Biodiversity and Conservation 13: 2567–2586, 2004.
# 2004 Kluwer Academic Publishers. Printed in the Netherlands.
Effects of forest fragmentation on small mammals
in an Atlantic Forest landscape
RENATA PARDINI
Departamento de Zoologia, Instituto de Biocie
ˆncias,
Universidade de Sa
˜
o Paulo, Rua do Mata
˜
o–
travessa 14, 101 CEP-05508-900, Sa
˜
o Paulo, SP, Brazil; e-mail: renatapardini@uol.com.br; fax:
+55-11-30917513
Received 25 March 2003; accepted inrevised form 1 September 2003
Key words: Atlantic forest, Edge effect, Forest fragmentation, Matrix quality, Small mammals
Abstract. Recent studies on the effects of tropical forest fragmentation indicate that fragmented
landscapes are complex and heterogeneous systems influenced by factors other than the size or
degree of isolation of forest remnants: of particular importance are the quality of the matrix and the
edge-induced habitat changes. In order to investigate the influence of these factors, small mammals
were surveyed in 36 sites in the landscape of Una, a region that encompasses some of the last and
largest Atlantic Forest remnants in northeastern Brazil. Six sites were distributed on each of six
landscape components – the interiors and edges of small remnants, the interiors and edges of large
remnants, and the most common forested habitats found in the matrix. The survey comprised
46,656 trap-nights and yielded 1725 individuals of 20 species of rodents and marsupials. Results
revealed: an increase in beta-diversity caused by fragmentation; the contrasting effects of the altered
forested habitats of the matrix, which harbor both forest and disturbance-adapted species; a greater
importance of edge effect than of patch size to the observed changes in small mammal community
in remnants; an association among terrestrial forest species and among arboreal forest species in
terms of the distribution and abundance in the Una mosaic; and a distinctive vulnerability of these
two groups of species to fragmentation. Results emphasize the biological importance and con-
servation value of both fragmented landscapes and small remnants in the Atlantic Forest, as well as
the importance of management techniques to control and attenuate edge effects.
Introduction
Expansion of human activities and the resulting habitat fragmentation is ex-
pected to affect several biological processes and factors, such as population
size, species dispersal, structure and quantity of available habitat and the
probability of invasion. However, research emphasis has often been placed on
the study of the effects of patch size and isolation on species abundance and
richness (Davies et al. 2001).
Recent studies on the effects of tropical forest fragmentation (e.g., Laurance
and Bierregaard 1997; Bierregaard et al. 2001) show that fragmented land-
scapes are complex and variable systems mainly because of the altered habitats
that surround fragments (Crome 1997; Laurance et al. 1997; Renjifo 2001). The
quality or permeability of the matrix is crucial to determine the functional
connectivity among remnants. It has been proposed that the occurrence of
similar habitat structures in the remnants and in the matrix increases the
connectivity among the remnants (Taylor et al. 1993).