Evaluating the relative contribution of changing farming methods to habitat loss in the mid-Zambezi Valley, Zimbabwe

Abstract

Agriculture expansion is a major contributor to wildlife habitat loss in the ecological frontier areas. However, little is known about the contribution of different crops to wildlife habitat loss. In this study we evaluated the relative contribution of changes in farming practices, particularly the introduction of cotton (Gossypium hirsutum L) to the loss of wildlife habitat with specific focus on the African elephant (Loxodonta africana) in the mid- Zambezi Valley, Zimbabwe. First, we developed a remote sensing method based on normalised difference vegetation index (NDVI) derived from 16 day multi-temporal Moderate Resolution Imaging Spectroradiometer (MODIS) remotely sensed data for the 2007 growing period, to test whether cotton (Gossypium hirsutum L) fields can significantly (p < 0.05) be distinguished from maize (Zea mays L) fields, as well as sorghum (Sorghum bicolor) fields. Second, we tested whether woodland fragmentation in the study area was best explained by the areal extent of cotton fields than the areal extent of cereal fields. Finally, we tested whether woodland fragmentation resulting from cotton fields explains elephant distribution better than woodland fragmentation resulting from the extent of cereal fields. Results show that multi-temporal remotely sensed data can be used to distinguish and map cotton and cereal fields. Cotton fields contributed more to woodland fragmentation than cereal fields. Also, we found out that woodland fragmentation from cotton fields significantly explained elephant distribution in the mid- Zambezi Valley. These results indicate that the areal extent of cotton fields explains elephant habitat fragmentation more than the areal extent of cereal fields. Thus, we conclude that the expansion of cotton fields contributes most to elephant habitat loss in the Mid-Zambezi Valley. These results imply that elephant conservation policy needs to address the reduction of the negative impact of cash crops such as cotton on the habitat particularly their threat to wildlife habitat which may eventually lead to loss these wild animals. Thus it is important to strike a balance between wildlife habitat conservation and agricultural production as advocated through the Communal Areas Management Programme For Indigenous Resources (CAMPFIRE) policy.