Search

Threatened species managers are often required to make swift decisions in the face of considerable uncertainty. We tested a structured approach for evaluating conservation options for the critically endangered orange-bellied parrot. The Orange-bellied Parrot Recovery Team provides advice to government agencies to inform the allocation of a limited number of captive-bred birds to different release scenarios. Using a structured expert elicitation approach, we determined that scenarios where more fledglings were released were more cost-effective compared to other options. Following this finding in 2019, the recovery team adjusted plans and allocated additional birds to fledgling release, a response that contributed to an increase in wild birds migrating in 2020 and 2021. The challenges facing orange-bellied parrot conservation, including limitations in animals, time and resources, and high uncertainty, are common for threatened species recovery programs. Here we show that a structured process can help managers grapple with these complex trade-offs to make timely decisions.

Aim: After environmental disasters, species with large population losses may need urgent protection to prevent extinction and support recovery. Following the 2019–2020 Australian megafires, we estimated population losses and recovery in fire-affected fauna, to inform conservation status assessments and management. Location: Temperate and subtropical Australia. Time period: 2019–2030 and beyond. Major taxa: Australian terrestrial and freshwater vertebrates; one invertebrate group. Methods: From > 1,050 fire-affected taxa, we selected 173 whose distributions substantially overlapped the fire extent. We estimated the proportion of each taxon’s distribution affected by fires, using fire severity and aquatic impact mapping, and new distribution mapping. Using expert elicitation informed by evidence of responses to previous wildfires, we estimated local population responses to fires of varying severity. We combined the spatial and elicitation data to estimate overall population loss and recovery trajectories, and thus indicate potential eligibility for listing as threatened, or uplisting, under Australian legislation. Results: We estimate that the 2019–2020 Australian megafires caused, or contributed to, population declines that make 70–82 taxa eligible for listing as threatened; and another 21–27 taxa eligible for uplisting. If so-listed, this represents a 22–26% increase in Australian statutory lists of threatened terrestrial and freshwater vertebrates and spiny crayfish, and uplisting for 8–10% of threatened taxa. Such changes would cause an abrupt worsening of underlying trajectories in vertebrates, as measured by Red List Indices. We predict that 54–88% of 173 assessed taxa will not recover to pre-fire population size within 10 years/three generations. Main conclusions: We suggest the 2019–2020 Australian megafires have worsened the conservation prospects for many species. Of the 91 taxa recommended for listing/uplisting consideration, 84 are now under formal review

Aim After environmental disasters, species with large population losses may need urgent protection to prevent extinction and support recovery. Following the 2019–2020 Australian megafires, we estimated population losses and recovery in fire-affected fauna, to inform conservation status assessments and management. Location Temperate and subtropical Australia. Time period 2019–2030 and beyond. Major taxa Australian terrestrial and freshwater vertebrates; one invertebrate group. Methods From > 1,050 fire-affected taxa, we selected 173 whose distributions substantially overlapped the fire extent. We estimated the proportion of each taxon’s distribution affected by fires, using fire severity and aquatic impact mapping, and new distribution mapping. Using expert elicitation informed by evidence of responses to previous wildfires, we estimated local population responses to fires of varying severity. We combined the spatial and elicitation data to estimate overall population loss and recovery trajectories, and thus indicate potential eligibility for listing as threatened, or uplisting, under Australian legislation. Results We estimate that the 2019–2020 Australian megafires caused, or contributed to, population declines that make 70–82 taxa eligible for listing as threatened; and another 21–27 taxa eligible for uplisting. If so-listed, this represents a 22–26% increase in Australian statutory lists of threatened terrestrial and freshwater vertebrates and spiny crayfish, and uplisting for 8–10% of threatened taxa. Such changes would cause an abrupt worsening of underlying trajectories in vertebrates, as measured by Red List Indices. We predict that 54–88% of 173 assessed taxa will not recover to pre-fire population size within 10 years/three generations. Main conclusions We suggest the 2019–2020 Australian megafires have worsened the conservation prospects for many species. Of the 91 taxa recommended for listing/uplisting consideration, 84 a

