【作者】 陈宝瑞；

【导师】 辛晓平；

【作者基本信息】 中国农业科学院 ， 草地资源利用与保护， 2010， 博士

【摘要】 不同尺度上生态学系统的格局和生态学过程以及二者之间的关系是生态学的中心问题之一,干扰作为生态学过程的一部分,是空间异质性的主要来源之一,能显著地改变不同尺度的生态格局和过程,使生态学系统的结构和功能发生明显移位。呼伦贝尔草原独特的生态系统特征、保存相对完好的自然环境、丰富的景观生态类型和生物多样性、相对先进和集约生产经营方式,是开展草甸草原生态系统自然生态格局与过程研究、不同尺度格局与过程对人为干扰响应最理想的综合生态单元。系统深入地研究呼伦贝尔草原多尺度植被格局及其对干扰的响应有助于拓展植被生态学研究领域,可为草地资源利用与保护,合理地制定生态系统管理方案提供科学依据,并对退化草地的恢复重建和畜牧业发展区划的制定具有重要的实践意义。本文以呼伦贝尔草原为研究对象,利用景观、群落和种群3个尺度的样方调查数据和群落格局数据,采用多样性分析方法和点格局分析、分形分析、回归分析等格局分析方法,分析不同尺度植被空间格局与过程的相互作用关系及其对干扰的响应,主要得出如下结论:本文第一部分分析了景观尺度生物多样性与生产力格局。结果表明:呼伦贝尔草原不存在特有种和古老种,研究区共登记维管植物135种,分属28科、93属,建群种区系地理成分未发生明显变化。物种丰富度和地上生物量均随着经度梯度的增加而增加,表现出很好的水分梯度。生物多样性和地上生物量表现为单峰曲线关系。第二部分研究了群落尺度群丛斑块的空间格局。结果表明:研究区共登记维管植物92种,分属22科、66属。干扰方式的不同,群落结构和功能各项指标显著不同,样地处在不同的演替阶段。斑块数目在不同样地间显著不同与样地内群丛的群落生态位和演替阶段有关。表征斑块面积的分布的Korcak相对斑块化指数,其数值的高低不仅与斑块面积大小有关,斑块的均匀度对其也有较大影响。边长-面积指数表征斑块边界的复杂性,其大小受到群丛斑块的群落生态位和物种扩散方式的影响。群落的稳定性不仅与演替方向和演替阶段有关,与演替的起始位置和优势种的特有属性(繁殖方式)有着某种必然的联系。第三部分分析了种群尺度的种群格局。结果表明:物种基盖度的变化与种群点格局、种间关联不存在一致的相关关系。在不同样地、同一样地不同处理之间种群格局的无显著差异性及同一样地同种处理的三个样方间的不一致性,主要与群落的自身属性、微生境的变化及干扰强度有关。在特定尺度下的种群空间分布格局取决于物种的生活型类型。种群分布格局的类型与物种本身的特性、物种的群落生态位、微生境的差异、物种之间相互作用、外界干扰及物种的抗干扰能力等诸多因素均有关,只是在不同的样地和不同的干扰方式下,对种群格局起控制作用的因素不同而已。从植物本身的角度分析,草本植物发生相互作用的距离可能在厘米级范围内。空间结构的规律性表面上取决于观察尺度,但更小尺度的数据对局域空间结构的生物学解释可能更有效。因此,选取2×2cm作为最小取样单元,对研究种群格局及动态是具有积极意义的。第四部分讨论了多尺度植被格局的综合模式。结果表明:研究尺度对植被的影响是不同的。从植物方面分析,种群尺度的空间格局由植物种本身的特性和随机性所约定。在群落尺度上,物种竞争和物种扩散主导着种间关系和群落的复杂性,群落的物种组成由局域种库决定。在景观尺度上,物种组成由区域种库决定。不同尺度植物群落的建群种由物种本身的特性决定。从环境因素方面分析,气候条件主导地带性植被,而局地条件则决定着非地带性植被的分布,可解释样地内异常值存在的合理性。更多还原

