气候因子和土壤养分对荒漠草原物种多样性、生产力及其关系的影响

发布时间：2018-08-26 14:38

【摘要】：环境因子对物种多样性和生态系统功能的影响是生态学领域的核心问题之一。内蒙古荒漠草原是内蒙古草地生态系统的重要组成部分,开展荒漠草原物种多样性与生态系统功能及其与环境因子之间关系的研究十分必要。本文选择了内蒙古荒漠草原80个具有代表性的典型样地,通过实地的植被和土壤调查,获取了群落物种多样性、生产力和土壤养分数据(全氮、全磷、速效氮、速效磷、有机碳)。结合气候资料探讨了年平均降水量、年平均温度、干燥指数与土壤养分对荒漠草原物种多样性和生产力的影响,确定了影响多样性和生产力的主导环境因子,分析了荒漠草原物种多样性与生产力的关系。得到以下主要结论：(1)内蒙古荒漠草原土壤养分含量匮乏,土壤肥力处于较低水平。全氮含量为0.116%,属于三级中等水平；全磷含量为0.036%,属于六级极度缺乏等级；速效氮含量为45ppm,属五级很匮乏等级；有机碳含量为1.298%,属于四级缺乏等级；只有速效磷含量为29ppm,属于二级相对丰富状态。(2)内蒙古荒漠草原物种多样性和生产力受气候因子的影响显著。物种多样性和生产力与年平均降水量呈现显著正相关,与年平均温度呈负相关,与干燥指数呈显著正相关。干燥指数同物种丰富度和初级生产力的相关性最高。(3)不同土壤养分对内蒙古荒漠草原物种多样性和生产力的影响存在差异,土壤氮素对荒漠草原物种多样性和生产力具有重要影响。物种多样性随速效氮含量的增加而升高,随全磷含量的增加而降低。生产力与土壤有机碳、全氮和速效氮含量呈显著的线性正相关。(4)相对于土壤养分而言,水热因子是影响内蒙古荒漠草原区物种多样性和生产力的主要环境因子。表征水热综合因子的干燥指数作为解释物种丰富度的第一因子和解释群落生产力的唯一最重要的因子被引入多元逐步回归模型,而且都呈现出显著的相关关系；年平均温度作为解释Shannon-wiener指数的第一因子被引入模型。(5)内蒙古荒漠草原物种多样性与群落初级生产力之间呈现线性正相关关系,二者关系受到了气候因子和土壤养分的制约。
[Abstract]:The influence of environmental factors on species diversity and ecosystem function is one of the core problems in ecology. Desert steppe in Inner Mongolia is an important part of grassland ecosystem in Inner Mongolia. It is necessary to study the relationship between species diversity, ecosystem function and environmental factors in desert steppe. In this paper, 80 representative typical plots of Inner Mongolia desert steppe were selected, and the community species diversity, productivity and soil nutrient data (total nitrogen, total phosphorus, available nitrogen, available phosphorus, available phosphorus) were obtained through field vegetation and soil survey. Organic carbon The effects of annual average precipitation, annual average temperature, drying index and soil nutrients on species diversity and productivity of desert steppe were discussed, and the dominant environmental factors affecting diversity and productivity were determined. The relationship between species diversity and productivity in desert steppe was analyzed. The main conclusions are as follows: (1) the soil nutrient content of Inner Mongolia desert steppe is deficient and the soil fertility is low. The total nitrogen content is 0.116, which belongs to the middle level of three levels; the total phosphorus content is 0.036, which belongs to the extreme lack grade of the sixth grade; the available nitrogen content is 45 ppm, which belongs to the five levels very deficient grade; the organic carbon content is 1.298, belonging to the fourth grade lack grade; Only the available phosphorus content was 29ppm, which belonged to the second order relatively rich state. (2) the species diversity and productivity of Inner Mongolia desert steppe were significantly affected by climatic factors. Species diversity and productivity were positively correlated with annual average precipitation, negatively correlated with annual mean temperature, and positively correlated with drying index. Drying index had the highest correlation with species richness and primary productivity. (3) the effects of different soil nutrients on species diversity and productivity in Inner Mongolia desert steppe were different. Soil nitrogen plays an important role in species diversity and productivity of desert steppe. Species diversity increased with the increase of available nitrogen content and decreased with the increase of total phosphorus content. There was a significant linear positive correlation between soil productivity and soil organic carbon, total nitrogen and available nitrogen content. (4) compared with soil nutrients, water and heat factors were the main environmental factors affecting species diversity and productivity in desert grassland of Inner Mongolia. As the first factor to explain the species richness and the single most important factor to explain the community productivity, the drying index which characterizes the water and heat synthesis factors was introduced into the multivariate stepwise regression model, and there was a significant correlation between them. The annual mean temperature was introduced into the model as the first factor to explain the Shannon-wiener index. (5) there was a linear positive correlation between species diversity and primary productivity of the community in Inner Mongolia desert steppe. The relationship between them was restricted by climate factors and soil nutrients.
【学位授予单位】：内蒙古大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812

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