The highly distinctive and mostly endemic Australian land mammal fauna has suffered an extraordinary rate of extinction (>10% of the 273 endemic terrestrial species) over the last ∼200 y: in ...comparison, only one native land mammal from continental North America became extinct since European settlement. A further 21% of Australian endemic land mammal species are now assessed to be threatened, indicating that the rate of loss (of one to two extinctions per decade) is likely to continue. Australia’s marine mammals have fared better overall, but status assessment for them is seriously impeded by lack of information. Much of the loss of Australian land mammal fauna (particularly in the vast deserts and tropical savannas) has been in areas that are remote from human population centers and recognized as relatively unmodified at global scale. In contrast to general patterns of extinction on other continents where the main cause is habitat loss, hunting, and impacts of human development, particularly in areas of high and increasing human population pressures, the loss of Australian land mammals is most likely due primarily to predation by introduced species, particularly the feral cat, Felis catus , and European red fox, Vulpes vulpes , and changed fire regimes.
Significance The island continent of Australia harbors much of the world’s most distinctive biodiversity, but this review describes an extent of recent and ongoing loss of its mammal fauna that is exceptionally high and appreciably greater than previously recognized. The causes of loss are dissimilar to those responsible for most biodiversity decline elsewhere in the world.
The 2019–2020 megafires in Australia brought a tragic loss of human life and the most dramatic loss of habitat for threatened species and devastation of ecological communities in postcolonial ...history. What must be done now to keep impacted species from extinction? What can be done to avoid a repeat of the impacts of such devastating bushfires? Here, we describe hard-won lessons that may also be of global relevance.
Understanding changes in species distributions is essential to disentangle the mechanisms that drive their responses to anthropogenic habitat modification. Here we analyse the past (1970s) and ...current (2017) distribution of 204 species of terrestrial non-volant mammals to identify drivers of recent contraction and expansion in their range. We find 106 species lost part of their past range, and 40 of them declined by >50%. The key correlates of this contraction are large body mass, increase in air temperature, loss of natural land, and high human population density. At the same time, 44 species have some expansion in their range, which correlates with small body size, generalist diet, and high reproductive rates. Our findings clearly show that human activity and life history interact to influence range changes in mammals. While the former plays a major role in determining contraction in species' distribution, the latter is important for both contraction and expansion.
Extinctions typically have ecological drivers, such as habitat loss. However, extinction events are also influenced by policy and management settings that may be antithetical to biodiversity ...conservation, inadequate to prevent extinction, insufficiently resourced, or poorly implemented. Three endemic Australian vertebrate species—the Christmas Island pipistrelle (Pipistrellus murrayi), Bramble Cay melomys (Melomys tuhicob), and Christmas Island forest skink (Emoia mtivitatis)—became extinct from 2009 to 2014. All 3 extinctions were predictable and probably preventable. We sought to identify the policy, management, research, and other shortcomings that contributed to their extinctions or failed to prevent them. These included a lack within national environmental legislation and policy of explicit commitment to the prevention of avoidable extinctions, lack of explicit accountability, inadequate resources for conservation (particularly for species not considered charismatic or not of high taxonomic distinctiveness), inadequate biosecurity, a slow and inadequate process for listing species as threatened, recovery planning that failed to consider the need for emergency response, inability of researchers to identify major threatening factors, lack of public engagement and involvement in conservation decisions, and limited advocacy. From these 3 cases, we recommend: environmental policy explicitly seeks to prevent extinction of any species and provides a clear chain of accountability and an explicit requirement for public inquiry following any extinction; implementation of a timely and comprehensive process for listing species as threatened and for recovery planning; reservation alone not be assumed sufficient to maintain species; enhancement of biosecurity measures; allocation of sufficient resources to undertake actions necessary to prevent extinction; monitoring be considered a pivotal component of the conservation response; research provides timely identification of factors responsible for decline and of the risk of extinction; effective dissemination of research results; advocacy by an informed public for the recovery of threatened species; and public involvement in governance of the recovery process. These recommendations should be applicable broadly to reduce the likelihood and incidence of extinctions. Las extinciones tienen comúnmente conductores ecológicos, como la pérdida de hábitat. Sin embargo, los eventos de extinción también tienen influencia de la política y los ambientes de manejo que pueden ser anti-éticos para la conservación de la biodiversidad, inadecuados para prevenir la extinción, tener fondos insuficientes o estar implementados pobremente. Tres especies de