Disentangling the drivers of vegetation change in a mobility-constrained pastoral landscape in Laikipia Kenya

Abstract Dryland ecosystems around the world support high biodiversity and extensive pastoralism, but the drivers of landscape change are often poorly understood. Reductionistic understandings have tended to overemphasize livestock impacts and support restrictive interventions, which can ironically undermine synergistic relationships between pastoralism and biodiversity. Within a collectively-titled pastoralist landscape in Laikipia, Kenya, we built on long-term research to examine spatial relationships between locally-varying livestock use intensity and patterns of vegetation change over a 26 year period. We integrated remote sensing, field vegetation measurements, and pastoralist expert accounts of vegetation change to map vegetation transitions and their spatial distribution. We triangulated between multiple lines of inference, including classifications of vegetation community types and transitions, maps of varying livestock use zones and topography, qualitative analysis of expert explanations of vegetation change, and NDVI time series, to infer the contributions of grazing intensity and other drivers to the observed vegetation transitions. First, the most salient landscape change was the loss of two Euphorbia spp. in ∼22% of the study area; with elephants largely driving the loss of one species, and climate being a probable driver of loss of the other. Second, approximately 40% of the area experienced some degree of shrub encroachment. Spatial comparisons with livestock use zones indicated that shrub encroachment was more likely driven by fire suppression and/or climate. Third, there was ∼26% decrease of area supporting moderate or dense herbaceous vegetation cover. These decreases were primarily associated with increasing temperature, woody encroachment, and higher livestock pressure in areas that both formerly supported Euphorbia spp. canopies and also experienced year-round livestock use imposed through a conservation intervention. We recommend integrative triangulation between multiple epistemologies to understand how landscape changes in dryland ecosystems are driven by complex, interacting drivers such as spatio-temporal climate variability, megaherbivores, fire suppression, sedentarization, and changing livelihoods.