Spatial dynamics of <I>Fabiana imbricata</I> shrublands in northwestern Patagonia in relation to natural fires

Abstract

Abstract.Fire is a critical disturbance in the structuring and functioning of most Mediterranean ecosystems. In northwestern Patagonia, vegetation patterns are strongly influenced by fire and environmental heterogeneity. Dendroecology, together with satellite imagery and GIS, have been demonstrated to be useful tools in studies that relate to fire effects with patches, patterns and species dynamics at landscape scale. Such studies can be approached from landscape ecology, which has evolved in the last years supported by the development of remote sensing and GIS technologies. This study evaluates the spatial dynamic of F. imbricata in response to fire using remote sensing, GIS and dendrochronology techniques, at landscape scale. Two sites were evaluated and one of them was affected by fire in the year 1999. The digital processing images (using the NBR spectral index) and the dendroecological analysis verified this. A fire, occurring in 1978, was also detected by the analysis of F. imbricata growth rings. The relation between F. imbricata shrubland dynamics and spatial configuration with fire, land topography and hydrography was established in the study area.

Are Fabiana imbricata shrublands advancing over northwestern Patagonian grasslands? A population dynamics study involving fire and precipitation

“…Seed production was estimated at 200 000 seeds per adult (Ruete, 2006), forming persistent banks (Gonzalez and Ghermandi, 2008). Very longlived individuals were found up to 140 years old (Oddi et al, 2010). This shrub has a broad distribution, extending from the south of Mendoza to Chubut in Argentina, and from Atacama up to Valdivia in Chile (Correa, 1999).…”

Estado del conocimiento en ecología y conservación de los roquedales de la Argentina: Una revisión

“…Estas características de los roquedales, junto con otras definidas tanto por su formación geológica como por su grado de exposición solar, determinarían en gran parte las diferencias que pueden encontrarse entre comunidades de distintos afloramientos (Speziale and Ezcurra 2012;Kristensen and Frangi 2015). En la Patagonia se estudiaron especies saxícolas, especialmente en algunos bosques y en el ecotono bosque-estepa (Anchorena and Cingolani 2002;Oddi et al 2010;Landesmann et al 2015). Además, se realizaron trabajos en las provincias de Córdoba (Menghi et al 1989;Vischi et al 2004), en los llanos del noroeste de San Juan (Carretero et al 2010) y en la Región Pampeana (Kristensen and Frangi 2015;Herrera et al 2017), principalmente enfocados en el estudio de la composición de las comunidades que ocupan esos sitios.…”

“…Para estas especies, los roquedales pueden constituir un refugio muy valioso, dado que, a diferencia de lo que ocurre en la matriz circundante, el fuego no suele afectarlos (Cantero et al 2017). Estudios realizados en Córdoba y en la Patagonia argentina sugieren que ciertas especies vegetales (e.g., F. imbricata, A. chilensis y P. australis) pueden crecer en los afloramientos rocosos y en sus cercanías gracias a que éstos les brindan protección contra incendios (Renison et al 2002;Oddi et al 2010;Souto et al 2012;Landesmann et al 2015).…”

Fire as a stimulant of shrub recruitment in northwestern Patagonian (Argentina) grasslands

“…In NW Patagonian ecotone (Argentina) is frequently found in rocky substrates, and also in drainage lines and streams (Anchorena and Cingolani 2002). F. imbricata is characterized by a longevity of approximately 150 years (Oddi et al 2010) reaching a height of 4 m (e.g., FJ Oddi, CONICET, Bariloche, Argentina pers. comm.).…”

“…This species is very important in the grassland dynamics because its encroachment related to fire (de Torres Curth et al 2012) can change vegetation physiognomy and ecosystem processes. The spatial configuration of F. imbricata is related to fire, soil topography, and hydrography (Oddi et al 2010). This species forms even-aged stands where no new recruitment is observed in the absence of extreme disturbances .…”