Population biological study on extinction and persistence of natural populations.

这一合作研究项目旨在研究动植物自然种群导致灭绝的关键过程，种群生态学家、社区生态学家、流行病学家、种群遗传学家和相关领域的其他研究人员密切合作，确定有效保护濒危物种所需的基础生物学关键问题。我们首先开了一次会，讨论了这门科学不同方面的潜在问题。然后，每个研究成员与其他成员合作取得了各自的进展。(1)对日本东京都多摩地区几种食肉动物之间传播的病毒病进行了流行病学研究和病毒基因序列分析。通过基因组分析研究了双子座病毒与其寄主植物的共同进化。(2)研究了马来西亚热带雨林中基于传粉者的遗传多样性保持机制。在博宁群岛，比较了入侵蜜蜂和居留物种在觅食和授粉行为方面的差异，以及它们对植物繁殖力和存活率的不同影响。考察了新入侵者对波动和异质生境中栖息物种的影响。(3)以淡水鱼类波动不对称性(Medaka)为基本适合度的候选性状。对经常受到干扰的河床多年生植物种群进行了遗传多样性研究。(4)从元种群动力学的角度研究了濒危植物和共生/食草昆虫的空间结构的影响。(5)发展了从现存物种的祖先系统发育来估计过去的大灭绝事件的方法和从遗传多样性估计过去的种群规模的方法。

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.