Jordan Hampton

Biological invasions by non-native species pose significant threats to agriculture, ecosystems, human health, and economies. Despite the efforts of management agencies, many populations of invasive species continue to persist and spread, necessitating a deeper understanding of the processes influencing their growth and expansion. We investigated the potential for unwanted genetic rescue to increase the population growth rate and spread of invasive European fallow deer (Dama dama) in south-eastern Australia. Using a single nucleotide polymorphism dataset from over 340 individuals, we assessed genetic diversity, levels of inbreeding, and population structure and connectivity. We found low genetic diversity and heightened inbreeding across most fallow deer surveyed, highlighting potential for inbreeding depression. However, a small number of populations had significantly higher diversity and lower inbreeding. We hypothesize that the high diversity populations stem from farmers importing diverse fallow deer lineages for artificial breeding, with some of those animals (or their progeny) subsequently escaping or being released into the wild. We explored the potential for recently imported genetic variants to spread across populations by examining population connectivity. Finally, to demonstrate the risk of unwanted genetic rescue in fallow deer, we simulated population growth under different scenarios and show that reduced inbreeding is expected to substantially increase population growth rates. Our study highlights the importance of integrating genetic considerations into invasive species control. To enhance deer management in Australia we recommend considering migration patterns in control program design, containing high-diversity populations, and strengthening the containment and biosecurity requirements of farmed and imported deer.

In different parts of the world the claim is increasingly being made that continuous confinement of pet cats (Felis catus) is beneficial for both wildlife conservation and cat welfare. The first part of the claim is almost incontrovertible, but the second is misleading. The assertion that confined animals have superior welfare is rooted in thinking pre-dating the 1960s that equates welfare with physical health. By contemporary accounts of animal welfare, confinement of animals presents major welfare risks, and this recognition has been a major driver of refinement in livestock industries, e.g. moves towards free-range systems. Yet, these risks have not been widely acknowledged in debates over pet cat management. We argue that the current pervasive rhetoric from conservationists and some regulators that cat confinement is beneficial for wildlife and cats is, at best, confusing health with welfare. At worst, it is a deliberate attempt to mislead the public through portraying a win-win scenario where, instead, a trade-off must be navigated. Failure to recognise this trade-off undermines conservation goals three-fold. First, it limits the efficacy of behaviour change interventions to increase confinement. Second, it erodes public trust in organisations perceived as knowingly misleading the public. Finally, it reduces the incentive to make the one decision yielding long-term benefits for both cats and ecosystems; ceasing to own cats at all. Policy-makers should be wary of the allure of false win-win narratives when tackling contentious issues that require trade-offs to be made.

Killing animals is a ubiquitous human activity consistent with our predatory and competitive ecological roles within the global food web. However, this reality does not automatically justify the moral permissibility of the various ways and reasons why humans kill animals – additional ethical arguments are required. Multiple ethical theories or frameworks provide guidance on this subject, and here we explore the permissibility of intentional animal killing within (1) consequentialism, (2) natural law or deontology, (3) religious ethics or divine command theory, (4) virtue ethics, (5) care ethics, (6) contractarianism or social contract theory, (7) ethical particularism, and (8) environmental ethics. These frameworks are most often used to argue that intentional animal killing is morally impermissible, bad, incorrect, or wrong, yet here we show that these same ethical frameworks can be used to argue that many forms of intentional animal killing are morally permissible, good, correct, or right. Each of these ethical frameworks support constrained positions where intentional animal killing is morally permissible in a variety of common contexts, and we further address and dispel typical ethical objections to this view. Given the demonstrably widespread and consistent ways that intentional animal killing can be ethically supported across multiple frameworks, we show that it is incorrect to label such killing as categorically unethical. We encourage deeper consideration of the many ethical arguments that support intentional animal killing and the contexts in which they apply.

