Did we underestimate forests as refugia from global warming?

Climatic conditions are milder under forest cover than out in the open. That is common knowledge: “forests are cooler during the day, warmer during the night!”. Extreme temperature are buffered under the canopy, decreasing maximum temperatures by 4-5°C on average.

However, this effect of forest cover is often discarded in species distribution models, also called niche models. These models are usually calibrated on large temperature grids with coarse resolution (up to 1 km²), interpolated from meteorological station that are systematically placed outside forests. Yet, temperatures that are experienced by biodiversity at fine-scale (i.e. microclimate) can be very different from regional macroclimate, especially in forest ecosystems. In the face of ongoing climate change, forest could act as a climate refugia for threatened species.

Anemone hepatica, growing in the shade of tree cover (photo by Eva Gril)

For further information on this matter, here are two open-access scientific papers:

[Lenoir et al. 2017] : Climatic microrefugia under anthropogenic climate change: implications for species redistribution

[Lembrechts et al. 2019] : Incorporating microclimate into species distribution models