Spine production is induced by fire. A natural experiment with three Berberis species

GOWDA, J.H.; RAFFAELE, E.

ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY

Año: 2004 vol. 26 p. 239 - 245

1146-609X

In arid and semiarid ecosystems, where the importance of spines in influencing the foraging pattern of browsing herbivores seems to increase, the recurrence and intensity of fire strongly conditions dynamics of the plant community. In these ecosystems a large number of plant species respond both to fires and browsing by resprouting. We compared the mass allocation pattern to the current year growth of three Berberis species growing in two areas that burned 1999 with samples collected in unburned areas within the same plant community, to test whether the production of spines is enhanced by fire. Our results show that plants resprouting after fire produced significantly longer spines than plants in unburned communities. Spine density also showed a significant increment in burned areas as compared to their controls. The increment in spine density was not explained by a reduction of shoot length. Earlier studies indicate that some species respond to browsing by allocating more biomass to spines. Here we present evidence that fire may induce an increment in spine production similar to that induced by browsing. We suggest that this may be an adaptation to the increased risk of herbivory faced by these shrubs following fire.