【作者】 丁志锋；

【导师】 丁平；

【作者基本信息】 浙江大学 ， 生态学， 2012， 博士

【摘要】 生境片段化是全球生物多样性最主要的威胁之一,因为生境面积的减少会导致物种丰富度的快速下降,而隔离度的增加会导致斑块剩留种群的灭绝风险增加。本文选用两种不同的尺度：集团多度和功能多样性,来探讨片段化后鸟类群落结构的变化,了解不同生境类型下物种组成的差异；同时也可以全面掌握生境片段化与群落功能多样性的变化模式,从而揭示功能多样性与生境片段化之间的关系,以及群落动态和预测群落演化规律。2006年至2009年繁殖季节(4、5、6月)和冬季(11、12、1月),选取41个面积呈梯度变化的岛屿,采用样线法记录鸟类的丰富度及多度数据。鸟类集团研究的结果显示,1)千岛湖鸟类群落主要由食虫鸟集团,杂食鸟集团,林下层鸟集团和林冠层鸟集团组成；2)留鸟与候鸟对岛屿面积的响应一致,食虫鸟集团和林下层鸟集团对岛屿面积最为敏感,而杂食鸟集团和林冠层鸟集团对面积敏感性相对较低；3)鸟类集团多度主要由岛屿面积所决定。尽管有研究指出周长面积比(perimeter-area ratio, PAR)或植物物种丰富度对鸟类丰富度十分重要,我们的研究表明了岛屿面积是决定千岛湖鸟类集团多度的最主要因素。功能多样性的研究结果显示,1)鸟类功能丰富度与功能歧异度间存在显著的负相关关系,其它功能多样性指数间无显著相关性；2)岛屿面积对鸟类的物种丰富度具有最大的解释度,而岛屿隔离度对鸟类物种多样性(香农--威纳指数)具有最大解释度,并且隔离度对物种均匀度(Pielou均匀度)有负效应；3)功能丰富度随岛屿面积的增加而增加,但功能均匀度随岛屿面积的增加而减小,功能歧异度与岛屿参数间无显著关系(与隔离度有显著关系,但其解释度很低)；4)千岛湖鸟类功能丰富度与均匀度的实际值均显著低于随机值,鸟类群落的构建主要受生境过滤作用的影响。我们的结果表明,在保护区的实际设计中,必须明确的考虑环境条件对功能多样性的影响,例如,在千岛湖大型岛屿上具有较低的功能均匀度,这在一定程度上说明了大型岛屿上功能稳定性较低,因此这类岛屿需给予特别的关注和保护。模型比较的研究结果表明,经典的物种面积模型比物种--面积--生境模型有更好的拟合度,物种--面积关系不存在生境效应。更多还原

【Abstract】 Habitat fragmentation is one of the greatest threats to global biodiversity as reduced habitat area and increased isolation almost invariably lead to rapid declines in local species richness and/or to increased extinction risks of remnant populations. We used guild abundance and functional diversity to explore the changes in bird community structure, understand species variations across different vegetation types and patterns of functional diversity on fragmented system.We censused the presence and abundance of bird species on each of the41study islands using standard line transect methods. Birds were censused during the breeding seasons (April-June) and winter seasons (November-January) each year from2006to2009. Applying the guild approach in such systems, the results were as follows.1) Bird communities at TIL were dominated by insectivores, omnivores or understory and canopy guilds.2) Our data showed that migrants and residents responded equally to island area, insectivores and understory guilds were sensitive to island area but omnivores and canopy guilds were not very sensitive.3) Most bird guild abundance was determined by island area, except for omnivores and canopy guilds. Although perimeter-area ratio (PAR) or habitat diversity found to be important for bird species richness, our results highlight the importance of island area in maintaining bird diversity in fragmented island systems.When applying a measure of functional diversity, the results were as follows.1) There were no correlations between FRic and FEve, FEve and FDiv, but negative correlations between FRic and FDiv.2) As predicted, island area accounted for most of the variation in bird species richness, whereas isolation explained most of the variation in species diversity and had negative impacts on species evenness.3) FRic increased with island area but FEve decreased with island area, and FDiv showed no clear patterns.4) Functional diversity appears to be more strongly influenced by habitat filtering as opposed to limiting similarity. Specifically, both FRic and FEve were significantly less than expected across all islands, but FDiv showed no clear patterns.5) Our findings support the need for the effects of fragmentation on functional diversity to be explicitly considered in reserve design. For example, low FEve values on large islands and/or patches may indicate low functional stability and as such these islands and/or patches may deserve extra attention and/or protection.Our analyses showed that the classic species-area model gave a better fit than the proposed model (species-area-habitat model).更多还原