Dispersal is a fundamental ecological process, and population density has been observed as a driver of dispersal in various taxa. Conflicting examples of positive and negative density-dependent dispersal, however, leave little consensus regarding any general effects of density on dispersal. Deer mice (Peromyscus maniculatus) have exhibited both negative and positive density-dependent dispersal. Using 51-years of data on P. maniculatus live-trapping abundances, we examined the spatial scale of density-dependent dispersal as well as its temporal stability within this long time-series. We examined these patterns over both the entire time-series and also in ten-year shifting windows to determine whether the nature and strength of the relationship changed through time. Overall, the probability of dispersal decreased with increased local and regional population density, and the negative effect of local density on dispersal was more pronounced in years with low regional densities. Females were less likely to disperse, but female dispersal was more density-dependent than male dispersal. Additionally, the strength of negative density-dependent dispersal changed through time, from very strong in some decades to absent in others. Our study shows that the relationship between density and dispersal is not temporally static and that studies of density-dependent dispersal should consider both local and regional population densities. As well, while male-biased dispersal is often considered ubiquitous in mammals, we demonstrate that male and female dispersal may have differing levels of density-dependence. Finally, our study highlights the importance of accounting for both local and regional processes in natural systems as these types of long-term, spatially broad examinations of dispersal are crucial if spatial processes are to be represented adequately and accurately in population modelling and theory.

中文翻译：

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时空变化：长期检查林地啮齿动物的密度依赖性扩散

分散是一个基本的生态过程，人们观察到人口密度是各个分类中分散的驱动力。然而，正负密度相关的色散的相互矛盾的例子，在密度对色散的任何一般影响上几乎没有共识。鹿小鼠（Peromyscus maniculatus）表现出负密度分布和正密度分布。使用51年的P. maniculatus活诱捕丰度数据，我们研究了在此较长时间序列内密度依赖性扩散的空间尺度及其时间稳定性。我们在整个时间序列以及十年的移动窗口中都检查了这些模式，以确定这种关系的性质和强度是否随时间变化。总体，分散的概率随着局部和区域人口密度的增加而降低，并且局部密度对分散的负面影响在区域密度较低的年份中更为明显。雌性散布的可能性较小，但雌性散布比雄性散布对密度的依赖性更大。另外，负密度依赖性分散的强度随时间变化，从几十年的非常强到其他几十年的消失。我们的研究表明，密度与扩散之间的关系在时间上不是一成不变的，并且密度相关的扩散研究应同时考虑本地和区域人口密度。同样，尽管男性偏见的散布在哺乳动物中通常被认为是普遍存在的，但我们证明了男性和女性散布可能具有不同的密度依赖性水平。最后，