Post-fire vegetation dynamic in the locality of Rastrojos, central Chile

Abstract

Fires are a frequent type of disturbance in many ecosystems, with strong consequences for vegetation. Despite the common nature of fires in central Chile, few studies have monitored changes in vegetation after they have occurred. This work describes the dynamic of the vegetation in the town of Rastrojos, Maule region, after the mega-fire that occurred in the summer of 2017 in central Chile. In September 2018, the composition and density of the regeneration of woody species were sampled, differentiating whether they came from seed or vegetative resprout, and the coverage of woody and herbaceous layer, in quadrants that were sampled again in September 2020. It was also evaluated the abundance of adult individuals surviving the fire. Rapid, diverse and abundant vegetative regeneration was observed after the fire. Regeneration from seed, although present, was lower in richness and density. The woody and herbaceous cover showed a rapid post-fire recovery. Although there was an important initial pulse of recovery of the vegetation, after a year and a half since the fire, the diversity, abundance and cover stopped increasing, suggesting a stagnation of the recovery. Only the abundance of woody alien species continued to increase with post-fire time. Our results suggest that woody vegetation recovers quickly after fires, mostly from vegetative regeneration. We propose that post-fire restoration in central Chile should be based mainly on passive strategies, although enrichment is required in open sites without vegetative regrowth.