Mediterranean shrubland growth responses to warming and drought conditions

Abstract

Evergreen sclerophyll shrubland is a prominent feature of Mediterranean Basin. Elevated temperatures and extended drought period are predicted to have a large influence on the functioning of natural and semi-natural environments both directly and through interactions with land management and pollutant loading (Larcher, 2000; Llorens et al., 2003). Climatic changes may have particular strong effects on vulnerable ecosystems, which are already subjected to other stresses such as elevated N deposition, intensive grazing or the risk of fire (Sala et al., 1998). An experimental manipulation of climatic conditions at field scale was conducted employing a newly developed "night-time warming" technique and an automated covering system to extend summer drought (Beier et al., 2002). The objective of this study was to test how a future extended drought period and an increase in temperature could affect plant response in terms of plant cover and biomass, plant growth and reproductive effort. In this paper preliminary results obtained during the two first years of experiment (2002 and 2003) are shown