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The 2024 state of the climate report highlights the urgent global climate emergency, emphasizing the perilous times Earth is facing due to irreversible climate disaster. The report underscores the increasing greenhouse gas emissions and ecosystem changes driving climate change, leading to unprecedented disasters and human suffering worldwide. The document calls for immediate action to reduce fossil fuel consumption, mitigate climate impacts, and address the systemic issues contributing to ecological overshoot and societal collapse. The report also emphasizes the need for transformative solutions, including phasing down fossil fuel use, reducing methane emissions, integrating climate change education, and protecting ecosystems to ensure a livable world for future generations. [Extracted from the article]

Carnivore predation on livestock often leads people to retaliate. Persecution by humans has contributed strongly to global endangerment of carnivores. Preventing livestock losses would help to achieve three goals common to many human societies: preserve nature, protect animal welfare, and safeguard human livelihoods. Between 2016 and 2018, four independent reviews evaluated >40 years of research on lethal and nonlethal interventions for reducing predation on livestock. From 114 studies, we find a striking conclusion: scarce quantitative comparisons of interventions and scarce comparisons against experimental controls preclude strong inference about the effectiveness of methods. For wise investment of public resources in protecting livestock and carnivores, evidence of effectiveness should be a prerequisite to policy making or large-scale funding of any method or, at a minimum, should be measured during implementation. An appropriate evidence base is needed, and we recommend a coalition of scientists and managers be formed to establish and encourage use of consistent standards in future experimental evaluations.

Extinction risk in vertebrates has been linked to large body size, but this putative relationship has only been explored for select taxa, with variable results. Using a newly assembled and taxonomically expansive database, we analyzed the relationships between extinction risk and body mass (27,647 species) and between extinction risk and range size (21,294 species) for vertebrates across six main classes. We found that the probability of being threatened was positively and significantly related to body mass for birds, cartilaginous fishes, and mammals. Bimodal relationships were evident for amphibians, reptiles, and bony fishes. Most importantly, a bimodal relationship was found across all vertebrates such that extinction risk changes around a body mass breakpoint of 0.035 kg, indicating that the lightest and heaviest vertebrates have elevated extinction risk. We also found range size to be an important predictor of the probability of being threatened, with strong negative relationships across nearly all taxa. A review of the drivers of extinction risk revealed that the heaviest vertebrates are most threatened by direct killing by humans. By contrast, the lightest vertebrates are most threatened by habitat loss and modification stemming especially from pollution, agricultural cropping, and logging. Our results offer insight into halting the ongoing wave of vertebrate extinctions by revealing the vulnerability of large and small taxa, and identifying size-specific threats. Moreover, they indicate that, without intervention, anthropogenic activities will soon precipitate a double truncation of the size distribution of the world's vertebrates, fundamentally reordering the structure of life on our planet.

Apex scavengers can perform an important ecosystem service by rapidly removing carrion, in turn regulating nutrient cycling linked to carcass decomposition. Yet, our understanding of the biotic and abiotic factors that influence rates of apex scavenging and their behaviour around carrion remains limited, in part because of the absence of replicated studies across different bioregions, habitats and seasons. Here, we examine the use of carrion by one of Australia's apex scavengers, the wedge‐tailed eagle Aquila audax, and uncover the extent and consequences of their social interactions at carrion. We applied a standardised design to monitor 120 kangaroo (Family: Macropodidae) carcasses using camera traps across contrasting bioregions (desert, forest and alpine), habitats (open and closed canopy) and seasons (warm and cool). We predicted that wedge‐tailed eagles would discover carcasses quicker in open habitats, and that intrinsic carrion value (ICV), or the desirability of carrion, would be related to dietary stress as a function of productivity and season (i.e. we expected to see increased carcass use by eagles in the less productive desert bioregion and in cooler seasons). Across all bioregions, we found that wedge‐tailed eagles discovered carcasses in open habitats 2.7 times faster than in closed habitats and 5.3 times faster in cool seasons compared with warm seasons. Scavenging was more likely to occur in open environments and was more frequent in cool seasons and in the desert bioregion. ICV largely governed social interactions; there were more aggressive encounters between wedge‐tailed eagles during cool seasons and in the desert bioregion. Our results highlight how bioregional, habitat, and seasonal variation can drive scavenging rates and social interactions between conspecific apex scavengers. Further studies considering both carrion use and corresponding behavioural interactions will enhance our understanding of how carrion contributes to shaping interactions between and within species groups as well as scavenger communities more broadly. [ABSTRACT FROM AUTHOR]

