Department of Ecology and Natural Resource Management, The Norwegian University of Life Sciences, As, Norway.
Oecologia. 2011 Jan;165(1):161-8. doi: 10.1007/s00442-010-1707-0. Epub 2010 Jul 6.
Human disturbance may change dominance hierarchies of plant communities, and may cause substantial changes in biotic environmental conditions if the new dominant species have properties that differ from the previous dominant species. We examined the effects of bamboos (Bambusa tulda and Cephalostachyum pergracile) and their litter on the overall woody seedling abundance, species richness and diversity in a mixed deciduous forest in northeastern Thailand. These bamboo species are gaining dominance after human disturbance. Our results show that seedling abundance and species richness were reduced by bamboo canopies. Seedling abundance and species diversity under bamboo canopies were affected by bamboo litter, whereas seedling abundance and species diversity outside bamboo canopies did not respond to the mixed-tree litter manipulation. Removal of bamboo litter increased seedling abundance and species diversity. However, bamboo litter addition did not affect seedling abundance or species diversity compared to either control or litter removal. This may indicate that the effect of natural amount of bamboo litter is as high as for litter addition in preventing seedling establishment by woody species and hence in minimizing resource competition. We conclude that undergrowth bamboos and their litter affect tree seedling regeneration differently from mixed-tree litter, causing changes in plant community composition and species diversity. Increased human disturbance, causing a shift in dominance structure of these forests, may result in a concomitant reduction in their overall woody species abundance, richness and diversity. Thus, management of bamboos by controlling their distribution in areas of high bamboo density can be an important forest restoration method.
人类干扰可能会改变植物群落的优势等级，如果新的优势物种具有与先前优势物种不同的特性，可能会导致生物环境条件发生重大变化。我们研究了在泰国东北部的一个混交落叶林中，竹子（Bambusa tulda 和 Cephalostachyum pergracile）及其凋落物对整体木本幼苗丰度、物种丰富度和多样性的影响。这些竹子物种在人类干扰后正在获得优势。我们的结果表明，竹林冠层减少了幼苗的丰度和物种丰富度。竹林冠层下的幼苗丰度和物种多样性受到竹子凋落物的影响，而竹林冠层外的幼苗丰度和物种多样性则不受混交树凋落物处理的影响。去除竹子凋落物会增加幼苗的丰度和物种多样性。然而，与对照或凋落物去除相比，添加竹子凋落物对幼苗丰度或物种多样性没有影响。这可能表明，天然数量的竹子凋落物的影响与添加凋落物一样高，可以防止木本物种幼苗的建立，从而最小化资源竞争。我们的结论是，林下竹子及其凋落物对树木幼苗再生的影响与混交树凋落物不同，导致植物群落组成和物种多样性发生变化。人类干扰的增加导致这些森林优势结构的转变，可能会导致其整体木本物种丰度、丰富度和多样性的相应减少。因此，通过控制竹林在高竹林密度区域的分布来管理竹子，可以成为一种重要的森林恢复方法。
