the challenge of managing landscapes during those stages of landscape colo-
nization is also self-evident.
Beyond action related specifically to primary and old secondary forest
habitats, the maintenance of biodiversity in general and of forest-dependent
species in particular could be evaluated and managed for in relation to overall
landscape structure and diversity. Shifting cultivation landscapes are diverse at
the scale of patch types in the landscape. As shown earlier, the increase in
diversity at this scale that accompanies conversion of part of a forested area to
shifting cultivation may in some circumstances be accompanied by increases
- The Biodiversity and Conservation Potential of Shifting Cultivation Landscapes 183
Box 8.1. Main Features of Landscape-Scale Biodiversity
in Shifting Cultivation Landscapes- Some shifting cultivation landscapes are permanent, others temporary
stages in the evolution of agricultural frontiers whose potential for bio-
diversity conservation therefore is transient. - Shifting cultivation landscapes may be tens or even hundreds of thou-
sands of hectares in extent.
•Proportions of shifting cultivation landscapes are delimited by sociopo-
litical criteria (e.g., Latin American municipalities, African village
land), covered by fallow vegetation, 50 percent or more, with less than
20 percent covered by disturbed primary vegetation and less than 10
percent by cropland. - Biodiversity in shifting cultivation landscapes therefore is strongly
dependent on anthropogenic communities; fallows are most important
in terms of area. - Rapid turnover of community types on individual patches in the land-
scape is a defining characteristic of shifting cultivation landscapes, of
fundamental ecological importance. - Relative proportions of land assigned to different uses vary between
stages in agricultural frontier evolution, with old-growth forest declin-
ing, fallows increasing, and, in more advanced stages of frontier devel-
opment, increases in non–shifting cultivation land uses. - Mature and perhaps old secondary forests are presumably keystone
communities, crucial for organisms that are forest dependent in some
way, including those that use many landscape patch types but need
well-developed forest for at least some of the conditions and resources
crucial to their survival. - Some community-level characteristics (e.g., the proportions of plants
regenerated from resprouts and those regenerated from seed or the
presence of forest-dependent vertebrates in anthropogenic habitats)
presumably depend on the structure and composition of the landscape
surrounding the community.