Population biological study on extinction and persistence of natural populations.

该合作研究项目旨在通过种群生态学家、群落生态学家、流行病学家、种群遗传学家和其他相关领域的研究人员密切合作，研究动植物自然种群导致灭绝的关键过程，并确定有效保护濒危物种所需的基础生物学关键问题。我们首先开了一个会，讨论了这门科学不同方面的潜在问题。然后每个成员学习他/她与他人合作取得自己的进步。(1)采用流行病学研究和病毒基因序列分析的方法，对日本东京多摩地区几种食肉动物之间传播的病毒病进行了研究。通过基因组分析研究了双子病毒及其寄主植物的协同进化。(2)研究了马来西亚热带雨林维持高遗传多样性的传粉媒介机制。比较了外来蜜蜂和留种蜜蜂的觅食和授粉行为，以及它们对植物繁殖力和存活率的差异影响。研究了在波动和异质生境中，新入侵物种对留种的影响。(3)淡水鱼（Medaka）的波动不对称性作为基本适应度的候选性状。对频繁受到干扰的河床多年生植物种群进行了遗传多样性研究。对近交抑制进行了理论研究。(4)从元种群动态的角度研究了濒危植物与共生/草食性昆虫的空间结构效应。(5)建立了从现存物种祖先系统发育估计过去大灭绝事件的方法和从遗传多样性估计过去种群规模的方法。

This cooperative research project was intended to study key processes for natural populations of animals and plants lead to extinction, in which population ecologists, community ecologists, epidemiologists, population geneticists and other researchers in related fields collaborate closely and identify key issues of basic biology needed for effective conservation of endangered species. We first had a meeting in which we discussed the potential problems in different aspects of this science. Then each member studies his/her made own progress in collaboration with others.(1) Virus disease that has spread among several carnivores in Tama district, Tokyo, Japan, has been studied using both epidemiological study and gene sequence analysis of virus. Coevolution of Gemini virus and its host plant has been examined by genomic analysis.(2) The pollinator-based mechanisms by which high genetic diversity is maintain are studied in tropical rain forest in Malaysia. In Bonin islands, invader honey bee and resident species are compared with respect to foraging and pollination behavior, and their differential effect on plant fecundity and survivorship. Effect of novel invader to resident species in fluctuating and heterogeneous habitat is examined.(3) Fluctuating asymmetry of freshwater fish (Medaka) is measured as candidate traits revealing basic fitness. Genetic diversity is studied for perennial plant populations of river bed that are frequently disturbed. Theoretical study of inbreeding depression has been carried out.(4) The effect of spatial structure of an endangered plant and mutualistic/herbivorous insects is studied from the viewpoint of meta-population dynamics.(5) Methods for estimating past mass extinction events from ancestral phylogeny of extant species and those for estimating past population sizes from genetic diversity are developed.