Densidade e tamanho populacional de aves endêmicas e ameaçadas dentro da IBA (Important Bird Area) MG06

AUTOR(ES)

José Francisco Da Silva

DATA DE PUBLICAÇÃO

2008

RESUMO

The purpose of this thesis was to assess the densities and population sizes of endemic bird species in one of Brazils Important Bird Areas IBA MG 06, in the Chapada do Catuní (1624S 4323W), Serra do Espinhaço, Minas Gerais State. Four transects of 800 m to 1 km long were established in the Cerrado savanna and sampled weekly from March to October 2007. The transects yielded eight of the twelve endemic and/or endangered species listed for the IBA, and density estimates were made for six of these. The study site was the largest block by far of continous cerrado in the IBA, covering 1,950 ha, and population estimates were made conservatively using only this one area. Population densities ranged from 3,3 ind./km2 for Euscarthmus rufomarginatus to 134,0 ind./km2 for Neothraupis fasciata and included also Embernagra longicauda (11 ind./km2), Melanopareia torquata (6 ind./km2), Cypsnagra hirundinacea (13,4 ind./km2), and Saltator atricollis (15,3 ind./km2). For all species, the local IBA populations were much lower than the mininum level of 7,000 individuals that would be an appropriate safeguard against extinction. Therefore, the long term survival of these species in the IBA will depend on their ability to colonize and disperse among fragments. A high priority is to ensure the conservation of the restricted range species, in particular Embernagra longicauda, which is endemic to the Espinhanço range and occurs at low densities. The nearest significant conservation unit is Grão Mogol State Park (33,000 ha), which is approximately 100 km away. This study reinforces the importance of securing large blocks of contiguous habitat to ensure conservation of Cerrado species, and the need for further studies on dispersal and colonization to determine whether these birds are able to maintain viable populations across fragmented landscapes.

ASSUNTO(S)

cerrado populações viáveis conservation áreas protegidas endemismo endemism ecologia protected areas viable population cerrado conservação

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