When all life counts in conservation

Mammals on the Margins: Identifying the Drivers and Limitations of Range Expansion

Accurately estimating species distributions is critical for tracking how biodiversity is shaped by global change. While some species are expanding their ranges, the importance of factors like climate change, habitat change, and human avoidance for explaining this expansion is not well understood. Here, we used observations of 94 North American mammals on iNaturalist to (1) identify errors of omission in the existing range maps; (2) differentiate between extra-range populations that are likely products of natural expansions vs. introductions; and (3) test hypotheses about where natural range expansions occur. We found a substantial percentage of observations were outside both IUCN (16%) and Area of Habitat (36%) maps, suggesting that integrating contemporary citizen science data would improve existing range maps. We estimated that most observations outside IUCN ranges were natural expansions and 95% of species had at least one naturally expanding population. We also identified introductions for 36% of species, which were particularly extensive for several species. We show that natural range expansions are generally associated with a lighter human footprint and less habitat change and are not associated with warming temperatures. This suggests that habitat modifications by humans constrain the ability of species to expand their range to track a changing climate. We also found substantial variation in the directionality of effects from all factors across species, meaning that our species-specific findings will be useful for conservation planning. Our study demonstrates that citizen science data can be useful for conservation by tracking how organisms are responding, or failing to respond, to global change.

No More Extinctions: Recovering Australia's Biodiversity

Most conservation programs and laws aim to prevent extinction. However, there is a gulf between such aspirations and the current reality of escalating biodiversity loss. This review focuses on efforts to prevent extinctions in Australia, but much of this consideration is likely to apply globally. As context, we consider the reasons for trying to prevent extinction, review Australia's extinction record, and note that there are likely to be many more extinctions than formally recognized. We describe recent cases where conservation actions have prevented extinction. We note that extinction is a pathway rather than solely an endpoint, and many decisions made or not made on that pathway can determine the fate of species. We conclude that all looming extinctions can and should be prevented. This will require transformational change in legislation, increased resourcing, more consideration of poorly known species, and increased societal recognition of the need to be responsible for the care of country.

Seasonal diversity, daily use and behaviour of birds using a green roof in a Mediterranean city

Urban green roofs offer environmental and social benefits and provide resources for urban wildlife; however, how birds use green roofs remains poorly studied in Mediterranean cities. Here, we develop a 1-year study in Madrid, Spain, recording the birds that use both an urban green roof and the adjacent conventional roofs throughout the four seasons. We recorded a total of 17 bird species in the area, of which 8 use the green roof surveyed. The most common species detected in both types of roofs was the feral pigeon (Columba livia), which exploited the green roof permanently, in contrast with the other species observed, which only appeared occasionally. We also found that more species visited the green roof in the central hours of the day and a higher richness of species in the spring. Moreover, we detect that most of the species were residents all year in the area and have granivorous or granivorous-omnivorous feeding habits. The main behaviour observed in the green roof was feeding, while no reproduction of any species was confirmed. We conclude that green roofs offer birds much-needed resources in metropolitan areas, promoting greener, more connected and more biodiverse cities.

Preventing extinction in an age of species migration and planetary change

International and national conservation policies almost exclusively focus on conserving species in their historic native ranges, thus excluding species that have been introduced by people and some of those that have extended their ranges on their own accord. Given that many of such migrants are threatened in their native ranges, conservation goals that explicitly exclude these populations may overlook opportunities to prevent extinctions and respond dynamically to rapidly changing environmental and climatic conditions. Focusing on terrestrial mammals, we quantified the number of threatened mammals that have established new populations through assisted migration (i.e., introduction). We devised 4 alternative scenarios for the inclusion of assisted-migrant populations in mainstream conservation policy with the aim of preventing global species extinctions. We then used spatial prioritization algorithms to simulate how these scenarios could change global spatial conservation priorities. We found that 22% (70 species out of 265) of all identified assisted-migrant mammals were threatened in their native ranges, mirroring the 25% of all mammals that are threatened. Reassessing global threat statuses by combining native and migrant ranges reduced the threat status of 23 species (∼33% of threatened assisted migrants). Thus, including migrant populations in threat assessments provides a more accurate assessment of actual global extinction risk among species. Spatial prioritization simulations showed that reimagining the role of assisted-migrant populations in preventing species extinction could increase the importance of overlooked landscapes, particularly in central Australia, Europe, and the southwestern United States. Our results indicated that these various and nonexhaustive ways to consider assisted-migrant populations, with due consideration of potential conservation conflicts with resident taxa, may provide unprecedented opportunities to prevent species extinctions.

