植物生态学报 ›› 2011, Vol. 35 ›› Issue (10): 1038-1049.DOI: 10.3724/SP.J.1258.2011.01038

• 研究论文 • 上一篇    下一篇

喀斯特森林土壤养分的空间异质性及其对树种分布的影响

张忠华1,2, 胡刚1, 祝介东3,4, 倪健2,3,*()   

  1. 1广西师范学院化学与生命科学学院, 南宁 530001
    2华东师范大学环境科学系, 上海 200062
    3中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
    4中国科学院研究生院, 北京 100049
  • 收稿日期:2010-12-06 接受日期:2011-01-31 出版日期:2011-12-06 发布日期:2011-11-07
  • 通讯作者: 倪健
  • 作者简介:* (E-mail: jni@ibcas.ac.cn)

Spatial heterogeneity of soil nutrients and its impact on tree species distribution in a karst forest of Southwest China

ZHANG Zhong-Hua1,2, HU Gang1, ZHU Jie-Dong3,4, NI Jian2,3,*()   

  1. 1School of Chemistry and Life Sciences, Guangxi Teachers Education University, Nanning, 530001, China
    2Department of Environmental Science, East China Normal University, Shanghai 200062, China
    3State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    4Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2010-12-06 Accepted:2011-01-31 Online:2011-12-06 Published:2011-11-07
  • Contact: NI Jian

摘要:

以贵州省茂兰国家级自然保护区喀斯特峰丛坡面中原生性常绿落叶阔叶混交林为研究对象, 以建立的100 m × 100 m样地的群落学调查数据和基于网格取样的土壤养分数据为基础, 采用半方差函数、Kriging空间插值和典范对应分析(canonical correspondence analysis, CCA)等方法分析了喀斯特森林土壤养分的空间异质性特征及其对树种分布的影响。结果表明: 喀斯特峰丛坡面土壤养分的变异系数为10%-80%, 变异程度中等。各土壤养分指标均具有良好的空间自相关性, 其中全磷(TP)、全钾(TK)、全镁(TMg)和pH值呈强烈的空间自相关, 而有机质(OM)、全钙(TCa)、速效磷(AP)和速效钾(AK)为中等程度的空间自相关; TCa的空间变异尺度最小, OM、TP和AK的空间变异尺度较大。土壤TK、TP、TCa、TMg、AP和pH值等随着海拔高度的增加和岩石裸露率的降低而逐渐减少, OM则随着海拔高度的增加而趋于增加, 这表明喀斯特地形因子是造成土壤养分空间变异的重要因素。CCA分析表明, 土壤养分的空间变异性显著影响到群落中树种的组成与空间分布, 其中TK、TMg、pH值、TCa和OM的影响最为明显, 体现了不同植物在土壤资源利用上的生态位分化, 这有助于喀斯特森林群落物种多样性与稳定性的维持。

关键词: 典范对应分析, 喀斯特森林, 茂兰国家级自然保护区, 半方差函数, 土壤养分, 空间异质性

Abstract:

Aims Studies of spatial variability of soil nutrients are valuable not only to the understanding of formation, structure, and function of soils, but also for understanding soil-plant associations and mechanisms of plant species coexistence. However, little is known about the spatial heterogeneity of soil nutrients in karst forest. Our objectives were to 1) characterize the spatial heterogeneity of soil nutrients in a karst forest, 2) examine correlations between spatial distribution of soil nutrients and local topographic variables and 3) assess the influence of soil nutrients on spatial distributions of tree species.
Methods A 100 m × 100 m forest plot was established on a hillside in a karst area in Maolan National Nature Reserve, Guizhou Province, Southwest China. All woody species with a diameter at breast height ≥1 cm were identified and surveyed. Surface soil samples (0-10 cm) were collected from a grid of 10 m × 10 m for the analysis of soil nutrients. The spatial variability of soil nutrients and its impact on distributions of tree species were analyzed by using geo-statistic methods (semivariogram and Kriging interpolation) and ordination (canonical correspondence analysis, CCA).
Important findings The coefficient of variation for soil nutrients ranges from 10% to 80%, and can be considered relatively moderate. Total phosphorus (TP), total potassium (TK), total magnesium (TMg) and pH show strong spatial autocorrelation, while organic matter (OM), total calcium (TCa), available phosphorus (AP) and available potassium (AK) show moderate spatial autocorrelation. The variation range of soil TCa is the smallest (56.2 m) and those of OM, TP and AK are larger. Spatial distribution of TP, TK, TCa, TMg, AP and pH decreases with increasing elevation and decreasing cover of bare rock, while OM increases with increasing elevation, which indicated that the spatial distributions and variability of soil nutrients were mainly affected by topographic factors and habitat characteristics (especially elevation, slope, slope aspect, slope location and cover of bare rock). CCA indicated that the spatial distribution of soil nutrients, especially TK, TMg, pH, TCa and OM, has an important impact on tree species composition and distribution, and thus showed a prevalence of soil resource-based niche differentiation among tree species. Our results suggested high spatial variability of soil nutrients contributes to promoting maintenance of species diversity and the stability of karst forest communities.

Key words: canonical respondence analysis (CCA), karst forest, Maolan National Nature Reserve, semivariogram, soil nutrient, spatial heterogeneity