Fire response syndromes of shrubs in grassy woodlands in the New England Tableland Bioregion

Abstract

In fire-prone grassy woodlands, fire response and time to reach reproductive maturity are two traits that can be used to provide an indication of the minimum interval between fires needed to maintain biodiversity. This study examined the effects of fire intensity and adult size on shrub mortality together with the primary and secondary juvenile periods of shrub species in the New England Tableland (NET) Bioregion. Most shrub species resprouted via basal lignotubers following fire, irrespective of fire intensity and shrub size. The primary juvenile period of most species was found to be greater than four years and the secondary juvenile period for most resprouting species was less than four years. These results suggest that a minimal interval between fires of eight years may be needed to maintain shrub species in grassy woodlands in the NET Bioregion, and that repeated fires at intervals of less than 8 years should be avoided. The time taken for shrubs in the grassy woodlands of the NET Bioregion to reach reproductive maturity appears to be longer than conspecifics in other Bioregions. Caution is needed when using data collected from outside a Bioregion to determine minimum fire frequency thresholds.