Australia's recently established predators restore complexity to food webs simplified by extinction

Since prehistory, humans have altered the composition of ecosystems by causing extinctions and introducing species. However, our understanding of how waves of species extinctions and introductions influence the structure and function of ecological networks through time remains piecemeal. Here, focusing on Australia, which has experienced many extinctions and introductions since the Late Pleistocene, we compared the functional trait composition of Late Pleistocene (130,00-115,000 years before present [ybp]), Holocene (11,700-3,000 ybp), and current Australian mammalian predator assemblages (≥70% vertebrate meat consumption; ≥1 kg adult body mass). We then constructed food webs for each period based on estimated prey body mass preferences. We found that introduced predators are functionally distinct from extinct Australian predators, but they rewire food webs toward a state that closely resembles the Late Pleistocene, prior to the megafauna extinctions. Both Late Pleistocene and current-day food webs consist of an apex predator and three smaller predators. This leads to food web networks with a similar total number of links, link densities, and compartmentalizations. However, this similarity depends on the presence of dingoes: in their absence, food webs become simplified and reminiscent of those following the Late Pleistocene extinctions. Our results suggest that recently established predators, even those implicated in species extinctions and declines, can restore complexity to food webs simplified by extinction.

Functional traits-not nativeness-shape the effects of large mammalian herbivores on plant communities

Large mammalian herbivores (megafauna) have experienced extinctions and declines since prehistory. Introduced megafauna have partly counteracted these losses yet are thought to have unusually negative effects on plants compared with native megafauna. Using a meta-analysis of 3995 plot-scale plant abundance and diversity responses from 221 studies, we found no evidence that megafauna impacts were shaped by nativeness, "invasiveness," "feralness," coevolutionary history, or functional and phylogenetic novelty. Nor was there evidence that introduced megafauna facilitate introduced plants more than native megafauna. Instead, we found strong evidence that functional traits shaped megafauna impacts, with larger-bodied and bulk-feeding megafauna promoting plant diversity. Our work suggests that trait-based ecology provides better insight into interactions between megafauna and plants than do concepts of nativeness.

Why humans kill animals and why we cannot avoid it

Killing animals has been a ubiquitous human behaviour throughout history, yet it is becoming increasingly controversial and criticised in some parts of contemporary human society. Here we review 10 primary reasons why humans kill animals, discuss the necessity (or not) of these forms of killing, and describe the global ecological context for human killing of animals. Humans historically and currently kill animals either directly or indirectly for the following reasons: (1) wild harvest or food acquisition, (2) human health and safety, (3) agriculture and aquaculture, (4) urbanisation and industrialisation, (5) invasive, overabundant or nuisance wildlife control, (6) threatened species conservation, (7) recreation, sport or entertainment, (8) mercy or compassion, (9) cultural and religious practice, and (10) research, education and testing. While the necessity of some forms of animal killing is debatable and further depends on individual values, we emphasise that several of these forms of animal killing are a necessary component of our inescapable involvement in a single, functioning, finite, global food web. We conclude that humans (and all other animals) cannot live in a way that does not require animal killing either directly or indirectly, but humans can modify some of these killing behaviours in ways that improve the welfare of animals while they are alive, or to reduce animal suffering whenever they must be killed. We encourage a constructive dialogue that (1) accepts and permits human participation in one enormous global food web dependent on animal killing and (2) focuses on animal welfare and environmental sustainability. Doing so will improve the lives of both wild and domestic animals to a greater extent than efforts to avoid, prohibit or vilify human animal-killing behaviour.

