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With large wildfires becoming more frequent 1,2 , we must rapidly learn how megafires impact biodiversity to prioritize mitigation and improve policy. A key challenge is to discover how interactions among fire-regime components, drought and land tenure shape wildfire impacts. The globally unprecedented 3,4 2019-2020 Australian megafires burnt more than 10 million hectares 5 , prompting major investment in biodiversity monitoring. Collated data include responses of more than 2,000 taxa, providing an unparalleled opportunity to quantify how megafires affect biodiversity. We reveal that the largest effects on plants and animals were in areas with frequent or recent past fires and within extensively burnt areas. Areas burnt at high severity, outside protected areas or under extreme drought also had larger effects. The effects included declines and increases after fire, with the largest responses in rainforests and by mammals. Our results implicate species interactions, dispersal and extent of in situ survival as mechanisms underlying fire responses. Building wildfire resilience into these ecosystems depends on reducing fire recurrence, including with rapid wildfire suppression in areas frequently burnt. Defending wet ecosystems, expanding protected areas and considering localized drought could also contribute. While these countermeasures can help mitigate the impacts of more frequent megafires, reversing anthropogenic climate change remains the urgent broad-scale solution., Competing Interests: Competing interests The authors declare that some of them work for government agencies involved in forestry and implementing planned burns (Supplementary Table 8). The lead author declares that, despite the potential for government agencies to impose policy positions on staff communications (see ref. 51), scientific independence and integrity has been maintained throughout this project., (© 2024. The Author(s).)

Understanding the factors that limit the abundance of threatened species is critical for the development of effective conservation strategies. However, gaining such knowledge from monitoring programs and using it to inform decision-making for rare species can be difficult due to methodological issues posed by the problems of distinguishing true absences from false absences and the analysis of datasets dominated by zero counts. The plains-wanderer (Pedionomus torquatus) is a critically endangered ground-nesting bird that occurs in grasslands of southeastern Australia. Decline of the plains-wanderer has been attributed to habitat modification but little emphasis has been placed on the role of introduced predators, such as the red fox (Vulpes vulpes), which have had a devastating effect on small ground-dwelling vertebrates in dryland regions of Australia. Here, we use a 9-year time series of spotlight counts to investigate the impact of vegetation structure and fox presence on plains-wanderer occupancy and abundance. We used distance sampling to determine the effective strip width for sighting plains-wanderers during spotlight surveys. We then used a hurdle model approach whereby binomial generalized additive models were fitted to presence/absence data within the effective strip-width across all sites and negative-binomial models were fitted to an index of abundance at sites where plains-wanderers were observed. Plains-wanderer occupancy and abundance fluctuated markedly through time. Where foxes were absent, occupancy (but not abundance) of plains-wanderers showed a humped relationship with grass height with an optimal height between 50 and 150 mm. Where foxes were present however, this relationship broke down and plains-wanderers were rarely recorded. Our results suggest that plains-wanderers should benefit from management strategies that maintain grass height at optimal levels and exclude foxes or effectively suppress their populations. A key message from this study is that if statistical analyses of data generated by monitoring programs for rare species are intended to inform management decisions by identifying relationships between threatened species and drivers of their abundance, there should be consideration of analytic approaches that account for true and false zeroes, high prevalence of zeroes, and the possibility of nonlinear responses., (© 2024 The Author(s). Ecological Applications published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)

