play an important role in the use value of a community or landscape to peo-
ple and in the maintenance of ecological functions in it, as we will see. But if
communities are composed largely of species adapted to human disturbance,
their importance in the context of biodiversity conservation will be low, how-
ever diverse they are. Our review of biodiversity and conservation in shifting
cultivation landscapes places particular emphasis on forest-dependent species
of both plants and animals.
Biodiversity of Crop Fields in Shifting Cultivation
In all shifting cultivation systems, the field is made of several strata of vegeta-
tion. It occupies a three-dimensional space and at first sight gives an impres-
sion of vegetable chaos. The various intermixed crops encompass all possible
life forms: grasses, shrubs, small and large trees, palms, and lianas. Crop mix-
tures vary between and within continents, regions, and ethnic groups, but
major crops belong to a limited number of taxa not really different from the
ones used in permanent agricultural systems: cassava (Manihot esculenta),
maize (Zea mays), banana and plantain (Musa spp.), rice (Oryzaspp.), sweet
potato (Ipomoea spp.), taro (Colocasia spp., Xanthosoma spp.), and yam
(Dioscoreaspp.). Important features of shifting cultivation systems from the
biodiversity point of view are as follows:
•Traditional shifting cultivation systems use numerous cultivars or landraces
(Table 8.1) of each of these major crops; these landraces generally are differ-
ent from the varieties used in intensive systems, making shifting cultivation
a possible reservoir of genetic resources for essential crops.
- The Biodiversity and Conservation Potential of Shifting Cultivation Landscapes 167
Table 8.1. The landraces used in shifting cultivation.
Crop Landraces Ethnic Group Country
Banana 28 Maring Papua New Guinea
17 Mvae Cameroon
Cassava 61 Caboclo French Guyana
31 Wayapi French Guyana
46 Kuikuru Brazil
76 Makushi Guyana
Rice 92 Harunôo Philippines
44 Kantu Borneo
Sweet potato 17 Daribi Papua New Guinea
Ta ro 69 Elia Papua New Guinea
20 Yafar Papua New Guinea
Yam32Maring Papua New Guinea
80 Wusi Vanuatu
Source:Modified from Dounias (2001).