Mechanisms of density dependence in fluctuating vole populations.

田鼠种群波动中的密度依赖性机制。

基本信息

批准号：
14340240
负责人：
SAITOH Takashi
金额：
$ 8.77万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14340240/
关键词：
Rodents The grey-sided vole Clethrionomys rufocanus population Periodicity Cycle Density dependence Seasonality Synchronism

项目摘要

It is essential to analyze the relationship between seasonal and annual dynamics in order to understand multi-annual cycles observed in small mammal populations. Based on recent advances in time-series analyses of ecological dynamics using statistical and mathematical models, we analyzed the seasonal and annual density dependence structure in 189 populations of the gray-sided vole (Clethrionomys rufocanus Sundevall, 1846) in Hokkaido, Japan. Annual direct density dependence was strong in almost all populations. In contrast, delayed density dependence was generally weak, although clear delayed density dependence was detected in some of the studied populations. Although seasonal density-dependence was observed both in winter and summer, direct density dependence was much more profound during winter, thus, winter density dependence contributed most to the overall annual direct density dependence. We found no correlation between the seasonal components of annual delayed density dependence ; however corresponding seasonal components for annual delayed density dependence were positively correlated. We conclude that winter conditions influence the strength of annual direct density dependence most profoundly and that direct density dependence during summer and winter may be generated by different mechanisms, whereas delayed density dependence seems to be generated by a common mechanism.Annual density dependence was stronger in north-eastern populations than in south-western ones for both direct and delayed density dependence. The temperature of Hokkaido becomes lower toward north-east, because Hokkaido Island is heavily influenced by warm (west) and cold (east) sea currents. Thus this geographic gradient that populations in areas with longer winter exhibit stronger density dependence well corresponds to the above results that density dependence is stronger in winter than in summer.

必须分析季节性和年度动力学之间的关系，以了解在小型哺乳动物种群中观察到的多年循环。基于使用统计和数学模型对生态动力学的时间序列分析的最新进展，我们分析了日本霍克卡多的189种灰色vole人群（Clethrionomys rufocanus Sundevall，1846）的季节性和年度密度依赖性结构（Clethrionomys Rufocanus Sundevall，1846年）。几乎所有人群中的年度直接密度依赖性都很强。相反，尽管在一些研究的人群中检测到明显的延迟密度依赖性，但延迟密度依赖性通常很弱。尽管在冬季和夏季都观察到季节性密度依赖性，但在冬季，直接密度依赖性更为深刻，因此，冬季密度依赖性对总体年度直接密度依赖性有很大贡献。我们发现年度延迟密度依赖性的季节性成分之间没有相关性。但是，年度延迟密度依赖性的相应季节性成分呈正相关。我们得出的结论是，冬季条件最大程度地影响了年度直接密度依赖性的强度，并且在夏季和冬季的直接密度依赖性可能是通过不同的机制产生的，而延迟密度依赖性似乎是通过共同的机制产生的。年轻的密度依赖性在东北人口的直接密度依赖性和延迟密度依赖性比西南人群中的种群。北海道的温度向东北降低，因为北海道岛受到温暖（西）和寒冷（东）海流的严重影响。因此，这种地理梯度是，冬季较长地区的种群的密度依赖性更强，这与上述结果相对应，即冬季密度依赖性比夏季更强。