Humans have moved domestic animals around the globe for thousands of years. These have occasionally established feral populations in nature, often with devastating ecological consequences. To understand how natural selection shapes re-adaptation into the wild, we investigated one of the most successful colonizers in history, the European rabbit. By sequencing the genomes of 297 rabbits across three continents, we show that introduced populations exhibit a mixed wild-domestic ancestry. We show that alleles that increased in frequency during domestication were preferentially selected against in novel natural environments. Interestingly, causative mutations for common domestication traits sometimes segregate at considerable frequencies if associated with less drastic phenotypes (for example, coat colour dilution), whereas mutations that are probably strongly maladaptive in nature are absent. Whereas natural selection largely targeted different genomic regions in each introduced population, some of the strongest signals of parallelism overlap genes associated with neuronal or brain function. This limited parallelism is probably explained by extensive standing genetic variation resulting from domestication together with the complex mixed ancestry of introduced populations. Our findings shed light on the selective and molecular mechanisms that enable domestic animals to re-adapt to the wild and provide important insights for the mitigation and management of invasive populations., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Irruption of herbivore populations due to the extirpation of predators has led to dramatic changes in ecosystem functioning worldwide. Herbivores compete with other species for their primary source of nutrition, plant biomass. Such competition is typically considered to occur between species in closely related clades and functional groups but could also occur with detritivores that consume senescent plant biomass. In this study, we tested predictions that in ecosystems where herbivores are not regulated by predators, their indirect impacts on dead vegetation increase with primary productivity and extend to termites that feed on senescent vegetation. We compared dead vegetation cover and termite activity in herbivore exclosures and associated grazed plots at three locations situated along a rainfall gradient in arid Australia where kangaroo populations have irrupted. Dead vegetation cover and termite activity increased with rainfall in ungrazed plots but showed a negligible response to rainfall in grazed plots. Our results suggest that grazing can disrupt the flow of energy to detritivores and decouple the relationship between termite activity and primary productivity. Such disruption could have far-reaching impacts on arid ecosystems because many organisms sit within "brown food webs" that are sustained by energy derived from the decomposition of senescent plant tissues., (© 2023 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)

Chemical information in canid urine has been implicated in territoriality and influences the spacing of individuals. We identified the key volatile organic compound (VOC) components in dingo (Canis lupus dingo) urine and investigated the potential role of scents in territorial spacing. VOC analysis, using headspace gas chromatography-mass spectrometry (GC-MS), demonstrated that the information in fresh urine from adult male dingoes was sufficient to allow statistical classification into age categories. Discriminant function analyses demonstrated that the relative amounts or combinations of key VOCs from pre-prime (3-4 years), prime (5-9 years), and post-prime (≥10 years) males varied between these age categories, and that scents exposed to the environment for 4 (but not 33) days could still be classified to age categories. Further, a field experiment showed that dingoes spent less time in the vicinity of prime male dingo scents than other scents. Collectively, these results indicate that age-related scent differences may be discriminable by dingoes. Previous authors have suggested the potential to use scent as a management tool for wild canids by creating an artificial territorial boundary/barrier. Our results suggest that identifying the specific signals in prime-age male scents could facilitate the development of scent-based tools for non-lethal management., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Removal of apex predators can have far-reaching effects on the organization and structure of ecosystems. This occurs because apex predators can exert strong suppressive effects on their prey and competitors and perturbation of these interactions can shift the balance of interactions between dyads of species at lower trophic levels and trigger trophic cascades. Dingoes (Canis dingo) are Australia's largest mammalian carnivore. Because they are a pest to livestock producers, dingo populations are suppressed in many regions. Suppression of dingo populations has been linked to a suite of ecosystem changes due to ensuing population irruptions of their prey and competitors. Here, we investigate the impact that the suppression of dingoes has on the diet of wedge-tailed eagles (Aquila audax) in Australia's Strzelecki Desert. Wedge-tailed eagles are generalist predators that readily shift their diet in relation to prey availability. We assessed the abundance of species frequently preyed on by eagles and quantified prey remains at eagle nests located on either side of a dingo-proof fence where dingoes were common and rare, respectively. Wedge-tailed eagles consumed more species where dingoes were rare compared to where dingoes were common. Kangaroos (Macropodidae) and western bearded dragons (Pogona vitticeps) were more abundant and were consumed more frequently by eagles where dingoes were rare. Introduced European rabbits (Oryctolagus cuniculus) were the prey item most frequently identified at eagle nests. However, rabbits were more abundant and their remains were found at a higher proportion of nests where dingoes were common. Our results provide evidence that shifts in the composition of vertebrate assemblages associated with the presence/absence of dingoes, particularly the irruption of kangaroos, influence the diet of wedge-tailed eagles. More generally, by showing that the presence/absence of dingoes can influence the diet of wedge-tailed eagles, our study highlights how pervasive apex predators' effects on ecosystems can be., (© 2022. The Author(s).)

