Effects of fire on a forest-grassland ecotone in De La Plata River, Argentina

Abstract

This study adds information on the dynamics of pioneer forest trees in the face of frequent fire. In particular, effects of fire on the regeneration dynamics and ecological attributes of a Tessaria integrifolia forest and a Cortaderia selloana grassland, located in the Costanera Sur Ecological Reserve, Buenos Aires, are analyzed. Based on the study of ten transects along a forest–grassland gradient, a considerable incidence of fire and resilient response to it were observed on grasslands. On the other hand, the forest proved resistant to fire, not showing evidence of its action. Despite its invasive tendencies, C. selloana was unable to establish itself in the forest or in the forest–grassland ecotones. Conversely, following the action of fire, T. integrifolia could be found in areas previously dominated by grassland, leading to an expansion of the forest. Replacement of grasslands with a T. integrifolia forest indicates a reduction in the incidence of and surface area susceptible to fire, as well as an increase in biodiversity. The post-fire colonization observed for T. integrifolia has not been previously described for this widely distributed South American species.