of fallows means that disturbance frequency is increasing. Farmers are reluc-
tant to abandon one of their most environmentally undesirable management
tools, fire, for alternative ways of accessing the nutrients contained in fallow
biomass (Szott et al. 1999). In any case, the fallows must be cut. It may turn
out to be easier to conserve forest vertebrates in shifting cultivation landscapes
than to conserve forest plants because the mobility of vertebrates allows them
to use different habitat patches in meeting their needs.
Landscape Management
Our summary of the characteristics of shifting cultivation landscapes (Box
8.1) points first to the application of simple basic principles to their manage-
ment in the context of objectives such as those set out in this chapter. Two
such principles stand out, neither of which is specific to this type of landscape
(Hartley 2002):
- Conserve as much of the remaining primary forest in landscapes as possible.Jus-
tification of such a measure hardly seems necessary, but if it were needed,
indications that the best single correlate of animal species diversity observed
in some studies of forest plantations is the amount of “native vegetation” in
the landscape (Hartley 2002) are more than adequate. In such a situation,
primary forest remnants arguably become keystone habitat patches in the
landscape, playing a similar role to that of keystone species (Meffe and Car-
roll 1994) in that they would have an effect on biodiversity in the landscape
that is disproportionate to their relative area. Forest in each of the major
physical environments of the landscape ideally would be included in that
conserved, a “coarse-filter” approach (Hunter 1991; Noss 1996) today
found in many precautionary frameworks for biodiversity conservation in
human-impacted ecosystems such as forests managed for timber production
(Finegan et al. 2001). - Maintain connectivity between patches of habitat that are essential for the main-
tenance of populations of forest-dependent organisms.Whether or not connec-
tivity (Meffe and Carroll 1994) exists depends on the species or group of
organisms under consideration, and as we have seen, even young fallow veg-
etation may provide part of the habitat used by some mobile organisms in
shifting cultivation landscapes. However, an important element of a precau-
tionary approach to the provision of connectivity would be to try to ensure
the physical continuity of areas of the most important and least extensive
habitats in the landscape: mature forest and older secondary forest.
Building on ideas set out by Smith et al. (2001), it is perhaps self-evident
that all the preceding ideas for landscape management for biodiversity would
best be implemented during the early stages of agricultural frontier develop-
ment, when significant areas of primary forest still remain. The magnitude of
182 III. The Biodiversity of Agroforestry Systems