Complete separation of endangered prey from introduced predators improves prey survival at the cost of reduced predator recognition and antipredator behaviours, termed 'prey naiveté'. Headstarting is a conservation strategy that has been used to improve the survival of juveniles for numerous species, whereby prey is separated from predators only in their vulnerable early life stage before release to the wild. However, by isolating prey from predators headstarting could compromise prey individuals' antipredator behaviour. Here, we evaluate the effects that headstarting has on the survival, dispersal, body condition and flight initiation distance (FID) of a terrestrial mammal, the bridled nailtail wallaby Onychogalea fraenata. Young bridled nailtail wallabies were isolated from predators in a 9.2 ha predator‐free fenced exclosure and were released into the wild once their body mass exceeded 3 kg. There was no difference in dispersal, body condition or survival of headstarted wallabies compared to wild‐raised wallabies. FID of headstarted wallabies assessed using night‐vision goggles was lower than wild‐raised wallabies in the week following release, but converged with that of wild‐raised wallabies within 4 weeks post‐release. Our results show that headstarting can be an effective conservation strategy for terrestrial mammals whose early life stages are vulnerable to introduced predators. [ABSTRACT FROM AUTHOR]

Nomadism is an advantageous life history strategy for specialised predators because it enables the predator to respond rapidly to changes in prey populations. The letter-winged kite (Elanus scriptus) is a nomadic nocturnal bird of prey endemic to arid and semi-arid zones of Australia. Letter-winged kites prey almost exclusively on nocturnal rodents and are often associated with rodent irruptions, but little is known about the ecology of letter-winged kites inside their core range. The Strzelecki Desert contains a known dingo-mediated predation refuge for native rodents. In this manuscript, we compare kite sightings, predator activity, and small mammal populations across survey sites in the Strzelecki Desert where dingoes were common and where dingoes were rare and use publicly available data from the Atlas of Living Australia (ALA) to assess trends in the occurrence of kites in the region. Ninety-five percent of ALA observations occurred in areas where dingoes were common. Similarly, all our observations of kites occurred where dingoes were common and during an extended population irruption of Notomys fuscus. Notomys fuscus was the most frequent item in the letter-winged kite diet at our study sites. We suggest that there is significant evidence that these sites in the Strzelecki Desert form part of the core range for the letter-winged kite whose use of this area is facilitated by a predation refuge for rodents mediated by the dingo. We conclude that predation refuges mediated by dingoes could be a factor driving the distributions of letter-winged kites and other predators of rodents, particularly nomadic predators., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Admixture between species is a cause for concern in wildlife management. Canids are particularly vulnerable to interspecific hybridisation, and genetic admixture has shaped their evolutionary history. Microsatellite DNA testing, relying on a small number of genetic markers and geographically restricted reference populations, has identified extensive domestic dog admixture in Australian dingoes and driven conservation management policy. But there exists a concern that geographic variation in dingo genotypes could confound ancestry analyses that use a small number of genetic markers. Here, we apply genome-wide single-nucleotide polymorphism (SNP) genotyping to a set of 402 wild and captive dingoes collected from across Australia and then carry out comparisons to domestic dogs. We then perform ancestry modelling and biogeographic analyses to characterise population structure in dingoes and investigate the extent of admixture between dingoes and dogs in different regions of the continent. We show that there are at least five distinct dingo populations across Australia. We observed limited evidence of dog admixture in wild dingoes. Our work challenges previous reports regarding the occurrence and extent of dog admixture in dingoes, as our ancestry analyses show that previous assessments severely overestimate the degree of domestic dog admixture in dingo populations, particularly in south-eastern Australia. These findings strongly support the use of genome-wide SNP genotyping as a refined method for wildlife managers and policymakers to assess and inform dingo management policy and legislation moving forwards., (© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)

