Sampling the vulnerability reduction– sustainable intensification continuum: a West African paradigm for selection of Dryland Systems sites

摘要

The CGIAR Research Program on Dryland Systems(hereafter Dryland Systems)initially segregated world regions into vulnerability reduction(strategic research theme 2 = SRT2)and sustainable intensification(SRT3)domains based on aridity index(AI)ranges(SRT2 = [0.03-0.35],SRT3 = [0.35-0.65]).While acceptable on global and continental scales,this simple approach is insufficient to adequately represent the diversity of systems trajectories observed in the West African drylands.In this paper,we argue that this may lead to sub-optimal research targeting,as the SRT2 – SRT3 continuum could be expressed on a variety of temporal and spatial scales in relative independence from the aridity factor.We provide illustrations of this impact at a regional scale for West Africa.We propose that Dryland Systems site selection in the West African drylands should reflect(i)the dominantly socio-economic nature of drivers of change;(ii)dynamic longitudinal population density gradients across a quasi-invariant,largely monotonic meridional climate gradient;(iii)the cost efficiencies of sampling spatial gradients with complementary action transects that maximize the regional representativeness of Dryland Systems sites.Burkina Faso,Ghana,Mali,Niger and Nigeria are selected as Dryland Systems countries.Two action transects are identified: the Kano-Katsina-Maradi(KKM)transect,with contrasted biophysical conditions from the Sahel to the Sudan savanna,and somewhat more homogeneous socio-economic conditions; and the contrasting and complementary Wa-Bobo-Sikasso(WBS)transect,with diverse socio-economic conditions against a more homogenous biophysical backdrop.Two satellite sites expand the regional representativeness of each transect biophysically(WBS)and socio-economically(KKM).This regional paradigm ensures that site selection(i)is made along the strongest gradients,effective spatial proxies for the temporal drivers of change that define SRT potential;(ii)discretely captures local systems variability,i.e.real-world SRT expression at community-to-district scales where smallholders operate,and(iii)therefore reflects the portability over space and time of the SRT2(?)SRT3 continuum.