Seasonal turnover of avian community assembly in a highly fragmented Tumbesian dry forest of southwestern Ecuador

Abstract

ABSTRACT Tropical dry forests are among the most threatened and yet the most biodiverse Neotropical ecosystems. However, current patterns of biological occupancy in these forests remain poorly studied. Here, we document the diversity, patterns of seasonal turnover and change of species composition over time of birds in a highly exploited but protected tropical dry forest of southwestern Ecuador, Bosque Protector Puyango. Using a combination of mist netting, song recording and direct observations, we surveyed the study site over a 2-month period of fieldwork during both the dry and rainy seasons. We then performed a literature review of the species reported in this site and compared the changes in composition over time using a historical survey. One hundred sixty-one species of birds belonging to 40 families were recorded inside the area. One hundred and six species were found in this survey and 55 were recovered from the literature. Seasonality did not significantly affect species abundance and richness; however, species dominance changed notably. Although the overall species richness of the site has been maintained, we found an overwhelming change of species composition during the last two decades in this forest. Our results show that this highly threatened forest still hosts a unique high avian diversity. Conservation actions should be encouraged in the region, motivating the local communities to develop non-extractive economic practices, such as birdwatching and ecotourism.