School of Biological Sciences, University of Aberdeen, Aberdeen, UK.
Oecologia. 2011 May;166(1):111-9. doi: 10.1007/s00442-010-1820-0. Epub 2010 Oct 30.
Dispersal can play an important role in both the local and regional dynamics of populations. Empirical studies have shown that the proportion of individuals dispersing is often density dependent, which may have implications for the effect of dispersal on populations. In this study, we manipulate the dispersal strategy of adults within two-patch laboratory populations of soil mites and compare the consequences of fixed (density-independent) and density-dependent dispersal in environments of constant and temporally varying resource availability. Effects of dispersal on population dynamics were dependent on the presence of environmental variation. Both dispersal strategies tended to spatially homogenize the population abundance of adults in a variable environment. However, the effect of environmental variation on mean adult abundance was greater with density-dependent dispersal than with fixed dispersal. Adult dispersal did not affect juvenile or egg abundance. This study demonstrates the potential significance of density-dependent dispersal for population dynamics, but emphasizes the role of the environmental context.
扩散在种群的局部和区域动态中起着重要作用。实证研究表明，个体扩散的比例通常与密度有关，这可能对扩散对种群的影响有一定意义。在这项研究中，我们在土壤螨的两个斑块实验室种群中操纵成体的扩散策略，并比较在资源恒定性和时变性环境中固定（密度无关）和密度依赖的扩散的后果。扩散对种群动态的影响取决于环境变化的存在。在可变环境中，这两种扩散策略都倾向于使成体的种群丰度在空间上均匀化。然而，与固定扩散相比，环境变化对成体平均丰度的影响更大。成体扩散不会影响幼体或卵的丰度。本研究证明了密度依赖扩散对种群动态的潜在重要性，但强调了环境背景的作用。