Brushtail possums (Trichosurus vulpecula) are becoming increasingly recognized as key members of local scavenger guilds in Australia. Yet, our understanding of the spatiotemporal scavenging dynamics of this mainly herbivorous marsupial species remains limited. We investigated abiotic and biotic factors influencing possum carcass use across an alpine and temperate bioregion in Australia. Using camera traps set on experimentally placed kangaroo carcasses, we first examined the influence of both open and closed canopy habitats and warm and cool seasons on possum scavenging behaviour across both bioregions. While scavenging was minimal in open habitats across both bioregions—likely a reflection of possums being an arboreal species—seasonality did significantly influence possum activity. Possums scavenged on carcasses in temperate regions entirely during cooler months. Scavenging was recorded year‐round in the alpine region, but with total possum feeding time on carcasses 5.9 times higher in cooler months. A more detailed 12‐month study in the alpine region confirmed this strong seasonal influence on possum scavenging, with possums up to 5.4 times more likely to discover carcasses in winter and spend up to 6.7 times longer feeding on carcasses during this season. The variability in possum scavenging behaviour between bioregions and seasons highlights the spatiotemporal complexity of possum scavenging behaviour and the importance of considering abiotic and biotic factors to understand the behaviours of scavengers more broadly. Recognizing primarily herbivorous animals as important yet often overlooked members of local scavenger guilds can help advance our understanding of complex scavenging networks and the intricate pathways through which energy flows in ecosystems, both in Australia and in other systems. Improving our understanding of the spatiotemporal scavenging dynamics of typically herbivorous species may also help to inform more nuanced and effective wildlife management strategies, where supplementary foraging on atypical food resources poses conservation concerns. [ABSTRACT FROM AUTHOR]

Context. The protection of threatened species in fenced safe havens has become a vital component of conservation management in Australia. However, despite their success, fenced safe havens face several ecological and economic constraints. There is a need to explore additional approaches to restore species beyond the fence. Aims. To explore naturally occurring mesas as potential 'sky-island safe havens', created by natural barriers in elevation and relief, which may restrict the movement of introduced predators and other mammals. Methods. We examined species occurrences at a mesa site (Mt. Talaterang in south-east NSW, Australia) as well as a nearby lower-lying site (Little Forest Plateau). We then provide a geospatial analysis of other mesas in NSW to investigate the number of potential sky-island safe havens in the state. Key results. Species assemblages differed between the two sites, with red foxes (Vulpes vulpes), dingoes/domestic dogs (Canis dingo/familiaris), and European rabbits (Oryctolagus cuniculus) absent from the mesa site, while Antechinus spp. were not detected from the lower-lying site. Feral cats (Felis catus) occurred at significantly lower densities on the mesa site compared to the lower-lying site. In NSW, we identified 91 other mesas of =10 ha with similar topology as Mt. Talaterang. Conclusions. Although differences in species assemblages are expected between different habitats, the absence of red foxes and lower number of feral cat detections at the mesa site suggest the need to further explore the potential for mesas in conservation initiatives. Implications. Our findings introduce a supplementary conservation strategy that could augment existing fenced safe haven approaches. [ABSTRACT FROM AUTHOR]

Large wild herbivores are crucial to ecosystems and human societies. We highlight the 74 largest terrestrial herbivore species on Earth (body mass ≥100 kg), the threats they face, their important and often overlooked ecosystem effects, and the conservation efforts needed to save them and their predators from extinction. Large herbivores are generally facing dramatic population declines and range contractions, such that ~60% are threatened with extinction. Nearly all threatened species are in developing countries, where major threats include hunting, land-use change, and resource depression by livestock. Loss of large herbivores can have cascading effects on other species including large carnivores, scavengers, mesoherbivores, small mammals, and ecological processes involving vegetation, hydrology, nutrient cycling, and fire regimes. The rate of large herbivore decline suggests that ever-larger swaths of the world will soon lack many of the vital ecological services these animals provide, resulting in enormous ecological and social costs.

