Ecologia, história evolutiva e conservação de Thalasseus sandvicensis/acuflavidus/eurygnathus (aves: sternidae)

• Ano de defesa: 2008
• Autor(a) principal: Efe, Márcio Amorim
• Orientador(a): Bonatto, Sandro Luis
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul; Porto Alegre
• Palavras-chave em Português: ZOOLOGIA; ORNITOLOGIA; AVES - BRASIL; TAXIONOMIA
• Link de acesso: http://hdl.handle.net/10923/5328

The first chapter presents data about breeding ecology of the Cayenne Tern, also nominated as Thalasseus sandvicensis eurygnathus, South American Tern, Sterna hirundinacea and Audubon’s Shearwater, Puffinus lherminieri and the important work of insular environmental conservation developed in the State of Espírito Santo. Every year thousands of individuals of S. s. eurygnatha and S. hirundinacea use the coastal islands of the southern coast of the state of Espírito Santo to breed. Studies on the bioecology of this species are being developed at the breeding sites and resting and feeding areas since 1985. The studies were developed mainly on the Itatiaia Islands, Escalvada Island and Branca Island. The second chapter presents data about the reproductive ecology, status and threats to conservation, populational status and recommendations about the topics of research and strategies for conservation of the Royal Terns (Thalasseus maximus maximus) and Cayenne Terns (Thalasseus sandvicensis eurygnathus) in South America, where breeding mostly in Argentina and Brazil. Royal Terns have been recorded in at least 22 locations. Cayenne Terns have been recorded in at least 38 locations. At 15 locations, mostly located in Argentina, Royal and Cayenne terns breed in association, often with their nests intermingled. Total population size for Royal Terns was estimated in at least 750 pairs in Brazil and less than 5000 in Argentina, while that of Cayenne Terns was estimated in at least 8000 pairs in Brazil and less than 10000 in Argentina. Main threats faced by their populations in both countries are human disturbance, fisheries, egging, and expanding Kelp Gull (Larus dominicanus) populations. Priority research and conservation actions are presented. The aim of the third chapter is to clarify the relationships among the Sandwich, Cayenne, and Cabot’s terns based on nuclear and mtDNA sequences, because one of the remaining taxonomic uncertainties in the Sternini is in the classification of the species complex. Material was collected for this study by the authors and collaborators, from a wide range of geographic locations. Phylogenetic relationships estimated by the different methods and sequence partitions (mtDNA, nuclear, and mtDNA+nuclear) were similar. Trees recovered with Neighbor-Joining and BI analysis of COI barcodes too were congruent. Our analysis indicates that the Old World (T. s. sandvicensis) and the New World (T. s. acuflavidus/eurygnathus) tern populations are genetically as divergent as different species in the genus, and do not form a monophyletic group. We propose that the appropriate taxonomic treatment of the acuflavidus/eurygnathus complex should be as Cabot’s Tern, Thalasseus acuflavidus. The fourth chapter presents the first genetic study of this species using mitochondrial and nuclear sequences as well as microsatellites data. MtDNA diversity is low in the species. All three populations present signals of bottleneck and population expansion. On the other hand, microsatellites data support a recent gene flow among populations. Results suggest the occurrence of a hybridization zone between Brazil and North America. The different breeding periods in Brazil and Argentina could be important in the recent isolation of these coastal birds. The last chapter evaluates the conservation status of T. acuflavidus in Brazil and discusses its threat category. The Brazilian population is mainly confined to the coast of Espírito Santo state. Our evaluation of the conservation status of this species follows the criteria and categories adopted by the IUCN. We review several parameters, including taxonomic level, main threats, area and extent of occurrence, and current population size. We recommend that this species should be defined as Vulnerable at the national level. It may also qualify as Endangered at the regional level. Finally, we suggest that research and conservation efforts should be increased on Espírito Santo coast, and that conservation actions should be implemented across the whole Brazilian coast.