黑眶蟾蜍的生活史表型地理变异和分布北扩趋势

One of the most important tasks in current studies of ecology is to assess the effects of climate change on adaptation, distribution and population persistence species that are sensitive to such effects. We will use data gathered from the field enclosure, thermal manipulation, reciprocal transplant and HSP70-expression experiments to reveal the influence of temperature on geographic variation in life history phenotypes in Bufo melanostictus, the genetic basis and adaptive significance of such variation, the influence of warming on the northerly dispersal trend of this species, and the restriction factors and mechanisms of geographic range. We will collect animals from four thermally different localities, Sanya in Hainan, Zhaoqing in Guangdong, and Lishui and Wuyi in Zhejiang, along a latitudinal gradient. Data collected in this study will allow us to compare reproduction, metamorphosis, and growth rate among individuals from the field populations and between field-caught individuals and those maintained under the laboratory conditions. We will examine the effects of population source, temperature, and their interaction on the traits examined, and analyse the relative contributions of environmental impact and genetic factors on phenotypic variation. We will conduct a reciprocal transplant experiment using individuals of B. melanostictus from the species' current northern limit of distribution and an adjacent population to clarify whether the northerly dispersal trend found in this species is directly related to temperature warming occurring in recent years. We will also expound the physiological limiting factors and mechanisms that determine the distributional range of B. melanostictus, according to the adaptive changes of thermal tolerance and differential expression of HSP70 among populations. Gene flows among four geographically different populations will be examined to further verifiy the possibility of range expansion, ther northerly dispersal in particular, of B. melanostictus. This study aims to reveal the short- and long-term effects of temperature warming on life history phenotypes of B. melanostictus, and to uncover the underlying causes and mechanisms for the northerly dispersal trend of this species.

评估气候变化对物种的影响是生态学领域的重要课题。申请者将利用野外围栏、热环境操纵、互换移植、HSP70表达实验中得到的数据，揭示温度对黑眶蟾蜍表型地理变异的影响、变异的遗传基础和适应意义、气温升高对其分布区北扩的影响、地理分布的限制因子和作用机制。拟在三亚、肇庆、丽水和武义采集动物，用当地野外围栏收集繁殖、变态、生长等方面的数据，检测被检表型的地理变异；对不同种群的个体进行热环境操纵实验，检测种群来源、温度及其相互作用对被检表型的影响，辨析环境近因性影响和遗传因素对表型变异的相对贡献；对当前分布北限和相邻种群的黑眶蟾蜍进行互换移植实验，检测分布区北扩是否与近年来的温度上升有关；通过比较不同种群热耐受性和HSP70表达，阐明生理因子对黑眶蟾蜍分布的影响和作用机制；通过检测种群间基因流，进一步验证北扩的可能性。本项目旨在揭示气温升高对黑眶蟾蜍生活史表型的短期和长期影响、分布区北扩的原因和机制。

评估气候变化对物种的影响是当前生态学领域的重要课题。本项目通过野外围栏、热环境操纵和互换移植等实验，揭示温度对黑眶蟾蜍表型地理差异及其分布区北扩的影响、表型差异的遗传基础和生态适应的意义及地理分布的限制因子和作用机制。2013年项目执行过程中，记录了生活史特征的大量数据，达到了预期的目标。在热环境不同的海南琼州、广东肇庆、浙江丽水和浙江武义进行野外围栏实验，收集黑眶蟾蜍繁殖、变态和生长等方面的数据，检测野外种群生活史表型的地理差异；利用实验设计的热环境操纵实验，收集在不同种群和不同温度组动物生活史表型数据，检测种群来源、温度及其相互作用对生活史表型的影响，辨析环境因素或/和遗传因素对表型变异的相对贡献；对当前黑眶蟾蜍分布北限的武义种群和相邻的丽水种群，进行互换移植实验收集生活史表型数据，检测该种分布区北扩是否与近年来的温度上升直接相关；在相同条件下，测定四个地理种群黑眶蟾蜍不同发育阶段的选择体温、耐受高低温，检测黑眶蟾蜍不同发育阶段热耐受性的地理差异及它们之间的相互关系。本项目取得了一些有意义的结果，发表SCI论文1篇(标注项目号)，录用1篇，投送2篇，授权专利1项。项目的核心是检测不同热环境条件下生活史表型特征的变异，如热环境操纵和互换移植等实验需要跨年度的工作，因此，数据的价值需要持续的数据采集才能显现。我们将多方面寻求后续经费的支持，包括国家基金委的支持，继续完成原申请书计划的后续实验设计。我们将深入发掘本项目及后续工作的科学价值，把结果发表在学科领域有重要影响的国际刊物上。