Department of Biology and Botanic Garden, University of Fribourg, Fribourg, Switzerland.
Department of Geosciences, University of Fribourg, Fribourg, Switzerland.
Glob Chang Biol. 2024 Feb;30(2):e17196. doi: 10.1111/gcb.17196.
Cliffs are remarkable environments that enable the existence of microclimates. These small, isolated sites, decoupled from the regional macroclimate, play a significant role in maintaining species biodiversity, particularly in topographically homogeneous landscapes. Our study investigated the microclimate of south-exposed forests situated at the edge of sandstone cliffs in the western part of the North Alpine Foreland Basin in Switzerland and its role in local forest community composition. Using direct measurements from data loggers, as well as vegetation analyses, it was possible to quantify the microclimate of the cliff-edge forests and compare it with that of the surrounding forests. Our results highlighted the significant xerothermic and more variable nature of the cliff-edge forest microclimate, with a mean soil temperature up to 3.72°C warmer in the summer, higher annual (+28%) and daily (+250%) amplitudes of soil temperature, which frequently expose vegetation to extreme temperatures, and an 83% higher soil drying rate. These differences have a distinct influence on forest communities: cliff-edge forests are significantly different from surrounding forests. The site particularities of cliff edges support the presence of locally rare species and forest types, particularly of Scots pine. Cliff edges must therefore be considered microrefugia with a high conservation value for both xerothermic species and flora adapted to more continental climates. Moreover, the microclimate of cliff-edge forests could resemble the future climate in many ways. We argue that these small areas, which are already experiencing the future climate, can be seen as natural laboratories to better answer the following question: what will our forests look like in a few decades with accelerated climate change?
悬崖是非常独特的环境，能够形成小气候。这些与区域大气候隔绝的小型孤立地点，对维持物种生物多样性起着重要作用，尤其是在地形均匀的景观中。我们的研究调查了瑞士阿尔卑斯山前地西部地区暴露在南侧的悬崖边缘森林的小气候及其对当地森林群落组成的作用。我们使用数据记录仪的直接测量以及植被分析，对悬崖边缘森林的小气候进行了量化，并将其与周围森林的小气候进行了比较。研究结果突出了悬崖边缘森林小气候明显的干旱和更具变异性的特点，夏季平均土壤温度高出 3.72°C，土壤温度的年振幅（+28%）和日振幅（+250%）更高，这使得植被经常暴露在极端温度下，土壤干燥速度快 83%。这些差异对森林群落产生了明显的影响：悬崖边缘森林与周围森林有显著的不同。悬崖边缘的特殊位置支持了局部稀有物种和森林类型的存在，特别是苏格兰松。因此，悬崖边缘必须被视为具有高度保护价值的微生境，对耐旱物种和适应更大陆性气候的植物都具有保护价值。此外，悬崖边缘森林的小气候在很多方面与未来的气候相似。我们认为，这些已经在经历未来气候的小面积区域，可以被视为自然实验室，以更好地回答以下问题：在加速气候变化的情况下，我们的森林在几十年后会是什么样子？
