Effects of fire on the populations of ground beetles (Coleoptera, Carabidae) in an equatorial Andean páramo

Man-made fires are frequent during the dry season in grasslands of the páramo ecosystem of equatorial Andes, at elevations above 3400 m above sea level. They have the short-term effect of biodiversity loss and soil erosion, and the medium to long-term impact of leaving more available niches, resulting in changes in the ecosystem structure. This study aimed to understand the effects of these fires on ground beetle populations. The study area was on Cerro Atacazo where 300 ha were burned in July 2017. Samplings were made in a burned area and an adjacent unburned area at ca. 4000 m above sea level, over 17 months using pitfall trapping. Nine ground beetle species were collected, seven of which were present in the burned and unburned areas. The variations observed over time in ground beetle abundance are more likely driven by climatic factors, such as precipitation, than by the effects of fire. The species assemblages were significantly different in the two areas and no increasing pattern of similarity was observed as time passed after the fire, suggesting that reversing the effects of the fire would take more than 17 months. The response to the disturbance induced by fire appeared to be species-specific, with a greater abundance of large-size species in the burned area. Conversely, the total absence of the small-size genus Oxytrechus in the burned area points to this taxon as a good indicator of the undisturbed páramo environment.