Data from: Population responses to perturbations: the importance of trait-based analysis illustrated through a microcosm experiment

Environmental change continually perturbs populations from a stable state, leading to transient dynamics that can last multiple generations. Several long-term studies have reported changes in trait distributions along with demographic response to environmental change. Here we conducted an experimental study on soil mites and investigated the interaction between demography and an individual trait over a period of nonstationary dynamics. By following individual fates and body sizes at each life-history stage, we investigated how body size and population density influenced demographic rates. By comparing the ability of two alternative approaches, a matrix projection model and an integral projection model, we investigated whether consideration of trait-based demography enhances our ability to predict transient dynamics. By utilizing a prospective perturbation analysis, we addressed which stage-specific demographic or trait-transition rate had the greatest influence on population dynamics. Both body size and population density had important effects on most rates; however, these effects differed substantially among life-history stages. Considering the observed trait-demography relationships resulted in better predictions of a population’s response to perturbations, which highlights the role of phenotypic plasticity in transient dynamics. Although the perturbation analyses provided comparable predictions of stage-specific elasticities between the matrix and integral projection models, the order of importance of the life-history stages differed between the two analyses. In conclusion, we demonstrate how a trait-based demographic approach provides further insight into transient population dynamics.环境变化持续使种群偏离稳定稳态，进而引发可延续多代的瞬态动力学（transient dynamics）。已有多项长期研究报道了性状分布随种群统计学响应环境变化而发生的改变。本研究以土壤螨类为实验对象，针对非稳态动力学过程开展实验，探究种群统计学（demography）与个体性状间的相互作用。通过追踪各生活史阶段的个体存活状态与体型大小，本研究分析了体型与种群密度对种群统计速率的影响。通过对比矩阵投影模型（matrix projection model）与积分投影模型（integral projection model）这两种备选方法的预测性能，本研究探究了纳入基于性状的种群统计学分析是否能提升对瞬态动力学的预测能力。通过采用前瞻性扰动分析（perturbation analysis），本研究明确了哪一阶段特异性种群统计速率或性状转换速率对种群动力学的影响最大。结果表明，体型与种群密度均对多数统计速率具有显著影响，但这类影响在不同生活史阶段间存在显著差异。纳入观测到的性状-种群统计学关联后，种群对扰动的响应预测精度得到提升，这凸显了表型可塑性（phenotypic plasticity）在瞬态动力学中的作用。尽管扰动分析在矩阵投影模型与积分投影模型间对阶段特异性弹性值（elasticity）的预测结果相近，但两种分析所得到的生活史阶段重要性排序存在差异。综上，本研究阐明了基于性状的种群统计学方法如何为瞬态种群动力学研究提供更深层次的科学认知。