摘要
生态位指一个种群占据的时空位置及其与相关种群之间的功能关系,密度是混生种群生态位发生变化的主要制约因子。2010年6—9月采用取代系列实验方法,在石羊河上游建立1年生人工混播草地,按燕麦(Avena sativa L.)与毛苕子(Vicia villosa Roth)的密度比例设置KY(1∶0)、A(8∶2)、B(6∶4)、C(5∶5)、D(4∶6)、E(2∶8)和KM(0∶1)7个密度组,研究了时间序列和密度梯度下燕麦与毛苕子生态位宽度和生态位重叠。结果表明:随着牧草的生长,5种混播草地中燕麦的生态位宽度逐渐减小,毛苕子的生态位宽度逐渐增加,燕麦与毛苕子的生态位重叠逐渐减小;混播草地中随着燕麦相对密度的减小和毛苕子相对密度的增加,燕麦的生态位宽度逐渐减小,毛苕子的生态位宽度逐渐增加,燕麦与毛苕子生态位重叠逐渐增加。牧草生长过程中密度制约使两种混播牧草应对种内、种间竞争的资源分配策略发生了调整,使种间关系和群落结构趋于稳定,形成一个相互稳定和相互影响的生态系统,实现了资源利用的最大化。
Niche refers to the space-time position of a population occupied and the functional relationship between it and related population. Niche including the requirements of the species on the environment and the influence of environment on species, it reflects the interaction between species and habitats quantitatively. Density-dependent is one of the important selecting pressure in nature, which makes the ground light competition between the neighborhood, by changing the number of populations within each plant availability of resources. Therefore, niche and density gradient are inseparable. To analyze the dynamic distribution rules of niche of mixed pasture from the density gradient is a significant approach to study the strategy of plant population ecological adaptation. Study sites are located in the HuangCheng town (37 ~58'26" N, 101 ~47' 34" E) which belongs to an upper reaches ShiYang River, SuNan county of alpine region (2530 m) lying in the north of Qilian Mountains. In replacement series experiments, the two species of planting densities were varied but the total density was held constantly. It was used to build mixed-seeding meadow ofAvena sativa L. and Vicia vilosa Roth in June 15,2010. This study set up seven grass-legume seeding ratios: KY(I:0), A (8:2), B (6:4), C (5:5), D (4:6), E (2:8), KM (0:1) which maintains about 300 plants total density constantly. There are total of 21 plots (2 m ×5 m) adopted randomized block arrangement with three replications. We recorded the phonological period, plant-height and branch (tiller) number of mixed grasses every 10 days started from July 17, 2010 to August 27, 2010. The sampling area is 50 cm × 50 cm in every plot, the mixed grasses were separately placed into an oven at 65℃ for 8 hours according to the block order until it reached the constant weight, thus the biomass were recorded respectively. Niche breadth is the metric of plants scale on environment and natural resource utilization, niche overlap occurs when two or more species to take possession of or make use of a certain kind of resources ( space, nutrient content, food, etc) together. Under density dependant, the niche breadth of Arena sativa L and Vicia vilosa Roth and the niche overlap of the two species transfer occurred to some extent during the growing period of grasses. The results showed that : ( 1 ) With the growth of forage, the density of Avena sativa L niche breadth decreases gradually and Vicia vilosa Roth showed a gradually increasing tendency in all group of mixed grassland, niche overlap of Vicia vilosa Roth and Avena sativa L. showed a reducing tendency. (2) In mixed grassland with Arena sativa L relative density decreases and the relative density increase of Vicia vilosa Roth.. Arena sativa L niche breadth decreases gradually and Vicia vilosa Roth showed a gradually increasing tendency, the niche overlap of Avena sativa L and Vicia vilosa Roth increases gradually. To sum up, in the course of grass growth, density dependence lead the resource allocation strategies of the two mixed pasture response to intraspecific, interspecific competition adjusted. Mixed pasture competition ability's change led to its niche in a certain degree of metastasis and differentiation, which made the relationship between species and community structure tend to be stable. To form a mutual stability and mutual influence ecological system, achieve maximum resource utilization.
出处
《生态学报》
CAS
CSCD
北大核心
2013年第17期5266-5273,共8页
Acta Ecologica Sinica
基金
国家自然科学基金项目(91125014
40971039)
甘肃省科技支撑计划项目(1011FKCA157)
甘肃省高校基本科研业务费项目
西北师范大学知识与科技创新工程项目(nwnu-KJCXGC-03-66)资助