An interdisciplinary analysis of landscape-level vegetation change in Laikipia, Kenya

Background/Question/Methods

Throughout East Africa, changes over the past century have decreased pastoralists’ access to seasonal grazing lands.  Changes in both the mobility and composition of herds are thought to amount to large differences in landscape level processes, but few studies have linked the interaction of vegetation and herder livelihoods analytically at the landscape scale.  The objective of this research is to understand how changes in vegetation that have occurred at multiple scales relate to domestic herbivore pressure in a herding community in central Kenya.  A desired outcome is to better understand both the dynamics of semi-arid landscapes and the implications of changes in landscape-level processes for herder livelihoods under novel herbivore pressures. I used household surveys and spatial analysis to model species-specific livestock pressure.  Land-cover change analysis of vegetation using coarse scale (30m) remotely-sensed images was conducted along gradients of livestock pressure.  Land-cover change analysis was compared to supervised classification of semi-arid vegetation.  Fine-scale plant community composition and vegetation patch structure data was compared to both livestock and environmental gradients.  

Results/Conclusions

Analysis of herding ranges reveals clear patterns of land use changes in the recent past, including reduced use of more distant forage resource areas.  I found that greater changes in both the local spatial autocorrelation of vegetation indices and image differencing occur in areas that have experienced changes in pressure from specific livestock types.  Preliminary spatial analyses indicate that areas which have experienced both specific livestock pressures and that show increased differences in vegetation indices also support distinct vegetation types today.  Preliminary gradient analysis indicates that there is a strong relationship between plant community gradients and recent changes in domesticated herbivore pressure.  Potential future outcomes of this research include an improved understanding of the dynamics of semi-arid ecosystems, an increased understanding of processes that directly impact plant diversity, and a more nuanced understanding of the interaction of ecological and livelihood factors.  In future research, I will solicit local community members to review the results, and engage in direct dialogue with non-governmental organizations in hopes of collaboratively developing a nuanced understanding of ecological changes, livelihood changes, and practical strategies for evaluating natural resource management regimes.