Use of indigenous ecological knowledge of the Maasai pastoralists for assessing rangeland biodiversity in Tanzania

摘要

This paper incorporates the indigenous ecological knowledge (IEK) of the Maasai pastoralists and ecological methods to assess effects of grazing and cropping on rangeland biodiversity at macro- and micro-landscape scales in northern Tanzania. The joint surveys with pastoralists identified indicator plant species and their associations with micro-landscapes and livestock grazing suitability (i.e. for cattle and small ruminant grazing), while traditional calf-pasture reserves (alalili pl. alalilia) were evaluated for preservation of rangeland biodiversity. The macro-landscapes comprising the cool high plateau (osupuko pl. isipuki) and montane forest highland (endim) were included in the survey. At micro-landscape scales, the osupuko was classified into uplands (orkung'u), slopes (andamata) and dry valley bottomlands (ayarata). The micro-landscapes were assessed in terms of herbaceous plant species and woody species richness and risks of soil erosion. Biodiversity varied at both the macro- and micro-landscape scales and in accordance with the land-use types. Greater plant species diversity and less erosion risks were found in the pastoral landscapes than in the agro-pastoral landscapes. The calf-grazing pastures had greater herbaceous species richness than the non-calf pastures, which in turn had more woody species. The study concludes that the indigenous systems of landscape classification provides a valuable basis for assessing rangeland biodiversity, which ecologists should incorporate into ecological surveys of the rangelands in East Africa in the future.