Variação sazonal e espacial na abundância de Calidris alba e Arenaria interpres (Aves: Scolopacidae) ao longo da faixa litorânea entre o povoado de Miaí de Baixo (Coruripe, AL) e a foz do rio São Francisco (Piaçabuçu, AL), apontando potenciais interferências do derramamento de petróleo ocorrido 2019 no litoral

Abstract

Waders are birds that feed on invertebrates found on the substrate in shallow aquatic environments, and many have migratory habits. The southern coast of Alagoas is recognized as being important for the conservation of these birds and, in September 2019, along with the entire northeastern coast of Brazil, this region suffered an extensive crude oil spill of unknown origin. The aim of this work was to profile the seasonality and verify patterns in habitat use during the feeding activity of the Sanderling (Calidris alba) and the Ruddy Turnstone (Arenaria interpres), trying to verify changes in these patterns with the arrival of the oil, bearing in mind that the “Laboratory of Morphology, Systematics and Ecology of Birds” (ICBS/UFAL) had been monitoring these birds prior to the tragedy. This monitoring was carried out through fortnightly motorized transects on the beach (during low tide) between Miaí de Baixo (Coruripe, AL) and the mouth of the São Francisco River (Piaçabuçu, AL), totaling 103 sampling surveys between September 2016 and August 2021. A total of 467 contacts with Ruddy Turnstone and 9,743 with Sanderling were recorded. When the oil arrived, the Ruddy Turnstone recorded a slight decline in abundance just after the event and, in the following breeding season (from May to August) a greater proportion of individuals stopped migrating and remained in the region. The Sanderling was frequent and abundant in the area throughout the sampling period. After the beaches were cleaned, the abundance of both species recovered, with Sanderling reaching a higher abundance at both feeding stations after the oil spill. In terms of habitat use, there was no obvious change when comparing before and after the oil spill. Considering that the abundances of the two pecies were maintained after the beach clean-up, and the decrease in the flow of tourists (also related to the Covid-19 pandemic), it is possible that the clean-up was successful and that the flow of tourists has a negative impact on these birds.