长白山原始阔叶红松林林下草本植物多样性格局及其影响因素

于2009年生长季(5～9月份)对布置在1.0hm2的原始阔叶红松林样地内的100个草本样方(1m×1m)进行物种及其植株高度、盖度以及土壤因子、光照环境进行调查,分析不同层片与土壤因子、光照环境的相关性以及乔木层、灌木层、土壤因子、光照环境对草本层多样性格局的影响,以阐明长白山阔叶红松林林下草本层多样性格局及其影响因素。结果表明:(1)阔叶红松林下的草本植物存在明显的季节动态变化,其中,5月份黑水银莲花(Anemone amurensis)、延胡索(Corydalis ambigua)等早春短命植物占优势,6月份部分早春短命植物和早夏植物、晚夏植物同时出现,物种丰富度最高,7月份是夏季植物的生长旺季,物种多样性最高,8～9月份草本植物逐渐枯萎。(2)灌木层的多样性与草本层的多样性呈极显著正相关,灌木层的株数密度与不同月份的草本层盖度呈正相关、与草本层多样性呈负相关,而乔木层对草本层盖度和多样性的影响均不显著。(3)土壤速效钾、光照和土壤水分是关联乔木层和草本层的重要环境因子。研究认为,阔叶红松林下的乔木层通过影响光照、降水及枯落物的含量而间接影响草本层的多样性格局。

Influence of Overstory on Seasonal Variability of Understory Herbs in Primary Broad-leaved Korean Pine Forest of Changbai Mountain

The relationships among the vertical layers(tree-,shrub-and herb-layer) of a temperate forest and the power of environmental and spatial factors were investigated to explain the variation in two attributes of herb-layer:cover and diversity.In the 1.0 hm2 study site,a total of 100 1-m2 sub-plots(each 20 m×20 m has 4 1-m2 sub-plots) were monitored monthly from May to September in 2009.Among the environmental factors,tree-and shrub-layer related factors(density,canopy cover and Shannon-diversity),soil attributes(soil organic matter,available nitrogen,available phosphorus,available potassium,soil water and pH) and light regime(LAI,PPFD and canopy presence) were studied.The results showed that:(1)The herbaceous composition varied over the growing season,Anemone amurensis and Corydalis ambigua dominating in May;and spring bloomers,early-summer bloomers and late-summer bloomers co-occurring in June,leading to species richness the highest;summer bloomers reaching their flourishing season in July,Shannon diversity index is the highest,from August to September,summer bloomers withered gradually.(2)The relationship between diversity of the shrub-layer and diversity in the herb-layer was positive,although non-significant relationship was found between tree-layer and herb-layer,and density of shrub-layer positively correlated with cover of herb-layer in some months and negatively correlated with diversity of herb-layer.(3)The relationship between cover and diversity of herb-layer with soil attributes,light regime,tree-and shrub-layer showed that available potassium,light regime and soil water content were key factors for linking the two strata.It was concluded that the diversity pattern was influenced by light,throughfall and litter amounts,which fluctuate with canopy density.