Diferencias en la composición florística en bosques de Araucaria- Nothofagus afectados por distintas severidades de fuego

Abstract

Forest fires can produce significant impacts on the structure and functioning of natural ecosystems. In march 2015, a largescale forest fire affected Araucaria araucana-Nothofagus pumilio (araucaria-lenga) forests of high ecological value in National Reserve China Muerta (Chile, 38° S), where fire adaptations are rare among native plants. The goal of this research was to evaluate the initial changes of plant composition in the forest along a severity gradient (i.e., high, medium and low severity) one year after fire. It is hypothesized that areas more affected by fire will have different species composition from the less-fire-affected areas, with decreased richness and abundance of native species, but exotic species will be favored by the less severe fire. Twenty sampling plots of 100 m 2 each were established throughout the fire-severity gradient, including an adjacent unburned forest that served as reference. Species richness and abundance of all vascular plants (native and exotic) were recorded in each plot. We analyzed and compared species richness and abundance of natives and exotics, and the floristic composition and similarity between the different levels of severity. The results show that species richness and abundance were significantly lower in areas of high and medium fire-severity compared to areas less-affected by fire. The richness and abundance of exotic species were greater in areas of low fire-severity, which were subject to cattle grazing after the fire. This research shows a rapid compositional change in the vascular plant community in Araucaria-Nothofagus forests one year after fire, and raises the potential for change in the forest structure if dominant tree species are unable to recover after fire.

Field-Validated Burn-Severity Mapping in North Patagonian Forests

“…Post-fire establishment of the obligate seeder N. pumilio decreases under conditions of higher severity [40]; if the accompanying species is N. antarctica, a post-fire cohort is rapidly created by vigorous resprouts that reach 1 m in height within three years [39]. In terms of the understory, higher severity induces decreases in richness and abundance and changes in composition, with exotic species being more abundant in situations of low severity [41]. Regeneration in burned areas is mainly controlled by burn severity and basal area, with influences of topography and biotic interactions, but fire refugia also play a role as seed sources for post-fire dynamics in the longer term [42].…”

Changes in the Structure of Assemblages of Three Liolaemus lizards (Iguania, Liolaemidae) in a Protected Area of South-Central Chile Affected by a Mixed-Severity Wildfire

“…This situation became evident in the most severe treatments, where the relative use of microhabitats changed, minimizing the occupation of trees. While this species has been recognized as insectivorous (Ortiz, 1974), eventually it can behave as omnivorous (Willson et al, 1995(Willson et al, , 1996, which would facilitate foraging activities in high severity treatments, considering the floristic diversity present in these patches (Urrutia-Estrada et al, 2018). A remarkable fact is the absence of statistical significance in almost T a b l e 4 .…”

Métodos fitoecológicos aplicados en la caracterización de ecosistemas de referencia

“…En el caso de China Muerta, la presencia de especies exóticas podría atribuirse al paso continuo de ganado vacuno en el área (Urrutia-Estrada et al, 2018), el impacto de estos animales sobre el piso del bosque y su relación con la llegada de especies exóticas ha sido documentada por varios autores (Chaichi et al, 2005;Savadogo et al, 2007;Amiri et al, 2008). La capacidad de una especie para invadir bajo el dosel de un bosque está en estrecha relación con el hábito de crecimiento que presente, siendo la vegetación herbácea la más común (Pauchard et al, 2014).…”