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CAS Workshop on Ecosystem Succession Theory and Practice of Ecological Restoration 东川干热退化山地不同植被恢复方式对当地物种组成与结构的影响 刘文耀
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张彦东 （中国科学院西双版纳热带植物园，昆明650223） 摘要：中国西南地区的江河沿线及其支流地带，分布着大量的干热河谷区域，由于其相对的农业优势，这些地方人为活动较早且强度大，留下了大量的退化山地。长期以来，已引进大量植物品种对该区域进行地表覆盖的恢复工作。但这些引进种对当地植被及整个系统的影响研究则未见报道。本研究探讨了云南东北部东川小江流域的干热河谷区域的严重砂石化土地上两种典型固氮树种恢复方式对当地系统的影响。研究表明不同恢复方式对地表植被物种组成与密度和土壤种子库有明显的影响。采用新银合欢（Leucaena glauca）的恢复方式，使得大量当地物种，特别是一些阳性物种从地表植被中消失或生长受到抑制，生物多样性降低。参照稀灌草丛设计的马桑（Coriaria sinica）恢复方式对原有草坡地物种的数量和多样性影响不大。两种恢复方式的土壤种子库的萌发试验表明，合欢恢复方式（L. glauca）使土壤种子库的种子密度增大，同时土壤中种子优势成分由原来的耐旱型种类转变为耐荫型种类；马桑（C. sinica）恢复降低了种子密度并减少了种子种类，但其优势成分的组成未发生明显的改变。一些当地物种仍存在于受影响后的地表植被和种子库中，使改变后的系统与当地草坡间存在着一定程度的相似性，但这种相似性随恢复的变化在地表植被与土壤种子库组成方面表现为随干扰与恢复变化的非同步性。 关键词：干热退化山地；植被恢复；当地物种；东川 Effect of different rehabilitations on composition
of native species on degraded mountain area of dry-hot valley,
Dongchuan, Yunnan Liu Wenyao Shen
Youxin Zhang Yandong
(Xishuangbanna
Tropical Botanical Garden, Chinese Academy of Sciences, Kunming
650223, China) Abstract: There
is a phenomenon called “valley bottom dryness” along rivers and
their tributaries in southwest China. In these kinds of valley,
human activities started early and strong due to their comparative
advantages in agriculture development, and therefore a lot of
degraded land systems were left behind this development. During the
past, a lot of tree and shrub species were introduced to these areas
to serve economic as well as ecological purpose, but there was no
research on the effect on local species and vegetation. In this
study, the effects of rehabilitation with two typical N-fixing
species on composition and structure of local species on degraded
mountain area were studied at dry-hot valley of Xiaojiang River,
Dongchuan district, Yunnan Province. The results showed that there
were obvious effects of different rehabilitation ways on the
standing vegetation and soil seed banks. A
lot of native species, especially some non-shade tolerant species
were excluded or restrained at the standing vegetation after rehabilitation
with Leucaena
glauca. The biodiversity index
of L. glauce community decreased in comparison with local grass-shrub
community. There were not great influences on composition of native
grass species at rehabilitated area (grass
dotted with scattered shrub or tree) with
Coriaria sinica. Density of seed in soil increased after
rehabilitated with L. glauca, and the composition of seeds had changed from dryness tolerant
species into shade-tolerant domination. Rehabilitation with C. sinica reduced seed density but did not change the original
composition so much. Some of native species still remained at the
rehabilitated ecosystems both at the stand vegetation and soil seed
bank composition. As a result, there was similarity between
rehabilitated ecosystem and local grassland even the similarity
index differed among standing vegetation, among soil seed banks and
between vegetation and soil seed banks. Key word: degraded mountain area; dry-hot valley; rehabilitation;
native species; Dongchuan Area
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