Carnivores fulfil important ecological roles in natural systems yet can also jeopardise the persistence of threatened species. Understanding their diet is, therefore, essential for managing populations of carnivores, as well as those of their prey. This study was designed to better understand the diet of an Australian apex predator, the dingo, and determine whether it poses a threat to at-risk small macropods in two floristically different yet geographically close reserves in subtropical Australia. Based on an analysis of 512 scats, dingo diets comprised 34 different prey taxa, of which 50% were common between reserves. Our findings add support to the paradigm that dingoes are opportunistic and generalist predators that prey primarily on abundant mammalian fauna. Their diets in the Border Ranges were dominated by possum species (frequency of occurrence (FOC) = 92.5%), while their diets in Richmond Range were characterised by a high prevalence of pademelon species (FOC = 46.9%). Medium-sized mammals were the most important dietary items in both reserves and across all seasons. The dietary frequency of medium-sized mammals was generally related to their availability (indexed by camera trapping); however, the avoidance of some species with high availability indicates that prey accessibility may also be important in dictating their dietary choices. Other prey categories were supplementary to diets and varied in importance according to seasonal changes in their availability. The diets included two threatened macropods, the red-legged pademelon and black-striped wallaby. Our availability estimates, together with earlier dietary studies spanning 30 years, suggest that the red-legged pademelon is resilient to the observed predation. The black-striped wallaby occurred in only two dingo scats collected from Richmond Range and was not detected by cameras so the threat to this species could not be determined. Two locally abundant but highly threatened species (the koala and long-nosed potoroo) were not detected in the dingoes' diets, suggesting dingoes do not at present pose a threat to these populations. Our study highlights the importance of site-based assessments, population monitoring and including data on prey availability in dietary investigations.

The diets of many animals are influenced by resource availability, competition, and evolutionary selected traits enabling the utilization of palatable foods. Omnivores are species that maintain their macronutrient balance by supplementing highly abundant but poor nutritional quality food items, with sporadically available but high nutritional quality food items. Although there are anecdotal observations of Australian geckos (Lacertilia: Gekkonidae) consuming plant exudates, the consumption of plant material has long been considered to be anomalous behavior among Australian geckos. Here, we test the idea that sap feeding may not be anomalous behavior but instead a dietary niche of geckos that has gone unappreciated due to constraints on the methods used to quantify geckos' diets. We tested this idea by investigating the consumption of Acacia victoriae gum by the gecko Gehyra versicolor using timed searches and time-lapse photography. We found that geckos frequently consumed gum, and G. versicolor numbers were five times greater on A. victoriae trees that exhibited significant gum bleeds compared to gecko numbers on non-bleeding trees. Taken together, our observations that G. versicolor spp. frequently feed on gum along with anecdotal reports of geckos consuming gum provide compelling evidence that gum/sap feeding is not anomalous behavior and suggest that many Australian gecko species are omnivores whose diets include plant exudates and animal prey.

