摘要
如何用环境属性空间异质性解释植被动态是生态学中的一个重要问题。在该项研究中,选择油蒿(Artemisia ordosica)演替群落为研究对象,在小区面积相同、样方数目和面积相同的条件下,将统计学方法和地统计学方法结合起来,讨论分析了土壤湿度和有机质与油蒿和冷蒿(A.frigida)密度空间异质性变化趋势的相关性,结果表明:在块尺度上(80m×80m),油蒿和冷蒿密度的空间异质性都与土壤湿度的空间异质性有关,其中与冷蒿密度呈现为单调递增,与油蒿密度不呈单调变化,说明土壤湿度与油蒿密度空间异质性的相关性已逐渐减弱,但与耐旱的冷蒿依然较强;土壤有机质的空间异质性也与两种植物密度的空间异质性有关,其中与油蒿密度呈现为单调递增,与冷蒿密度不呈单调变化,说明油蒿的长期定居增加了土壤有机质含量,并促进了冷蒿的侵入;进一步分析表明,该群落中油蒿种群和冷蒿种群均呈集群分布,这种集群分布使得油蒿或冷蒿的密度与土壤湿度或有机质空间异质性之间的关系增强,这从一定程度上说明了冷蒿和油蒿之间的竞争替代关系。因而,土壤空间异质性的变化是半荒漠带油蒿群落演替的基础。
Aims Using environmental spatial heterogeneity to explain the heterogeneity of vegetation is an important issue in ecology.We approached relationships between the spatial heterogeneity of soil moisture,organic matter and densities of Artemisia ordosica and A.frigida in a successional community of A.ordosica.Our objective was to discuss stability mechanisms of the plant community based on changes in spatial heterogeneity.Methods The study area is located at Tengri Desert（arid zone）,which belongs to Alashan League of Inner Mongolia.Our sample plot was 80 m× 80 m,which contained 400 quadrats（4 m×4 m）.In every quadrat,we determined soil moisture at 40 cm depth（oven-drying method）and soil organic matter at 0-5 cm top soil（potassium dichromate volumetric method）,and recorded density of A.ordosica and A.frigida.We analyzed densities in response to the spatial heterogeneity of soil moisture and organic matter using statistics and geostatistics.Important findings The spatial heterogeneities of densities of A.ordosica and A.frigida were related to soil moisture and organic matter at the plot-scale（80 m×80 m）.There were a significant positive linear correlation between the heterogeneities of the density of A.frigida and moisture and a significant positive power cortelation between heterogeneties of the density of A.ordosica and soil organic matter.We suggest that A.ordosica enriched the content of organic matter,thus promoting establishment of A.frigida.Both A.frigida and A.ordosica had clumped distributions,which enhanced soil spatial heterogeneity.Findings indicate a competitive displacement relationship between the two species.Thus,changes of soil spatial heterogeneity are factors in A.ordosica community succession in semi-desert zone.
出处
《植物生态学报》
CAS
CSCD
北大核心
2007年第6期1145-1153,共9页
Chinese Journal of Plant Ecology
基金
国家973项目(G2007CB106802)
关键词
油蒿
土壤湿度
有机质
空间异质性
群落演替
Artemisia ordosica,soil moisture,organic matter,spatial heterogeneity,succession of community
