Influence of habitat amount, fragment size and connectivity in Atlantic Forest bird species conservation

Author(s)

Alexandre Camargo Martensen

• Document type: Master's Dissertation
• Press: São Paulo. , ilustrações.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2008-07-02

Examining board members

Jean Paul Walter Metzger; João Luis Ferreira Batista; Cintia Cornelius Frische

• Advisor: Jean Paul Walter Metzger
• Field of knowledge: Biological Sciences - Ecology
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca do Instituto de Biociências; IB/M-1360

Abstract

Landscape aspects such as habitat amount, fragment size and connectivity, have been suggested as key features for maintaining species in altered landscapes, and thus are essential to be modeled and comprehended for management and conservation purposes. To test their effects on understory Atlantic forest bird species, we built models with variables representing fragment size and functional connectivity in 3 landscapes with different proportions of forest (14, 31 and 45%), and confronted with data from more than 4,818 individuals captured in 53 fragments of different sizes (2.06 to 158.45 ha) and connectivitys (connected by corridors, or by short distances), and then we ranked under a model selection approach (AIC). A total of 117 species were recorded, and the landscape with higher amount of forest was richer (87) than the two others which presented a similar lower richness (62 and 70), what suggests a threshold amount of habitat between 32 to 44%. Configuration aspects were important in all cases; however, different characteristics influenced species richness and abundance in each landscape. Patch size was important in determining species richness and abundance in the landscape with low amount of habitat, while connectivity aspects were crucial in the landscapes with higher amounts of habitat. Within the connectivity models, particularly the ones that take in to account the connectivity by corridors, but also the ones that consider short movements through the matrix are far better supported, then the ones by longer distances gaps. Moreover, specieslevel analyses yielded results similar to the pattern found for the whole assemblage, and the configuration variable influence varied along the habitat conversion gradient. The results presented here are important for management planning towards conservation, and should be considered in site selection for conservation, restoration or any other kind of management. (AU)

• FAPESP's process: 04/11279-7 - Conservation of understory birds in fragmented landscapes: importance of cover and configuration of the habitat
• Grantee: Alexandre Camargo Martensen
• Support Opportunities: Scholarships in Brazil - Master