Extinction Of Mammals Research Articles

Demography and spatial requirements of the endangered northern quoll on Groote Eylandt

Abstract ContextAustralia has experienced the highest number of mammal extinctions of any continent over the past two centuries. Understanding the demography and spatial requirements of populations before declines occur is fundamental to confirm species trajectory, elucidate causes of decline and develop effective management strategies. AimsWe evaluated the demography and spatial requirements of a northern quoll, Dasyurus hallucatus, population on Groote Eylandt, Northern Territory. Groote Eylandt is considered a refuge for the species because key threatening processes are absent or limited; cane toads and introduced ungulates are absent, feral cats are infrequently detected and the fire regime is benign compared with mainland Northern Territory. MethodsWe conducted a 4-year capture–mark–recapture study to monitor growth, reproduction and survival of northern quolls within a 128-ha area, and we evaluated spatial requirements by attaching GPS units to both sexes. To assess the status of the Groote Eylandt population, we compared the demographics with existing data from mainland populations. Key resultsThe average density of northern quolls was 0.33ha−1. However, there was a 58% decline in female density, primarily between 2012 and 2013, corresponding with a decrease in female body mass. Females survived and bred in up to 3 years and adult survival rates did not vary among years, suggesting that juvenile recruitment drives population fluctuations. Male quolls were semelparous, with die-off occurring in the months following breeding. The median female and male home ranges were 15.7ha and 128.6ha respectively, and male ranges increased significantly during breeding, with 1616ha being the largest recorded. ConclusionsThe northern quoll population on Groote Eylandt had a higher density, female survival and reproductive success than has been previously recorded on the mainland. However, a marked decline was recorded corresponding with a decrease in female mass, indicating below-average rainfall as the likely cause. ImplicationsGroote Eylandt remains a refuge for the endangered northern quoll. However, even in the absence of key threatening processes, the population has declined markedly, highlighting the impact of environmental fluctuations. Maintaining the ecological integrity of Groote Eylandt is imperative for population recovery, and managing threats on the mainland over appropriate spatial scales is necessary to increase population resilience.

About geoecological situation in the Selenga river basin (Western Transbaikalia) in the Palaeolithic

The data are presented on the time of the first appearance of prehistoric humans in the Selenga River Basin, where human interaction with the natural environment took place during the cooling period, with its maximum registered in the end of the Pleistocene. It is shown that the changes in the relief were controlled by the activity of tectonic phases, one of which having caused the uprising of the Baikal Depression shoulders and the lowering of its bottom to the current depth. It has been noted that denudation and accumulation contributed to the formation of foothills and river terraces, inhabited by Palaeolithic humans. Stepwise climatic changes being non-antagonistic to the surrounding environment favoured the preservation of many species of the Pleistocene mammals, which nowadays compose the current teriofauna. The extinction of key mammals (Mammuthus, Coelodonta) is not attributed to the ancient human activities. The presented research results allow considering ancient humans being an integral component of geosystems, which influenced them indirectly by impacts though of a small force but long-acting and destabilizing their balance, i.e., extension of settlements and ancient residential landscapes.

The Real Stranded Assets of Carbon Lock-In

Climate debates over stranded assets are focusing on the wrong assets. Fossil-fuel companies and petrostates argue that they will suffer economic losses from climate policies. Although true, this ignores assets that will be stranded in the absence of climate policy. These are the real stranded assets of carbon lock-in and could prove much more costly.

Reading the black book: The number, timing, distribution and causes of listed extinctions in Australia

Through collation of global, national and state/territory threatened species lists, we conclude that 100 Australian endemic species (one protist, 38 vascular plants, ten invertebrates, one fish, four frogs, three reptiles, nine birds and 34 mammals) are validly listed as extinct (or extinct in the wild) since the nation’s colonisation by Europeans in 1788. This tally represents about 6–10% of the world’s post-1500 recognised extinctions. The actual number of extinctions is likely to be far more than those recognised in formal lists. Mammals have suffered the highest proportional rate of extinction (ca. 10% of the endemic mammal fauna). There are four main distributional features of these extinctions: (i) consistent with global patterns, island endemic species are disproportionately represented; (ii) many non-island extinct species had highly restricted mainland ranges; but conversely (iii) many extinct mammals had extensive ranges; and (iv) there have been no recognised extinctions of species confined to Australia’s mainland monsoonal tropics. Extinctions have occurred largely continuously since Australia’s European settlement, with at least three extinctions in the last decade. Mammal extinctions were caused mainly by introduced predators; plant extinctions by habitat loss; frog extinctions by disease; reptile extinctions by an introduced snake; and invertebrate extinctions by a range of anthropogenic processes. Causality has changed over time, with recent extinctions more likely to be associated with disease, introduced reptiles and introduced fish and less likely to be associated with hunting and introduced mammalian predators. The most recent extinction is the sole case for which climate change was a major factor.

