How does prescribed fire shape bird and plant communities in a temperate dry forest ecosystem?

To mitigate the impact of severe wildfire on human society and the
environment, prescribed fire is widely used in forest ecosystems to reduce
fuel loads and limit fire spread. To avoid detrimental effects on
conservation values, it is imperative to understand how prescribed fire
affects taxa having a range of different adaptations to disturbance. Such
studies will have greatest benefit if they extend beyond short-term
impacts of burning. We used a field study to examine the effects of
prescribed fire on birds and plants across a 36-year post-fire
chronosequence in a temperate dry forest ecosystem in south-eastern
Australia, and by making comparison with long-unburnt reference sites (79
years since wildfire). We modelled changes in the relative abundance of 22
bird species and the cover of 39 plant species, and examined how
individual species, functional groups, species richness and community
composition differed between sites with different fire history. For most
individual bird and plant species modelled, relative abundance or cover at
sites subject to prescribed fire did not change significantly with time
since fire or differ from that of long-unburnt vegetation. When bird
species were pooled into functional groups, time since prescribed fire had
strong effects on birds that forage in the lower-midstorey,
facultative-resprouting shrubs and obligate-seeding shrubs. Species
richness for both taxa did not differ between sites subject to prescribed
fire and those in long-unburnt vegetation. Bird communities varied
significantly between the youngest (0-3 years) and oldest (79 years)
post-fire age-classes, driven by species associated with understorey
vegetation. Plant community composition showed little evidence of a
post-fire successional trajectory. The prevalence of bird species with
broad habitat and dietary niches and plant regeneration through
resprouting, make bird and plant communities in these forests relatively
resilient to small and patchy prescribed fires they have experienced to
date. Application of prescribed fire will be most compatible with
maintaining biodiversity by taking a landscape approach that: 1) plans for
a geographic spread of stands with a range of between-prescribed-fire
intervals to ensure provision of suitable habitat for all taxa, and 2)
avoids burning in moist gullies to maintain their value as fire refuges.