Cambios temporales en la abundancia y composición del ensamble de aves acuáticas en tranques artificiales en chile central

Abstract

Central Chile is characterized by a Mediterranean type environment with a strong climatic seasonality. In this zone of high agricultural activity there are artificial ponds intended for irrigation which can generate environments that constitute alternative habitats for development and nesting of water birds. Despite the existence of census data in these types of ponds, there are no studies addressing climatic seasonality as a factor which could influence temporal variability and abundance of the ornithological population. With this purpose, we studied temporal changes of the bird community in two types of ponds in the metropolitan region (33° 29' S - 70° 54′W): a seasonal-type pond with pluvial regime that dries during summer season, and a managed pond, with permanent wastewater flow. In the pond with pluvial regime we observed a seasonal variation in the abundance of birds, which correlates positively with the Martonne's aridity index. On the other hand, the abundance remained relatively constant in the controlled environment, registering a non significant increase of the abundance during the summer season. Moreover, we observed in the two types of ponds; seasonal changes in the composition of the assemblage, numeric variation of certain populations and dispersion of birds between near ponds by the effects of summer desiccation. Finally, we discuss the importance of the controlled regime pond (e.g. water treatment plants or wastewater pond) as optional summer habitats during the desiccation process of seasonal sites.