Near-Term Climate Change Impacts on Kenyan Tree Cover

Abstract

Afforestation efforts within tropical landscapes are continuing apace to achieve goals related to climate change mitigation, sustainability and conservation. Outcomes from these efforts are likely to be determined by future changes in climate and disturbance regimes. In Kenya, a tropical nation dominated by dryland ecosystems, the government is undertaking an ambitious ecosystem restoration effort via an afforestation program. Using L-Range, an ecosystem model tuned to the conditions extant across Kenya, and the most recent downscaled climate projections we, explored the durability and wider impacts of these efforts. Conditioning the simulations on the achievement of 10% tree cover by 2030, we explored how woody vegetation, herb cover, and ecosystem productivity will respond in the near-term (2050) under multiple Shared Socioeconomic Pathways and scenarios of fire frequency. Our simulations indicate that, under all scenarios, tree cover across Kenya will remain stable or show increasing trends in the near term. This will be accompanied by increases in overall woody vegetation, driven by shrub cover expansion and the contraction of herb cover. These impacts will be particularly pronounced in areas dominated by savannas and deciduous tree cover. Alongside these changes in vegetative cover, simulations indicate declines in net primary productivity and aboveground live biomass. Thus, we find that the persistence of existing and expanded Kenyan tree cover may not be impeded by climate change or disturbance; however, climate change and afforestation can act in concert to undermine achievement of Kenyan goals related to conservation and sustainability.