高寒退化草地甘肃臭草种群分布格局及其对土壤水分的响应  

Melica przewalskyi population spatial pattern and response to soil moisture in degraded alpine grassland

作　　者：赵成章[1] 高福元[1] 石福习[1] 任珩[1] 盛亚萍[1] 

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070

出　　处：《生态学报》2011年第22期6688-6695,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(40971039);甘肃省科技支撑计划项目(1011FKCA157);甘肃省高校基本科研业务项目

摘　　要：植物种群对土壤水分响应的异质性是其格局形成和演变的环境基础。在石羊河上游的高寒草地,运用点格局分析法和群落调查法,研究了甘肃臭草单一优势种群斑块发育过程中的种群小尺度点格局和土壤水分特征。在4个发育阶段甘肃臭草种群的空间格局由聚集分布过渡为随即分布,土壤水分均呈现出从斑块中心向边缘增大的趋势;在斑块形成、扩散、稳定阶段,甘肃臭草斑块以类似"同心圆"的方式向周围土壤水分高的空间扩散,斑块半径由0.5m扩大至1.5m,种群的高度、密度、盖度由斑块中心向边缘递减;在衰退阶段斑块中心出现裸斑,种群的高度、密度、盖度以类似"同心圆"方式从中心向边缘逐层递增。在甘肃臭草斑块消长过程中,种群的分布格局和主要生物学特征与土壤水分之间不同阶段表现出不同的对应关系。Heterogeneity for response of plant populations to soil moisture is the environmental basis of their pattern formation and evolution.Melica przewalskyi is rhizomatous clonal grass with strange taste and not edible for grazing animals.With the infuluence of climate change and overgrazing,in the northern slope of Qilian Mountains,the Melica przewalskyi gradually formed a great number of single dominant species patches due to their biological characteristics and the adaptbility to adversity.Therefore,it is very important to understand their biologic characteristic of population distribution,distribution patterns and the soil moisture,and study the change of their population characteristic and soil moisture and the mechanism in the process of patch formation and recession.It is critical for revealing the plasticity mechanism of soil moisture and understanding the conspiracy relationship between the plant and the environment.The experiments were conducted in Yue ya ai grassland（38°47′15.8″N,99° 43′ 35.9″E）which is located in the upper reaches of Shiyang river in Sunan country Gansu province,China.In early August,2010,three different patches in the different stage,such as formation stage,diffusion stage,stable stage and recession stage respectively were selected in the study area.Square quad rat was made using red chopstick and sample line,the patches were places into quad rat,the quadrats center was founded by diagonal of 4 fixed vertice,thus red chopsticks were used to state the quadrat center position.sampling points were set from centre to four directions,thesampling point on each direction was selected at least 50 cm,adjacency grid sample in each point was used,the coverage was measured using the needle puncturing method in 50 cm × 50 cm sample box and tested the density of Melica przewalskyi in the same sample box by counting,measuring the natural height by tape repeat six,recording the relative position of each plant and determine the moisture content of 0—20 cm by oven drying method.the measure

关 键 词：甘肃臭草 斑块 点格局 土壤水分 石羊河上游 

分 类 号：S812[农业科学—草业科学]