Predation is a key factor contributing to the failure of reintroductions of vertebrates but there is variation in predation risk between individuals. Understanding the traits that render some animals less susceptible to predation, and selecting for these traits, may help improve reintroduction success. Here, we test whether prior exposure to predators or specific morphological and/or behavioural attributes explained variation in post‐reintroduction survival in a moderate and low predator density environment. We exposed a population of the threatened burrowing bettong (Bettongia lesueur) to controlled densities of feral cats (Felis catus) for ≥3 years. We then conducted two translocations of cat‐exposed and control populations that had no exposure to predators to a new site where cats were present at moderate, then low density. Variation in survival of burrowing bettongs was not explained by prior predator exposure to predators or measured individual traits at moderate cat density. At lower cat densities, males died sooner and burrowing bettongs with larger hind feet survived longer. Although prior cat‐exposure did not confer a survival advantage at low cat densities, the cat‐exposed burrowing bettong population had larger hind feet (n = 44) compared to the control population (n = 45) suggesting that trait divergence between cat‐exposed and non‐cat‐exposed burrowing bettongs may not yet be sufficient for improved survival. Alternatively, prior predator exposure may not confer a survival advantage because they are "outgunned" by evolutionarily novel cats. Predation is a major problem thwarting successful reintroductions world‐wide. Exposing populations to predators over longer time periods and periodically testing survival will be required to determine whether pre‐release predator exposure prepares animals for life with novel predators. Our study highlights the importance of reducing predator activity at release sites prior to reintroduction to enable any benefits from intraspecific variation in survival traits to be realised. [ABSTRACT FROM AUTHOR]

Harnessing natural selection to improve conservation outcomes is a recent concept in ecology and evolutionary biology and a potentially powerful tool in species conservation. One possible application is the use of natural selection to improve antipredator responses of mammal species that are threatened by predation from novel predators. We investigated whether long-term exposure of an evolutionary naïve prey species to a novel predator would lead to phenotypic changes in a suite of physical and behavioral traits. We exposed a founder population of 353 burrowing bettongs (Bettongia lesueur) to feral cats (Felis catus) over 5 years and compared the physical and behavioral traits of this population (including offspring) to a control (non-predator exposed) population. We used selection analysis to investigate whether changes in the traits of bettongs were likely due to phenotypic plasticity or natural selection. We also quantified selection in both populations before and during major population crashes caused by drought (control) and high predation pressure (predator-exposed). Results showed that predator-exposed bettongs had longer flight initiation distances, larger hind feet, and larger heads than control bettongs. Trait divergence began soon after exposure and continued to intensify over time for flight initiation distance and hind foot length relative to control bettongs. Selection analysis found indicators of selection for larger hind feet and longer head length in predator-exposed populations. Results of a common garden experiment showed that the progeny of predator-exposed bettongs had larger feet than control bettongs. Results suggest that long-term, low-level exposure of naïve prey to novel predators can drive phenotypic changes that may assist with future conservation efforts., (© 2022 The Authors. Ecological Applications published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)

How to manage hybridization and introgression in wild animals is controversial. Wildlife managers and researchers may often rely upon phenotypic variables such as coat colour to inform on ground management decisions. In Australia, dingoes are typically believed to be ginger in colour, and unusual coat colours such as brindle or sable are widely posited to be evidence of contemporary domestic dog hybridization. We carried out microsatellite‐based genotyping on 1325 wild canids from southeastern Australia of known coat colour to estimate the extent of domestic dog introgression. A key aim of our study was to examine the relationship between coat colour and ancestry in wild dingoes. We observed that 27.4% of our samples were dingoes with no evidence of domestic dog ancestry whilst 72.6% were dingoes with some domestic dog ancestry. Our data confirm that feral dogs, domestic dogs with no dingo ancestry, are rare in the wild, representing less than 1.5% of the population. There was no coat colour that could distinguish dingoes with or without dog ancestry from each other. Contrary to popular belief, colours such as brindle and patchy were positively associated with dingoes with no dog ancestry and were less common in dingoes of mixed ancestry. A key finding of this work is that coat colour should not be used to assess ancestry in dingoes. Further research is needed to uncover the antiquity, origin and potential adaptive value of these genomic regions. It is possible that this is a similar example of adaptive introgression as has been observed in North American wolves with black coat colour. These data add perspective to global debates about how to manage and conserve enigmatic animal populations in the presence of modern or historical introgression. [ABSTRACT FROM AUTHOR]