vertebrados endémicos de Australia - el murciélago de Isla Navidad (Pipistrellus murrayi), el melomys de Cayo Bramble (Melomys rubicola) y el eslizón de bosque de Isla Navidad (Emoia nativitatis) - se extinguieron entre 2009 y 2014. Las tres extinciones fueron predecibles y probablemente prevenibles. Buscamos identificar la política, la administración, la investigación y otros defectos que contribuyeron a su extinción o que fallaron en prevenirlas. Los factores que contribuyeron a estas extinciones incluyen la carencia de un compromiso explícito con la prevención de las extinciones evitables dentro de la legislación ambiental nacional y la política, la carencia de una responsabilidad explícita, los recursos inadecuados para la conservación (particularmente para las especies que no son consideradas carismáticas o que no tienen una diferencia taxonómica alta), la bioseguridad inadecuada, el proceso lento e inadecuado para enlistar a las especies como amenazadas, la planeación de la recuperación que falló en considerar la necesidad de una respuesta de emergencia, la incapacidad de los investigadores de identificar factores de amenaza mayores, la falta de un compromiso público y la participación en las decisiones de conservación, y la defensa limitada. A partir de estos tres casos de extinción recomendamos una política ambiental que busque explícitamente prevenir la extinción de cualquier especie y que proporcione una cadena entendible de responsabilidad y un requerimiento explícito de la indagación pública después de cualquier extinción; la implementación de un proceso oportuno y comprensible para enlistar a las especies como amenazadas y para la planeación de la recuperación; que no se asuma que la reservación es la única forma de mantener a las especies; el mejoramiento de las medidas de bioseguridad; la asignación de suficientes recursos para llevar a cabo las acciones necesarias para prevenir la extinción; que el monitoreo no sea considerado como un componente crucial de la respuesta a la conservación; que las investigaciones proporcionen la identificación oportuna de los factores responsables de la declinación y del riesgo de extinción; la diseminación efectiva de los resultados de las investigaciones; y la defensa por parte de un público informado para la recuperación de las especies amenazadas; y la participación del público en la gobemanza del proceso de recuperación. Estas recomendaciones deberían ser aplicables de manera general para reducir la probabilidad y la incidencia de las extinciones.
Free-ranging cats (Felis catus) are globally distributed invasive carnivores that markedly impact biodiversity. Here, to evaluate the potential threat of cats, we develop a comprehensive global ...assessment of species consumed by cats. We identify 2,084 species eaten by cats, of which 347 (16.65%) are of conservation concern. Islands contain threefold more species of conservation concern eaten by cats than continents do. Birds, reptiles, and mammals constitute ~90% of species consumed, with insects and amphibians being less frequent. Approximately 9% of known birds, 6% of known mammals, and 4% of known reptile species are identified in cat diets. 97% of species consumed are <5 kg in adult body mass, though much larger species are also eaten. The species accumulation curves are not asymptotic, indicating that our estimates are conservative. Our results demonstrate that cats are extreme generalist predators, which is critical for understanding their impact on ecological systems and developing management solutions.
Human modification of the environment is driving declines in population size and distributional extent of much of the world's biota. These declines extend to many of the most abundant and widespread ...species, for which proportionally small declines can result in the loss of vast numbers of individuals, biomass, and interactions. These losses could have major localized effects on ecological and cultural processes and services without elevating a species’ global extinction risk. Although most conservation effort is directed at species threatened with extinction in the very near term, the value of retaining abundance regardless of global extinction risk is justifiable based on many biodiversity or ecosystem service metrics, including cultural services, at scales from local to global. The challenges of identifying conservation priorities for widespread and abundant species include quantifying the effects of species’ abundance on services and understanding how these effects are realized as populations decline. Negative effects of population declines may be disconnected from the threat processes driving declines because of species movements and environment flows (e.g., hydrology). Conservation prioritization for these species shares greater similarity with invasive species risk assessments than extinction risk assessments because of the importance of local context and per capita effects of abundance on other species. Because conservation priorities usually focus on preventing the extinction of threatened species, the rationale and objectives for incorporating declines of nonthreatened species must be clearly articulated, going beyond extinction risk to encompass the range of likely harmful effects (e.g., secondary extinctions, loss of ecosystem services) if declines persist or are not reversed. Research should focus on characterizing the effects of local declines in species that are not threatened globally across a range of ecosystem services and quantifying the spatial distribution of these effects through the distribution of abundance. The case for conserving abundance in nonthreatened species can be made most powerfully when the costs of losing this abundance are better understood.
