Comparative usefulness of dNBR and RdNBR indexes to detect fire severity in semiarid steppe.

GHERMANDI L.; LASAPONARA R.; LANORTE A. ; ODDI F.

Global Journal of Science Frontier Research

Global Journals

Año: 2019

0975-5896

Abstract- Available remote sensing historical Landsat TM images allow identifying of first order effects ofwildfires also in huge and inaccessible regions. In this paper the usefulness of the best known satellitederived severity indices was tested on a large wildfire occurred in January 1999 in a steppe ofNorthwestern Patagonia. The main objective of the work was to analyze and compare the behavior ofdNBR and RdNBR in their ability to discriminate the degrees of fire severity in semiarid ecosystemsprincipally dominated by herbaceous vegetation. For this purpose the values of the two indexes werecompared in all vegetation communities (shrubl and, meadow, grassland and forestation). To interpret theresults, we considered the variability of the principal factors that influence the fire severity, as fire intensity,fire duration and vegetation susceptibility to fire. The analysis showed that the interaction between fire andvegetation changes the fire effects because the vegetation parameter as fuel load, moisture content,species composition, horizontal continuity and the topography affect the fire behavior and then the fireseverity. Furthermore the results suggest that dNBR and RdNBR provide substantially differentinformation respectively related to the effects on soil and vegetation. This work is an importantcontribution to the utilization of fire severity indexes in ecosystems dominated by herbaceous species thatchange more subtly the post-fire biomass than ecosystems dominated by woody species.