【摘要】 林线是气候变化敏感指示区,林窗和林缘是草本植物进入的重要窗口。研究林线过渡带林窗和林缘生境内草本物种的格局有利于揭示这两种生境内重要的生态过程。本文选取五台山自然保护区林线过渡带内的林窗(海拔2350 m)和林缘(海拔2300 m)为样地(5 m×5 m),每个样地设置25个1 m×1 m样方,分别记录样方内6个优势物种(光稃茅香(Hierochloe glabra)、小花草玉梅(Anemone rivularis)、平车前(Plantago depressa)、珠芽蓼(Polygonum viviparum)、三叶委陵菜(Potentilla freyniana)、蒲公英(Taraxacum mongolicum))位置信息。运用完全空间随机过程(CSR)、异质性泊松过程(HP)、泊松聚块过程(PC)零模型在不同尺度下进行格局模拟分析。结果如下:(1)林窗内6个物种的聚集分布的尺度范围都分别大于林缘,在两个生境内珠芽蓼和小花草玉梅聚集尺度较宽,蒲公英和平车前聚集尺度较窄,最常见的聚集尺度在0～40、100～140和200～230 cm。(2)异质性泊松过程模拟及检验结果表明:在林窗和林缘,微生境异质性对具有广适性的5个物种的格局影响不显著,而无性繁殖较发达的光稃茅香的格局在林窗和林缘生境内受微生境影响显著。(3)泊松聚块过程模拟及检验结果表明:林缘的物种格局显著受到种子扩散过程的影响。在0～50 cm的尺度范围内种子扩散过程受重力影响分布在母体周围。在大于100 cm尺度上,种子特殊的传播方式或特殊种子附属结构影响种子扩散的距离。此外,在风力帮助下,特殊结构的物种分布有可能达到250 cm。更多还原

【Abstract】 Treeline is sensitive to climate change. Forest gap and edge are important windows for the invasion of herbaceous species. Research on distribution patterns of herbaceous species in forest gaps and forest edges of treeline ecotones could help explain important ecological processes.We selected a forest gap( elevation: 2350 m) and a forest edge( elevation: 2300 m) as plots( 5 m×5 m) in a treeline ecotone of Wutai Natural Reserve. Twenty-five quadrats( 1 m×1 m)were set up in each of both plots,within which the locations of six dominant species( Hierochloe glabra,Anemone rivularis,Plantago depressa,Polygonum viviparum,Potentilla freyniana,and Taraxacum mongolicum) were recorded. Complete spatial random process( CSR),heterogeneous Poisson process( HP),and Poisson cluster( PC) were used to simulate the spatial patterns of the six species at different scales. The results showed that:( 1) Aggregated sizes of the six species in forest gaps were broader than those in the forest edge,with those of Polygonum viviparum and Anemone rivularis were broader than other species in both plots. The aggregated sizes of Taraxacum mongolicum and Plantago depressa were narrower than other species in both plots. The most common aggregation occurred on 0-40,100-140 and 200-230 cm.( 2) For both forest gap and edge,HP simulation and significance tests showed that micro-habitat differences between plots had no significant effect on species distribution with broad ecological amplitude. However,the distribution of Hierochloe glabra was significantly affected by micro-habitat differences in forest gap and edge due to ramet growth.( 3) Results from PC simulations and significance tests showed that seed dispersal significantly affected species distribution in the forest edge. Seed dispersal around maternal individuals often occurred at 0-50 cm scales as affected by gravity. At the scale of >100 cm,species with special dispersal modes or structures affected their dispersal distance. Additionally,species with special structures could reach 250 cm with the help of strong winds.更多还原