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

Abstract

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-yr post-fire chronosequence in a temperate dry forest ecosystem in southeastern Australia, and by making comparison with long-unburned reference sites (79 yr since wildfire). We modeled 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 modeled, relative abundance or cover at sites subject to prescribed fire did not change significantly with time since fire or differ from that of long-unburned 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-unburned vegetation. Bird communities varied significantly between the youngest (0-3 yr) and oldest (79 yr) 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.

Fire and functional traits: Using functional groups of birds and plants to guide management in a fire‐prone, heathy woodland ecosystem

“…Data are available from the Dryad Digital Depository: (Rainsford et al. 2021; DOI https://doi.org/10.5061/dryad.qfttdz0gj).…”

“…In south‐eastern Australia, for example, post‐fire age classes, determined by compositional and structural changes to vegetation, have been defined to represent key “growth stages” in post‐fire succession in an ecosystem (e.g., Cheal, 2010). Even though much of the fauna of temperate south‐east Australia has not shown strong preferences for particular successional stages (e.g., Rainsford et al., 2021; Swan et al., 2015), the assumption that such categories represent distinct successional communities has rarely been tested for animal taxa.…”

Metabarcoding clarifies the diet of the elusive and vulnerable Australian tjakura (Great Desert Skink, Liopholis kintorei)

“…This can be due to reduced opportunities for dispersal and colonisation (McAlpin, 2001;Lazzari, 2019) and loss of vegetation cover which is ideal for survival of this species (Ridley et al, 2020;Ridley and Schlesinger, 2023). On the other hand, properly prescribed burning can be a driver of species richness and community composition on natural ecosystems (Cadenhead et al, 2016;Rainsford et al, 2021;Zylinski and Swan, 2022). Our study demonstrated that time since the last fire had an influence on dietary diversity though it was not statistically significant (Figure 3).…”