Adil GÜNER, Vehbi ESER - optima

Oral Lectures
44
GLOBAL CHANGE EFFECTS ON RELICT WESTERN-
MEDITERRANEAN MOUNTAIN FORESTS
JUAN CARLOS LINARES, 1 , J.J. CAMARERO, 2 , P. TISCAR, 3 , L. TAÏQUI, 4 &
J.A.CARREIRA 5
1: Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. de Utrera s/n,
Sevilla, España. e-mail: jclincal@upo.es
2: ARAID, Instituto Pirenaico de Ecología, CSIC Avda. Montaña, 1005. 50192 Zaragoza, España. e-mail:
jjcamarero@ipe.csic.es
3: Centro de Capacitación y Experimentación Forestal.
23470 Cazorla (Jaén).*e-mail: pedroa.tiscar@juntadeandalucia.es
4: Faculté des Sciences. Mhannech II. 93002. B.P 2121 Tétouan (Maroc). e-mail: lahcent@gmail.com
5: Departamento de Biología Animal, Vegetal y Ecología, Universidad de Jaén, Campus “Las Lagunillas” s/n, Jaén,
España. e-mail: jafuente@ujaen.es
Long-term basal area increment (BAI) in Abies pinsapo from south Spain and north Morocco,
Cedrus atlantica from Middle Atlas in Morocco, Pinus nigra from south-east Spain, and Abies
alba from north Spain, were studied to investigate growth trend in relic Western-Mediterranean
mountain forests. We want to elucidate the way land-use history and density-dependent factors
modulate the responses of radial growth to climatic stresses for several drought-sensitive conifer.
First, we verified that land-use history and density-dependent factors predicts mean BAI for the
studied species; i.e. it modulates the degree to which the average climate-driven potential for
growth is expressed. Then, we verified that the long-term pattern of temperature predicts the
long-term pattern of BAI, estimated as the main trend over the XX century. We applied Dynamic
Factor Analysis (DFA) to regional data of temperature in order to test the hypothesis Western-
Mediterranean Basin has experienced similar temperature increase. DFA was also applied to
mean BAI to quantify common growth trends among the studied trees species. The mean BAI
was mainly determined by site mean precipitation, land-use history and density-dependent
factors, whereas growth trends obtained by DFA were similar among species. Common trends of
growth decline were strongly related to long-term, late-winter to summer temperatures, while the
residuals were related to total annual precipitation, although with decreasing significance as mean
site precipitation increased. Our results support the contention that global warming is related to
widespread growth decline and death recently observed in relic Mediterranean mountain forest.
Long-term climatic drought stress was the main driving factor of growth decline in the studies
species. Moreover, trees from drier sites, growing at higher stand density, were predisposed to
decline given an additional short-term stress, such as a severe drought.
Keywords: adaptive capacity, basal-area increment, climatic change, drought, Dynamic Factor
Analysis, global warming, linear mixed models, vulnerability
32