Grazing, fire, and climate in grasslands and savannas: regimes and effects on primary productivity

OESTERHELD, M.; LORETI, J.; SEMMARTIN, M.; PARUELO, J.M.

?Ecosystems of disturbed grounds?. Series Ecosystems of the World

Elsevier

Lugar: Amsterdam; Año: 1999; p. 287 - 306

The objective of this chapter is to show the major effects of these three disturbances on grasslands and savannas of the world. It is focus on those aspects that the authors believe have received less attention and now because of the existence of new data and the development of new ideas that they are in the position of analyzing. The authors believe that most reviews have concentrated on structural aspects of vegetation at the community level while neglecting the functional ecosystem level attributes. Thus, they have chosen a single functional response variable as the center of the chapter: aboveground net primary productivity (ANPP). They have attempted to study the effects of grazing, fire and climate fluctuations as agents of disturbance on productivity in comparable ways considering their relative importance. They have framed all the analysis in the context of a gradient of annual precipitation that encompasses a wide range of grassland and savanna ecosystems. The chapter is organized in the following way: first, they describe the disturbance regime of grasslands and savannas; second, they show how disturbances affect aboveground net primary productivity.