Frugivorous Birds, Habitat Preference and Seed Dispersal in a Fragmented Costa Rican Montane Oak Forest Landscape

Abstract

Frugivorous birds play an important role in seed dispersal (Levey et al. 2005), especially in the tropics (Stiles 1985; Guevara et al. 1986; Corlett 1998). Their role in lowland rainforest recovery on abandoned pastures has been extensively documented (Debussche et al. 1982; McDonnell and Stiles 1983; Guevara et al. 1986; Gorchov et al. 1993; Guevara and Laborde 1993; MartinezRamos and Soto-Castro 1993; McClanahan and Wolfe 1993; Robinson and Handel 1993; Galindo-Gonzalez et al. 2000). Numerous bird species thrive well in secondary growth tropical lowland habitats where croplands, shrublands and pastures alternate (Estrada et al. 1993; Gorchov et al. 1993). In such patchy landscapes, isolated remnant forest trees may offer protection to birds, and serve as stepping stones during their journey in search for closed old-growth forest fragments (Guevara et al. 1986; McClanahan and Wolfe 1987). In this way, isolated bird-dispersed forest trees may act as ‘seed-trapping’ centers of succession following lowland rainforest clearing (Debussche et al. 1982; McDonnell and Stiles 1983; Guevara et al. 1986; Guevara and Laborde 1993). To date, however, little is known on the ecology of frugivorous birds in human-influenced tropical montane forest landscapes. Neither do we know much about their role in the recovery of cleared upland forest (Stiles 1985; Kappelle et al. 1994; Poulsen 1994; Long 1995; Shiels and Walker 2003). Even less is known on the interaction between frugivorous bird species and specific ornithochorous tree species in relation to montane forest succession (Chap. 25). To further gain insight into these processes, we studied the role of frugivorous, seed-dispersing birds in montane oak forest recovery following clearing, burning and grazing in Costa Rica’s Talamanca highlands.