Habitat heterogeneity rather than the limits of protected areas influence bird communities in an Andean biosphere reserve

The páramo ecosystem harbors a high concentration of restricted range and threatened bird species. However, human modifications to the high Andean landscape have generated habitat loss and fragmentation throughout this ecosystem. Therefore, protected areas in this region are a priority for biodiversity conservation. Buffer zones around protected areas aim to reduce perturbation within them. However, these areas are still not exempt from sources of stress. We used abundance and diversity of birds, recorded by walking transects, in order to compare the community composition occurring in protected areas and adjacent buffer zones in a hotspot of diversity and endemism: the Macizo del Cajas Biosphere Reserve, in the southern high-Andes of Ecuador. The bird community did not vary in its composition between protected areas and buffer zones. However, the habitat characteristics explained differences in the presence and abundance of trophic guilds. Particularly, increasingly heterogeneous páramo grassland with greater woody plant cover and less intervention explained a greater presence and abundance of more specialized trophic guilds such as nectarivores in shrubs and aerial insectivores in trees and shrubs. We conclude that there are heterogeneous páramo habitats in buffer zones that should be considered in more formal conservation planning to maintain the diversity of specialized birds and therefore functionality of the páramo grassland ecosystem.