Temperature extremes from a leaf perspective: Micro- vs macro-climate predictors of dwarf-shrub thermal tolerance limits

作者：Sonya R. Geange, A. La Torre, Sebastian Sangha, Vanessa Carteron, Yanis Oudina, Mathéo Touriere, Kristine Birkeli, Josef C. Garen, Nicole Bison, Sean Michlaetz, Hui Tang, Dagmar Egelkraut, Aud H. Halbritter, Vigdis Vandvik · 年份：2025 · DOI：10.5194/egusphere-egu25-14439 · 研究领域：Plant Water Relations and Carbon Dynamics、Tree-ring climate responses、Remote Sensing in Agriculture

Despite their broad climatic and geographic ranges and dominant ecosystem roles across boreal, alpine and arctic vegetation zones; dwarf shrubs can be sensitive to climatic changes, in particular shifting thermal regimes. But questions remain as to the macro-or micro-climatic conditions we should focus upon when considering these changing plant-climate relationships. As a case study highlighting how microclimate insights may contribute at scales from the field through to land-surface models, in the DURIN project we explore how thermal microclimate measures at plant- and leaf-levels can be used to better inform models regarding the thermal tolerance limits of leaves. At high-latitudes, increasing summer heat extremes and aseasonal freezing events associated with changing snowpack dynamics, will expose dwarf-shrubs to potentially stressful conditions for photosynthesis and carbon gain. We explore thermal damage by quantifying temperature at which there is a 50% decline in the maximum quantum yield of photosystem II (FV/FM), for a range of dwarf shrub species growing across habitats and bioclimatic zones. We then compare the extent of photosystem damage to various estimates of temperature extremes as derived from plant-level climate sourced from TOMST loggers, FLIR imagery, and leaf-level thermocouples deployed in dwarf-shrub and non-dwarf-shrub plots. The time-series of fine-scale characterization of dwarf-shrub microclimates in-situ will be correlated with downscaled microclim...