摘要
光照和水分对林下植物的分布具有重要作用,浅根系的地生蕨类植物对光照和水分比较敏感,可以作为林下生境变化的指针。研究选取热带雨林、喀斯特森林以及人工橡胶林3种不同的林型,研究林冠开阔度对地生蕨类生物多样性的影响。采用2.5 m×1 m的样方,每个样方10 m的间距比较地生蕨类生物多样性。结果显示,热带雨林和喀斯特森林具有类似的地生蕨类多样性(2.52±1.68,2.47±0.68),两者的多样性指数明显高于人工橡胶林(1.47±0.72,P<0.000 1)。但是热带雨林具有更多的个体总数(2 769)和更高的物种丰富度(3.29±0.04),而同样指标喀斯特森林(319,2.94±0.05)和人工橡胶林(175,2.39±0.09)则相对较低。另外,随着林冠开阔度增加,地生蕨类多样性和丰富度急剧降低。地生蕨类的分布状态取决于上层的林冠开阔度,光照对地生蕨类的生物多样性具有决定性的影响,相对较弱的地表根系缺乏足够的吸水能力,不足以应付强光照带来的蒸腾损失。因此绝大多数的地生蕨类植物在林下空地间采取了避退策略。由于相对较低的林冠开阔度,使得喀斯特森林保存了相对较高的林下生物多样性,它具有重要的生态价值而必须加以保护。
The biodiversity under forest in different ecotypes is important in ecology research. Shaded plants are influenced by the sunlight and moisture. A research focused on ground ferns was carried out in three forest types,namely rainforest,karst forest and rubber plantations which located in or around the Xishuangbanna Tropical Botanical Garden,Yunnan,China. A 2. 5m × 1m plot in 10 m intervals was applied to calculate the diversity and abundance of all ground ferns. The results showed that a similar diverse index existed in rainforest（ 2. 52 ± 1. 68） and karst forest（ 2. 47 ± 0. 68）,which were obviously higher than that in the rubber plantations（ 1. 47 ± 0. 72,P 0. 000 1）. The abundance and richness in rainforest（ 2769,3. 29 ± 0. 04） were higher than that in the other two. Furthermore,the probability of finding ground ferns decreased quickly with increasing of canopy openness. The root system of ferns could not support the plant very well under shining light because the weak vascular could not get enough water,which led to an imbalance with the evaporation lose. It was like a back off strategy popularly adopted by most of ground fern species. In a word,the canopy openness played a fundamental role on the diversity and distribution of ground ferns. Karst forest kept relative high biodiversity under the low canopy openness,which proved ecologically value and should be taken to conserve this kind of forest.
出处
《林业科技开发》
北大核心
2015年第2期23-27,共5页
China Forestry Science and Technology
基金
中国科学院战略生物资源技术支撑体系专项(CZBZX-1)
