Changing landscapes: consequences for the recruitment of animal-dispersed plants

Seed dispersal by frugivores plays a key role in plant community and population dynamics, yet direct and indirect effects of habitat and landscape changes on the recruitment of animal-dispersed plants remain poorly known. We examined if, and to what extent, recruitment at early life-stages of a bird-dispersed tree differs between and within forest fragments varying in size, surrounding matrix and microhabitats. Three years of field experiments revealed that patterns of seed germination and seedling survival were largely inconsistent, both in space and time. However, two clear patterns emerged from this study. First, performance of seeds and seedlings was consistently better away from than under conspecific fruiting trees. This indirectly translates into reduced recruitment in heavily disturbed fragments, where most seeds remain undispersed due to the loss of key disperser species. Second, exotic plantations bordering indigenous forest fragments may provide suitable conditions for native tree recruitment. Individual based modelling predicts a 90% recruitment increase in tiny forest remnants buffered by exotic plantations compared to those surrounded by farmland, this nursing effect being less effective under dryer conditions. We conclude that habitat changes affect frugivorous seed dispersal and plant recruitment in complex and context-dependent ways, having important implications for on-site habitat management in view of current global change