Interactive effect of flooding and grazing on the growth of Serengeti grasses.

MARTÍN OESTERHELD; MCNAUGHTON, S.J.

OECOLOGIA

SPRINGER

Año: 1991 vol. 88 p. 153 - 156

0029-8549

Summary. Grazing and flooding may potentially interact in particular habitats of many grassland regions around the world. We tested the hypothesis that grazing and flooding induce different and largely opposed allocation responses in individual plants. As a result, their com- bined effect on plant growth would be negative. We studied the response of three grass species from the Serengeti ecosystem (Tanzania) to the effects of flooding and clipping. Plants under the combined effect of flood- ing and clipping had lower growth rates than plants growing under the effect of either of the two factors individually. Plants under flooding grew taller and allo- cated more resources to stem growth than controls; for two of the three species, flooded plants also generated a new root system above soil level. All these morphologital and physiological responses conflict with the ability of a plant to respond to defoliation with minimum reduction in growth rates. The three species showed a response to