Fire in a neotropical dry forest: Cultural uses and ecological effects

Fires ignited by human activities frequently impact neo-tropical dry forests. While anthropogenic fires are generally considered a destructive disturbance, relatively little is known about their effect on the dry forest plant community and species of conservation concern. In addition, little attention has been paid to the socio-cultural motives that lead to wildfire ignition. This study examines the cultural use of fire and plant community and life history responses to fire in an upland dry forest within the Rio Escalante-Chacocente Wildlife Refuge in southwestern Nicaragua. Members of farming communities located within and surrounding the refuge were interviewed about fire practices and the perceived benefits of fire. Fire was described as an essential step for preparing agricultural land and was crucial to many aspects of subsistence farming. The effect of fire was measured in the composition and density of dry forest species in four permanent one hectare forest plots burned by a wildfire and in experimentally burned 15 x 75 m forest plot. Three years of post-fire monitoring revealed that the impact on vegetation is most significant within the first year post-fire. Diameter was positively correlated with survivorship for woody species, with individuals of >6 cm dbh suffering less than 20% mortality. Lianas were most negatively affected by fire, suffering high mortality and decreased post-fire recruitment. There was an increase is seedling richness and density post-fire, particularly for overstory tree species. Dry forest species exhibited various responses to fire (sprouting, resistance, post-fire recruitment), but few succumbed to single fire events. Sprouting was the most common response to fire. Three tree species of conservation concern responded positively to fire, showing increased recruitment following fire. Our research demonstrates that fire has complex effects on dry forest, and even in some cases, may serve to enrich the forest. Further research on the ecological role of fire is merited in order to develop a fire policy that meets both ecological and human needs.