Trophic structure of a neotropical frugivore community: is there competition between birds and bats?

Dietary overlap and competition between frugivorous birds and bats in the Neotropics have been presumed to be low, but comparative data have been lacking. We determined the diets of volant frugivores in an early successional patch of Costa Rican wet forest over a one month period. Ordination of the diet matrix by Reciprocal Averaging revealed that birds and bats tend to feed on different sets of fruits and that diets differed more among bat species than among bird species. However, there was overlap between Scarlet-rumped Tanagers and three Carollia bat species on fruits of several Piper species which comprised most of the diet of these bats. Day/night exclosure experiments on P. friedrichsthalli treetlets provided evidence that birds deplete the amount of ripe fruit available to bats. These results indicate that distantly related taxa may overlap in diet and compete for fruit, despite the apparent adaptation of animal-dispersed plant species for dispersal by particular animal taxa.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47779/1/442_2004_Article_BF00384321.pd

Bandages for wounded landscapes: faunal corridors and their role in wildlife conservation in the Americas

The loss and fragmentation of natural habitats is probably the single greatest threat to the world's biological diversity. Fragmentation has a variety of effects including the isolation of habitat remnants, a sharp increase in the amount of habitat edge and, often, a disproportionate loss of certain habitat types - such as accessible areas on fertile, well-drained soils that are most productive for agriculture (Laurance et al. 1999).\ud \ud Wildlife corridors have been advocated as a strategy to lower extinction rates in fragmented landscapes since at least the 1970s (e.g., Willis 1974; Diamond 1975; Wilson and Willis 1975; Wegner and Merriam 1979). By definition, a wildlife corridor is a linear remnant that differs from the surrounding vegetation and connects patches of similar habitat that were more extensively connected in the recent past (Saunders and Hobbs 1991). It is important to emphasize that corridors are not an artificial feature of the landscape, but are intended to help maintain historical habitat connectivity (Noss 1991; Bennett 1999). By facilitating movements of individuals among habitat remnants, corridors can increase population persistence in two ways. First, the demographic and genetic contributions of immigrants can bolster small, dwindling populations in fragments, providing a buffer against local extinction (Brown and Kodric-Brown 1977). Second, if a fragment population should go extinct, immigrants may eventually recolonize the fragment and reestablish the population