, Volume 22, Issue 3, pp 375–384

Limited capacity to cope with excessive light in the open and with seasonal drought in the shade in Mediterranean Ilex aquifolium populations


    • Instituto Nacional de Investigaciones Agrarias y Tecnologías AgroalimentariasCentro de Investigación Forestal, Unidad Mixta INIA-UPM
  • Thomas Matthew Robson
    • Instituto Nacional de Investigaciones Agrarias y Tecnologías AgroalimentariasCentro de Investigación Forestal, Unidad Mixta INIA-UPM
  • Jesus Rodríguez-Calcerrada
    • Unidad de Anatomía, Fisiología y Genética Forestal, Escuela Técnica Superior de Ingenieros de MontesUniversidad Politécnica de Madrid, Unidad Mixta INIA-UPM Ciudad Universitaria s/n
  • Fernando Valladares
    • Instituto de Recursos Naturales, Centro de Ciencias Medioambientales, CSIC
    • Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y TecnológicasUniversidad Rey Juan Carlos
Original Paper

DOI: 10.1007/s00468-007-0192-5

Cite this article as:
Aranda, I., Robson, T.M., Rodríguez-Calcerrada, J. et al. Trees (2008) 22: 375. doi:10.1007/s00468-007-0192-5


Climate change is expected to involve more-frequent and intense summer droughts in the Mediterranean region. This represents a threat for long-term persistence of woody species, such as European holly (Ilex aquifolium), that originated under humid climates during the Tertiary period. The capacity of this species to persist under increased water stress, both in gaps and in the understory of an oak-dominated woodland, was assessed by quantifying phenotypic plasticity in response to drought and shade. Physiological responses in plant-water relations and gas exchange were used as performance indicators under the different environments. Phenotypic plasticity of drought-stressed holly trees in response to changes in the light environment was low relative to the known response of co-occurring forest trees. Differences between morphological traits (e.g. specific leaf area and leaf: sapwood ratio in twigs) of sun- and shade-grown trees were small but significant while physiological traits were largely unresponsive to light availability. This supports the hypothesis that late-successional shade-tolerant species exhibit greater morphological than physiological plasticity. Sapling acclimation capacity through physiological mechanisms such as osmotic adjustment was insufficient to protect from summer drought. Holly mainly inhabits oceanic climates where extreme temperatures and droughts are unusual. Our results suggest that the species occupies a narrowing niche in continental Mediterranean habitats, and may lack the capacity to persist under more-severe future climate scenarios because of its low phenotypic plasticity in response to light and drought stresses.


Water stressPlasticityAcclimationHollyClimate change

Copyright information

© Springer-Verlag 2007