Model complexity affects transient population dynamics following a dispersal event: a case study with pea aphids.
Model complexity affects transient population dynamics following a dispersal event: a case study with pea aphids.
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模型复杂性影响扩散事件后的瞬时种群动态：豌豆蚜的案例研究。
作者：
B. Tenhumberg;A. Tyre;R. Rebarber
阶段结构种群模型预测瞬态种群动态，如果人口偏离稳定的阶段分布。生态学家对瞬态动态的兴趣正在增长，因为种群经常偏离稳定阶段分布，这可能导致瞬态动态与稳定阶段动态显着不同。因为人口矩阵的结构（即，生活史阶段的数量）可以影响偏差的预测规模，我们探讨了矩阵大小对预测的瞬态动力学的影响以及由此产生的种群大小的放大。首先，我们通过实验测定了豌豆蚜不同生活史阶段之间的转换速率以及成虫的生殖力和存活率。其次，我们使用这些数据来参数化具有不同阶段数的模型。第三，我们比较了模型预测与经验测量的瞬时人口增长后，引入一个单一的成年蚜虫。我们发现，最大数量的生活史阶段的模型预测的最大的瞬态人口增长率，但在所有的模型中有预测和经验测量的瞬态峰值和最终人口规模的显着低估之间有相当大的差异。例如，20天后的平均种群大小为2394只蚜虫，而最高预测种群大小为531只蚜虫;预测的渐近增长率（lamdamax）与实验一致。这种差异的可能解释进行了讨论。
Stage-structured population models predict transient population dynamics if the population deviates from the stable stage distribution. Ecologists' interest in transient dynamics is growing because populations regularly deviate from the stable stage distribution, which can lead to transient dynamics that differ significantly from the stable stage dynamics. Because the structure of a population matrix (i.e., the number of life-history stages) can influence the predicted scale of the deviation, we explored the effect of matrix size on predicted transient dynamics and the resulting amplification of population size. First, we experimentally measured the transition rates between the different life-history stages and the adult fecundity and survival of the aphid, Acythosiphon pisum. Second, we used these data to parameterize models with different numbers of stages. Third, we compared model predictions with empirically measured transient population growth following the introduction of a single adult aphid. We find that the models with the largest number of life-history stages predicted the largest transient population growth rates, but in all models there was a considerable discrepancy between predicted and empirically measured transient peaks and a dramatic underestimation of final population sizes. For instance, the mean population size after 20 days was 2394 aphids compared to the highest predicted population size of 531 aphids; the predicted asymptotic growth rate (lamdamax) was consistent with the experiments. Possible explanations for this discrepancy are discussed.