47,700 ha studied in young (3- to 10-year), intermediate (ca. 20-year), and
advanced (40- to 70-year) fallow and secondary vegetation, respectively. Tak-
ing into account the 12 percent of land area covered by primary forest, again
mainly riparian, total forest cover exceeds 50 percent in this municipality if a
broad definition of forest is adopted (discussed later in this chapter), despite
more than a century of agricultural settlement. In northern Thailand, the
Lawa people of Ban Tung cultivate around 30 ha per year for an available fal-
low area of 800 ha (Schmidt-Vogt 1999). In a drier savanna context, Petit
(1999) showed that the proportion of village land under various types of fal-
low was 34.5 percent for the Senufo people of northern Côte d’Ivoire and 64
percent for the Musey of northern Cameroon.
Beyond the overriding importance of fallows, it is important to note that
secondary forests or old fallows play a significant and often overlooked role in
shifting cultivation systems. The proportion of new crop fields established in
primary forests is only 5 percent for the ethnic groups of south Cameroon
(Mvae, Ntumu), 13 percent for the Kenyah of Sarawak, 24 percent for the
Palikur in French Guyana, and 31 percent for the Kantu of Borneo (Dounias
2001).
Overall, it is clear that shifting cultivation in general and fallows in partic-
ular are the defining characteristics of many tropical landscapes and are there-
fore of fundamental importance to prospects for biodiversity conservation in
such landscapes.
Dynamic Processes at the Landscape Scale and the Dynamics
of Agricultural Frontiers
The temporal dimension of the analysis of shifting cultivation and biodiver-
sity at the landscape scale is as important as the spatial. Tropical agricultural
landscapes are dynamic at different temporal and spatial scales, and these
dynamics must be understood if the potential of shifting cultivation to gener-
ate and maintain biodiversity is to be understood. Land use dynamics under
traditional shifting cultivation differ from those imposed by modern coloniza-
tion processes. Modern deforestation is synonymous with the advance and
development of agricultural frontiers, a process for which numerous authors
have proposed models. For example, Henkel (1971, cited by Thiele 1993)
proposed that originally forested land passes through four stages after the
arrival of the first colonists. This model may be summarized as follows, draw-
ing parallels with the model proposed by Richards (1996, cited by Smith et al.
2001). A pioneer fringe (Richards’s early pioneer stage) advances into the for-
est, with deforested areas then evolving into the commercial core of the fron-
tier, a stage in which farmers take advantage of improved infrastructure and
access to markets; Richards calls this the stage of the emerging market econ-
omy. This commercial core may evolve into a zone of decay as agricultural
- The Biodiversity and Conservation Potential of Shifting Cultivation Landscapes 157