Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Elephants, trees, grass, grazers : relationships between climate soils, vegetation and large herbivores in a semi-arid savanna ecosysteem (Tsavo, Kenya)

Auteur : Wijngaarden, W. van

Université de soutenance : Wageningen Universiteit

Grade : PhD thesis 1985

Résumé
Based on descriptions of the climate, soils, vegetation and large herbivore populations, relationships are described between the different components of the Tsavo ecosystem. It appears that there is a strong correlation between the floristic composition of the vegetation and the physical environment (climate and soil). The structure of the vegetation, however, is related more to the density of elephants and the activity of man (fire). The production of the vegetation is strongly related to rainfall and the percentage cover of the relevant vegetation component. Large herbivore distribution and density is related to human activity and the amount and type of forage that is available in a dry year. Static and dynamic models describing these relationships quantitatively are developed and, on the basis of simulations, some conclusions are drawn on the future management options for the national park and the nearby ranches.

Mots clés : animals / biotopes / ecological balance / ecology / elephantidae / equilibrium / grazing / herbivores / kenya / landscape / landscape ecology / mountain grasslands / natural grasslands / pampas / plant succession / proboscidea (mammals) / rangelands / savanna woodlands / semiarid zones / stability / steppes / vegetation / animal communities / disturbances

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