Helicopter-based shooting using either a .308 semi-automatic rifle or a semi-automatic 12-gauge shotgun is widely used to manage non-native ungulate populations in Australasia, but the animal welfare outcomes of these two firearms have not been robustly compared. We conducted a randomised field study to compare the animal welfare outcomes of helicopter-based shooting of fallow deer (Dama dama) using a shotgun with three types of lead-based shot (Winchester® 00 Buck, 1 Buck or 4 Buck) relative to a .308 rifle with 135-grain lead-based bullets in New South Wales, Australia, in 2023. All deer that were shot at (n = 390) were killed. Time-to-event curves for times from pursuit to first shot, first shot to insensibility, and the sum of these two metrics (‘total time’), were similar among the four ammunition types. The mean number of shots fired per deer was similar across all four ammunition types, but the mean number of wound tracts per deer increased across the four ammunition types with the number of projectiles per cartridge. All deer subjected to post mortem examination had 1 wound tract or projectile in the thorax. Our study indicates that using a .308 semi-automatic rifle or a 12-gauge semi-automatic shotgun for helicopter-based shooting of non-native deer, when the latter is used at ranges ≤ 30 m, provides similar animal welfare outcomes.

The One Health concept has been enthusiastically adopted in conservation. However, there are some underrecognized trade-offs that must be navigated when it comes to applying One Health ideas to wild animals. One of these relates to conflicts between the health of individual animals and the wildness and resilience of ecosystems when it comes to natural processes such as predation. Over the past few decades, there is evidence of wildlife managers providing veterinary treatment to animals injured in predation events. These efforts need to be tempered in light of concerns for biodiversity, wildness and human interests. We recognize that animals injured through predation can be distressing to contemplate for some humans, but allowing nature to take its course for these animals is enabling an essential ecological process. On this basis, we argue that there is not a strong ethical justification for interfering with predation.

Conservation is an evolving discipline, with its values changing over time. Animal welfare is gaining attention, but can conflict with other conservation values. We illustrate how different management decisions arise from prioritizing different values, and show how these conflicts can depend on value prioritization, as well as how values such as animal welfare are defined. This includes the limits (type of welfare states), scope (range of species), and timescales considered. Since small changes in value articulation and prioritization can lead to major changes in management decisions, we argue for making values and trade-offs explicit. An established structured decision-making (SDM) framework can enhance transparency, reducing misunderstanding in conservation controversies and helping maintain public trust in science.

Heavy metals are cumulative toxicants that frequently create negative health effects for waterbirds inhibiting contaminated freshwater systems. Although levels of exposure to heavy metals have been well documented for many waterbird species, the adverse effects of exposure remain relatively poorly understood. One emerging field that allows the exploration of such effects is metabolomics. The aim of this study was to characterize metabolomic profiles in relation to long-term heavy metal exposure in a waterbird species. In 2021, wings from 44 Pacific black ducks (Anas superciliosa) were collected by recreational hunters at three sites in Victoria, southeastern Australia. The concentrations of seven heavy metals were measured in feathers and these data were quantified via inductive coupled plasma mass spectrometry and compared with a semiquantitative assessment of 21 metabolites identified in muscle tissues from the same birds via gas chromatography-mass spectrometry. Principal component analysis was conducted to test associations between metabolites, heavy metals, and sites. Mean heavy metal concentrations detected were copper (9.97 µg/g), chromium (0.73 µg/g), iron (123.24 µg/g), manganese (13.01 µg/g), mercury (0.58 µg/g), lead (0.86 µg/g), and zinc (183.95 µg/g; dry wt). No association was found between heavy metals and 17 metabolites, whereas four metabolites were negatively associated with some heavy metals: α-linolenic acid with iron, glucose with lead and manganese, lactic acid with mercury, and propanoic acid with mercury. There were few differences in the studied metabolites in ducks between the three sites. This study provides a novel approach to combining toxicological and metabolomic data for an ecologically important species from a relatively poorly studied global region.