Spines of Acacia tortilis, what do they defend and how?

GOWDA, J.H.

OIKOS

Año: 1996 vol. 77 p. 279 - 284

0030-1299

Spines, prickles and thorns are assumed to act as plant defenses against mammalian herbivores. In this study, I tested experimentally whether increasing densities of spines affect the feeding rate and behaviour of goats browsing shoots of Acacia tortilis in Tanzania.  Goats may harvest their food by pruning (removal of both twig and leaves) or by picking (only leaves removed). Feeding rate (biomass consumed /minute) was positively correlated with biomass pruned, and negatively related with biomass picked, both for spiny and spineless shoots. Increased spine density negatively affected the proportion of the shoot that could be pruned, but had no effect on leaf biomass removed by picking. Feeding rate was negatively correlated with spine density.