干旱区生态环境知识资源中心

1. It is generally considered that the open woodlands of north-west Namibia are experiencing widespread degradation due to over-use of resources by local herders.

2. Data are presented regarding community floristics, diversity, density, cover and population structure for woody vegetation. These are analysed in relation to abiotic factors of topography and substrate, and to settlement impacts represented indirectly by distance from settlement and directly by measures of branch cutting and browsing.

3. None of the vegetation indices upheld predicted patterns of degradation except on a small scale, confined to within settlements. Moreover, in nearly all cases, local settlement effects were within the range of variability observed at larger scales.

4. It is concluded that continuing perceptions and fears of degradation in this area relate more to ideology than evidence. In particular, it is argued that factors conferring resilience and persistence on both the environment and the regional herding economy are obscured by: (1) disregard for the implications of spatial and temporal scale in interpretations of ecological data; (2) a conceptual adherence to equilibrium dynamics that stresses density-dependent impacts of people and livestock over and above the role of abiotic factors in constraining and driving primary productivity; and (3) remnants of a colonial ideology, which tends to view 'traditional communal farming' practices as environmentally degrading.