Do introduced apex predators suppress introduced mesopredators? A multiscale spatiotemporal study of dingoes and feral cats in Australia suggests not

Abstract The role of apex predators in structuring ecosystems through the suppression of mesopredator activity and abundance is receiving increasing attention, largely due to the potential benefits for biodiversity conservation. In Australia, invasive mesopredators such as feral cats (Felis catus) have been identified as major contributors to Australia's mass mammal extinctions since European arrival. The introduced dingo (Canis familiaris) has been proposed as a novel way to suppress the impacts of feral cats, however, scientific evidence of the dingo's suppressive role is equivocal. We used camera traps to investigate whether a large introduced predator (dingo) suppresses the activity of an established introduced mesopredator (feral cat) across a national park site conserving endangered species, and an agricultural site supporting cattle grazing enterprises. Feral cats and dingoes exhibited marked overlap in both temporal and spatial activity, indicating coexistence. Some temporal separation was evident at the agricultural site, however, this reflected higher diurnal activity by dingoes, not a responsive shift in cat activity. Cat activity times were unrelated to dingo presence and did not differ between areas occupied by dingoes and dingo‐free areas. There was no evidence of dingoes excluding cats from patches at either site, nor was there evidence of within‐night fine‐scale spatiotemporal avoidance of dingoes by cats. Species co‐occurrence models revealed dingoes had no negative effect on the probability of cat presence. The probability of detecting a cat on the national park was significantly higher in areas with dingoes than in dingo‐free areas, while on agricultural land, cat detectability did not differ between areas with and without dingoes. Cats remained active, abundant and widespread across both sites, with evidence of cats hunting and breeding successfully in areas occupied by dingoes. Synthesis and applications. Our findings indicate that feral cats can coexist with dingoes, without apparent suppression of cat activity, abundance or fitness. Proposals to reintroduce or restore dingoes and other large predators to suppress invasive mesopredators and conserve biodiversity should be carefully evaluated on a site‐by‐site basis, as their ability to suppress cats and protect species of conservation significance will likely be context dependent.

Historical range contractions can predict extinction risk in extant mammals.

Climate change is amongst the main threats to biodiversity. Considering extant mammals endured Quaternary climate change, we analyzed the extent to which this past change predicts current mammals’ extinction risk at global and biogeographical scales. We accessed range dynamics by modeling the potential distribution of all extant terrestrial mammals in the Last Glacial Maximum (LGM, 21,000 years ago) and in current climate conditions and used extinction risk from IUCN red list. We built General Linear Mixed-Effects Models to test the magnitude with which the variation in geographic range (ΔRange) and a proxy for abundance (ΔSuitability) between the LGM and present-day predicts current mammal’s extinction risk. We found past climate change most strongly reduced the geographical range and climatic suitability of threatened rather than non-threatened mammals. Quaternary range contractions and reduced suitability explain around 40% of species extinction risk, particularly for small-bodied mammals. At global and biogeographical scales, all groups that suffered significant Quaternary range contractions now contain a greater proportion of threatened species when compared to groups whose ranges did not significantly contract. This reinforces the importance of using historical range contractions as a key predictor of extinction risk for species in the present and future climate change scenarios and supports current efforts to fight climate change for biodiversity conservation.

Historical records reveal the distinctive associations of human disturbance and extreme climate change with local extinction of mammals

Accelerated anthropogenic impacts and climatic changes are widely considered to be responsible for unprecedented species extinction. However, determining their effects on extinction is challenging owing to the lack of long-term data with high spatial and temporal resolution. In this study, using historical occurrence records of 11 medium- to large-sized mammal species or groups of species in China from 905 BC to AD 2006, we quantified the distinctive associations of anthropogenic stressors (represented by cropland coverage and human population density) and climatic stressors (represented by air temperature) with the local extinction of these mammals. We found that both intensified human disturbances and extreme climate change were associated with the increased local extinction of the study mammals. In the cold phase (the premodern period of China), climate cooling was positively associated with increased local extinction, while in the warm phase (the modern period) global warming was associated with increased local extinction. Interactive effects between human disturbance and temperature change with the local extinction of elephants, rhinos, pandas, and water deer were found. Large-sized mammals, such as elephants, rhinos, and pandas, showed earlier and larger population declines than small-sized ones. The local extinction sensitivities of these mammals to the human population density and standardized temperature were estimated during 1700 to 2000. The quantitative evidence for anthropogenic and climatic associations with mammalian extinction provided insights into the driving processes of species extinction, which has important implications for biodiversity conservation under accelerating global changes.