Conservación de la Abundancia de Especies No Amenazadas
Resumen
La modificación del ambiente causada por los humanos está resultando en la declinación del tamaño poblacional y de la extensión de la distribución de la mayor parte de la biota mundial. Estas declinaciones llegan hasta muchas de las especies más abundantes y con mayor distribución, para las cuales una declinación proporcionalmente pequeña puede resultar en la pérdida de un número extenso de individuos, biomasa e interacciones. Estas pérdidas podrían tener mayores efectos localizados sobre los procesos y servicios ecológicos y culturales sin elevar el riesgo de extinción mundial de la especie. Aunque casi todos los esfuerzos de conservación están dirigidos hacia especies bajo amenaza de extinción a corto plazo, el valor de mantener la abundancia sin importar el riesgo de extinción mundial es justificable con base en muchas medidas de biodiversidad o de servicios ambientales, incluyendo los servicios culturales, a escalas desde lo local hasta lo global. El reto de identificar prioridades de conservación para especies abundantes y de distribución extensa incluye la cuantificación de los efectos que la abundancia de la especie tiene sobre los servicios y el entendimiento de cómo estos efectos ocurren conforme las poblaciones declinan. Los efectos negativos de la declinación poblacional pueden estar desconectados del proceso que ocasiona la declinación por causa del movimiento de las especies y los flujos ambientales (p. ej.: la hidrología). La priorización de la conservación de estas especies comparte muchas más similitudes con la evaluación de riesgo de las especies invasoras que las evaluaciones de extinción de riesgo debido a la importancia del contexto local y los efectos per cápita de la abundancia sobre otras especies. Ya que los esfuerzos de conservación generalmente se enfocan en la prevención de la extinción de las especies amenazadas, la lógica y los objetivos detrás de la incorporación de las declinaciones de las especies no amenazadas deben estar articulados claramente, llegando más allá del riesgo de extinción para englobar la gama de efectos dañinos probables (p. ej.: extinciones secundarias, pérdida de servicios ambientales) en el caso de que las declinaciones persistan o no sean revertidas. La investigación debería enfocarse en la caracterización de los efectos de las declinaciones locales de especies que no estén amenazadas mundialmente a lo largo de una gama de servicios ambientales y en la cuantificación de la distribución espacial de estos efectos por medio de la distribución de la abundancia. Se puede argumentar de manera más poderosa el caso para la conservación de la abundancia de especies no amenazadas cuando se entienden mejor los costos de la pérdida de esta abundancia.
Article impact statement: Importance of conserving the abundance of nonthreatened species must be assessed against the costs of its loss to ecosystems and society.
Animal mortality during fire Jolly, Chris J.; Dickman, Chris R.; Doherty, Tim S. ...
Global change biology,
March 2022, Volume:
28, Issue:
6
Journal Article
Peer reviewed
Earth's rapidly warming climate is propelling us towards an increasingly fire‐prone future. Currently, knowledge of the extent and characteristics of animal mortality rates during fire remains ...rudimentary, hindering our ability to predict how animal populations may be impacted in the future. To address this knowledge gap, we conducted a global systematic review of the direct effects of fire on animal mortality rates, based on studies that unequivocally determined the fate of animals during fire. From 31 studies spanning 1984–2020, we extracted data on the direct impacts of fire on the mortality of 31 species from 23 families. From these studies, there were 43 instances where direct effects were measured by reporting animal survival from pre‐ to post‐fire. Most studies were conducted in North America (52%) and Oceania (42%), focused largely on mammals (53%) and reptiles (30%), and reported mostly on animal survival in planned (82%) and/or low severity (70%) fires. We found no studies from Asia, Europe or South America. Although there were insufficient data to conduct a formal meta‐analysis, we tested the effect of fire type, fire severity, fire regime, animal body mass, ecological attributes and class on survival. Only fire severity affected animal mortality, with a higher proportion of animals being killed by high than low severity fires. Recent catastrophic fires across the globe have drawn attention to the plight of animals exposed to wildfire. Yet, our systematic review suggests that a relatively low proportion of animals (mean predicted mortality 95% CI = 3% 1%–9%) are killed during fire. However, our review also underscores how little we currently know about the direct effects of fire on animal mortality, and highlights the critical need to understand the effects of high severity fire on animal populations.
Our understanding of animal mortality rates during fire is rudimentary. Here, we conducted a global systematic review of the direct effects of fire on animal mortality rates. From 31 studies spanning 1984–2020, we extracted data on the direct impacts of fire on the mortality of 31 species from 23 families. Our systematic review suggests that a relatively low proportion of animals (3% 1%–9%) are killed during fire. However, our review also underscores how little we currently know about the direct effects of fire on animal mortality, and highlights the critical need to understand the effects of high severity fire on animal populations.
