Integrating satellite images and topographic data for mapping seasonal grazing management units in pastoral landscapes of eastern Africa

Abstract

We present a framework for mapping grazing management units in extensive pastoral landscapes. Mapping such units from remote sensing, particularly in the pastoral landscapes of East Africa, is usually hampered by high cost of field data collection and by the fact that the relationship between rangeland ecological characteristics and rangeland use for adaptive grazing management by mobile pastoralists is context specific and reflects complex socio-ecological interactions. We propose, therefore, a flexible framework that combines topographic descriptors with rangeland greenness and phenology indicators derived by remote sensing imagery to derive thematic classes that users can query, according to their requirements, to produce grazing management units. The framework is illustrated for an extensive pastoral region in Southern Ethiopia. The thematic classes generated were statistically compared with Plant Functional Types (PFTs) classes obtained by interpretation of GPS-tagged photos, showing a highly significant relationship (Chi-Square test, χ2 = 5971.4, p = 0.0001). Then, the same classes were further classified into grazing management units by integrating information about rangeland seasonal use and accessibility from pastoral communities. This approach could support the definition of adaptive community-based rangeland management strategies by combining ecologically meaningful maps derived by satellite indicators with local knowledge about rangeland use and accessibility.