A novel trophic cascade between cougars and feral donkeys shapes desert wetlands

Introduced large herbivores have partly filled ecological gaps formed in the late Pleistocene, when many of the Earth's megafauna were driven extinct. However, extant predators are generally considered incapable of exerting top-down influences on introduced megafauna, leading to unusually strong disturbance and herbivory relative to native herbivores. We report on the first documented predation of juvenile feral donkeys Equus africanus asinus by cougars Puma concolor in the Mojave and Sonoran Deserts of North America. We then investigated how cougar predation corresponds with differences in feral donkey behaviour and associated effects on desert wetlands. Focusing on a feral donkey population in the Death Valley National Park, we used camera traps and vegetation surveys to compare donkey activity patterns and impacts between wetlands with and without cougar predation. Donkeys were primarily diurnal at wetlands with cougar predation, thereby avoiding cougars. However, donkeys were active throughout the day and night at sites without predation. Donkeys were ~87% less active (measured as hours of activity a day) at wetlands with predation (p < 0.0001). Sites with predation had reduced donkey disturbance and herbivory, including ~46% fewer access trails, 43% less trampled bare ground and 192% more canopy cover (PERMANOVA, R²  = 0.22, p = 0.0003). Our study is the first to reveal a trophic cascade involving cougars, feral equids and vegetation. Cougar predation appears to rewire an ancient food web, with diverse implications for modern ecosystems. Our results suggest that protecting apex predators could have important implications for the ecological effects of introduced megafauna.

Re-Thinking Felid–Human Entanglements through the Lenses of Compassionate Conservation and Multispecies Studies

Simple Summary

Felids have long and complex historical associations with humans, ranging from fear and persecution to worship and care. With many felid species in widespread decline, re-thinking the messy entanglements of feline predators and human societies is a necessary step for fostering coexistence as current conservation frameworks that rely on the separation of people from nature are failing felids. Here, we explore two distinct but related interdisciplinary fields that, when put into dialogue with one another, offer novel perspectives and insights on felid–human relationships and conservation initiatives more broadly. We identified numerous similarities and emergent properties within compassionate conservation and multispecies studies, despite these fields arising from the sciences and social sciences and humanities respectively. Combined, reorientation of conservation values and practices to be morally inclusive of individual animals and their subjective experiences has the potential to support cohabitation and tolerance for felids, promoting multispecies flourishing.

Abstract

With many felid species in widespread decline, re-thinking the messy felid–human entanglements is a necessary step for fostering coexistence as current conservation frameworks centered on human exceptionalism and widespread violence toward wild animals are conspicuously failing felids. This paper argues for fostering a critical awareness of how we understand our relationships with nonhuman animals, particularly in the context of conservation. We bring two distinct but related interdisciplinary fields into a dialogue to critically question the values and conceptual assumptions that frame the practices of felid conservation today. Compassionate conservation and multispecies studies share many synergies and conceptual overlaps despite emerging from different academic domains. We identified four key areas for further exploration: (1) A shift in emphasis from practices of killing to the underlying assumptions that make forms of killing permissible and ethically unproblematic. (2) Re-engagement with individuals, not just species, in conservation settings. (3) Unsettling human exceptionalism through an emphasis on the agency of animals and an ethic involving compassion. (4) Acknowledging the ways in which humans co-become with other animals and cultivating relationships of multispecies cohabitation and flourishing.

Compassionate Conservation is indistinguishable from traditional forms of conservation in practice

Animal welfare and ethics are important factors influencing wildlife conservation practice, and critics are increasingly challenging the underlying ethics and motivations supporting common conservation practices. “Compassionate Conservationists” argue that all conservationists should respect the rights of individual sentient animals and approach conservation problems from a position of compassion, and that doing so requires implementing practices that avoid direct harm to individual animals. In this way Compassionate Conservationists seek to contrast themselves with “Traditional Conservationists” who often express consequentialist decision-making processes that ostensibly aim to dispassionately minimize net animal harms, resulting in the common use of practices that directly harm or kill some animals. Conservationists and other observers might therefore conclude that the two sides of this debate are distinct and/or that their policy proscriptions produce different welfare outcomes for animals. To explore the validity of this conclusion we review the ethical philosophies underpinning two types of Compassionate Conservation—deontology and virtue ethics. Deontology focusses on animal rights or the moral duties or obligations of conservationists, whereas virtue ethics focusses on acting in ways that are virtuous or compassionate. We demonstrate that both types permit the intentional harm and killing of animals when faced with common conservation problems where animals will be harmed no matter what the conservationist does or does not do. We then describe the applied decision-making processes exhibited by Compassionate Conservationists (of both types) and Traditional Conservationists to show that they may each lead to the implementation of similar conservation practices (including lethal control) and produce similar outcomes for animals, despite the perceived differences in their ethical motivations. The widespread presence of wildlife conservation problems that cannot be resolved without causing at least some harm to some animals means that conservationists of all persuasions must routinely make trade-offs between the welfare of some animals over others. Compassionate Conservationists do this from an explicit position of animal rights and/or compassion, whereas Traditional Conservationists respect animal rights and exhibit this same compassion implicitly. These observations lead to the conclusion that Compassionate Conservation is indistinguishable from traditional forms of conservation in practice, and that the apparent disagreement among conservationists primarily concerns the effectiveness of various wildlife management practices at minimizing animal harm, and not the underlying ethics, motivations or morality of those practices.

