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|Title: ||Understanding the savanna dynamics in relation to rangeland management systems and environmental conditions in semi-arid Botswana|
|Authors: ||Kgosikoma, Olaotswe Ernest|
|Supervisor(s): ||Harvie, Barbra|
van Gardinge, Paul
|Issue Date: ||25-Jun-2012|
|Publisher: ||The University of Edinburgh|
|Abstract: ||This thesis investigates the effects of rangeland management systems on savanna
ecosystems under different environmental conditions in Botswana, Southern Africa.
The soil sampling and vegetation assessment were conducted in twenty–three
transects located in communal and ranching grazing lands across three sites.
Pastoralists were also interviewed on vegetation change on their respective grazing
Soil texture, pH, bulk density and soil organic carbon differed between sites, but not
between communal and ranching lands. Soil organic carbon was positively affected
by soil clay content. The herbaceous vegetation composition showed heterogeneity
between sites, but Matlolakgang and Xanagas rangelands were in poor condition,
particularly the communal grazing land that had high cover of increasers II species.
Higher herbaceous biomass was observed in ranches than communal lands and
biomass also increased with increasing soil organic carbon.
Bush encroachment was observed in communal and ranching grazing lands at
Matlolakgang and Xanagas, but not Goodhope. Woody plant cover, density and
diversity increased with decline in soil clay content, but not linearly. Pastoralists
indicated that herbaceous vegetation compositions had changed in some areas, with
increase of unpalatable grass species and bush encroachment especially in communal
land. Pastoralists considered bush encroachment a problem as it suppress herbaceous
vegetation productivity, but they also considered woody vegetation as a valuable
The long-term indicators of ecosystem degradation (soil and woody cover) showed
that communal and ranching grazing did not affect the savanna ecosystem
differently. This is contrary to assumptions of Tribal Grazing Land Policy of
Botswana, which promote ranching as a more sustainable management system. The
results revealed that rainfall and soil clay strongly influence rangeland condition.
These results have implications for the management policies of communal grazing
lands throughout sub-Saharan Africa and in similar arid habitats across the world.|
communal and ranching grazing
|Appears in Collections:||Geography PhD thesis collection|
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