A mathematical analysis on the dependence of extinction probability on life history characteristics in plant populations

我们监测了四种不同生活史的林地草本植物在其永久样地中的个体命运(生长、存活和死亡)。我们还进行了一项研究，以测量每个物种在结实期的结果和/或种子结果，并收集关于繁殖力的信息。此外，以延龄草为研究对象，测定了北海道东京地区不同大小的碎片化森林从边缘到内部的光照强度和土壤水分，评价了自然环境梯度对延龄草种群的影响。在理论分析中，探索了密度依赖矩阵模型中种群增长率的敏感性和弹性的评价方法，即估算生活史参数变化对种群增长率影响的量值。关于这一结果的两篇论文被提交并被学术期刊接受(见背面的`参考文献‘)。我们还对已经获得的人口普查数据进行了统计分析，以便在模拟程序中使用来计算种群灭绝概率。由此得出各物种的繁殖力与死亡率之间的关系，以及种子繁殖和营养繁殖的依赖率。利用所获得的结果，我们构造了一个模拟程序来计算100年后种群灭绝的概率。计算结果已发表在英文论文中，并已提交学术期刊，现正在审阅中。

We have monitored the fate (growth, survival and death) of individuals of four woodland herbaceous species with different life histories in their permanent plots. We also conducted a research to measure fruit and/or seed set in each species at the fruiting period and collected the information on fecundity. Furthermore, as for Trillium camschatcense, we measured the light intensity and soil moisture from the edge to inside of fragmented forests with various sizes in Tokachi area of Hokkaido, and evaluated the effect of the gradient of physical environment on Trillium camschatcense population.In theoretical analysis, we explored a method to evaluate the sensitivity and elasticity of population growth rate in density-dependent matrix model, which is the quantities to estimate the effect of the change of life history parameters on population growth rate. Two papers on the results are submitted and accepted in academic journals (see `References` on back page). We also conducted a statistical analysis of the census data already obtained in order to employ in simulation programs to calculate extinction probability of populations. Consequently, we obtained the correlation between fecundity and mortality rate, and the dependence rate of seed reproduction and vegetative reproduction in each species. Utilizing those obtained results, we constructed a simulation program to calculate the extinction probability of populations after 100 years. The calculated results are written in the English papers and they are submitted to academic journal and in review now.