Integrating GPS technologies in dynamic spatio-temporal models to monitor grazing habits in dry rangelands

Land degradation in drylands occurs due to a combination of drought and mismanagement of the land while areas of rough topography or undeveloped soils are under greater threat. The role of habitat preference by grazers in these processes is difficult to study because of the complexity involved with animal tracking and mapping of spatio-temporal variation in vegetation status. We addressed this problem by integrating GIS and GPS technologies. In this chapter we assess the time spent by sheep and goat herds in plant habitats in a semi-arid environment. We used a predictive habitat distribution model which is spatially and temporally explicit, based on rules formulated using fuzzy logic. The results show that biomass availability together with a number of abiotic factors (slope decline and orientation, distance from the corral and topographic sub-slope units) could not fully explain the pathway of herds in the study area. However, the effect of these variables on the time spent by the herd in the different habitats was significant. Specifically, the time spent by the herd at a given location (grid cell) along the herding route was positively correlated with the biomass availability in the cell. Furthermore, the time spent by the herd in a cell responded non-linearly to the distance from the corral, being relatively low at near and far distances, and high at intermediate distances. The results imply that additional factors in these systems have a strong influence on the grazing habits.