Invasive vertebrates are frequently reported to have catastrophic effects on the populations of species which they directly impact. It follows then, that if invaders exert strong suppressive effects on some species then other species will indirectly benefit due to ecological release from interactions with directly impacted species. However, evidence that invasive vertebrates trigger such trophic cascades and alter community structure in terrestrial ecosystems remains rare. Here, we ask how the cane toad, a vertebrate invader that is toxic to many of Australia's vertebrate predators, influences lizard assemblages in a semi-arid rangeland. In our study area, the density of cane toads is influenced by the availability of water accessible to toads. We compared an index of the abundance of sand goannas, a large predatory lizard that is susceptible to poisoning by cane toads and the abundances of four lizard families preyed upon by goannas (skinks, pygopods, agamid lizards and geckos) in areas where cane toads were common or rare. Consistent with the idea that suppression of sand goannas by cane toads initiates a trophic cascade, goanna activity was lower and small lizards were more abundant where toads were common. The hypothesis that suppression of sand goannas by cane toads triggers a trophic cascade was further supported by our findings that small terrestrial lizards that are frequently preyed upon by goannas were more affected by toad abundance than arboreal geckos, which are rarely consumed by goannas. Furthermore, the abundance of at least one genus of terrestrial skinks benefitted from allogenic ecosystem engineering by goannas where toads were rare. Overall, our study provides evidence that the invasion of ecosystems by non-native species can have important effects on the structure and integrity of native communities extending beyond their often most obvious and frequently documented direct ecological effects., (© 2020 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

The conservation benefits of maintaining social groupings during and after animal translocations are unclear. Although some studies report improved post-release survival, others found no discernible influence on reintroduction success. Understanding the effects of social groupings is difficult because release methods can influence the animals' ability to maintain social groups. We explored this relationship by first studying whether release protocols influenced post-release cohesion in the communal burrowing bettong Bettongia lesueur , and then investigating whether maintenance of social cohesion conferred any post-release advantage. We released bettongs into a small (8 ha) and large (2,600 ha) area and compared the proportion that maintained social groupings in the different settings. The proportion of bettongs sharing with previous warren co-occupants was higher than expected by chance in both areas, however, a significantly higher proportion of bettongs maintained social groupings in the small (75%) compared to the large release area (13%). This suggests bettongs prefer to maintain social groupings but are unable to locate members of their group in large release areas. Bettongs that did maintain social groupings showed no difference in reproductive or health outcomes compared to those that formed new social groupings, suggesting no benefit to reintroduction success. We conclude that release protocols can influence post-release cohesion, but that greater cohesion does not necessarily confer advantages to group-living animals. To test the importance of social cohesion, further research on reintroductions should compare post-release parameters for animals released using protocols that do and do not facilitate maintenance of social groupings. [ABSTRACT FROM AUTHOR]

Biological invasions are a major cause of environmental and economic disruption. While ecological factors are key determinants of their success, the role of genetics has been more challenging to demonstrate. The colonization of Australia by the European rabbit is one of the most iconic and devastating biological invasions in recorded history. Here, we show that despite numerous introductions over a 70-y period, this invasion was triggered by a single release of a few animals that spread thousands of kilometers across the continent. We found genetic support for historical accounts that these were English rabbits imported in 1859 by a settler named Thomas Austin and traced the origin of the invasive population back to his birthplace in England. We also find evidence of additional introductions that established local populations but have not spread geographically. Combining genomic and historical data we show that, contrary to the earlier introductions, which consisted mostly of domestic animals, the invasive rabbits had wild ancestry. In New Zealand and Tasmania, rabbits also became a pest several decades after being introduced. We argue that the common denominator of these invasions was the arrival of a new genotype that was better adapted to the natural environment. These findings demonstrate how the genetic composition of invasive individuals can determine the success of an introduction and provide a mechanism by which multiple introductions can be required for a biological invasion.