Efecto de la frecuencia del fuego en la diversidad funcional asociada a la inflamabilidad de un bosque seco tropical de la Cuenca Alta del Río Magdalena

Abstract

Changes in the fire regimes of ecosystems have generated alterations in plant communities, making them more or less susceptible or tolerant to such disturbance. It has been proven that recurrent fires in altered regimes favor the appearance of functional traits associated with flammability. In the case of Colombian tropical dry forests, there are traits associated with flammability, however, it is not known how these traits change with alterations in the recurrence of fires. The objective of this research was to study the effect of fire frequency on the functional diversity associated with the flammability of TDF in the Upper Magdalena River Basin. To this end, the variability in fire frequency in TDF relics in the study area was characterized using Geographic Information Systems. Subsequently, the functional traits associated with flammability were compared between the different fire frequencies, and finally, the changes in the metrics of functional diversity and functional types of plants associated with flammability at the different sites were evaluated. It was found that all evaluated species present some degree of flammability, and that a higher fire frequency generated significant changes in the functional diversity associated with flammability. Thus, two functional types of plants were found, one associated with medium flammability and another with high flammability. Additionally, it was detected that the most flammable species presented a strong association with the dry matter content in branches and leaves, and the basic density of the wood. All the functional traits evaluated presented significance in response to changes in fire frequency. We also detected greater functional uniformity under a higher fire frequency, in contrast to greater functional divergence and dispersion and quadratic entropy in unburned sites. These results suggest that Colombian inter-Andean tropical dry forests could be tolerant to fire, and that a higher fire frequency could be causing these ecosystems to be more flammable. These results should be considered in management and restoration programs of Colombian TDF in favor of their conservation and in the search for less flammable systems in the face of climate change scenarios and alterations in fire regimes.