The role of climate in determining range margins is often studied using species distribution models (SDMs), which are easily applied but have well‐known limitations, e.g. due to their correlative nature and colonization and extinction time lags. Transplant experiments can give more direct information on environmental effects, but often cover small spatial and temporal scales. We simultaneously applied a SDM using high‐resolution spatial predictors and an integral projection (demographic) model based on a transplant experiment at 58 sites to examine the effects of microclimate, light and soil conditions on the distribution and performance of a forest herb, Lathyrus vernus, at its cold range margin in central Sweden. In the SDM, occurrences were strongly associated with warmer climates. In contrast, only weak effects of climate were detected in the transplant experiment, whereas effects of soil conditions and light dominated. The higher contribution of climate in the SDM is likely a result from its correlation with soil quality, forest type and potentially historic land use, which were unaccounted for in the model. Predicted habitat suitability and population growth rate, yielded by the two approaches, were not correlated across the transplant sites. We argue that the ranking of site habitat suitability is probably more reliable in the transplant experiment than in the SDM because predictors in the former better describe understory conditions, but that ranking might vary among years, e.g. due to differences in climate. Our results suggest that L. vernus is limited by soil and light rather than directly by climate at its northern range edge, where conifers dominate forests and create suboptimal conditions of soil and canopy‐penetrating light. A general implication of our study is that to better understand how climate change influences range dynamics, we should not only strive to improve existing approaches but also to use multiple approaches in concert.

中文翻译：

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寒冷边缘的气候限制：物种分布模型和移植实验的对比视角

通常使用物种分布模型 (SDM) 来研究气候在确定范围边缘中的作用，这些模型易于应用但具有众所周知的局限性，例如由于它们的相关性以及殖民和灭绝时间滞后。移植实验可以提供更多关于环境影响的直接信息，但通常涵盖较小的空间和时间尺度。我们同时应用了使用高分辨率空间预测因子的 SDM 和基于 58 个地点的移植实验的积分投影（人口统计）模型，以检查小气候、光照和土壤条件对森林草本植物 Lathyrus vernus 的分布和性能的影响，在瑞典中部的寒冷边缘。在 SDM 中，事件与温暖的气候密切相关。相比之下，在移植实验中仅检测到气候的微弱影响，而土壤条件和光照的影响占主导地位。气候在 SDM 中的较高贡献可能是由于其与土壤质量、森林类型和潜在的历史土地利用的相关性，而这些在模型中没有得到解释。两种方法产生的预测栖息地适宜性和人口增长率在移植地点之间没有相关性。我们认为，移植实验中的地点栖息地适宜性排名可能比 SDM 中的更可靠，因为前者中的预测因子更好地描述了林下条件，但该排名可能因年份而异，例如由于气候差异。我们的研究结果表明，L. vernus 受土壤和光照的限制，而不是直接受其北部山脉边缘的气候限制，针叶树在森林中占主导地位，并造成土壤和树冠穿透光的次优条件。我们研究的一般含义是，为了更好地了解气候变化如何影响范围动态，我们不仅应该努力改进现有方法，而且还应协同使用多种方法。