浑善达克沙地榆树疏林幼苗更新空间格局  

Spatial pattern of seedling regeneration of Ulmus pumila woodland in the Otindag Sandland

作　　者：刘振[1] 董智[1] 李红丽[1] 李钢铁[2] 

机构地区：[1]山东省土壤侵蚀与生态修复重点实验室,泰山森林生态站,山东农业大学林学院,泰安271018 [2]内蒙古农业大学林学院,呼和浩特010019

出　　处：《生态学报》2013年第1期294-301,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金(31260202,30972420)

摘　　要：榆树疏林广泛分布于浑善达克沙地,是适应半干旱、半湿润气候的沙地植被类型。采用Ripley的K函数统计方法,分析了浑善达克沙地固定沙丘与丘间低地封育状态下的榆树幼苗空间分布及更新格局。结果表明:两种生境下榆树幼苗密度分别为88株/hm2和77株/hm2,丘间低地更适合幼苗的生长。固定沙丘和丘间低地榆树幼苗均呈聚集分布,但丘间低地的幼苗聚集强度更高。固定沙丘上榆树幼苗与成熟树种群在小尺度上呈负关联,而丘间低地幼苗与成熟树种群呈现较显著的正关联,但二者在大尺度上均无关联性。研究对揭示浑善达克沙地榆树幼苗分布、更新空间格局及其恢复保护具有重要意义。Ulmus pumila woodland widely distributing in the Otindag sandland, is a kind of sand vegetation types and adapted to seml-arid and semi-humid climate. It is a important local species to protect the ecosystem from desertification and defense the sandstorms. However, the seedlings and small trees are found to be few in natural ecosystem because of overgrazing and felling of great trees, which has seriously affected the distribution of U. pumila and regeneration of population. The aims of the study are to investigate the patterns for seedlings regeneration and the relationship between seedlings density and mature trees in two different habitats of fenced sites. With Ripley＇s K flmetion statistical method, the seedlings distribution and regeneration spatial pattern of Ulmus pumila were analyzed in fenced fixed sand dunes and lowland between dunes in the Otindag sandland. The results showed that the vegetation was regenerated very well in U. pumila sparse forest after exempt from the damage of animals and human being by fence. The coverage of shrubs and grasses is getting to about 60% of land area and the density of seedlings in the two different habitats was 88 seedlings per hectare and 77 seedlings per hectare. The seedlings with the same ages have a better growth conditions in lowland between dunes than those in fixed sand dunes. So the lowland between dunes is thought to be more suitable for seedlings development than the fixed sand dunes. The patterns for distributions of Ulmus pumila seedlings were aggregated distributions in two habitats in the area with radius being 0 to 50 m, but the aggregation intensity of seedlings was higher in lowland between dunes than the fixed sand dunes. The distribution patterns were affected by seed shadow, aggregation of seedlings, arid environmentand sand blown by the wind. The patterns for distribution 30 m, and random distribution with radius 〉 30 m. The of mature trees were aggregated soil water content and nutrients distributions in radius being 0 to were poorer in fixed

关 键 词：榆树疏林 幼苗更新 空间格局 空间关联 浑善达克沙地 

分 类 号：Q948[生物学—植物学]