Physiological Ecology of Neotropical Savanna Plants

Abstract

Savanna is a distinctive vegetation type found within the tropical climate belt and is characterized by a continuous cover of mainly C4 perennial grasses with or without scattered trees, or these forming a semi-closed canopy with grasses underneath. They constitute a long-standing phytogeographical problem, since they occupy the same climatic regions as the tropical deciduous forest. Explanations for the existence of grass dominated landscapes where deciduous forest is to be expected differ markedly. Savannas in the tropics have been considered to be determined by a special savanna climate, by edaphic conditions, by fire or by man-made influences. There is apparently now enough evidence to consider savannas as a natural vegetation type whose range has changed at least during and since the pleistocene, mainly due to variations in rainfall patterns (Beard 1953; Hueck 1957; Sarmiento and Monasterio 1975; Walter 1973).