Mathematics Department, University of Wisconsin, La Crosse, WI 54601, USA.
Am Nat. 2013 Aug;182(2):180-90. doi: 10.1086/670987. Epub 2013 Jun 21.
Seed banks are critically important for disturbance specialist plants because seeds of these species germinate only in disturbed soil. Disturbance and seed depth affect the survival and germination probability of seeds in the seed bank, which in turn affect population dynamics. We develop a density-dependent stochastic integral projection model to evaluate the effect of stochastic soil disturbances on plant population dynamics with an emphasis on mimicking how disturbances vertically redistribute seeds within the seed bank. We perform a simulation analysis of the effect of the frequency and mean depth of disturbances on the population's quasi-extinction probability, as well as the long-term mean and variance of the total density of seeds in the seed bank. We show that increasing the frequency of disturbances increases the long-term viability of the population, but the relationship between the mean depth of disturbance and the long-term viability of the population are not necessarily monotonic for all parameter combinations. Specifically, an increase in the probability of disturbance increases the long-term viability of the total seed bank population. However, if the probability of disturbance is too low, a shallower mean depth of disturbance can increase long-term viability, a relationship that switches as the probability of disturbance increases. However, a shallow disturbance depth is beneficial only in scenarios with low survival in the seed bank.
种子库对于受干扰的特有植物至关重要，因为这些物种的种子只有在受干扰的土壤中才会发芽。干扰和种子深度会影响种子库中种子的生存和发芽概率，进而影响种群动态。我们开发了一个密度依赖的随机积分投影模型，以评估随机土壤干扰对植物种群动态的影响，重点是模拟干扰如何在种子库中垂直重新分配种子。我们对干扰的频率和平均深度对种群准灭绝概率的影响，以及种子库中种子总密度的长期均值和方差进行了模拟分析。我们表明，增加干扰的频率会增加种群的长期生存能力，但对于所有参数组合，干扰的平均深度与种群的长期生存能力之间的关系不一定是单调的。具体来说，干扰概率的增加会增加总种子库种群的长期生存能力。然而，如果干扰的概率太低，较浅的干扰平均深度可以增加长期生存能力，这种关系会随着干扰概率的增加而改变。然而，浅度干扰仅在种子库中生存能力较低的情况下才有益。
