Range use and dynamics in the agropastoral system of southeastern Kenya

Abstract

Occurrence of equilibrium and non equilibrium system dynamics in semiarid environmenls present
\nserious management challenges. ln these areas, resource management strategies are increasingly
\nbased on equilibrium rather than non equilibrium dynarnics that assume simple systern dynamics and
\nstrong coupiinE of a.imal-plant responses. This ffiar:agemeni approach underlies increasing trends of
\nrange degradation and low livestock productivity in these environments. To reverse these trends
\ndictates greater understanding and alignment of grazing resource extraction strategies in space and
\ntlme to prevailing system dynamics behaviour. ln ihis study, range use patterns by free ranging herds
\nunder agropastoral herding were studied in two cycles of four consecutive grazing periods, in semiarid
\nsoutheastern Kenya. The bites count and herd locations per area methods were used. While grazing
\nthresholds in the system were derived from biweekly sward biomass measured by the qiadrant
\ntechnique in the growing period and stocking rales applied to a growth-consumption iate model. The
\nanalysis tested the responsiveness of the agropastoral herding strategies to the predominant system
\ndynamics in the area. ln this environment, high rainfall variability ranging from 71 to gB% is experienced
\nacross years and seasons, pointing to non-equilibrium dynamics in the system. The agropasloraiisis
\npracticed seasonal range use and tracking strategies. During the dry season, areas of concentrated
\ndrainage; river valleys, bottomlands and ephemeral drainage ways absorbed a greater grazing load,
\ntaking 57.1 to 60% of the grazing time by the animals. ln Contrast, areas of limiGd moisture
\nconcenlration, the open sandylclay plains, were rnainly exploited in the wet season and accounted for
\n52.6 to 55.6% of the grazing time. The agropastoralists tracked forage availability through use of
\nrnultispecies livesicck (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
\nand thus productivity throughout the seasons. Based on the growth-consumption rite model, grazing
\nthresllglds in the system are achieved at 13800, 13000,4000 and 12300,4600 and 12000, anO 6olo anO
\n11000 kgha-' of grass biomass aL,2.5,5,7,8 and 10 TLUha-1, respectively. 7 TLUha-1 represent the upper
\nstocking 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 ta-nd use
\ninterventions and limiting farm sizes that restrict livestock mobility and negatively afflct grazing
\nresource diversity will undermine system stability and sustainable Iivestock production in the area.