Global change is expected to impact on the distribution and abundance of forests. Spain represents the southwestern limit of distribution for several types of deciduous forests and, as part of the Mediterranean Basin, it has all the characteristics to be affected by climate change. This study analyses the effects of climate change on habitat suitability and vulnerability in four categories of deciduous forests: Fagus sylvatica L., Quercus petraea (Matt.) Leibl., Quercus robur L. and Betula celtiberica Rothm. and Vasc. The approach combines an ensemble platform for species distribution models (SDMs) using three algorithms applied to four global circulation models (GCMs) driven by two representative concentration pathways (RCPs). Bioclimatic, biogeographic, soil and topographic variables were taken into consideration as predictors to build 320 single distribution models. Ensemble-forecasting models were then produced for each forest category and RCPs by computing a consensus of single-model projections. The adapted proposal of the Intergovernmental Panel on Climate Change (IPCC) was also applied to deal with the uncertainty and notify the likelihood of the outcomes.

The results revealed generalized losses in habitat suitability compared to current conditions for all the forest categories, which were more drastic for the RCP 8.5 emission pathway. Exceptions worth noting are forests of Fagus sylvatica (likelihood 25%-50%) and Quercus robur (likelihood 75%-100%) in the Orocantabrian biogeographic subprovince, and Quercus petraea formations in the Cantabrian Atlantic subprovince (likelihood 25%-50%). Betula celtiberica would suffer the largest losses of habitat suitability under the climate change scenarios analysed. The vulnerability analysis confirmed that the deciduous formations least affected by climate change in future will be the Orocantabrian forests, while the Pyrenean and Oroiberian communities are the most vulnerable.

The models developed in this study provide decision-makers with basic information and a useful tool for designing plans for the conservation and management of these forests in order to mitigate the impact of climate change. The study also highlights the importance and usefulness of conducting analyses at the biogeographic level, since the effects of climate change may be different and require management and conservation policies at local level.

预计全球变化将影响森林的分布和丰度。西班牙代表了几种落叶林分布的西南边界，作为地中海盆地的一部分，它具有受气候变化影响的所有特征。本研究分析了气候变化对四类落叶林的栖息地适宜性和脆弱性的影响：Fagus sylvatica L. 、Quercus petraea (Matt.) Leibl。, Quercus robur L. 和Betula celtiberica罗姆。和瓦斯克。该方法结合了物种分布模型 (SDM) 的集成平台，使用三种算法应用于由两个代表性浓度路径 (RCP) 驱动的四个全球环流模型 (GCM)。生物气候、生物地理、土壤和地形变量被考虑作为预测因子来构建 320 个单一分布模型。然后通过计算单一模型预测的共识，为每个森林类别和 RCP 生成集合预测模型。政府间气候变化专门委员会 (IPCC) 的改编提案也被应用于处理不确定性和通知结果的可能性。

结果显示，与所有森林类别的当前条件相比，栖息地适宜性的普遍损失，这对于 RCP 8.5 排放途径更为严重。值得注意的例外是Orocantabrian 生物地理亚省的Fagus sylvatica（可能性 25%-50%）和Quercus robur（可能性 75%-100%）的森林，以及Cantabrian Atlantic 亚省的Quercus petraea地层（可能性 25%-50%） . 白桦在所分析的气候变化情景下，栖息地适宜性将遭受最大的损失。脆弱性分析证实，未来受气候变化影响最小的落叶地层将是 Orocantabrian 森林，而 Pyrenean 和 Oroiberian 群落是最脆弱的。

本研究中开发的模型为决策者提供了基本信息和有用的工具，用于设计保护和管理这些森林的计划，以减轻气候变化的影响。该研究还强调了在生物地理层面进行分析的重要性和有用性，因为气候变化的影响可能不同，需要地方层面的管理和保护政策。