不同放牧强度下典型草原植被空间分异过程研究

The research of space differentiation of vegetation under different grazing intensity on typical steppe.Overgrazing causes patch of soil nutrient resources, and plant community appears space differentiation in the process influenced directly or indirectly. The composition, properties and structure of grassland patches can reflect the succession stage, driving force and trend of grassland to a certain extent. It is of great significance of cognize and confirm degradation degree of grassland. Therefore, research the effect of grazing on grassland patches and the environmental effects of the patches, explore the means and methods of grazing regulation and improvement of grassland utilization is the important scientific issue of grazing ecology. The research scan the grassland patches by Li-Dar measurement system on 2 grazing platforms (conducted grazing experiment for 2 years and 10 years) of typical steppe, defining the standard of grassland patches by combining with ground survey of the relevant indicators of vegetation-soil system, parsing the synchronism/ asynchronism characteristic of the relevant indicators of vegetation-soil system under grazing by different time series; thoroughly and carefully research will done with the influence of animal behavior on formation of patches by animal behavior monitoring method, in order to deeply explain the mechanism of the formation of patches and establish a grazing optimization model on typical steppe.

过度放牧导致土壤养分斑块化，同时植物群落在此过程中也受到直接或间接的影响出现空间异质性。草地斑块的组成、性状和格局在一定程度上反映了草地现时演替阶段、驱动力及其趋势，对于认知和确定草地的退化程度具有重要意义。因此，研究放牧对草地斑块形成的影响及斑块化所产生的环境效应，从而探究放牧干扰调控、提高草地利用率的方法和途径是目前放牧生态学亟待解决的重大科学命题。以往的草地斑块化研究大多采用传统的地面植被样方-土壤调查方法，很难达到斑块化分布研究所需的数字化统计需求。本研究拟在典型草原2个（实验进行2年和10年）放牧强度研究平台，采用目前先进的无人机和地面基站激光雷达测量系统对植被斑块进行扫描，结合植被-土壤系统相关指标地面调查，界定草地斑块划分标准，解析不同时间序列放牧驱动下植被-土壤相关参数变化的同/异步特征；并采用动物牧食行为跟踪监测方法、从动物牧食行为对斑块化形成的影响进行深入细致的研究。

研究基于典型草原不同放牧强度平台对植被、土壤及草地斑块化相关指数进行分析研究。结果表明，适度放牧利用有利于草地生态系统生态和生产功能的维持，从草地功能性状连续观测指标（建群种羊草和针茅植物生物量、牧草再生量、群落净生产力水平、补偿性生长量、群落多样性 Shannon-wiener 指数和 Simpson 指数、土壤理化性质）以及草地斑块分布特征来看，适度放牧利用提高了草地的利用效率，而且有利于激发草地植被生长的活力，实现超补偿性生长，对草地生态系统具有非常重要的作用。因此放牧利用管理应该在适应性管理理论与方法的指导下制定合理的放牧制度和高效的调控策略，而试验研究得到的这一阈值仍需要进一步验证和优化。