Tr ee conservation is another measure that would obviously be more effective
if taken during the early phases of frontier development; it is important to take
into account that this is a temporary measure because once they are gone, pri-
mary forest trees will not be replaced in the landscape.
Vegetation structure of individual fallow and secondary forest patches
could usefully be diversified to promote vertebrate diversity. The conservation
of forest trees would contribute to the diversification of vegetation structure,
as would the favoring of some individuals of fast-growing pioneers regenerat-
ing from seed, all with the aim of broadening foliage height profiles and
increasing vertical and horizontal structural diversity. Among more specific
habitat features identified in this chapter as important to vertebrates and to be
conserved are vine tangles, continuous tree canopy cover at all possible levels
in habitat patches, and moribund or dead trees. Many pioneer plants provide
food to frugivorous or omnivorous vertebrates, and by the very nature of these
plants maintaining this function might take little management attention.
However, management interventions designed to accelerate the increase of
stand diversity or favor forest-dependent plant species in older vegetation
could also increase the frequency and size of fruit crops if they were to involve
canopy opening. Moves to diversify stand vertical structure could be inte-
grated with the conservation of species providing fruits to vertebrates, taking
into account that some vertebrate fruit consumers also have foraging height
preferences. Any manipulation of habitat characteristics would need to take
the avoidance of a return to early-successional microclimates and their associ-
ated species as a basic rule.
Conclusions
Debate on shifting cultivation tends to become polarized, with the practice
characterized as either the fate or the future of tropical forests and their biodi-
versity, over significant areas of the tropics. However, polarization is based on
fundamental misunderstandings of the nature of shifting cultivation and its
effects on biodiversity, including gross simplification of an agricultural pro-
duction system that in fact consists of a variety of practices applied under a
variety of conditions. Effects on biodiversity will be very different from place
to place because of variation in agricultural systems, sociocultural organiza-
tions, external drivers, and site ecological conditions. Before any sensible con-
clusion can be reached regarding shifting cultivation and biological conserva-
tion, this variety must be analyzed. This chapter is an attempt to begin such
an analysis.
Claims by conservationists or foresters that shifting cultivation in general
is a major cause of deforestation or forest degradation, and hence of biodiver-
- The Biodiversity and Conservation Potential of Shifting Cultivation Landscapes 187