Effects of Fragmentation of the Atlantic Forest on Mammal Communities in South-Eastern Brazil

Background

The author presents a detailed analysis of the community of large and medium-sized mammals present in six remnants of the low Atlantic forest in Brazil. The six remnants had varying sizes: small (200 ha), medium (2,000 ha) and large (20,000 ha). The study seeks to (1) identify the mammal species richness and the relative abundance of individuals surviving in each reserve, and (2) analyze changes in the structure of the mammal community contrasting the relative abundances of orders and dietary categories between reserves of differing sizes.

Research Goals & Methods

Reserves were censused for mammals from October 1994 to April 1996 by using line-transects samplings of 1500-2000 m of length and 1.5 m wide during day and night. The relevant abundance of species in the six fragments was compared.

Conclusions & Takeaways

The number of mammal species recorded was strongly related to the forest area, with larger reserves having the richest and more structurally complex community. Small reserves lacked predators and were dominated by herbivores. They also had a stronger presence of secondary vegetation and lianas. Meanwhile, larger reserves had a predominance of frugivores. All reserves were found to have varying levels of poaching, with disastrous consequence for isolated forest fragments of smaller size.