草果种植对植物多样性的影响

Influence of plant diversity by Amomum tsao-ko(Zingiberaceae)plantation

关键词:  草果  天然林  植物多样性  可持续性

Key words:  Amomum tsao-ko  natural forest  plant diversity  sustainability

摘要:

从林下植物物种数、株数、乔木盖度、多样性指数等方面,对种植草果的天然林片断与未种植草果的天然林地的植物进行调查与比较分析,结果发现:(1)不同草果种植时间乔灌木层的盖度在20.0%～50.0%之间变动;(2)随着种植时间的延长,乔灌层植物株数明显下降,乔灌层物种数趋向单一,主要保留旱冬瓜作为草果的遮荫树种;(3)天然林的草本层物种数为13种,草果种植到80年后草本层物种数只有8种; 草本层株数在草果种植5年后在48～285株间的波动,远低于种植初期;(4)乔灌层Shannon-Wiener指数在草果种植30年降低到0,但草本层Simpson指数在种植草果半年至一年期间多样性指数较低为0.2266～0.33990。虽然5年后稳定在0.4351～0.8062,但普遍低于天然林(0.7681)。为了维持天然林的可持续性和稳定性,建议草果栽培在人工林下进行。

Abstract:

Species number,individual number,coverage of trees and biodiversity index of plants in forest planting with Amomum tsao-ko and natural forest were investigated and compared. The result showed that:(1)the coverage of overstorey canopy(including arbor and shrub crown)was fluctuated between 20.0 and 50.0% in different growing phases of A.tsao-ko plantation;(2)with aging A.tsao-ko plantation,individual number of arbors and shrubs was decreased gradually,the species number also inclined to single,Alnus nepalensis was maintained as a great shading species in the A.tsao-ko plantation;(3)the herbaceous species in the natural forest was 13,and then decreased into 8 when the plantation time arrived 80 years; individual number of herbaceous plants was varied between 48 and 285 after the plantation of A.tsao-ko exceeded 5a,which was lower than the number in the beginning time of A.tsao-ko plantation;(4)the Shannon-Wiener index of arbors and shrubs was reduced to 0 at the plantation time of 30a,the Simpson index of herbaceous species was varied 0.2266-0.3399 between the plantation time from 0.5a to 1a. Although this index became stable at 0.4351-0.8062 after 5a plantation,they were all lower than the natural forest(0.7681). Therefore,in order to maintain the sustainability and stability of natural forests,A.tsao-ko was suggested to plant under the artificial forests.