A research that included the involvement of the UAB and CREAF has studied the factors that help forests maintain stable productivity over time and concludes that water and biodiversity are key determinants. The study has been published in the European Journal of Forest Research.
The study was conducted by Rafael Poyatos and Jordi Martínez-Vilalta, researchers in the Department of Animal Biology, Plant Biology and Ecology of the UAB and CREAF. Researchers from the Global Change Research Institute (IICG-URJC), the Functional Ecology and Biogeochemistry of Soils and Agroecosystems Unit (UMR Eco&Sols), and the Norwegian Bioeconomy Research Institute (NIBIO) were also involved.
The study is based on 20 years of observations of forests in Catalonia, a region of particular interest because it combines temperate and Mediterranean conditions and exhibits significant variations in water availability for plants across different areas. The researchers also incorporated data from 548 plots from the Ecological and Forest Inventory of Catalonia, which contains field-measured information on forest structure and species' functional traits. Functional traits are characteristics that reflect the distinctive ecological strategies of species within an ecosystem—such as growing faster or slower, utilising resources differently, and varying in their resistance to drought.
"This research is important because it shows how the diversity of functional strategies in Mediterranean forests can contribute to greater stability in the face of climate change," Rafael Poyatos points out.
Water and functional diversity
Based on the Normalised Difference Vegetation Index (NDVI) time series obtained by the Terra satellite between 2000 and 2019, researchers evaluated each plot's capacity to maintain stable productivity over time and linked this stability to climatic characteristics, vegetation structure, and functional composition and diversity.
The results show that, in general, forests with better water conditions tend to maintain more stable productivity over time—which is to be expected, given that tree growth is directly linked to water availability. However, researchers also observed that forests with greater functional diversity—that is, those containing species with a wider range of ecological strategies—tend to be more stable. These findings are highly significant in a context where many Mediterranean regions are expected to experience longer and more intense droughts.
"In the case of CREAF, we contributed a dataset on functional strategies—compiled from the Ecological and Forest Inventory of Catalonia—as well as our expertise in analysing this data, combined with remote sensing data, within the field of functional forest ecology", Jordi Martínez-Vilalta states.
Applications against climate change
Raúl García Valdés, from the IICG-URJC and senior researcher in this study, explains that "functionally diverse forests can better respond to changing conditions, because not all species react in the same way to drought, heat, or other stressors". This idea has direct implications for forest management and policy.
In a context of climate change, it is not enough to assess whether a forest is productive at a given moment; one must also consider whether it will be able to maintain its productivity over time. Indeed, forest management can contribute to this goal by fostering communities with a greater diversity of functional strategies and avoiding the excessive simplification of forests.
"The combination of forest inventories in the field and satellite observation offers a very useful tool for monitoring the stability of forests on a large scale and over long periods, by providing information on what the best management strategies may be in an increasingly unstable and extreme climate context", points out Robinson Vauthier, a member of the research team, about these measures to anticipate risks.
Considering the changes our forests are experiencing, environmental managers should take all these studies into account, since research such as that presented here can serve to guide decisions on restoration, species selection, conservation of mixed stands, and adaptive forest planning, always taking into account the local conditions of each area.
Original article: Vauthier, R., Martínez-Vilalta, J., Poyatos, R. et al. Water availability and functional trait diversity drive temporal stability in temperate and Mediterranean forests. Eur J Forest Res 145, 90 (2026). https://doi.org/10.1007/s10342-026-01933-2
