García-López, M. A., García-Cervigón, A. I., Elias, R. B., Calvo, V., Fernández-Palacios, J. M., García-Hidalgo, M., Gómez-González, S., Gouveia, M., Sequeira, M. M., Olano, J. M., Pescador, D. S., Sangüesa-Barreda, G., & Rozas, V. (2025). Cloud forest tree growth responses to climate and drought vary by island and species in the Macaronesian region.
Journal of Biogeography, Online early, . DOI:10.1111/jbi.15091 (IF2024 3,4; Q1 Ecology)Aim: Macaronesian cloud forests are insular ecosystems subjected to local environmental variability, but the responses of theirtree species to climate variations have never been studied. Our aim was to assess how the variation in environmental conditionsassociated with the geographical location of several islands in three Macaronesian archipelagos affects the growth patterns anddrought-resistance of the dominant cloud forests trees.
Location: Azores, Madeira and Canary archipelagos. Portugal and Spain.
Taxon: Lauraceae, Aquifoliaceae, Clethraceae, Oleaceae, Rosaceae and Cupressaceae.
Methods: We assessed variations in the radial growth response of 10 cloud forest tree species from 18 populations on 5 is-lands along a geographical gradient in Macaronesia. We quantified the influence of local climatic variables and North AtlanticOscillation (NAO) and East Atlantic Pattern (EA) circulation patterns on tree growth and how drought events affected to theresistance, recovery and resilience indices estimated for these species.
Results: Trees from the same island showed similar growth patterns, particularly in islands with marked hydric stress. In Madeira and the Canary Islands, radial growth was mainly determined by water availability, winter NAO negatively affected growth and droughts caused abrupt narrow growth-ring width. In the Azores, the effect of the EA was positive, as it increasedtemperature and relative humidity and promoted growth. Trees from wetter environments demonstrated higher growth resist-ance to drought, while trees from drier sites showed faster growth recovery after drought events.Main
Conclusions: Homogeneous growth patterns among species from the same island suggested that the radial growth of treesin cloud forests is mostly determined by local environmental conditions, which are more important for their growth than pheno-typic traits. The variability in water availability determined by a latitudinal geographical gradient throughout the Macaronesianregion influenced both the climatic response of the trees and their resilience to drought.
