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A whole plant approach to evaluate the water use of mediterranean maquis species in a coastal dune ecosystem
1Sapienza University of Rome, Dept. of Plant Biology, P.le Aldo Moro 5, 00185 Rome, Italy
2Catholic University of the Sacred Heart, Dept. of Mathematics and Physics, Via Musei 41, 25121 Brescia, BS, Italy
3Katholieke Universiteit Leuven, Dept. Forest, Nature and Landscape, Celestijnenlaan, 200E, 3001 Leuven, Belgium
Abstract. An integrated approach has been used to analyse the water relations of three Mediterranean species, A. unedo L., Q. ilex L. and P. latifolia L. co-occurring in a coastal dune ecosystem. The approach considered leaf level gas exchange, sap flow measurements and structural adaptations between 15 May and 31 July 2007, and was necessary to capture the different response of the three species to the same environment. The complexity of the response was proportional to the complexity of the system, 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 species differences in this responses have been partially attributed to a different root distribution. Sap flow of A. unedo decreased rapidly in response to the decline of Soil Water Content, while that of Q. ilex decreased only moderately. Midday leaf water potential of P. latifolia and A. unedo was between 2.2 and 2.7 MPa through the measuring period, while in Q. ilex it reached a value of 3.4 MPa at the end of the season. A. unedo was the only species to decrease the leaf area to sapwood area ratio from 23.9±1.2 (May) to 15.2±1.5 (July), as a response to drought. A. unedo also underwent an almost stepwise loss on hydraulic conductivity, such a loss didn't occur for Q. ilex, while P. latifolia was able to slightly increase hydraulic conductivity, showing how different plant compartments coordinate differently between species as a response to drought. Such different coordination affects the gas exchange between vegetation and the atmosphere, and has implications for the response of the Mediterranean coastal dune ecosystems to climate change.
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Citation: Mereu, S., Salvatori, E., Fusaro, L., Gerosa, G., Muys, B., and Manes, F.: A whole plant approach to evaluate the water use of mediterranean maquis species in a coastal dune ecosystem, Biogeosciences Discuss., 6, 1713-1746, 2009. Bibtex EndNote Reference Manager
