Distribuição e conservação de aves migratórias neárticas da ordem Charadriiformes (famílias Charadriidae e Scolopacidae) no Brasil

Abstract

Despite the research efforts in recent years, some aspects of neartic Charadriidae and Scolopacidae migration in Brazil remained unknown. To detect the major movements patterns of these species in the country, local and regional scale studies had their data comprehensively organized. The identification of the patterns of neartic Charadriidae and Scolopacidae distribution and migration in the Brazilian territory is a major objective of this thesis. The data analysis also aims to develop conservation strategies for the envolved species. More specific objectives are the characterization of their main migratory routes and the identification of critical areas for their conservation, using the criteria proposed by the IBAs and KBAs; the assessment of the current state of conservation of critical areas accordingly to the National System of Units Conservation (SNUC); the assessment whether critical neartic shorebirds areas were designated as priority areas for biodiversity conservation in Brazil; and the use of Ramsar Convention and WHSRN criteria to identify critical areas for these species. The database was established from literature review, scientific collections of Brazilian and foreign museums, from birds banded in Brazil and U.S.; data provided by researchers from Brazil, Argentina and the United States, personal field data from the Pantanal (MS), coast of Maranhão and Rio Grande do Sul states coast. Nineteen of 24 species have important data set, the remaining 5 being either occasional or having little information in Brazil. The coastal areas have greater data concentration with lower coverage of inland areas. The western Amazon proved to be the least known in spite of some species use as a migratory route. The coast among the mouth of the Amazon and Sao Luis, Maranhão has been the main area in terms of numbers of neartic shorebirds. The coast of the state of Rio Grande do Sul was second. Not all individuals migrate every year to the northern hemisphere, as shown by the 15 species recorded year round in Brasil. Considering the global flyways, eight species were found using the Atlantic flyway and 10 the Mississippi flyway or the center of North America. The other six species may possibly use both flyways. Five flyways are proposed for neartic shorebirds in Brasil (Antas, 1983). During the northward migration some species have records in the Amazon region, period when possibly their habitats should be seasonnaly flooded. The pattern of arrival in the southward migration in Brazil is from August till October, increasing from September on. The northward migration occurs from mid March till April in most species. During the non breeding season there is a distributional pattern along the coast used by nine species. Seven other species use the inland pattern and five species are distributed both on the coast and in the inland, in the disperse pattern. We identified 260 critical areas using all species data. Amongst the identified KBAs, 72% are not within the SNUC. Overlap of the KBAs with the MMA´s Priority Areas for Conservation has shown 46% of major importance outside of this program. As much as 69 ACBs are eligible using the Ramsar Convention criteria, while 65 can be pinpointed using the WHSRN program criteria. As conclusions, it is necessary to improve the knowledge on biological processes envolving the maintainance the life cycle on the course of their annual migrations. Also the moult, body mass, sex ratio and age of migrant populations are aspects still insufficiently known for these species, either in Brazil or even in South America. There is an urgent research need of population estimates and trends, as many of these species have declining populations on global scale.