Forests all around the world have been fragmented into small patches, and forest structure and species composition have been influenced by this fragmentation and habitat loss. Reduction of habitat has been described as one of the main causes of diminishing biological diversity in the tropics (Hill and Curran, 2001; Ross et al, 2002; Santos et al, 2007). Dry Afromontane forests in the northern Ethiopian highlands represent a particular case in this respect. Extensive deforestation in the Ethiopian highlands has led to small and isolated forest patches around churches and in poorly accessible mountain areas and these patches are located within a landscape matrix of intensively used agricultural land. The thousands of church forests in the dry Ethiopian mountains can be considered a special case of sacred groves, traditionally managed small forest patches with considerable potential for conservation (Bhagwat and Rutte, 2006). While the highly fragmented Ethiopian highland landscape is centuries
old (McCann, 1997; Boerma, 2006), in some areas fragmentation is still increasing (Bekele, 2003). Zeleke and Hurni (2001), for instance, used remote sensing combined with field verification to show that in Gojam at 1800-2800m altitude the Afromontane forest cover reduced from 27 per cent in 1957 via 2 per cent in 1982 to 0.3 per cent in 1995. Most conversion was to agricultural land. Many remaining church forest patches are also currently declining in area and have been degrading over the last decades (Bingelli et al, 2003; Wassie et al, 2005a and b; Aerts et al, 2006b). Understanding the factors that influence patterns of species and structural composition in fragmented systems may be critical to conserving the remaining forests (Turner, 1996; Ewers and Didham, 2006).