To understand how the environment drives spatial variation in population dynamics, we need to assess the effects of a large number of potential drivers on vital rates (survival, growth, and reproduction) and explore these relationships over large geographical areas and broad environmental gradients. In this study, we examined the effects of a wide variety of abiotic and biotic environmental factors on the demography of the forest understory herb Actaea spicata between 2017 and 2019 at 40 sites across Sweden, including the northern range margin of its distribution. We assessed the effects of potential environmental drivers on vital rates using generalized linear mixed models (GLMMs) and then quantified the impact of each important driver on population growth rate (λ) using integral projection models (IPMs). Population dynamics of A. spicata were mostly driven by environmental factors affecting survival and growth, such as air humidity, soil depth, and forest tree species composition, and thus, those drivers jointly determined the realized niche of the species. Soil pH had a strong effect on the flowering probability, while the effect on λ was relatively small. In addition to identifying specific drivers for A. spicata’s population dynamics, our study illustrates the impact that spatial variation in environmental conditions can have on λ. Assessing the effects of a broad range of potential drivers, as done in this study, is important not only to quantify the relative importance of different drivers for population dynamics but also to understand species distributions and abundance patterns.

中文翻译：

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多年生植物大规模空间人口变化的驱动因素

要了解环境如何驱动人口动态的空间变化，我们需要评估大量潜在驱动因素对生命率（生存，增长和繁殖）的影响，并在较大的地理区域和广泛的环境梯度中探索这些关系。在这项研究中，我们研究了多种非生物和生物环境因素对林下草本植物Actaea spicata的人口统计学的影响。在2017年至2019年期间，在瑞典的40个站点​​（包括分布范围的北部边界）进行了调查。我们使用广义线性混合模型（GLMM）评估了潜在环境驱动因素对生命率的影响，然后使用积分投影模型（IPM）量化了每个重要驱动因素对人口增长率（λ）的影响。香菇的种群动态主要由影响生存和生长的环境因素驱动，例如空气湿度，土壤深度和林木物种组成，因此，这些驱动因素共同决定了该物种的已实现生态位。土壤pH值对开花概率的影响很大，而对λ的影响相对较小。除了识别特定的驱动程序A.兰香的种群动态，我们的研究表明环境条件的空间变化可能对λ产生影响。像本研究一样，评估各种潜在驱动因素的影响不仅对于量化不同驱动因素对种群动态的相对重要性，而且对于了解物种分布和丰度模式都很重要。