Conservação de aves limícolas no Brasil: padrões de distribuição e riqueza no presente e no futuro

Abstract

Shorebirds are considered one of the most impressive groups of birds due to their long migratory movements between breeding and wintering sites located in wetlands, and sometimes located in different hemispheres. This complex movement associated with the great diversity of habitats used by species during migration also implies threats at different scales, and a challenge for conservation policies that prioritize the protection of wetlands. Despite international efforts and the creation of a national instrument for the conservation of the group, few protection areas have been implemented. In this thesis, we assessed information on patterns of richness, distribution, movements, besides to discuss how habitats used by shorebirds will respond to climate change. In chapter 1, we assessed patterns of distribution, movement, and richness of 28 migratory and resident shorebirds species along Brazilian wetlands, using the kernel density method and generalized additive models. We found two distribution patterns assessed by the projections of the kernel estimates: some species were widely distributed, mainly along coastal and inland areas, and others had more restricted records, mainly along the coastline. These data also show movement patterns that varied for species, with some migrating only along the Atlantic flyways, others using both flyways (Atlantic and Central flyways), and some species using both. The best candidate model explained 97% of the data and it was influenced by the agricultural, forest remnants, urbanism, beaches and dunes and non-forested natural areas, the first two negatively affecting the shorebirds richness and the last three positively. In chapter 2, we used spatial predictors of climate, energy, and habitat heterogeneity to test which hypothesis best explains the patterns of shorebird richness in Brazil. We identified a negative relationship between species richness and the variation between maximum and minimum temperatures, indicating that more climatically stable environments are associated with higher levels of richness in the shorebirds group. In Chapter 3, we combined occurrence records with climate, topography and land cover data, to model the habitats availability of resident and migratory shorebirds in Brazil, and to identify how their habitats will be affected in future forecasts on different scenarios of carbon concentration (RCP 4.5 and RCP 8.5). Our results showed that both RCP’s scenarios indicated a balance of losses greater than that of gains, with most predicted species losing more than 50% of their projected habitats for 2050 and 2070. Still, these results also raise the need to implement urgent measures to control impact on habitats where there is economic exploration, through the protection and management of wetlands (e.g., sustainable land use and low impact production) and implementation of public policies aimed at protecting these environments (e.g., restoration of degraded areas, management of water resources, incorporation of climate change in management plans and monitoring and evaluation of actions).