Benefiting from change: range-expanding native thrushes in Argentina

Abstract

Abstract The widespread human activity on Earth exerts strong selective pressures on the species with which we coexist. Faced with constant environmental change, species respond with mechanisms of adaptation, expansion, retraction or displacement. Species that establish new populations outside their former range as a result of human-induced environmental change are called 'neonatives'. Many birds now appear to be expanding their ranges in response to habitat modification and climate change. In this study, we use data from three citizen science platforms (eBird, GBIF and VertNet) to document the range expansion of four thrushes in Argentina: Turdus amaurochalinus, T. chiguanco, T. falcklandii, and T. rufiventris. The genus has a history of recent expansion and seems to have benefited from forestation and the landscaping of towns and villages. We found that thrushes have expanded their range about 10-fold since their known distribution in the mid-1980s, expanding at an average linear rate of 35 km/year. In all cases, they also appear to have accelerated their expansion in the last 20 years. Turdus amaurochalinus, T. chiguanco and T. rufiventris have mainly expanded southwards, while T. falcklandii has expanded northwards. This expansion is likely to result in novel ecological interactions, affecting other native species in different ways, and also establishing new relationships with productive activities and urban environments. Thrushes provide an opportunity to understand the response of wild species to human change on the planet, and to design conservation strategies adapted to this new reality.