Adil GÜNER, Vehbi ESER - optima

CLIMATIC SUITABILITY OF TREE SPECIES FROM THE IBERIAN
PENINSULA UNDER CLIMATE CHANGE SCENARIOS
Francisco LLORET 1,2 , J. SERRA 3 , M. NINYEROLA 3 , T. KEENAN 2 , S. SABATE 2,4 .
1 Ecology Unit, Department of Animal Biology, Plant Biology and Ecology, Autonomous University of Barcelona
(UAB), 08193, Barcelona, Spain.; Francisco.Lloret@uab.es
2 Center of Ecological Research and Forestry Applications (CREAF), Autonomous University of Barcelona (UAB),
08193, Barcelona, Spain.
3 Botany Unit, Department of Animal Biology, Plant Biology and Ecology, Autonomous University of Barcelona
(UAB), 08193, Barcelona, Spain.
4 Department of Ecology, University of Barcelona (UB), 08007, Barcelona, Spain.
Assessing the potential future of current forest stands is key to designing conservation strategies
and understanding potential future impacts to ecosystem service supplies. This is particularly true
in the Mediterranean basin, where important future climatic changes are expected. We have
characterized the climatic suitability of more than fifty tree species of the Iberian Peninsula from
current information of the distribution of these species. Then we have mapped the areas with
future climatic suitability for each species under scenarios of climatic change. We used
Generalized Linear Models to model topo-climatic species suitability, based on presence/absence
plots from the Third Spanish National Inventory (SNI). To ensure robustness, only uncorrelated
topo-climatic variables were chosen and 250 subsets of presence/absence were used for each
species. Area Under the ROC Curve (AUC) was used to assess the accuracy of the models,
showing good performance of the models. Climate change impact on the distribution was
addressed projecting the models to the A1FI and A2 scenarios derived from the HadCM3
simulation, developed at the Hadley Centre-UK. We downscaled these values by adding the
predicted mean increase or decline of temperature and precipitation (2050-2080) to the Digital
Climatic Atlas of the Iberian Peninsula.
In addition to the performance of each individual species, pattern of co-occurrence of some pair
of species such as Abies alba and Fagus sylvatica were also investigated. The results showed an
overall decrease of the topo-climatic suitability of both species, allowing identify areas
potentially playing a crucial role as a climatic refugee (Pyrenees mountain range). Accordingly,
current mixed forests of these species will not undergo significant changes because of its current
restricted distribution in the Pyrenees.
Finally we have also compared the modeling approach of climatic suitability (niche-based
models) to the results of the process-based terrestrial biogeochemical model GOTILWA+ that
has been developed in the Mediterranean region to explore how forests are influenced by water
stress, tree stand structure, management techniques, soil properties, and climate (including CO2)
change. We projected the future of current stands of three forest species (Pinus sylvestris, Pinus
halepensis, Quercus ilex) with contrasting distributions, using regionalized climate for
continental Spain. Results highlight variability in model ability to estimate current distributions,
and the inherent large uncertainty involved in making projections into the future. Despite
increased drought stress, CO2 fertilization through projected increased atmospheric CO2
concentrations is shown to increase forest productivity in the mechanistic process based model
that of the non- CO2 fertilisation scenario by the period 2050-2080. This highlights the
importance of introducing aspects of plant biogeochemistry into current niche-based models for a
realistic projection of future species distributions.
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Keywords: climate change, Iberian Peninsula, niche-based model, Pinus sylvestris, Pinus
halepensis, process-based biogeochemical, model species distribution, Quercus ilex tree.
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Oral Lectures