Do Wildfires Promote Woody Species Invasion in a Fire-Adapted Ecosystem? Post-fire Resprouting of Native and Non-native Woody Plants in Central Argentina

Abstract

We asked whether prescribed fire could be a useful management tool to reduce invasion by non-native plants in an ecosystem where native plants are supposed to be adapted to fires. Specifically, we compare the post-fire resprouting response of native and non-native woody species in Chaco Serrano forest of central Argentina. The measurements were carried out in five burnt areas where we selected ten native and seven non-native species. Our response variables were (1) post-fire survival, (2) types of resprouts, and (3) the growth of the resprouts. Our main results show that one year after the fire, survivals of native and non-native species were 0.84 and 0.89, respectively, with variances in survival seven times smaller in the native species group. Type of resprout was also less variable in native species, while growth of the resprouts was similar in native and non-native groups. We interpret that in most cases, the burning a forest with mixed native and non-native plants through prescribed fires will not differentially stop the invasion by non-native woody species even in ecosystems which are presumed to be relatively resistant to fires such as our study area.

Cambios florísticos inducidos por la frecuencia de fuego en el Chaco Serrano.

“…No obstante, la ocurrencia de especies indicadoras en escenarios sin fuego no necesariamente estaría relacionada con la falta de rasgos de tolerancia a disturbios (e.g., capacidad de rebrote). En este sentido, resulta contra intuitivo que el único árbol que resultó indicador de esta condición, Celtis ehrembergiana, presenta altos niveles de rebrote basal y supervivencia post-fuego (Herrero et al, 2016). Sin embargo, esta especie presenta una corteza delgada escasamente aislante del fuego (Kunst et al, 2014) y un extendido periodo juvenil hasta alcanzar edad reproductiva, los que podrían ser rasgos de sensibilidad a las elevadas frecuencias de fuego.…”

“…En este sistema montañoso, la principal estrategia de regeneración post-fuego de las plantas leñosas es el rebrote, presentando alta supervivencia y rápida recuperación de su biomasa después del fuego (Torres et al, 2014;Herrero et al, 2016). En efecto, se ha sugerido que comunidades dominadas por especies de plantas rebrotadoras mostrarían poco cambio de la composición de especies después de la ocurrencia de un incendio (Bond & Midgley, 2001).…”

Post‐burning germination responses of woody invaders in a fire‐prone ecosystem

“…; Herrero et al . ). Therefore, considering both the fire history in the region and the widespread post‐fire resprouting capacity, it can be surmised that plant species in the Chaco have been subjected to little evolutionary pressure to develop traits that enhance germination after fire (Paula & Pausas ).…”

“…; Ferreras & Galetto ; Herrero et al . ). Four of these species are the dominant elements of different communities in the study area, forming ‘ Gleditsia triacanthos woodlands’ (Furey et al .…”

Frequent fires do not affect sexual expression and reproduction in Vachellia caven

“…To assess the hypothesis that fire may indirectly shape the sexual expression and reproduction of plants through its negative effects on abiotic resources, pollination service and/or by decreasing the size of surviving individual plants (Alinari ; Carbone & Aguilar ), we studied Vachellia caven (Molina) Seigler & Ebinger (ex Acacia caven (Molina) Molina), a dominant species of the native flora and a main component of the post‐fire communities in the Chaco Serrano (Herrero et al . ). This species is andromonoecious, having hermaphrodite and male flowers in the same plant (Peralta et al .…”