While habitat loss is a known key driver of biodiversity decline, the impact of other landscape properties, such as patch isolation, is far less clear. When patch isolation is low, species may benefit from a broader range of foraging opportunities, but are at the same time adversely affected by higher predation pressure from mobile predators. Although previous approaches have successfully linked such effects to biodiversity, their impact on local and metapopulation dynamics has largely been ignored. Since population dynamics may also be affected by environmental disturbances that temporally change the degree of patch isolation, such as periodic changes in habitat availability, accurate assessment of its link with isolation is highly challenging. To analyze the effect of patch isolation on the population dynamics on different spatial scales, we simulate a three-species meta-food chain on complex networks of habitat patches and assess the average variability of local populations and metapopulations, as well as the level of synchronization among patches. To evaluate the impact of periodic environmental disturbances, we contrast simulations of static landscapes with simulations of dynamic landscapes in which 30 percent of the patches periodically become unavailable as habitat. We find that increasing mean patch isolation often leads to more asynchronous population dynamics, depending on the parameterization of the food chain. However, local population variability also increases due to indirect effects of increased dispersal mortality at high mean patch isolation, consequently destabilizing metapopulation dynamics and increasing extinction risk. In dynamic landscapes, periodic changes of patch availability on a timescale much slower than ecological interactions often fully synchronize the dynamics. Further, these changes not only increase the variability of local populations and metapopulations, but also mostly overrule the effects of mean patch isolation. This may explain the often small and inconclusive impact of mean patch isolation in natural ecosystems.

虽然栖息地的丧失是生物多样性下降的已知关键驱动因素，但其他景观特性（如斑块隔离）的影响却远未弄清楚。当斑块隔离度较低时，物种可能会从更广泛的觅食机会中受益，但同时会受到来自移动捕食者的更高捕食压力的不利影响。尽管以前的方法已经成功地将这种影响与生物多样性联系起来，但是它们对当地和种群动态的影响却被很大程度上忽略了。由于种群动态也可能会受到环境干扰的影响，这些干扰会暂时改变斑块隔离的程度，例如栖息地可用性的周期性变化，因此准确评估其与隔离的联系非常具有挑战性。要分析斑块隔离对不同空间尺度上种群动态的影响，我们在栖息地斑块的复杂网络上模拟了一个三物种的元食物链，并评估了当地种群和metapopulations的平均变异性，以及斑块之间的同步水平。为了评估周期性环境干扰的影响，我们将静态景观的模拟与动态景观的模拟进行了对比，在动态景观中，有30％的斑块周期性地无法用作栖息地。我们发现，依赖于食物链的参数化，平均补丁隔离度的提高通常会导致更多的异步种群动态。但是，局部种群的变异性也由于在较高的平均斑块隔离下增加的散布死亡率的间接影响而增加，因此使不稳定的种群动态和增加的灭绝风险。在动态景观中，在比生态相互作用慢得多的时间尺度上，补丁可用性的周期性变化通常会完全同步动态。此外，这些变化不仅增加了局部种群和后代种群的变异性，而且在很大程度上抵消了平均斑块隔离的影响。这可以解释平均斑块隔离在自然生态系统中通常产生的微小而不确定的影响。