Restauración De Araucarias

Restoration of Araucaria Forest: The Role of
Perches, Pioneer Vegetation, and Soil Fertility
Lessandra Zanini1 and Gislene Ganade1,2
Abstract
The Araucaria forest is Brazil’s highly threatened subtropical forest ecosystem that has been disappearing in
recent decades. Restoration programs involving this forest
type are scarce, and there is a lack of scientific information
on how ecologicalprocesses such as competition, facilitation, and seed dispersal influence natural forest restoration. This work aims to investigate how use of perches to
attract seed dispersers and the influence of pioneer vegetation and soil fertilization could affect the colonization of
woody species in a degraded area. An experiment was
conducted in an abandoned field where the natural establishment of seedsand seedlings of woody species was
monitored under factorial combinations of the following
treatments: (1) pioneer vegetation (presence and absence);
(2) soil fertility (addition of NPK and control); and (3)
perches (presence and absence). Seed and seedling abundance, seed and seedling species richness, and seedling

Introduction
The Araucaria forest is a subtropical forest located withinthe fourth most important conservation hot spot of the
world (Myers et al. 2000). This forest has been extensively
exploited since the nineteenth century (IBGE 1986). In
the southern limit of its distribution, the Araucaria forest
has lost about 95% of its native cover (Gorgonio 1992;
Secretaria Estadual do Meio Ambiente 2001). Although
this forest has been highly threatened, programs offorest
restoration are scarce, and there is a lack of scientific
information on how ecological processes may influence
natural forest regrowth.
The rates of arrival of forest seeds in degraded areas
can influence the speed of forest restoration. Seed arrival
greatly depends on the abundance and behavior of dispersal agents such as birds, bats, and wind (Nepstad et al.
´
1990; Janzen &Vasquez-Yanes 1991; Ganade 2001). Studies have shown that seeds of the majority of tropical forest
tree species are dispersed by birds (Howe & Smallwood
1982). Nevertheless, activity of seed-dispersing bird species in pasture areas is low, and their movements are

1
´
Laboratorio de Ecologia da Restauracao, Biologia, Universidade do Vale do
x˜
˜
Rio dos Sinos—UNISINOS, CP 275, CEP 93022-000, SaoLeopoldo, Rio
Grande do Sul, Brazil.
2
Address correspondence to G. Ganade, email gganade@unisinos.br

Ó 2005 Society for Ecological Restoration International

SEPTEMBER 2005

Restoration Ecology Vol. 13, No. 3, pp. 507–514

mortality were recorded monthly during 12 months. Seed
abundance and species richness were significantly greater
in places with perches than in control plots. Theseresults
were consistent over the year and more pronounced when
the surrounding forest produced a higher amount of fruit.
Species richness and abundance of seedlings were significantly greater in places with perches than in control plots,
and in places with vegetation than without. Soil fertility
did not influence seedling establishment. Facilitation and
seed dispersal are important factorsaffecting the colonization of woody species in this subtropical area. Nutrient
availability neither regulates the facilitation process nor influences species replacement during the early stages of
Araucaria forest succession.
Key words: bird seed dispersal, Brazil subtropical forest,

early successional processes, facilitation, nutrient competition, seed predation, seedling establishment.limited and dependent upon the availability of fruit or
branches for perching (Guevara et al. 1986; McClanahan
& Wolfe 1993; Robinson & Handel 1993; Silva et al.
1996). Because arrival of forest bird species in pastures occurs very slowly, lack of seed dispersal becomes an important barrier for forest restoration (McDonnel & Stiles
1983; Uhl et al. 1988; Nepstad et al. 1990, 1991; Aide &
Cavalier...