## 2 Materials and Methods  
### Study Area  
This study was conducted in the IT3120018 \"Scanuppia\" Natura 2000 site, an area (529 ha) protected under the Directive 92/43/CEE [24] in Trento Province, south-eastern Alps (45\({}^{\circ}\)57\({}^{\prime}\) N 11\({}^{\circ}\)09\({}^{\prime}\) E) (Figure 1). The forest is dominated by Norway spruce (_Picea abies_ (L.) [PERSON]) with some areas covered with silver fir (_Abies alba_ [PERSON]), European larch (_Larix decidua_ [PERSON]), and European beech (_Fagus sylvatica_ [PERSON]). Mixed stands as well as small pastures are also found in the area.  
The forest management plan [25] highlights a decreasing pressure on natural resources. Half of the forests in the protected area are grazed, although numbers of grazing animals decreased from more than 130 cows and 900 sheep in 1839, to 75 cows in 2007. At the beginning of the 20 th century, timber yield was higher than 700 m\({}^{3}\)/y and firewood production more than 20,000 kg/y [25]. Since the 1950s timber harvests have been reduced to zero and the site has been integrally protected since 1990. The reduction in the intensity of logging and grazing has led to rewind the area with the gradual spread of shrubs and vertical stratification of the canopy structure. The existence of this trend is supported both by aerial photos observation (Figure 2) and by the expansion of trees and shrubs on former open landswhich has been quantified (0.1% forest cover annual growth rate) in the region by comparing remote sensed data from different time periods [5; 26].  
The altitude of the Natura 2000 site ranges between 1450 m and 2130 m a.s.l. (highest summit located at its north-eastern vertex) and has western facing slopes. To understand recent climate changes, data series from 1989 to 2010 available from three nearby (12 km NW of the study area) weather stations on Mt. Bondone can be used as they are at a similar altitude (1490-1552 m a.s.l.) and latitude to our study site. Mean annual rainfall and temperature of this period are 1407 mm and 5.7 \({}^{\circ}\)C, respectively. Using a linear time trend model, the averaged surface air temperature has increased by 1.3 \({}^{\circ}\)C in April (mean = 3.6 \({}^{\circ}\)C, std = 1.2), 2.5 \({}^{\circ}\)C in May (mean = 8.8 \({}^{\circ}\)C, std = 1.3), and 2.7 \({}^{\circ}\)C in June (mean = 12 \({}^{\circ}\)C, std = 1.5). Similar trends have been observed in maximum temperatures. These changes may affect capercaillie hatching time and number of brood rearing females, and hence breeding success [18].  
Following a request to the Autonomous Province of Trento, which performs them annually, we obtained historical data derived from local censuses of capercaillie presence. The annual estimated number of individuals is available for a period between 1991 and 2011 and, for the latest years, capercaillie population ranged between 20 and 30 individuals with an estimated annual breeding success that varied from 0.7 to 3.5 chicks per female (mean = 2.5). In general, for this period of analysis, no marked decreasing or increasing population trend was observed.  
Figure 1: **(a)** The black star indicates the study area in northern Italy. (**b**) Distribution of the capercaillie sampling plots (circle = summer presence–absence surveyed in 2001 and 2011, empty circle = habitat surveyed in 2001, filled circles = habitat surveyed in 2001 and 2011) in the Scanuppia Natura 2000 site (black dashed line) is reported (background: 2008 aerial photo).  
Figure 2: Historical aerial photos comparison which show the reduction of open lands from (**a**) 1954; to (**b**) 1973; and (**c**) 2006, in the Scanuppia Natura 2000 site.