水分条件变化对哀牢山亚热带常绿阔叶林林下幼苗死亡率的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 水分条件变化对哀牢山亚热带常绿阔叶林林下幼苗死亡率的影响 DOI: 10.5846/stxb201306101572 作者: 作者单位: 中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;哈佛大学,中国科学院西双版纳热带植物园,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站,中国科学院西双版纳热带植物园;中国科学院哀牢山亚热带森林生态系统研站 作者简介: 通讯作者: 中图分类号: 基金项目: 中国科学院哀牢山亚热带森林生态系统研究站研究基金 The influence of changes in water availability on seedling mortality of a subtropical evergreen broadleaf forest on Ailao Mountain Author: Affiliation: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences; Ailaoshan Station for Subtropical Forest Ecosystem Studies, Chinese Academy of Sciences,Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences; Harvard University,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨环境水分条件变化对亚热带森林林下乔木幼苗动态的影响,以及木材密度和幼苗在干旱中死亡率的关系,研究了哀牢山常绿阔叶林2005-2011年的总体和主要树种幼苗(黄心树、多果新木姜子、多花山矾、鸭公树和大花八角)的死亡率,并分析了幼苗死亡率和旱季幼苗根系所在土层土壤质量含水量、旱季降水量、旱季降水日数以及木材密度的关系。结果表明:1)幼苗死亡率与旱季降水日数、旱季浅层土壤平均质量含水量有显著的负相关关系,和旱季降水量无显著相关性;2)总幼苗及5种乔木幼苗的死亡率均在2010年(西南干旱)达到有观测以来最高,是2009年的2-10倍,其中多花山矾、黄心树幼苗的死亡率最高,大花八角幼苗的死亡率最低;3)在种间,幼苗2010年干旱中的死亡率和木材密度显著正相关,即木材密度较大的物种幼苗死亡率更高。研究表明林下幼苗由于根系较浅,对降雨变化较为敏感,因而受到了这次干旱的较大影响。由于木材密度较低的树种在干旱中有较低的死亡率,干旱频度和强度的增加可能使低木材密度幼苗的丰富度增加,森林的组成也将受到影响。 Abstract:In order to understand the influence of changes in water availability on the seedling dynamics of subtropical forests and the relationship between wood density and seedling mortality during a prolonged drought period, we studied seedling mortality patterns across all species and of 5 common tree species from an evergreen broadleaf forest on Ailao Mountain, southwest (SW) China from 2005 to 2011. The five tree species studied were Machilus bombycina, Neolitsea polycarpa, Symplocos ramosissima, Neolitsea chuii, and Illicium macranthum. The relationships between seedling mortality and rainy days, rainfall, soil water mass content (0-20 cm) during the dry season, and wood density were also analyzed. Our results showed that 1) Seedling mortality was negatively correlated with number of rainy days in the dry season and dry season soil water mass content, but not with total dry season rainfall; 2) The seedling mortalities of all species as a whole and of each of the 5 species studied reached a historical maximum in the 2010 SW China extreme drought, which were 2 to 10 times more intense than for 2009 (Machilus bombycina and Symplocos ramosissima had the highest seedling mortalities while Illicium macranthum had the lowest in 2010); 3) Across species, the seedling mortality in the 2010 drought was positively correlated with species-specific wood densities; species with higher wood densities had higher seedling mortalities. Previous studies have shown that trees in this forest did not experience severe drought stress during the 2010 SW China drought. However, the present study suggests that the seedlings were severely influenced by the rainfall anomaly during the 2010 dry season, probably owing to their shallow rooting depths and consequently high sensitivities to changes in rainfall. Additionally, because of the lower seedling mortalities in lower wood density species, the potential increase in drought frequency and severity in the future may increase the relative abundance of low wood density species, which may potentially lead to changes in forest species composition. 参考文献 相似文献 引证文献