Revista Chilena de Historia Natural 76 (1): 105-115, 2003
RESEARCH ARTICLE
Date of prescribed fire and herbaceous diversity of an Elionorus muticus
(Spreng.) O. Kuntze savanna
CARLOS KUNST SANDRA BRAVO, FABIO MOSCOVICH, JULIO HERRERA, JOSÉ GODOY & SILVIA
Fire is both a natural disturbance and a range management tool in the savannas of
Elionorus muticus (Spreng) O. Kuntze, of the Chaco region of Argentina. Our objective was to assess the effect of
different dates of fire application on the herbaceous diversity of the savanna. Plots were burn at random in four successive dates, in
two experiments initiated in 1993 and 1994, respectively. Richness and abundance of grasses and broadleaf species were registered
in each plot, before the fire and after three growing seasons from fire. Data were summarized using the Shannon-Wiener diversity
index (H’). A variable ∆H’ was defined as the difference between the H’ observed before and after the fire for each plot/ year, and used
as dependent variable in an ANOVA; fire application date, experiment, their interaction and year of observation (t) were considered as
independent variables, with a repeated measures approach. Results indicate that although fire increased herbaceous diversity
significantly, this general outcome was significantly modified by the date of fire application. This result is attributed to the pre and post
fire environmental conditions as well as the phonological status of the species. Fire application at the mid-fire season generates higher
diversity than any other time, probably due to plant resistance and better post fire environmental conditions.
savanna, fire,
herbaceous diversity, Chaco region
