Journal of Environmental Biology

Root-surface phosphatase activity in shrublands across a

European gradient: Effects of warming

M. Estiarte*¹, J. Peuuelas¹, J. Sardans¹, B.A. Emmett², A. Sowerby², C. Beier³, I.K. Schmidt⁴, A. Tietema⁵,

M.J.M. Van Meeteren⁵, E. Kovacs Lang⁶, P. Mathe⁷, P.  De Angelis⁸ and G. De Dato⁸

¹Ecophysiology and Global Change Unit CSIC-CEAB-CREAF, CREAF (Center for Ecological Research and Forestry Applications), Edifici C, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona), Spain

²Centre for Ecology and Hydrology-Bangor, Deiniol Rd, Bangor, Gwynedd, LL57 2UP, United Kingdom

³RISØ National Laboratory, P.O.B. 49, DK-4000 Roskilde, Denmark

⁴Danish Centre for Forest, Landscape and Planning. Royal Veterinary and Agricultural University,

Hørsholm Kongevej 11, DK-2970 Hørsholm, Denmark

⁵Center for Geo-ecological Research (ICG), Institute for Biodiversity and Ecosystem Dynamics (IBED) – Physical

Geography, University of Amsterdam, Nieuwe, Achtergracht 166, 1018 WV Amsterdam, The Netherlands

⁶Institute of Ecology and Botany, Hungarian Academy of Sciences, HU-2163, Vacratot, Hungary

⁷Karoly Robert College of Economics and Agriculture, H-3200 Gyongyos, Hungary

⁸Department of Forest Environment and Resources, University of Tuscia, Via San Camillo De Lellis snc, 01100 Viterbo, Italy

(Received: November 13, 2006 ; Revised received: July 03, 2007 ; Accepted: August 14, 2007)

Abstract: Root-surface phosphatase activities were measured in natural and semi-natural shrublands across an European climatic gradient of temperature and rainfall including Wales (WL), Denmark (DK), Netherlands (NL), Hungary (HU), Italy (IT) and Spain (SP). In each site a warming experiment was conducted since 1999 or 2001 by means of passive night-time  warming using reflective curtains that covered the vegetation at night. The treatments increased yearly average  soil temperatures around 0.8^oC in most of sites. Root-surface phosphatase activity values ranged between 56 mg PNP g^-1 h^-1 in IT and 3.5 mg PNP g^-1 h^-1 in HU. Warming had no effect on root-surface phosphatase activity across the sites and only in Hungary a slight increase was detected. Plants at Mediterranean sites (IT, SP) showed a higher root-surface phosphatase activity than plants at temperate sites (WL, NL, DK). We suggest it might be an adaptation of plant species evolved under Mediterranean climate that allows them a) to compensate in wet period for the decrease in phosphatase activity, and thus P uptake, during drought periods, and/or b) to benefit from soluble organic P flushes following the frequent drying-rewetting episodes experienced by soils in Mediterranean ecosystems.

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