiener indices were 7. 607 6,7. 344 9 and 6. 910 5,Levins indices were0. 531 4,0. 593 1 and 0. 651 5,respectively,which showed that they are all widely distributed within the community,having strong ability to adapt to the environment; Cinnamomum wilsonii and Mallotus repandusniche proportional similarity value was 0. 998 6,it was the biggest in all species pairs; Ficuslaceratifolie Levl and Beilschmiedia delicata niche overlap values were the biggest,the index was 0. 336 5. Normally,if the niche breadth of the species pairs is wider,the interspecific niche proportional similarity value is higher,niche overlap is also bigger,but niche overlap and niche proportional similarity of some species does not necessarily high. It was closely related to ecological and biological characteristics of species. From the view of the distribution pattern of niche overlap and proportional similarity,there were generally niche overlaps among main populations,but the niche overlaps were mostly at low level,indicated that the interspecific competition generated by utilizing same resources or occupying specific resources was not intense,and the environmental resources could be sufficiently shared by different populations. The Alsophila spinulosa forest communities of Danxia Landform in North Guizhou were at relatively stable stage.