Abstract Spruce-fir-beech mixed forests cover a large area in European mountain regions, with high ecological and socio-economic importance. As elevation-zone systems they are highly affected by climate change, which is modifying species growth patterns and productivity shifts among species. The extent to which associated tree species can access resources and grow asynchronously may affect their resistance and persistence under climate change. Intra-specific synchrony in annual tree growth is a good indicator of species specific dependence on environmental conditions variability. However, little attention has been paid to explore the role of the inter-specific growth asynchrony in the adaptation of mixed forests to climate change. Here we used a database of 1790 tree-ring series collected from 28 experimental plots in spruce-fir-beech mixed forests across Europe to explore how spatio-temporal patterns of the intra- and inter-specific growth synchrony relate to climate variation during the past century. We further examined whether synchrony in growth response to inter-annual environmental fluctuations depended on site conditions. We found that the inter-specific growth synchrony was always lower than the intra-specific synchrony, for both high (inter-annual fluctuations) and low frequency (mid- to long-term) growth variation, suggesting between species niche complementarity at both temporal levels. Intra- and inter-specific synchronies in inter-annual growth fluctuations significantly changed along elevation, being greater at higher elevations. Moreover, the climate warming likely induced temporal changes in synchrony, but the effect varied along the elevation gradient. The synchrony strongly intensified at lower elevations likely due to climate warming and drying conditions. Our results suggest that intra- and inter-specific growth synchrony can be used as an indicator of temporal niche complementarity among species. We conclude that spruce-fir-beech mixtures should be preferred against mono-specific forests to buffer climate change impacts in mountain regions.

中文翻译：

---

海拔依赖性气候变暖对混交山林种内和种间生长同步性的影响

摘要 云杉-冷杉-山毛榉混交林覆盖欧洲山区大面积，具有较高的生态和社会经济重要性。作为海拔带系统，它们受气候变化的影响很大，气候变化正在改变物种的生长模式和物种之间的生产力变化。相关树种获取资源和异步生长的程度可能会影响它们在气候变化下的抵抗力和持久性。树木年生长的种内同步性是物种对环境条件变异性的特定依赖性的一个很好的指标。然而，很少有人关注探讨种间生长不同步在混交林适应气候变化中的作用。在这里，我们使用从欧洲云杉-冷杉-山毛榉混交林的 28 个试验地块收集的 1790 个树轮系列的数据库来探索过去种内和种间生长同步的时空模式如何与气候变化相关。世纪。我们进一步研究了生长响应年际环境波动的同步性是否取决于场地条件。我们发现，对于高（年际波动）和低频（中长期）生长变化，种间生长同步总是低于种内同步，这表明物种生态位之间在两个时间上的互补性水平。年际生长波动中的种内和种间同步性随海拔变化显着变化，在较高海拔处更大。而且，气候变暖可能会引起同步的时间变化，但影响随海拔梯度变化。由于气候变暖和干燥条件，同步性在低海拔地区强烈加强。我们的结果表明，种内和种间生长同步可用作物种间时间生态位互补性的指标。我们得出结论，云杉-冷杉-山毛榉混合物应优先于单一特定森林，以缓冲山区气候变化的影响。我们的结果表明，种内和种间生长同步可用作物种间时间生态位互补性的指标。我们得出结论，云杉-冷杉-山毛榉混合物应优先于单一特定森林，以缓冲山区气候变化的影响。我们的结果表明，种内和种间生长同步可用作物种间时间生态位互补性的指标。我们得出结论，云杉-冷杉-山毛榉混合物应优先于单一特定森林，以缓冲山区气候变化的影响。