Prescribed burning is widely used to mitigate the effects of severe fires across the landscape and to maintain biodiversity. Just like wildfires, the severity of prescribed burns can vary; this study was an opportunistic investigation. In one fortnight during autumn months of 2012, several prescribed burns were carried out in heathy-dry forests of central Victoria, Australia. We used measurements of canopy scorch, bark burn and ground cover burn to calculate a severity score for each site. The severity scores across sites ranged from low (2.5) to high (10). A before-after control-impact (BACI) design was utilised to model the potential impacts of fire and fire severity on birds. We used generalised linear mixed models (GLMM’s), and incorporated first- and second-year post-fire spring/summer observations from 2012 to 2014, against bird data from observations carried out in 2010. The total combined abundances of individual species showed that broadly, bird abundance rebounded to pre-burn levels by the second spring post-fire. There was little response detected in either species richness or turnover. The muted turnover result aligns to other studies that indicate a scarcity of early-successional-stage species in eucalyptus forests and woodlands that rapidly regenerate post-fire. Ten individual species were also examined, and only one species, the White-throated Treecreeper (Cormobates leucophaea), responded to both fire and its severity. The BACI design was informative in illustrating that while the forest birds were resilient to small-scale prescribed burns of any severity, abundances in general may have been in decline, a result aligning with the years of reduced rainfall in the region.

Fire is a global driver of ecosystem structure, function, and change. Problems common to fire scientists and managers worldwide include a limited knowledge of how multiple taxonomic groups within a given ecosystem respond to recurrent fires, and how interactions between fire regimes and environmental gradients influence biodiversity. We tested six hypotheses relating to fire regimes and environmental gradients in forest ecosystems using data on birds (493 sites), mammals (175 sites), and vascular plants (615 sites) systematically collected in dry eucalypt forests in southeastern Australia. We addressed each of these hypotheses by fitting species distribution models which differed in the environmental variables used, the spatial extent of the data, or the type of response data. We found (1) as predicted, fire interacted with environmental gradients and shaped species distributions, but there was substantial variation between species; (2) multiple characteristics of fire regimes influenced the distribution of forest species; (3) common to vertebrates and plants was a strong influence of temperature and rainfall gradients, but contrary to predictions, inter‐fire interval was the most influential component of the fire regime on both taxonomic groups; (4) mixed support for the hypothesis that fire would be a stronger influence on species occurrence at a smaller spatial extent; only for vertebrates did scale have an effect in the direction expected; (5) as predicted, vertebrates closely associated with direct measures of habitat structure were those most strongly influenced by fire regimes; and (6) the modeled fire responses for birds were sensitive to the use of either presence–absence or abundance data. These results underscore the important insights that can be gained by modeling how fire regimes, not just fire events, influence biota in forests. Our work highlights the need for management of fire regimes to be complemented by an understanding of the underlying environ

The montane forests of the Central Highlands, Victoria, are managed for multiple uses that include biodiversity conservation and timber harvesting. Old-growth communities within mountain ash forest have been shown to support a range of fauna. These communities have a restricted distribution, as a result of combined effects of previous wildfires and timber harvesting. Patches of mountain ash old-growth forest vary in size, shape, topographic position, structure, and isolation from other patches. The study investigated effects of this spatial patterning on selected fauna that require old trees. Arboreal marsupials were used to measure these effects, focusing on the yellow-bellied glider (Petaurus australis) and the greater glider (Petauroides volans). Forty-nine old-growth forest sites were surveyed for gliders using spotlight transects and owl-call playback, and for a variety of landscape and habitat variables. Occurrence of the greater glider was significantly related to overstorey basal area (P<0.001). An alternative model found greater glider occurrence to be significantly related to old-growth patch size (P=0.004). The probability of yellow-bellied glider occurrence was highest at sites located in large patches of old-growth forest (P=0.03). These results appear to be related to the foraging requirements and population biology of the yellow-bellied glider and shelter requirements of the greater glider. The abundance of greater gliders at a site was also found to be significantly related to overstorey basal area (P<0.001). The size and quality of old-growth forest patches (quality measured by overstorey basal area) were shown to influence their value for fauna conservation.

A model of the metapopulation dynamics of Powerful Owls Ninox strenua in Victoria, Australia is described, and its parameters were derived from available data. Sensitivity analysis indicates that the survival rate of adult owls is the most important parameter in the model. Because estimates of this parameter are uncertain, the predictions of the model are uncertain and unreliable. Using the best estimates of the parameters, the predicted risk of decline across Victoria is low, and local populations larger than 100 pairs have a low risk of extinction. If the lower estimates of adult and sub-adult survival are used, the abundance of Powerful Owls across Victoria is predicted to decline exponentially and faces extinction from deterministic forces. A prohibitively large field programme involving monitoring of individually-recognizable owls would be required to obtain an improved estimate of adult survival, and so further use of population viability analysis to assess the adequacy of particular management strategies is unlikely to be useful for this species. An alternative is to establish a long-term monitoring programme to document changes in abundance of the species in logged and unlogged landscapes.