Fire is an integral part of savanna ecology and changes in fire patterns are linked to biodiversity loss in savannas worldwide. In Australia, changed fire regimes are implicated in the contemporary ...declines of small mammals, riparian species, obligate-seeding plants and grass seed-eating birds. Translating this knowledge into management to recover threatened species has proved elusive. We report here on a landscape-scale experiment carried out by the Australian Wildlife Conservancy (AWC) on Mornington Wildlife Sanctuary in northwest Australia. The experiment was designed to understand the response of a key savanna bird guild to fire, and to use that information to manage fire with the aim of recovering a threatened species population. We compared condition indices among three seed-eating bird species--one endangered (Gouldian finch) and two non-threatened (long-tailed finch and double-barred finch)--from two large areas (> 2,830 km2) with initial contrasting fire regimes ('extreme': frequent, extensive, intense fire; versus 'benign': less frequent, smaller, lower intensity fires). Populations of all three species living with the extreme fire regime had condition indices that differed from their counterparts living with the benign fire regime, including higher haematocrit levels in some seasons (suggesting higher levels of activity required to find food), different seasonal haematocrit profiles, higher fat scores in the early wet season (suggesting greater food uncertainty), and then lower muscle scores later in the wet season (suggesting prolonged food deprivation). Gouldian finches also showed seasonally increasing stress hormone concentrations with the extreme fire regime. Cumulatively, these patterns indicated greater nutritional stress over many months for seed-eating birds exposed to extreme fire regimes. We tested these relationships by monitoring finch condition over the following years, as AWC implemented fire management to produce the 'benign' fire regime throughout the property. The condition indices of finch populations originally living with the extreme fire regime shifted to resemble those of their counterparts living with the benign fire regime. This research supports the hypothesis that fire regimes affect food resources for savanna seed-eating birds, with this impact mediated through a range of grass species utilised by the birds over different seasons, and that fire management can effectively moderate that impact. This work provides a rare example of applied research supporting the recovery of a population of a threatened species.
Feral cats are among the most damaging invasive species worldwide, and are implicated in many extinctions, especially in Australia, New Zealand and other islands. Understanding and reducing their ...impacts is a global conservation priority.
We review knowledge about the impacts and management of feral cats in Australia, and identify priorities for research and management.
In Australia, the most well understood and significant impact of feral cats is predation on threatened mammals. Other impacts include predation on other vertebrates, resource competition, and disease transmission, but knowledge of these impacts remains limited.
Lethal control is the most common form of management, particularly via specifically designed poison baits. Non‐lethal techniques include the management of fire, grazing, food, and trophic cascades. Managing interactions between these processes is key to success.
Given limitations on the efficacy of feral cat management, conservation of threatened mammals has required the establishment of insurance populations on predator‐free islands and in fenced mainland enclosures.
Research and management priorities are to: prevent feral cats from driving threatened species to extinction; assess the efficacy of new management tools; trial options for control via ecosystem management; and increase the potential for native fauna to coexist with feral cats.
Tropical savannas are the world's most fire‐prone biome, and savanna biotas are generally well adapted to frequent fire. However, in northern Australia there are concerns that recent increases in the ...frequency and extent of high‐intensity fires are causing substantial declines in regional biodiversity values. In this paper we use two well‐studied and contrasting faunal groups, ants and small mammals, as case studies for reviewing faunal responses to fire in Australian savannas. The Australian savanna ant fauna is dominated by arid‐adapted taxa that are highly resilient to frequent fire and are not considered to be threatened by prevailing fire regimes. Indeed, frequent fire promotes ant diversity because it maintains an open habit that makes the dominant arid‐adapted taxa feel at home. Long‐term fire exclusion reduces ant diversity due to a marked decline in arid‐adapted taxa, and favours highly generalized, more shade‐tolerant taxa. In contrast, many small mammal species of high conservation value are highly sensitive to frequent fire, and there are widespread concerns that their populations are threatened by current fire management. Many of the species have shown dramatic population declines over recent decades, and, although the causes are poorly understood, there is little doubt that fire is an important contributing factor. It is likely that fire is acting synergistically with other underlying causes of decline, particularly predation by feral cats. The overall resilience of most savanna animal species in relation to frequent fire suggests that they are secure under all but the most extreme fire regimes. However, it is clear that more fire‐sensitive groups such as small mammals need special fire management attention. This needs to involve less frequent and finer‐scale burning, along with the protection of some large, infrequently burnt source areas.
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