荒漠绿洲额济纳胡杨与柽柳生态位分异过程研究

Study on ecological niche differentional process of Populus euphratica and Tamarix ramosissima in the Ejina oasis

以内蒙古额济纳绿洲分布的胡杨和柽柳为研究对象,通过建立二种植物生长的生态环境资源谱,对胡杨和柽柳实生苗、幼龄株、壮龄株和老龄株间进行X2、种间相遇率和联结指数等相关性分析,进行生态位宽度和重叠等种间和种内指标分析。分析结果表明:胡杨实生苗分布与胡杨幼龄林相关性显著,与胡杨壮龄林和老龄林相关性不显著,与柽柳实生苗分布相关性极显著,而与柽柳壮龄林和老龄林的分布相关性极不显著;二者生态位宽度和重叠程度研究表明,胡杨的实生苗与柽柳的实生苗生态位重叠程度高,柽柳的实生苗较胡杨的实生苗生态位较宽,由此胡杨和柽柳在资源利用方面具有一定的相似性,特别在二者早期,其重叠程度较高,但二者又在绿洲资源利用方面出现生态位分异,总的资源利用能力柽柳的生态位较胡杨较宽,说明柽柳在绿洲具更为广阔的分布和适应范围,胡杨适应于干旱但沙埋程度低、土壤可溶性盐和pH值较低、地下水埋深变化程度大和地表於泥变化较大的环境中,而柽柳适于生长于土壤湿润且沙埋程度高、土壤可溶性盐和pH值较高、地下水埋深变化程度小和地表於泥覆盖较轻的环境。

This paper made a study of Populus euphratica and Tamarix ramosissima distribuiion in Ejina oasis Inner Mongolie, by constructing resource spectrum of ecology and environment of the two plants, seedlings, juvenile bunches, adult bunches and senior bunches of Populus euphratica and Tamarix ramosissima were analysed through X^2, percentage co - occurrence and index association and so on, as well as index of niche breadth and niche overlap both interspecific and innerspecific. The results showed： Populus euphratica seedlings distributing and Populus euphratica juvenile bunche correlation was obvious, and Populus euphratica adult bunches and senior bunches correlation was not obvious, and Tamarix ramosissima seedlings distributing correlation was significant, and Tamarix ramosissima adult bunches and senior bunches correlation was not significant;study on niche breadth and niche overlap degree of the two plants was showed, seedlings of Populus euphratica and seedlings Tamarix ramosissima niche overlap degree was high, compared seedlings breadth of Populus euphratica seedlings breadth of Tamarix ramosissima was breadth, so Populus euphratica and Tamarix ramosissima had a certain comparability, in particular the two plants forepart, overlap degree was higher, but the two plants appeared niche different ional in oasis resource utilizing aspect, total resource utilizing ability, compared to Populus euphratica, Tamarix ramosissima was breadther, explained Tamarix ramosissima had wide distributing and adapted area, Populus euphratica adopt dry, but sand level was lower, soil solubility salt and pH values was lower, underground water tables change degree was obvious, and the earth ＇s surface silt change was outstanding, and Tamarix ramosissima like growth in soil wetness and high sand level area, soil solubility salt and pH values was higher, underground water tabless change degree was low,and silt bestrow of the earth＇s surface was light.