Scavenging on carrion is critical and often fiercely competitive for a range of vertebrate species, from native apex predators to invasive species and even reptiles. Within Australia, a notable reptilian scavenger is the lace monitor (Varanus varius). In this study, we quantified lace monitor activity at carcasses and compared their use of the resource to common co‐occurring predators that also scavenge; the invasive red fox (Vulpes vulpes) and a native apex predator, the dingo (Canis dingo). To do so, we deployed 80 macropod carcasses equally across seasons (summer and winter) and habitats (open and closed canopy) in a temperate bioregion and monitored vertebrate scavenging with camera traps. Lace monitor activity (visitation at carcass sites inclusive of both non‐scavenging and scavenging events) was 1.67 times higher in summer than in winter, but it did not differ across closed and open habitats. Monitor activity occurred earlier after carcass deployment at sites deployed in summer than winter (1.47‐fold earlier), and at carcasses in open than closed habitats (0.22‐fold earlier). Lace monitors initially discovered carcass sites faster in summer than winter and before both red foxes and dingoes in summer. The species was active diurnally in both summer and winter, differing from the red fox, which was strictly a nocturnal scavenger and the dingo, which was significantly more active at night across both seasons. Finally, we found that lace monitor activity at carcass sites decreased slightly with higher rates of activity for dingoes (0.04‐fold decrease as dingo activity increased), but not with red fox activity. Our results have implications for understanding lace monitor foraging and scavenging and highlight the value of monitoring carcasses to provide important insights into the behaviour of varanid lizards that scavenge. [ABSTRACT FROM AUTHOR]

Context. Deer species are expanding in distribution and abundance in Australia. There is increasing focus on the ecology of these species, but effective deer capture methods are needed for telemetry studies. Aims. The aims of this study were to develop, assess and refine a helicopter-based capture technique for wild sambar deer (Rusa unicolor) and red deer (Cervus elaphus), based on trials in south-eastern Australia. Methods. We captured and collared 14 sambar deer and five red deer in two operations in Kosciuszko National Park in 2021, using a combination of aerial net gunning and chemical immobilisation delivered via hand injection. Captured animals were fitted with GPS collars to track their movements and activity post-capture. Physiological measurements were recorded as a means of assessing responses to capture and to optimise animal welfare outcomes. Key results. Twenty-two deer were pursued and captured, with a total mortality rate of 14% (n = 3). The frequency of mortalities decreased from the first operation (17%) to the second operation (10%), largely attributed to allowable helicopter pursuit times being reduced. Post-release movement data indicated that delayed mortality due to capture did not occur. Activity of collared deer was lowest immediately following collaring, suggesting the procedure caused short-term decreases in deer activity. Conclusions. Aerial capture of wild sambar deer and red deer poses animal welfare risks, but these can be minimised through the refinement in net gunning and pharmacological proceduresto minimise animalstress. Implications. Thisstudy describes an effective method forthe safe capture of sambar deer and red deer, which will assist future wildlife researchers to further refine helicopter-based capture protocols and to collect spatial ecology and survival information about these species. [ABSTRACT FROM AUTHOR]

Context. Carrion is a high-energy and nutrient-rich resource that attracts a diverse group of vertebrate scavengers. However, despite the carrion pool being highly seasonal in its availability, there is little understanding of how scavengers utilise carcasses across all four seasons. Aim. To assess how season influences carcass-detection times by vertebrate scavengers and their rates of scavenging. Methods. We used remote cameras to monitor vertebrate scavenging at 15 eastern grey kangaroo (Macropus giganteus) carcasses in four consecutive seasons (summer, autumn, winter, and spring; total 58 carcasses) in the Australian Alps. Key results. In total, 745 599 remote-camera images were captured, within which 34 vertebrate species were identified, nine of which were recorded to actively scavenge. Time to first detection of carcasses by vertebrate scavengers was 5.3 and 9.6 times longer during summer (average 144 h) than during spring (average 34 h) and winter (average 24 h) respectively. Rates of vertebrate scavenging were highest in winter and spring, with brushtail possums (Trichosurus vulpecula) accounting for 78% of all scavenging events during winter, and ravens (Corvus spp.) accounting for 73% during spring. High rates of carcass use by these mesoscavengers may reflect a scarcity of other food sources, the demands of their breeding season, or a relative absence of scavenging by larger dominant species such as dingoes (Canis dingo) and wedge-tailed eagles (Aquila audax). Conclusions. These findings demonstrate the highly seasonal nature of vertebrate scavenging dynamics in an alpine ecosystem, and that mesoscavengers, not apex scavengers, can dominate the use of carcasses. Implications. Accounting for the effects of season is integral to understanding the way animals utilise carcasses in alpine and other strongly seasonal environments; and for developing further our knowledge of ecosystem processes linked to decomposition. [ABSTRACT FROM AUTHOR]