12.4.4.2 Shrublands

The area of European shrublands has increased over recent decades, particularly in the south (Moreira et al., 2001; Mouillot et al., 2003; Alados et al., 2004). Climate change is likely to affect its key ecosystem functions such as carbon storage, nutrient cycling, and species composition (Wessel et al., 2004). The response to warming and drought will depend on the current conditions, with cold, moist sites being more responsive to temperature changes, and warm, dry sites being more responsive to changes in rainfall (Peñuelas et al., 2004). In northern Europe, warming will increase microbial activity (Sowerby et al., 2005), growth and productivity (Peñuelas et al., 2004), hence enabling higher grazing intensities (Wessel et al., 2004). Encroachment by grasses (Werkman and Callaghan, 2002) and elevated nitrogen leaching (Emmet et al., 2004; Gorissen et al., 2004; Schmidt et al., 2004) are also likely. In southern Europe, warming and, particularly, increased drought, are likely to lead to reduced plant growth and primary productivity (Ogaya et al., 2003; Llorens et al., 2004), reduced nutrient turnover and nutrient availability (Sardans and Peñuelas 2004, 2005), altered plant recruitment (Lloret et al., 2004; Quintana et al., 2004), changed phenology (Llorens and Peñuelas, 2005), and changed species interactions (Maestre and Cortina, 2004; Lloret et al., 2005). Shrubland fires are likely to increase due to their higher propensity to burn (Vázquez and Moreno, 2001; Mouillot et al., 2005; Nunes et al., 2005; Salvador et al., 2005). Furthermore, increased torrentiality (Giorgi et al., 2004) is likely to lead to increased erosion risk (de Luis et al., 2003) due to reduced plant regeneration after frequent fires (Delitti et al., 2005).

12.4.4.3 Grasslands

Permanent pastures occupied 37% of the agricultural area in Europe in 2000 (FAOSTAT, 2005). Grasslands are expected to decrease in area by the end of this century, the magnitude varying depending on the emissions scenario (Rounsevell et al., 2006). Climate change is likely to alter the community structure of grasslands in ways specific to their location and type (Buckland et al., 2001; Lüscher et al., 2004; Morecroft et al., 2004). Management and species richness may increase resilience to change (Duckworth et al., 2000). Fertile, early succession grasslands were found to be more responsive to climate change than more mature and/or less fertile grasslands (Grime et al., 2000). In general, intensively-managed and nutrient-rich grasslands will respond positively to both increased CO₂ concentration and temperature, given that water and nutrient supply is sufficient (Lüscher et al., 2004). Nitrogen-poor and species-rich grasslands may respond to climate change with small changes in productivity in the short-term (Winkler and Herbst, 2004). Overall, productivity of temperate European grassland is expected to increase (Byrne and Jones, 2002; Kammann et al., 2005). Nevertheless, warming alone is likely to have negative effects on productivity and species mixtures (Gielen et al., 2005; de Boeck et al., 2006). In the Mediterranean, changes in precipitation patterns are likely to negatively affect productivity and species composition of grasslands (Valladares et al., 2005).