Journal article

Boulders as microrefugia: Quantifying a continental-like microclimate supporting Pinus cembra at its oceanic range margin

DOKPE

  • 2026
Published in:
  • Journal of Forest Science . - Czech Academy of Agricultural Sciences (CAAS). - 2026, vol. 72, no. 2, p. 82-92
English Climatic microrefugia allow some forest tree species to persist outside their main distribution range by locally decoupling site conditions from the regional climate. At its western, oceanic range margin in the Swiss Prealps, the Swiss stone pine (Pinus cembra L.) occurs on large boulders embedded within subalpine forests dominated by Norway spruce [Picea abies (L.) H. Karst.]. We hypothesised that these landforms generate a continental-like microclimate enabling P. cembra persistence under otherwise sub-oceanic conditions, and we aimed to quantify this phenomenon. Using high-resolution data loggers, we measured air and soil temperature, thermal amplitudes, and soil moisture on the summits and at the bases of ten limestone boulders over a two-year period. Linear mixed-effects models revealed a pronounced microclimatic decoupling between positions. Boulder summits were consistently warmer and drier during the growing season. In contrast, during winter, summits were significantly colder, while boulder bases remained thermally stable due to persistent snow insulation. The strongest microclimatic divergence occurred in spring, when temperatures at the bases remained stable near 0 °C, whereas summit temperatures were markedly warmer and more variable. This continental-like microclimate likely promotes P. cembra persistence. Our results highlight the importance of topographic heterogeneity for maintaining marginal tree populations.
Faculty
Faculté des sciences et de médecine
Department
Département de Biologie
Language
  • English
Other electronic version

Published version

License
CC BY
Open access status
green
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/335171
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