额尔齐斯河河谷杨树天然林可分为欧洲黑杨林(Form. Populusnigra)、银白杨林(Form. ***)、银灰杨林(Form. ***)、额河杂交杨林(Form. P. jrtyschensis)、苦杨林(Form. P. laurifolia)、欧洲山杨林(Form. P. tremula)、胡杨林(Form. P. e...
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额尔齐斯河河谷杨树天然林可分为欧洲黑杨林(Form. Populusnigra)、银白杨林(Form. ***)、银灰杨林(Form. ***)、额河杂交杨林(Form. P. jrtyschensis)、苦杨林(Form. P. laurifolia)、欧洲山杨林(Form. P. tremula)、胡杨林(Form. P. euphratica)7个类型,本文在野外调查的基础上,对各类型的组成和一般特征进行了描述。额尔齐斯河平原河谷区4个主要杨树种群的大小结构和高度结构均表现出双峰型,具有丰富的一年生幼苗贮备,但是从Ⅰ级苗进入Ⅱ级苗的死亡率极高,没有幼树个体。由于生态系统的压力不断增大,致使绝大多数现存的杨树天然林群落大都变成了垂直结构单一、径级结构集中、伴生种类减少、不能完成更新的濒危生态系统。额尔齐斯河河谷杨树天然林的保育可以从流域整体管理、建立杨树基因库自然保护区、改变放牧打草方式及解决林牧用地矛盾、合理利用水资源等几个方面加以进行。
The study showed that at low elevation of Three Gorges Reservoir area,Pinus massoniana,Cupressus funebris and Cunninghamia lanceolata were the main coniferous forests,which were respectively divided into 14,9 and 5 co...
详细信息
The study showed that at low elevation of Three Gorges Reservoir area,Pinus massoniana,Cupressus funebris and Cunninghamia lanceolata were the main coniferous forests,which were respectively divided into 14,9 and 5 community types based on field *** whole trend of their species richness index,species diversity index and species evenness index was that shrub layer and herb layer were larger than tree *** diversity indices had no obvious trend along the low elevation gradients,which was probably relevant to the high intensity of human activities in the area.
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