1 research outputs found
Disentangling the climatic and biotic factors driving changes in the dynamics of Quercus suber populations across the speciesâ latitudinal range
We thank A.J. MuñozâPajares, L. RodrĂguez and G. Rutten for their
help and logistic support during field sampling and M.E. SĂĄnchez,
M. Serrano and M.A. Romero for pathogen analyses and interestâ
ing discussions.Data will be available from the Dryad Digital Repository upon
acceptance.Aim: Impacts of different global change drivers are altering the performance of plant
species worldwide. However, these pressures usually differ across the speciesâ distriâ
bution range. To properly assess the combined effect of global change at species
level, we need to evaluate its consequences across their complete distribution. We
focused on recent decline in Cork oak (Quercus suber L.) populations given its high
ecological and economic relevance.
Location: We selected 10 different sites (and two populations per site) separated
about one degree in latitude across the core distribution of Q. suber, following a
transcontinental aridity gradient.
Methods: To evaluate the current trends in population dynamics across the speciesâ
distribution and the factors implied on population decline, we evaluated the effect of
latitude, aridity, pathogens (Phytophthora cinnamomi), stand density and tree size on
seed and crop size, demographic structure, dominance of recruitment bank, defoliaâ
tion and mortality.
Results: We found an increase in seed weight as latitude decreased, with a homogeneâ
ous low crop size across the complete distribution. Demographic structure was deterâ
mined by latitude, precipitation and pathogen abundance. We detected a trend towards
reduced sapling densities towards the southern edge of the distribution, with a demoâ
graphic structure dominated by old trees. The low sapling density at the southern edge
translates into a loss of dominance with respect to other woody species, suggesting an
alteration of community structure in the midâterm future. Tree density, precipitation
and pathogen abundance determined tree mortality across the species distribution,
with a higher abundance of pathogens in centralâlatitude populations.
Main conclusions: Our results allow the early detection of declining trends and the
evaluation of the main risks for speciesâ conservation, suggesting potential for range
displacement of the species driven by the recruitment failure at the southern edge of
the distribution and a likely range expansion at northern populations.This research was funded by the Large Research
Grant (6007210) awarded from the British Ecological Society to L.M.
L.G.A. acknowledges support from the MICINN project INTERCAPA
(CGLâ2014â56739âR) and European FEDER Fund