【Abstract】 Spatial pattern of ecological systems and ecological processes at different scales, and their relationship are central issues of ecology. Disturbance as part of the process, is the main sources of spatial heterogeneity, which can significantly change the ecological pattern and processes at different scales, causing apparently shift of the structure and function of ecological systems. Hulunber steppe with the unique ecosystem characteristics, relatively well-preserved natural environment, abundant landscape types and biodiversity, relatively advanced and intensive production mode, is the optimal object for researching the natural ecological patterns and process in steppe ecosystems, and its responses to human-caused disturbances.It may benefit for expanding the field of vegetation ecology, providing a scientific basis for grassland resources utilization and protection, establishing ecosystem management scheme reasonably, and has important practical significance for restoration and reconstruction of degraded grassland so that formulating livestock development plan by systematically and thoroughly study of multi-scale vegetation patterns and its responses to disturbances.This paper took Hulunber steppe as research object, made use of field survey data and community patterns at landscape, community and population scales, diversity analysis methods, point pattern analysis, fractal analysis and regression analysis methods has been used to analysis vegetation spatial patterns and ecological processes, and its responses to disturbances at different scales. The main results were as followed.The first part, the pattern of biodiversity and productivity was analysised at landscape scale. The results showed that: there were no old and endemic species in Hulunber steppe. There were 135 species of vascular plants, which belonged to 28 families and 93 genera in the study area. Floristic composition of constructive species did not change significantly. The species richness and aboveground biomass increased with the longitude gradient. The relationship between biodiversity and aboveground biomass was unimodal.The second part, the association patch pattern was studied at community scale. The results showed that: there were 92 species of vascular plants, which belonged to 22 families and 66 genera in the study area. Indices of community structure and function were significantly different, and the community status located in different successional stages because of different disturbances. Species niche and succesional stages were different between sample plots, so as the number of patches were significantly different. The level of Korcak patchness exponent value, which expressed area distribution, was not only related to patch area, but also related to evenness of patch. The value of Perimeter-area exponent, which expressed the complexity of patch boundaries, was due to the niche of association patch and species diffusion. The stability of community not only lied on the direction and stages of community succession, but also lied on the starting position and the special attribution of dominant species, such as reproduction.The third part, the species spatial pattern was analysised at population scale. The results showed that: there were no consistent relationship between the root cover of species and population point pattern, spatial association. The population spatial pattern was no significant difference in experimental sample plots and in different treatment of same sample plot, and the population spatial pattern of the same treatments in same sample plots was not consistent, related to the community properties, changed in microhabitat and the intensity of disturbance. The population spatial pattern depended on the type of the species’life forms in the special scale. The types of population distribution pattern were influenced by the species themselves, the species niche in communities, the different microhabitat, the interaction between species, outside disturbances, and the anti-disturbances ability of species. Control factors of population pattern were just different in different sample plots and disturbances. From the plant’s-eye view, herbages may interact in centimeter range. The nature of spatial structure appeared to depend on the scale of observation, but the smaller-scale data were more likely to provide a biologically interpretable measure of local spatial structure in this community. So, it was a positive meaning in studying population pattern and dynamics by selection of the 2×2 cm as the smallest sampling unit.The fourth part, the synthetical mode of vegetation pattern was discussed at multi-scale. The results showed that: they were different for studying vegetation at different scale. From the plant’s-eye view, spatial pattern was due to characteristics of the species itself and randomcity at population scale. Species competition and diffusion determined interspecific relationship and complexity of community, species composition of community was determined by local species pool at community scale. Species composition of community was determined by regional species pool at landscape scale. The edificators of plant communities were all determined by characteristics of the species itself at different scale. From the environment’s-eye view, climate determined zonal vegetation pattern, but the local condition determined the distribution of azonal vegetation, which could interpret existance of outlier.更多还原