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Study in the mechanisms of species diversity in temperate hardwood forests and the restoration programs

温带阔叶林物种多样性机制及恢复方案研究

基本信息

批准号：
17380087
负责人：
SEIWA Kenji
金额：
$ 10.02万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

1. Analysis of the mechanisms of species-diversity in temperate deciduous broad-leaved forests.To investigate the relative importance of several biotic and abiotic environmental factors in determining species diversity, we investigated number of tree species, nutrient and water contents, light, coverage of understory vegetation (e.g., shrubs, dwarf bamboo), depth of leaf litter, and distance from conspecific adults in each of 600 individual quadrats (10 m x 10m) in a 6ha plot. In the analysis of sequential equation model (SEM), we found that distance of conspecific adult had a strong effects on abundance and diversity of tree species in seedling stage, but the effect decreased with increasing plant size. For saplings, the abundance was strongly affected by the abiotic factor such as nitrogen contents, light level and water availability. We also analyzed the causes of distance-dependent mortality of tree seedlings for 8 tree species in a hardwood forests by sowing thei seeds at two distances (i.e. far and near from conspecific adults). In the six of the eight species studied, we found distance and/or density-dependent seedling mortality which was mainly caused by pathogenic fungi. In the analysis of pathogenic fungi, we observed speies-preference, which preferentially attack conspecific seedlings compared to hetero-specific seedlings in Prunus grayana.2. Analysis of the recovery mechanisms of species diversity in coniferous plantation and the restoration programs. In the Criptomeria japonica plantation, heavy-thinning (67% of total basal area) had a greater effects on species diversity rather than light-thinning (33%). Distance from neibouring hardwood forests also strong effects on the species diversity.

1.温带落叶阔叶林物种多样性机制的分析为了探讨几个生物和非生物环境因子在决定物种多样性中的相对重要性，我们调查了树种数量、养分和水分含量、光照、林下植被覆盖度（例如，灌木，矮竹），落叶层深度，距离同种成年人在600个单独的样方（10米× 10米）在6公顷的地块。序列方程模型（SEM）分析发现，同种成虫的距离对苗期树种的丰富度和多样性有很大影响，但这种影响随着植株的增大而减小。对于幼树而言，氮素含量、光照水平和水分供应等非生物因子对多度有很大影响。本文还分析了阔叶林中8个树种在离同种成虫远、近两个距离播种时幼苗死亡率随距离变化的原因。在所研究的8个物种中，我们发现了距离和/或密度依赖的幼苗死亡率主要是由病原真菌引起的。在病原真菌的分析中，我们观察到了种的偏好性，相对于异源种，它们更倾向于攻击灰叶李的同种幼苗.针叶种植园物种多样性恢复机制分析及恢复方案。在日本柳杉种植园中，重度间伐（占总断面积的67%）比轻度间伐（占33%）对物种多样性的影响更大。与邻近阔叶林的距离对物种多样性也有显著影响。