Published source details
Pelaez D.V., Boo R.M., Elia O.R. & Mayor M.D. (1997) Effect of fire intensity on bud viability of three grass species native to central semi-arid Argentina. Journal of Arid Environments, 37, 309-317
Fire is a major management tool of temperate grasslands in semi-arid central Argentina. This study (undertaken in south-east La Pampa province (38º45'S, 63º45'W) on 20 ha of grassland and scrub closed to grazing since 1982) evaluated the effect of fire intensity on axillary bud viability of three important native perennial grasses, Piptochaetium napostaense, Stipa gynerioides and Stipa tenuis.
There were three treatments applied to 10 plants of each species: 300-400°C (low fire intensity), 500-600°C (high fire intensity) and no fire (control). Fire was applied in April 1994 and May 1995 using a portable propane burner until the plant crown temperature reached the required temperature (as recorded by a thermocouple placed in the centre of each tussock at the soil surface).
On the day of burning and after each burn (on 13 July 1994 and 1995) four tillers from four plants of each species per treatment were randomly sampled. Total number of axillary buds and bud viability were determined on each tiller.
The average number of buds prior to treatment was similar for each species (range 2.1-2.6/tiller in both years). For S.gynerioides after each burn the number of dead buds was higher at the centre of the plant (approx. 2 compared to 1) than the periphery. S.tenuis showed a similar response although differences between the 1995 high and low intensity treatments were marginal (1.6 vs. 1.2 dead buds). No differences in mortality were detected between central or peripheral buds for P.napostaense.
Overall, within each fire intensity treatment in both years, there were no statistical differences among species in the number of total, metabolically active, dormant and dead buds. In general, the number of dead buds was slightly higher in the high fire intensity than the low fire intensity treatment. Burned tillers had more dead buds and fewer active buds compared with controls.
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