The development of estimation method of extinction probability in population under varying environment

不同环境下种群灭绝概率估计方法的研究进展

• 批准号: 13640637
• 负责人: TAKADA Takenori
• 金额: $ 1.6万
• 依托单位: Hokkaido Tokai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640637/
• 关键词: Varying environment; Extinction probability; projection matrix model; population dynamics; 多年生草本; コンピュータシュミレーション

We analyzed the popular dynamics of Trillium apetalon and T. camschatcense under varying environment, using the census data during about 15 years. Moreover, we developed a method to check the reliability of elasticity matrix, which is an index of population dynamics, in density-dependent matrix model.As for the former, we estimated the mean and variance of important life-history parameters (survival rate and fecundity etc.) and examined the effect of temporal variation of those parameters on the expectation of population growth rate. As the result, we obtained the probabilities of increase and decrease of the population and clarified several points; (1) The probability that the population of Trillium apetalon decreases under 30% after 50 years is 75.6%, while the probability that the population of Trillium camschatcense decreases under 30% after 50 years is 0%. (2) In both species, elements with high sensitivity are different from elements that contribute more to the decrease of the population size.As for the latter, we obtained the theoretical elasticity matrix at equilibrium and the elasticity matrix under actually varying dynamics, and compared them. We found that the discrepancy between them depend largely on the life history pattern and the pattern of density-dependence. In the case of Beverton-Holt-type density dependent function, the discrepancy is relatively small, while in the case of Ricker-type density dependent function, the discrepancy is large. The reliability of elasticity matrix is becoming low when the species in question is monocarpic and delayed growth.

我们分析了延龄草无瓣和延龄草的流行动态。在不同环境下的camschatcense，使用大约15年的普查数据。此外，我们还提出了一种检验密度依赖矩阵模型中种群动态指标弹性矩阵可靠性的方法，对于密度依赖矩阵模型，我们估计了重要的生活史参数（存活率、繁殖力等）的均值和方差。并研究了这些参数随时间变化对人口增长率预期的影响。结果表明：（1）无瓣延龄草种群在50年后减少到30%以下的概率为75.6%，而延龄草种群在50年后减少到30%以下的概率为0%。(2)在这两个物种中，敏感性高的元素与对种群规模下降贡献较大的元素不同，对于后者，我们得到了平衡态下的理论弹性矩阵和实际变化动力学下的弹性矩阵，并对它们进行了比较。我们发现，它们之间的差异在很大程度上取决于生活史模式和密度依赖模式。在Beverton-Holt型密度依赖函数的情况下，差异相对较小，而在Ricker型密度依赖函数的情况下，差异较大。当所研究的树种为一次结实和延迟生长时，弹性矩阵的可靠性变低。

项目成果

Ohara, M., Takada, T., Kawano, S.: "The demography and reproductive strategies of a polycarpic perennial, Trillium apetalon (Trilliaceae)"Plant Species Biology. 16. 209-217 (2001)

Ohara, M.、Takada, T.、Kawano, S.：“多果多年生延龄草（延龄草科）的人口统计学和繁殖策略”植物物种生物学。