Community and species-specific responses of coastal birds to COVID-19 “anthropause” in the largest hypersaline lagoon of South America

Abstract

Abstract The COVID-19 pandemic led to a reduction in human mobility, known as “anthropause.” Few studies have compared birds’ community patterns between lockdown and “new normal” periods, especially in extremophile environments. This study presents the first baseline by monitoring coastal birds on 10 beaches along the largest hypersaline lagoon in South America. The birds were counted in September and October 2021 (during a lockdown period) and in October 2022 (after the lockdown – “new normal”) during the morning. The continuous route transect methodology was applied by the same observer in all beaches. The Analysis of Covariance (ANCOVA) was used to investigate the response of community abundance to urbanization (raster-based variable) and time of COVID-19 pandemic (lockdown vs. new normal). Rarefaction curve and Permutational Analysis of Variance (PERMANOVA) were used to compare community richness and composition, respectively, between lockdown and new normal periods. Generalized Linear Models (GLM) with negative binomial distribution were applied to test the effect of the same predictors on the three more abundant species. The bird community structure and composition did not change when comparing lockdown and new normal periods, mainly due to dominance of synanthropic species. Among species-specific responses to lockdown, the Southern Lapwing Vanellus chilensis was more abundant during the lockdown on six of the nine beaches where it occurred. Oppositely, the Kelp Gull Larus dominicanus and the Neotropic Cormorant Nannopterum brasilianus were more abundant in new normal period, reinforcing that these species benefit from human subsidies. This may provide a unique opportunity for science-based sustainable ecotourism activities in urban areas with synanthropic species, capitalizing activities such as birdwatching, that would certainly contribute to environmental education actions.