The effects of agricultural fields and human settlements on the use of rivers by wildlife in the mid-Zambezi valley,Zimbabwe |
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| Authors: | Fritz Hervé Saïd Sonia Renaud Pierre-Cyril Mutake Snoden Coid Craig Monicat François |
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| Institution: | (1) CEBC – CNRS UPR 1934, P.O. Box 14, 79360, Beauvoir Sur Niort, France, 49 09 61 11;(2) INRA-IRGM, B.P. 27, Castanet-Tolosan Cedex, F 31326, France;(3) Biodiversity project, P.O. Box 1378, Harare, Zimbabwe;(4) CIRAD-EMVT, Econap, Campus International de Baillarguet, BP 5035, 34032 Montpellier Cedex 01, France |
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| Abstract: | After the eradication of the Tse-Tse fly in the Mid-Zambezi valley, human settlements and fields extended mainly along the main rivers. In order to investigate the consequences of this human development on wildlife diversity we monitored three rivers of the Mid-Zambezi valley in Zimbabwe: Angwa, Manyame and Kadzi. The rivers were divided in segments of 200 m which were checked for spoors in order to assess the number of species and the number of individuals that used the segments. Human settlements were also recorded. We used a GIS to define the spatial characteristics of the fields present along the rivers, and related them to the distribution and abundance of wild species spoors in the river beds and banks. Our results show that the number of species in one segment of the river decreased with the increasing size of the field area bordering the segment. For all the major ungulate species, the numbers of individuals recorded per segment decreased with increasing field area. A similar trend was observed for small and medium-sized carnivores, though they were in lower numbers when present. Our analyses thus confirm that the extension of human agriculture in wildlife areas has an impact on most wild species, but we also define some threshold value of field size above which there seem to be an acceleration of the decrease in wildlife density and diversity: 3.2 ha for medium and small herbivores and carnivores; only the elephant seem to tolerate larger field area with a threshold value of 32 ha.This revised version was published online in May 2005 with corrections to the Cover Date. |
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| Keywords: | diversity GIS human settlements landscape species richness wildlife species Zimbabwe |
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