Lost, gained, and regained functional and phylogenetic diversity of European mammals since 8000 years ago

Mammals have experienced high levels of human-mediated extirpations but have also been widely introduced to new locations, and some have recovered from historic persecution. Both of these processes-losses and gains-have resulted in concern about functional losses and changes in ecological communities as new ecological states develop. The question of whether species turnover inevitably leads to declines in functional and phylogenetic diversity depends, however, on the traits and phylogenetic distinctiveness of the species that are lost, gained, or regained. Comparing ~8000 years ago with the last century, we show that extirpations and range retractions have indeed reduced the functional and phylogenetic diversity of mammals in most European regions (countries and island groups), but species recoveries and the introduction of non-native species have increased functional and phylogenetic diversity by equivalent or greater amounts in many regions. Overall, across Europe, species richness increased in 41 regions over the last 8000 years and declined in 1; phylogenetic diversity increased in 33 and declined in 12, while functional diversity results showed 20 increases and 25 decreases. The balance of losses (extirpations) and gains (introductions, range expansions) has, however, led to net increases in functional diversity on many islands, where the original diversity was low, and across most of western Europe. Historically extirpated mega- and mesofaunal species have recolonized or been reintroduced to many European regions, contributing to recent functional and phylogenetic diversity recovery. If conservation rewilding projects continue to reintroduce regionally extirpated species and domestic descendants of "extinct" species to provide replacement grazing, browsing, and predation, there is potential to generate net functional and phylogenetic diversity gains (relative to 8000 years ago) in most European regions.

Misleading estimates of economic impacts of biological invasions: Including the costs but not the benefits

The economic costs of non-indigenous species (NIS) are a key factor for the allocation of efforts and resources to eradicate or control baneful invasions. Their assessments are challenging, but most suffer from major flaws. Among the most important are the following: (1) the inclusion of actual damage costs together with various ancillary expenditures which may or may not be indicative of the real economic damage due to NIS; (2) the inclusion of the costs of unnecessary or counterproductive control initiatives; (3) the inclusion of controversial NIS-related costs whose economic impacts are questionable; (4) the assessment of the negative impacts only, ignoring the positive ones that most NIS have on the economy, either directly or through their ecosystem services. Such estimates necessarily arrive at negative and often highly inflated values, do not reflect the net damage and economic losses due to NIS, and can significantly misguide management and resource allocation decisions. We recommend an approach based on holistic costs and benefits that are assessed using likely scenarios and their counter-factual.

The virtue of compassion in compassionate conservation

The role of ethics is becoming an increasingly important feature of biodiversity conservation dialogue and practice. Compassionate conservationists argue for a prohibition of, or at least a strong presumption against, the adoption of conservation policies that intentionally harm animals. They assert that to be compassionate is to care about animals and that it is antithetical to caring for animals to intentionally harm them. Compassionate conservationists thus criticize many existing conservation practices and policies. Two things together challenge the philosophical foundation of compassionate conservation. First, compassionate conservationists ground their theory in virtue ethics, yet virtue ethics permits exceptions to moral rules, so there cannot be an in-principle prohibition on adopting intentional harm-inducing policies and practices. But not all compassionate conservationists advocate for a prohibition on intentionally harming animals, only a strong presumption against it. This leads to the second point: compassion can motivate a person to adopt a harm-inducing conservation policy or practice when doing so is the best available option in a situation in which animals will be harmed no matter what policy or practice is adopted. Combining these insights with the empirical observation that conservationists regularly find themselves in tragic situations, we arrive at the conclusion that conservationists may regularly advocate for harm-inducing policies and practices from a position of compassion. Article Impact Statement: Compassionate conservationists should accept that the virtuously compassionate person may adopt harm-causing conservation policies.

