Diferencias en la composición florística en bosques de Araucaria- Nothofagus afectados por distintas severidades de fuego
Diferencias en la composición florística en bosques de Araucaria- Nothofagus afectados por distintas severidades de fuego
Authors
Urrutia Estrada, Jonathan
Fuentes Ramírez, Andrés
Hauenstein Barra, Enrique
Fuentes Ramírez, Andrés
Hauenstein Barra, Enrique
Authors
Date
Datos de publicación:
Gayana Botánica, Vol. 75, N° 2, 625-638, 2018
Keywords
Post fire regeneration - Gradiente de severidad - Regeneración post fuego - Riqueza de especies
Collections
Abstract
El fuego tiene impactos importantes en la estructura y funcionamiento de ecosistemas naturales. En marzo de 2015 un incendio de gran magnitud afectó bosques de alto valor ecológico de Araucaria araucana-Nothofagus pumilio (araucaria- lenga) en la Reserva Nacional China Muerta (Chile, 38° S), donde las adaptaciones al fuego son poco frecuentes en la flora nativa. El objetivo del presente trabajo fue evaluar los cambios en la composición florística del bosque en un gradiente de severidad de fuego (i.e., alta, media y baja severidad) un año después del disturbio. Se hipotetiza que las zonas más afectadas por el fuego presentarán una composición de especies distinta a la de zonas menos afectadas, con una menor riqueza y abundancia de especies nativas, y que las especies exóticas se verán favorecidas por el fuego poco severo. Se establecieron 20 parcelas de 100 m2 cada una en todo el gradiente de severidad de fuego, incluyendo un bosque adyacente no quemado que sirvió como referencia. En cada parcela se registró la riqueza y abundancia de toda la flora vascular (nativas y exóticas). Se analizó y comparó la riqueza y abundancia de especies, la composición y similitud florística entre los distintos niveles de severidad. Se encontró que la riqueza y abundancia de especies son significativamente más bajas en áreas de alta y media severidad de fuego. La riqueza y abundancia de especies exóticas fue mayor en áreas de baja severidad de fuego, las cuales estuvieron sujetas a pastoreo después del fuego. Existe un rápido cambio composicional de la comunidad de plantas en el bosque de Araucaria-Nothofagus un año después del incendio, sugiriendo un potencial cambio en la estructura del bosque si las especies arbóreas dominantes no se recuperan después del fuego.
Forest fires can produce significant impacts on the structure and functioning of natural ecosystems. In march 2015, a large- scale 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 m2 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.
Forest fires can produce significant impacts on the structure and functioning of natural ecosystems. In march 2015, a large- scale 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 m2 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.