Range use and dynamics in the agropastoral system of southeastern Kenya
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Date
2008Author
Nyangito, M. M
Musimba, N. K. R
Nyariki, D. M
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
Occurrence of equilibrium and non equilibrium system dynamics in semiarid environments present serious management challenges. In these areas, resource management strategies are increasingly based on equilibrium rather than non equilibrium dynamics that assume simple system dynamics and strong coupling of animal-plant responses. This management approach underlies increasing trends of
range degradation and low livestock productivity in these environments. To reverse these trends
dictates greater understanding and alignment of grazing resource extraction strategies in space and
time to prevailing system dynamics behavior. ln this study, range use patterns by free ranging herds
under agropastoral herding were studied in two cycles of four consecutive grazing periods, in semiarid
southeastern Kenya. The bites count and herd locations per area methods were used. While grazing
thresholds in the system were derived from biweekly sward biomass measured by the quadrant
technique in the growing period and stocking rates applied to a growth-consumption rate model. The
analysis tested the responsiveness of the agropastoral herding strategies to the predominant system
dynamics in the area. ln this environment, high rainfall variability ranging from 71 to gB% is experienced
across years and seasons, pointing to non-equilibrium dynamics in the system. The agropastoralists
practiced seasonal range use and tracking strategies. During the dry season, areas of concentrated
drainage; river valleys, bottomlands and ephemeral drainage ways absorbed a greater grazing load,
taking 57.1 to 60% of the grazing time by the animals. ln Contrast, areas of limited moisture
concentration, the open sandy clay plains, were mainly exploited in the wet season and accounted for
52.6 to 55.6% of the grazing time. The agropastoralists tracked forage availability through use of
multispecies livestock (cattle, goats and sheep) that exploited different grazing resources in space and lime. These range use patterns and strategies tend to stabilize nutrient and energy flow to livestock
and thus productivity throughout the seasons. Based on the growth-consumption rite model, grazing
thresholds in the system are achieved at 13800, 13000,4000 and 12300,4600 and 12000, and 5600 and
11000 kgha-' of grass biomass at,2.5,5,7,8 and 10 TLUha-1, respectively. 7 TLUha-1 represent the upper
stocking rate limit in the system during the growing period. In this system, resource use strategies are in line with the predominantly non-equilibrium system behaviour. However, sedentary land use
interventions and limiting farm sizes that restrict livestock mobility and negatively affect grazing
resource diversity will undermine system stability and sustainable Iivestock production in the area.
Citation
African Journal of Environmental Science and Technology Vol. 2 (s). pp. 222-230, August, 2009Publisher
Department of Land Resource Management and Agricultural Technology,