Effect of Season and Habitat on Two Congeneric Bat Species in a Fragmented Forest Landscape, Central Amazon, Brazil

Abstract

Bats are an important component of Amazonian mammal communities but are often ignored during conventional biodiversity assessments. Much is therefore unknown regarding spatial and temporal forest use and the partitioning between different bat species in the community. The objectives of this study were to examine how different habitats and seasons affects the activity of two congeneric species (Pteronotus alitonus and P. rubiginosus), and how temporal partitioning of activity in these two species varies with habitat types and seasonality. I used ultrasound recordings of the two Pteronotus species collected in three different habitat types (continuous primary forest, secondary forest and 10ha forest fragments) and during two seasons (wet and dry) in the Biological Dynamics of Forest Fragments Project in central Amazon, Brazil. The activity levels of both Pteronotus species were found to significantly increase during the wet season, suggesting that insect abundance during the wet season would positively affect bat activity levels. Furthermore, P. alitonus had highest activity levels in secondary forest, whereas P. rubiginosus exhibited high activity levels in both primary and secondary forest. Forest fragments were least favoured by both species. The same patterns were found in spatial hourly activity. The results suggest that P. alitonus and P. rubiginosus spatially and temporally partition activity and that this partitioning may be a way to reduce competition.