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Browsing by Author "Coughenour, M."

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    Addressing management questions for Ngorongoro Conservation Area, Tanzania, using the Savanna modelling system
    Boone, Randall B.; Coughenour, M.; Galvin, Kathleen A.; Ellis, J. (Oxford, UK: Blackwell Science Ltd, 2002)
    Ngorongoro Conservation Area (NCA), in northern Tanzania, is a multiple-use area of importance to Maasai pastoralists and wildlife conservation. We adapted the Savanna modelling system to the NCA, creating an Integrated Management and Assessment System that allows users to assess responses to alternative management actions. We used the system to conduct fifteen experiments reflecting potential management questions. Results suggest that: the distribution of rainfall throughout the year may have a greater impact on the ecosystem than its quantity; cattle may be near a carrying capacity determined not by forage limitations but because of disease risks; increasing survival and reducing disease in livestock yields greater returns than increasing birth rates; allowing livestock to graze in areas where they are currently excluded may lead to a slight increase in livestock populations, but sometimes leads to large declines in wildlife populations; few ecosystem effects were noted when households and cultivation were allowed to grow at 3% per year for 15 years; and when up to 5% of the study area was in cultivation, there were declines 16% in livestock and wildlife populations, except for elephants, which declined by 48%. Users may modify our experiments using tools we have developed, or address other NCA management questions.
  • The Ellis paradigm - humans, herbivores and rangeland systems
    Coughenour, M. (Grahamstown, South Africa: NISC Pty Ltd, 2004)
    The scientific and conceptual contributions Jim Ellis made throughout the course of his career reveal a logical progression towards increased understanding of pastoral ecosystems worldwide. Research in wildlife, large herbivores, systems ecology and energy flows through grazing ecosystems formed the basis of his approach. A leader of the South Turkana Ecosystem Project (STEP), he showed the adaptive basis for opportunistic and spatially extensive resource use in temporally and spatially variable environments. After the STEP, he examined pastoral ecosystems in northern and central Asia and elsewhere in Africa. Spatial extensivity, or scale, emerged as being critically important to pastoral ecosystem function. Livestock development schemes based upon inappropriate ecological and economic assumptions are all too often ecologically and economically unsustainable. However, a new paradigm of pastoral ecology and development is emerging. The paradigm is derived from basic, but comprehensive, understanding of the ecologically adaptive features of pastoral resource utilisation strategies, and the ecological processes and constraints that determine energy flows from plants to livestock and humans in spatially and temporally variable environments. Jim Ellis contributed greatly to improved understanding of the importance of mobility and opportunism in these ecosystems. This understanding could benefit humans, ecosystems and wildlife over a vast portion of the earth's surface.