【作者】 张宏伟；

【导师】 张健；

【作者基本信息】 华东师范大学 ， 生态学， 2022， 硕士

【摘要】 作为全球变化的重要组成部分,外来植物入侵与扩散是当前生物多样性和生态系统功能发生变化的关键驱动因素。探究外来植物多样性的海拔梯度格局及其对本土植物多样性的影响对于宏生态学研究和生物多样性保护具有重要意义。本论文以植物调查资料丰富、人类干扰历史较长、地处经济发展迅速地区的浙江天目山国家级自然保护区为研究对象,基于天目山植物志资料、本研究组实地调查数据、标本数据和公众调查数据,收集和调查外来和本土植物的物种信息和海拔分布范围等,对本土和外来植物多样性与系统发育多样性进行比较,探究外来植物如何影响本土植物多样性、群落组成以及系统发育结构,并分析气候、人类干扰等对外来和本土植物海拔梯度多样性格局的主要驱动因素。主要结论如下:(1)外来植物与本土植物区系特征不同,主要体现在科属组成、生活型谱、分布区类型等方面存在显著差异,木本植物和热带分布属的比例在外来植物区系中显著增加;随海拔升高,外来植物丰富度呈递减趋势,主要聚集在人类干扰较强的低海拔区域;本土植物丰富度则呈单峰格局,在500-600 m海拔达到峰值;年均温、降水季节性和最干月降水量是限制高海拔植物丰富度的主要环境因子。(2)外来植物增加了各海拔段的物种β多样性,改变了沿海拔梯度的植物物种更替规律,增加植物多样性的空间异质性;外来植物减少了系统发育β多样性,使同一海拔段的物种在进化上更加相似,导致了系统发育同质化;外来种的加入对系统发育结构的影响,在使用净相关度指数(NRI)时显著降低了群落系统发育聚集趋势,当使用最近分类单元指数(NTI)时无显著差异,且这些结果在不同生活型间存在差异。综上,本论文详细阐述了外来植物海拔梯度格局及其对山地生态系统的影响,分析了物种多样性、系统发育多样性及系统发育群落结构的变化规律,强调了在亚热带山地生态系统中气候与人类活动对外来植物分布与本土植物多样性分布格局的重要作用,为理解人类介导的外来植物驱动区域植物多样性变化的生态和进化机制提供科学依据。更多还原

【Abstract】 As an important part of global change,the invasion and diffusion of alien plants are the key driving factors influencing changes in biodiversity and ecosystem functions.Exploring the elevational pattern of alien plant diversity and its influence on native biodiversity is of great significance to macroecology and biodiversity conservation.This work took Tianmushan National Nature Reserve in Zhejiang Province as the study area.This reserve is located in an area with rapid economic development recently,with rich document in herbarium specimen collection and plant surveys and long history of human activities.Data from the flora of Mt.Tianmu,field surveys,herbarium specimen records and the filed investigations from citizen scientists were compiled and used to map elevational distribution ranges of all alien and native plants.In this study,I compared the elevational patterns of native and alien plant taxonomic and phylogenetic diversity,evaluated how alien plants affect native plant diversity,community composition and phylogenetic structure,and analyzed the main drivers of these diversity patterns,including climate and human disturbance.The main results are below:(1)The flora characteristics of alien plants and native plants were different,mainly reflected in family and genus composition,life form spectrum and distribution type.The proportion of woody plants and tropical distribution genera increased significantly in the alien flora.With the increase in elevation,the abundance of alien plants showed a decreasing trend,mainly concentrated in low-elevation areas with strong human interference.The abundance of native plants showed a unimodal pattern,reaching a peak at 500-600 m elevation.Annual mean temperature,precipitation seasonality and precipitation in the driest month are the main environmental factors limiting plant richness at high elevations.(2)Alien plants increased the β diversity of the community,changed the replacement rule of plant species along the elevational gradient,and increased the spatial heterogeneity of plant diversity.It reduced phylogenetic β diversity and made species at the same elevation more evolutionarily relative,leading to phylogenetic homogeneity.As for the effects of alien species on phylogenetic structure,when estimated with the Net Relatedness Index(NRI),the aggregation trend of community phylogeny was significantly reduced,but there was no significant difference when the Nearest Taxon Index(NTI)was used,and those results differed among different life forms.To conclude,this research demonstrated the elevational gradient pattern of exotic plant diversity and its impact on mountain ecosystems,analyzed the changing rules of species diversity,phylogenetic diversity and phylogenetic community structure,and emphasized the effects of climate and human activities on alien and native plant diversity distribution in subtropical mountain ecosystems.This work provided a scientific basis for understanding the ecological and evolutionary mechanisms behind regional alien plant diversity mediated by human beings.更多还原