The effects of conspecific densities on dispersal have been well documented. However, while positive and negative density-dependent dispersal based on conspecific densities are often shown to be the result of intraspecific competition or facilitation respectively, the effects of heterospecific densities on dispersal are examined far less frequently. This despite the potential for the analogous processes of interspecific competition and heterospecific attraction to influence dispersal. Here we use 51 years of live-trapping data on deer mouse (Peromsycus maniculatus), eastern chipmunk (Tamias striatus), red-backed vole (Myodes gapperi), and jumping mice (Napaeozapus insignis and Zapus hudsonius) to examine the effects of both conspecific and heterospecific densities on dispersal frequency. In terms of conspecific densities, jumping mice were more likely to disperse from areas of low conspecific densities, while red-backed voles and chipmunks did not respond to conspecific densities in their dispersal frequencies. When considering interspecific density effects, while there were no statistically clear effects of density on dispersal frequency, the effects of chipmunk and jumping mice densities on dispersal by red-backed vole were greater than the effects of conspecific densities, with voles more likely to disperse from areas of high chipmunk densities and low jumping mice densities. Likewise, the effect of chipmunk densities on dispersal by jumping mice was greater than the conspecific density effect. Conspecific densities clearly can affect dispersal by two of these four species, but the effects of heterospecific densities on dispersal frequency are less clear. Based on effect sizes it appears that there is potential for heterospecific effects on dispersal by some species in the community, but future experimental work could elucidate the strength and causes of these relationships.

中文翻译：

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检查森林中小型哺乳动物的种间密度依赖性扩散

同种密度对分散的影响已得到充分证明。然而，尽管经常显示基于同种密度的正负密度依赖性分散分别是种内竞争或促进的结果，但异种密度对分散的影响却很少被检查。尽管存在种间竞争和异种吸引的相似过程可能影响分散的潜力，但这仍然存在。在这里，我们使用了鹿鼠（Peromsycus maniculatus），花栗鼠（Tamias striatus），红背田鼠（Myodes gapperi）和跳跃鼠（Napaeozapus insignis和Zapus hudsonius）的51年实时诱捕数据来研究两者的影响扩散频率上的同种和异种密度。就具体密度而言，跳跃的小鼠更有可能从低同种密度的区域分散，而红背田鼠和花栗鼠对它们的分散频率不响应同种密度。当考虑种间密度效应时，虽然密度对分散频率没有统计学上的明确影响，但花栗鼠和跳跃小鼠的密度对红背田鼠的分散影响大于同种密度的影响，田鼠更可能从高花栗鼠密度和低跳鼠密度的区域。同样，花栗鼠密度对跳跃小鼠扩散的影响大于同种密度效应。同种密度显然可以影响这四个物种中的两种，但异种密度对分散频率的影响尚不清楚。