A critical review of the compassionate conservation debate

Compassionate conservation holds that compassion should transform conservation. It has prompted heated debate and has been criticized strongly. We reviewed the debate to characterize compassionate conservation and to philosophically analyze critiques that are recurring and that warrant further critical attention. The necessary elements of compassionate conservation relate to the moral value of sentient animals and conservation and to science and conservation practice. Although compassionate conservation has several nontraditional necessary conditions, it also importantly allows a degree of pluralism in values and scientific judgment regarding animals and conservation practice. We identified 52 specific criticisms from 11 articles that directly critique compassionate conservation. We closely examined 33 of these because they recurred regularly or included substantial questions that required further response. Critics criticized compassionate conservation's ethical foundations, scientific credentials, clarity of application, understanding of compassion, its alleged threat to conservation and biodiversity. Some criticisms, we found, are question begging, confused, or overlook conceptual complexity. These criticisms raise questions for critics and proponents, regarding, for example, equal versus differential intrinsic moral value of different sentient animals (including humans), problems of natural and human-caused suffering of wild animals and predation, and the acceptability of specific conservation practices within compassionate conservation. By addressing recurring and faulty critiques of compassionate conservation and identifying issues for compassionate conservation to address, this review provides a clearer basis for crucial ongoing interdisciplinary dialogue about ethics, values, and conservation.

Emotion as a source of moral understanding in conservation

Recent debates around the meaning and implications of compassionate conservation suggest that some conservationists consider emotion a false and misleading basis for moral judgment and decision making. We trace these beliefs to a long-standing, gendered sociocultural convention and argue that the disparagement of emotion as a source of moral understanding is both empirically and morally problematic. According to the current scientific and philosophical understanding, reason and emotion are better understood as partners, rather than opposites. Nonetheless, the two have historically been seen as separate, with reason elevated in association with masculinity and emotion (especially nurturing emotion) dismissed or delegitimated in association with femininity. These associations can be situated in a broader, dualistic, and hierarchical logic used to maintain power for a dominant male (White, able-bodied, upper class, heterosexual) human class. We argue that emotion should be affirmed by conservationists for the novel and essential insights it contributes to conservation ethics. We consider the specific example of compassion and characterize it as an emotional experience of interdependence and shared vulnerability. This experience highlights conservationists' responsibilities to individual beings, enhancing established and widely accepted beliefs that conservationists have a duty to protect populations, species, and ecosystems (or biodiversity). We argue compassion, thus understood, should be embraced as a core virtue of conservation.

Expanded Ethical Principles for Research Partnership and Transdisciplinary Natural Resource Management Science

Natural resource researchers have long recognized the value of working closely with the managers and communities who depend on, steward, and impact ecosystems. These partnerships take various forms, including co-production and transdisciplinary research approaches, which integrate multiple knowledges in the design and implementation of research objectives, questions, methods, and desired outputs or outcomes. These collaborations raise important methodological and ethical challenges, because partnering with non-scientists can have real-world risks for people and ecosystems. The social sciences and biomedical research studies offer a suite of conceptual tools that enhance the quality, ethical outcomes, and effectiveness of research partnerships. For example, the ethical guidelines and regulations for human subjects research, following the Belmont Principles, help prevent harm and promote respectful treatment of research participants. However, science-management partnerships require an expanded set of ethical concepts to better capture the challenges of working with individuals, communities, organizations, and their associated ecosystems, as partners, rather than research subjects. We draw from our experiences in collaborative teams, and build upon the existing work of natural resources, environmental health, conservation and ecology, social science, and humanities scholars, to develop an expanded framework for ethical research partnership. This includes four principles: (1) appropriate representation, (2) self-determination, (3) reciprocity, and (4) deference, and two cross-cutting themes: (1) applications to humans and non-human actors, and (2) acquiring appropriate research skills. This framework is meant to stimulate important conversations about expanding ethics training and skills for researchers in all career-stages to improve partnerships and transdisciplinary natural resources research.

