Terrestrial Ecology Unit, Department Biology, Ghent University, K.L. Ledeganckstraat 35, B-9000, Ghent, Belgium.
Centre for Biodiversity Theory and Modelling, Station d'Ecologie Expérimentale du CNRS, 09200, Moulis, France.
J Anim Ecol. 2015 Nov;84(6):1565-74. doi: 10.1111/1365-2656.12400. Epub 2015 Aug 6.
The spatial and temporal variation in the availability of suitable habitat within metapopulations determines colonization-extinction events, regulates local population sizes and eventually affects local population and metapopulation stability. Insights into the impact of such a spatiotemporal variation on the local population and metapopulation dynamics are principally derived from classical metapopulation theory and have not been experimentally validated. By manipulating spatial structure in artificial metapopulations of the spider mite Tetranychus urticae, we test to which degree spatial (mainland-island metapopulations) and spatiotemporal variation (classical metapopulations) in habitat availability affects the dynamics of the metapopulations relative to systems where habitat is constantly available in time and space (patchy metapopulations). Our experiment demonstrates that (i) spatial variation in habitat availability decreases variance in metapopulation size and decreases density-dependent dispersal at the metapopulation level, while (ii) spatiotemporal variation in habitat availability increases patch extinction rates, decreases local population and metapopulation sizes and decreases density dependence in population growth rates. We found dispersal to be negatively density dependent and overall low in the spatial variable mainland-island metapopulation. This demographic variation subsequently impacts local and regional population dynamics and determines patterns of metapopulation stability. Both local and metapopulation-level variabilities are minimized in mainland-island metapopulations relative to classical and patchy ones.
在复群中，合适生境的时空可利用性变化决定了定居-灭绝事件，调节了局部种群的大小，最终影响了局部种群和复群的稳定性。了解这种时空变化对局部种群和复群动态的影响主要来源于经典复群理论，尚未经过实验验证。通过操纵人工叶螨 Tetranychus urticae 复群的空间结构，我们检验了生境可利用性的时空（大陆-岛屿复群）和时空变化（经典复群）在多大程度上影响了相对于时空上持续存在生境的系统（斑块复群）的复群动态。我们的实验表明：（i）生境可利用性的空间变化降低了复群大小的方差，并降低了种群水平上密度依赖的扩散；而（ii）生境可利用性的时空变化增加了斑块灭绝率，降低了局部种群和复群的大小，并降低了种群增长率的密度依赖性。我们发现扩散与密度呈负相关，在空间变量大陆-岛屿复群中总体上扩散率较低。这种人口变化随后影响了局部和区域种群动态，并决定了复群稳定性的模式。与经典和斑块复群相比，大陆-岛屿复群中局部和复群级别的变异性最小化。
