Figure 2: Estimated average fire response for species richness using the spline of species recovery. Biodiversity The results showed that the biodiversity (defined using the Shannon-Wiener biodiversity index as outlined in the methods)) of the ground cover was back to pre-fire levels after about 1.5 years, whereas the biodiversity of the midstorey layer took about two years to recover (Figure 3). The overstorey took much longer to fully recover. Biodiversity in the midstorey and overstorey was still increasing five years after the 2003 fire. Since the species composition of sites did not change greatly, the increasing value of the index shows that site cover of the midstorey and overstorey is more even after five years than it was immediately post-fire. Analysis of biodiversity by the dominant Eucalyptus type showed that there was little difference in recovery rates. The exception to this was in the overstorey of Peppermint forests, which recovered more quickly after the fire than the other forest types (Alpine Ash, Snow Gum or Mountain Gum). Figure 3: Estimated average response profile of biodiversity for each of the three height categories Recovery by dominant eucalypt The analysis of species richness recovery grouped by the dominant eucalypt speciese showed that there is a slower recovery in the number of species present after fire in Alpine Ash than other vegetation communities (Snow gum, Peppermint or Mountain Gum) (see Figure 4). Figure 4: Change in numbers of species (as species richness) from 1996 to 2008 for dominant eucalypt types 5.3 Recovery in species richness of grass and shrub layers In general, the species richness of the grass/herb layer increased across all the forest types in response to the 2003 fire (Figure 5). The increase in species richness in the first year after the 2003 fires was higher for the grass/herb layer than for the shrub or overstorey layers. While dipping marginally during subsequent years, by 2008 the species richness of the grass/herb layer was well above the shrub layers. This increase is most likely attributed to the increase in weed species or
Figure 2: Estimated average fire response for species richness using the spline of species recovery. Biodiversity The results showed that the biodiversity (defined using the Shannon-Wiener biodiversity index as outlined in the methods)) of the ground cover was back to pre-fire levels after about 1.5 years, whereas the biodiversity of the midstorey layer took about two years to recover (Figure 3). The overstorey took much longer to fully recover. Biodiversity in the midstorey and overstorey was still increasing five years after the 2003 fire. Since the species composition of sites did not change greatly, the increasing value of the index shows that site cover of the midstorey and overstorey is more even after five years than it was immediately post-fire. Analysis of biodiversity by the dominant Eucalyptus type showed that there was little difference in recovery rates. The exception to this was in the overstorey of Peppermint forests, which recovered more quickly after the fire than the other forest types (Alpine Ash, Snow Gum or Mountain Gum). Figure 3: Estimated average response profile of biodiversity for each of the three height categories Recovery by dominant eucalypt The analysis of species richness recovery grouped by the dominant eucalypt speciese showed that there is a slower recovery in the number of species present after fire in Alpine Ash than other vegetation communities (Snow gum, Peppermint or Mountain Gum) (see Figure 4). Figure 4: Change in numbers of species (as species richness) from 1996 to 2008 for dominant eucalypt types 5.3 Recovery in species richness of grass and shrub layers In general, the species richness of the grass/herb layer increased across all the forest types in response to the 2003 fire (Figure 5). The increase in species richness in the first year after the 2003 fires was higher for the grass/herb layer than for the shrub or overstorey layers. While dipping marginally during subsequent years, by 2008 the species richness of the grass/herb layer was well above the shrub layers. This increase is most likely attributed to the increase in weed species or
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