Fragmentation is the major threat to tropical forest biodiversity (Tabarelli et al., 1999) as it tends
to lower species number, modify community composition (Laurance et al., 1998), decrease
population productivity (Robinson et al., 1995) as well as changing the micro-environmental
conditions (Didham and Lawton, 1999). Usually, fragmentation occurs when the continuity of
original vegetation is disrupted and reduced into smaller isolated fragments or patches (Franklin
et al., 2002; Fahrig, 2003). It is most often a consequence of anthropogenic activities, for
instance deforestation/clearance for agriculture, road construction, logging and urbanization
(Tabarelli et al., 2004; Jha et al., 2005), which significantly alter pattern, composition and extent
of vegetation due physical and biological changes (Newmark, 2001; Yan et al., 2007) as well as
alteration in the flow of resources (such as organisms propagules and nutrients) in the forest
environment (Walker et al., 2006).
Besides reductions in total area, fragmentation also modifies natural habitat by increasing the
proportion of forest associated with edges, decreasing interior habitat, and isolating habitat
fragment from other areas of habitat (Franklin et al., 2002). The formation of edges is considered
to be an important feature of fragmentation (Murcia, 1995). It has been observed that as the
proportion of the edge zone increases, changes in microclimate occur, given that forest edges
tend to be warm, windy and receive more light than forest interior (Didham and Lawton, 1999;
Newmark, 2005). The modification in spatial configuration and microclimate within edges tends
to affect species composition, abundance, natural regeneration and spatial distribution of
biodiversity within fragments (Benitez-Malvido, 1998; Laurance et al., 2007; Oliveira et al.,
2004). For that reason, fragmentation of habitat has become major topic of research and debate
among conservation biologists and plant ecologists worldwide (Jongejans and de Kroon, 2005).
Thus, assessing impacts associated with habitat fragmentation is an important step in prioritizing
forest fragments for biodiversity conservation (Hill and Curran, 2001).