Chestnut, the birch, the spruce could disappear on the most part of their historical European distribution. Beech, fir, larch, Scots pine, English and Sessile Oaks could experience negative impacts in some areas of their historical distribution partially compensated by suitability gain for others. Other forest species, such as Maritime pines and Mediterranean oaks, could suffer from minor or no impacts while enlarging their area of distribution.
How will the changing climate affect the forest landscape in Europe in the future? How will geographical distribution, composition and -diversity of forest species in Europe evolve under climate change conditions? What about the Mediterranean region, projected to be one of the future major hotspots of climate change with an increase in water scarcity, temperatures and fire disturbances, with negative consequences for forest ecosystems?
Forest ecosystems are strategic for biodiversity conservation; on a centennial scale, they have evolved their resilience and adaptation capability to disturbances (e.g., droughts, fires, windstorms, pests, diseases, and invasive species), including migration as an option. Under climate change conditions, forest communities have to face an additional challenge: coping with a quickly increasing variability of extreme events and disturbances as well as novel perturbations (e.g., new diseases). Such complex transformations are occurring too fast and forest species have no time to implement adaptation or migration strategies.
Therefore forest conservation strategies and plans can be unsuccessful if the new habitat conditions determined by climate change are not considered.

In a study recently published on Ecology and Evolution, Sergio Noce, Monia Santini and Alessio Collalti, CMCC Foundation researchers at IAFES – Impacts on Agriculture, Forests and Ecosystem Services Division, investigated the likelihood of future suitability, distribution and diversity for some common European forest species under the projected changes in climate, focusing on Southern Europe, and the Mediterranean Basin in particular, as they are among the world’s major areas for plant biodiversity and endemism. The study area covers the territories of 18 countries (Albania, Andorra, Austria, Bosnia and Herzegovina, Bulgaria, Croatia, France, Greece, Italy, Republic of Macedonia, Montenegro, Portugal, Romania, San Marino, Serbia, Slovenia, Spain, and Switzerland): approximately 2.34 million square kilometers, about 30% of it covered by forest. In turn, the 44% of forests is included into protected areas.
Researchers combined an Ensemble Platform for Species Distribution Models (SDMs) to five Global Circulation Models (GCMs) driven by two Representative Concentration Pathways (RCP4.5 and RCP8.5), to produce maps of future climate-driven habitat suitability for ten categories of forest species and two time horizons. More in detail, the aim of the study was to predict the possible impacts of climate change in terms of geographic range shifts, over medium and long term, for the following ten forest categories (groups of species): Fir tree (Abies); Birch (Betula); Chestnut tree (Castanea); Beech (Fagus); Larch (Larix); Spruce (Picea); Maritime Pine (Pinus pinaster); Scots Pine (Pinus sylvestris); English and Sessile Oaks (Quercus rob. – pet.); Mediterranean Oaks (Quercus sp.).

Future impacts of climate change appear to be diversified across forest categories but in general, the whole domain is expected to suffer from a reduced suitability for the forest species analyzed. Considering the different sub-regions, some peculiarities emerge, with the Atlantic and Mediterranean regions suffering from larger losses and significant modifications in forest distribution and diversity. For the Atlantic subregion, the main modification is determined by the reduction of suitability for Betula, Castanea, Fagus, Quercus rp, against a spread of Quercus sp and Pinus pinaster (see the relative maps HERE for the different forest species). The Mediterranean region presents the most affected trends suggesting accelerated dynamics of suitability loss for the considered forest categories and a rearrangement in distribution.

To summarize, results highlighted that while some forest categories will find more suitable conditions in previously unsuitable locations, for other categories, the same new conditions will become less suited. A decrease in local species diversity is projected in most of the area, with Alpine region showing the potentiality to become a refuge for species migration. The Alpine region, in fact, shows a diverging trend, with new species seem finding suitable conditions in the Alps, thus a sort of “quantitative” diversity is preserved.

The results presented in the study represent useful and immediate information to be communicated to stakeholders and policy makers for supporting their design of future forest conservation as well as protection or restoration strategies and plans that account for climate change and its uncertainty range.

Read the integral version of the paper:

Noce S., Collalti A., Santini M.
Likelihood of changes in forest species suitability, distribution, and diversity under future climate: The case of Southern Europe

2017, Ecology and Evolution, Early view, DOI: 10.1002/ece3.3427

Look at the future likelihood suitability map for forest species and their changes in range distribution: the maps developed by CMCC researchers and published on Esri Living Atlas of the World