Equids engineer desert water availability

Megafauna play important roles in the biosphere, yet little is known about how they shape dryland ecosystems. We report on an overlooked form of ecosystem engineering by donkeys and horses. In the deserts of North America, digging of ≤2-meter wells to groundwater by feral equids increased the density of water features, reduced distances between waters, and, at times, provided the only water present. Vertebrate richness and activity were higher at equid wells than at adjacent dry sites, and, by mimicking flood disturbance, equid wells became nurseries for riparian trees. Our results suggest that equids, even those that are introduced or feral, are able to buffer water availability, which may increase resilience to ongoing human-caused aridification.

Functional traits of the world's late Quaternary large-bodied avian and mammalian herbivores

Prehistoric and recent extinctions of large-bodied terrestrial herbivores had significant and lasting impacts on Earth's ecosystems due to the loss of their distinct trait combinations. The world's surviving large-bodied avian and mammalian herbivores remain among the most threatened taxa. As such, a greater understanding of the ecological impacts of large herbivore losses is increasingly important. However, comprehensive and ecologically-relevant trait datasets for extinct and extant herbivores are lacking. Here, we present HerbiTraits, a comprehensive functional trait dataset for all late Quaternary terrestrial avian and mammalian herbivores ≥10 kg (545 species). HerbiTraits includes key traits that influence how herbivores interact with ecosystems, namely body mass, diet, fermentation type, habitat use, and limb morphology. Trait data were compiled from 557 sources and comprise the best available knowledge on late Quaternary large-bodied herbivores. HerbiTraits provides a tool for the analysis of herbivore functional diversity both past and present and its effects on Earth's ecosystems.

The moral residue of conservation

Should conservationists use lethal management to control introduced wildlife populations? Should they kill individual animals to protect endangered species? Are trade-offs that prioritize some values at the expense of others morally appropriate? These sorts of ethical questions are common in conservation. In debating such questions, conservationists often seem to presume 1 of 2 possible answers: the act in question is right or it is wrong. But morality in conservation is considerably more complex than this simple binary suggests. A robust conservation ethic requires a vocabulary that gives voice to the uncertainty and unease that arise when what seems to be the best available course of action also seems to involve a measure of wrongdoing. The philosophical literature on moral residue and moral dilemmas supplies this vocabulary. Moral dilemmas arise when one must neglect certain moral requirements to fulfill others. Under such circumstances, even the best possible decision leaves a moral residue, which is experienced emotionally as some form of grief. Examples of conservation scenarios that leave a moral residue include management of introduced rabbits in Australia, trophy hunting in Africa, and forest management trade-offs in the Pacific Northwest. Moral residue is integral to the moral experience of conservationists today, and grief is an appropriate response to many decisions conservationists must make. Article impact statement: Defensible conservation decisions may neglect moral requirements, leaving a moral residue; conservationists should respond with grief.

Recognizing animal personhood in compassionate conservation

Compassionate conservation is based on the ethical position that actions taken to protect biodiversity should be guided by compassion for all sentient beings. Critics argue that there are 3 core reasons harming animals is acceptable in conservation programs: the primary purpose of conservation is biodiversity protection; conservation is already compassionate to animals; and conservation should prioritize compassion to humans. We used argument analysis to clarify the values and logics underlying the debate around compassionate conservation. We found that objections to compassionate conservation are expressions of human exceptionalism, the view that humans are of a categorically separate and higher moral status than all other species. In contrast, compassionate conservationists believe that conservation should expand its moral community by recognizing all sentient beings as persons. Personhood, in an ethical sense, implies the individual is owed respect and should not be treated merely as a means to other ends. On scientific and ethical grounds, there are good reasons to extend personhood to sentient animals, particularly in conservation. The moral exclusion or subordination of members of other species legitimates the ongoing manipulation and exploitation of the living worlds, the very reason conservation was needed in the first place. Embracing compassion can help dismantle human exceptionalism, recognize nonhuman personhood, and navigate a more expansive moral space.