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www.biogeosciences.net/6/2599/2009/
doi:10.5194/bg-6-2599-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
An integrated approach shows different use of water resources from Mediterranean maquis species in a coastal dune ecosystem
1Sapienza University of Rome, Department of Plant Biology, P.le Aldo Moro 5, 00185, Rome, Italy
2Catholic University of the Sacred Heart, Department of Mathematics and Physics, Via Musei 41, 25121 Brescia, BS, Italy
3Katholieke Universiteit Leuven, Department Forest, Nature and Landscape, Celestijnenlaan 200E, 3001, Leuven, Belgium
Abstract. An integrated approach has been used to analyse the dependence of three Mediterranean species, A. unedo L., Q. ilex L., and P. latifolia L. co-occurring in a coastal dune ecosystem on two different water resources: groundwater and rainfed upper soil layers. The approach included leaf level gas exchanges, sap flow measurements and structural adaptations between 15 May and 31 July 2007. During this period it was possible to capture different species-specific response patterns to an environment characterized by a sandy soil, with a low water retention capacity, and the presence of a water table. The latter did not completely prevent the development of a drought response and, combined with previous studies in the same area, response differences between species have been partially attributed to different root distributions. Sap flow of A. unedo decreased rapidly with the decline of soil water content, while that of Q. ilex decreased only moderately. Midday leaf water potential of P. latifolia and A. unedo ranged between −2.2 and −2.7 MPa throughout the measuring period, while in Q. ilex it decreased down to −3.4 MPa at the end of the season. A. unedo was the only species that responded to drought with a decrease of its leaf area to sapwood area ratio from 23.9±1.2 (May) to 15.2±1.5 (July). While A. unedo also underwent an almost stepwise loss on hydraulic conductivity, such a loss did not occur for Q. ilex, whereas P. latifolia was able to slightly increase its hydraulic conducitivity. These differences show how different plant compartments coordinate differently between species in their responses to drought. The different responses appear to be mediated by different root distributions of the species and their relative resistances to drought are likely to depend on the duration of the periods in which water remains extractable in the upper soil layers.
Final Revised Paper (PDF, 3431 KB) Discussion Paper (BGD)
Citation: Mereu, S., Salvatori, E., Fusaro, L., Gerosa, G., Muys, B., and Manes, F.: An integrated approach shows different use of water resources from Mediterranean maquis species in a coastal dune ecosystem, Biogeosciences, 6, 2599-2610, doi:10.5194/bg-6-2599-2009, 2009. Bibtex EndNote Reference Manager XML
