FIRE AFFECTS SIZE AND SHAPE OF Fabiana imbricata SHRUBLANDS IN NORTHWESTERN PATAGONIA

ODDI F. ; GHERMANDI L.

Congreso; EGU General Assembly 2010; 2010

Fire is a major environmental ecological agent acting in the landscape configuration and a factor that modelsvegetation in Mediterranean environments. Fire impacts differently in the landscape due to the intrinsicheterogeneity of the environments and the characteristics associated with each fire event. After fire, densityof patches may be increased and the size of them may be reduced because fire generates areas of differentsuccessional stages. Landscape ecology seems to be the ideal theoretical approach to study the fire impact in fireprone environments. Landscape ecology has been greatly favoured by a significant progress in the last years ofgeographic information technologies (GIT) (remote sensing, GIS, GPS). The study area of this work is the SanRamon ranch (22,000 ha) located in Northwester Patagonia in the ecotone between the sub Antarctic forest in theWest and the Patagonian steppe in the East. We studied sectors of the ranch with different fire recurrence in thelast 40 years and we mapped Fabiana imbricata shrubland with GPS. This specie is a native shrub characteristicof Northwester Patagonia grasslands and its dynamic is not very known. Shrublands compete for the space withpalatable grasses that are used for forage and livestock production, the main economic resource of the region.We analysed the mapped patches with GIS software, and we assessed landscape metrics to determine differencesbetween sites with different fire recurrence. In the future we foresee the integrated use of satellite imagery withdifferent resolution to add to GIS other important spatial variables (topography, hydrography, aspect, soil) todevelop models that can explain landscape metrics, spatial configuration and the potential shrub invasion in thegrassland.