Biodiversity of Early Holocene large mammals from the territory of Bulgaria according to remains from archaeological sites

Animal remains from archeological sites give a rather good sample of data, showing habitats and biodiversity during the early Holocene . In multiple settlements in the Eastern Balkans, there are numerous remains of wild mammals that were hunted by humans through the prehistory (7200-5800 BP). This gives a general idea of the habitats around and near the settlements. Such deposits of animal remains are the main source of data on fauna during this period and give us information on the processes leading to the extinction of some species. This paper analyzes more than 26000 animal remains (bones, horns, antlers and teeth) from large mammals from orders: Аrtiodactyla, Perissodactyla and Carnivora from 4 still unpublished deposits from Bulgaria. I summarize data from already published remains from 33 sites in East Balkans. These analyses provide a general picture of both habitats and biodiversity and some of the major factors that caused extinction of some large mammals in Bulgaria during the early Holocene.

Introduced cats Felis catus eating a continental fauna: inventory and traits of Australian mammal species killed

Abstract Mammals comprise the bulk of the diet of free‐ranging domestic cats Felis catus (defined as including outdoor pet cats, strays, and feral cats) in most parts of their global range. In Australia, predation by introduced feral cats has been implicated in the extinction of many mammal species, and in the ongoing decline of many extant species. Here, we collate a wide range of records of predation by cats (including feral and pet cats) on Australian mammals and model traits of extant, terrestrial, native mammal species associated with the relative likelihood of cat predation. We explicitly seek to overcome biases in such a continental‐scale compilation by excluding possible carrion records for larger species and accounting for differences in the distribution and abundance of potential prey species, as well as study effort, throughout each species’ range. For non‐volant species, the relative likelihood of predation by cats was greatest for species in an intermediate weight range (peaking at ca. 400 g), in lower rainfall areas and not dwelling in rocky habitats. Previous studies have shown the greatest rates of decline and extinction in Australian mammals to be associated with these traits. As such, we provide the first continental‐scale link between mammal decline and cat predation through quantitative analysis. Our compilation of cat predation records for most extant, terrestrial, native mammal species (151 species, or 52% of the Australian species’ complement) is substantially greater than previously reported (88 species) and includes 50 species listed as threatened by the IUCN or under Australian legislation (57% of Australia's 87 threatened terrestrial mammal species). We identify the Australian mammal species most likely to be threatened by predation by cats (mulgaras Dasycercus spp., kowari Dasyuroides byrnei, many smaller dasyurids and medium‐sized to large rodents, among others) and hence most likely to benefit from enhanced mitigation of cat impacts, such as translocations to predator‐free islands, the establishment of predator‐proof fenced exclosures, and broad‐scale cat poison baiting.

An upper bound for the background rate of human extinction

We evaluate the total probability of human extinction from naturally occurring processes. Such processes include risks that are well characterized such as asteroid impacts and supervolcanic eruptions, as well as risks that remain unknown. Using only the information that Homo sapiens has existed at least 200,000 years, we conclude that the probability that humanity goes extinct from natural causes in any given year is almost guaranteed to be less than one in 14,000, and likely to be less than one in 87,000. Using the longer track record of survival for our entire genus Homo produces even tighter bounds, with an annual probability of natural extinction likely below one in 870,000. These bounds are unlikely to be affected by possible survivorship bias in the data, and are consistent with mammalian extinction rates, typical hominin species lifespans, the frequency of well-characterized risks, and the frequency of mass extinctions. No similar guarantee can be made for risks that our ancestors did not face, such as anthropogenic climate change or nuclear/biological warfare.

Habitat and introduced predators influence the occupancy of small threatened macropods in subtropical Australia.

Australia has had the highest rate of mammal extinctions in the past two centuries when compared to other continents. Frequently cited threats include habitat loss and fragmentation, changed fire regimes and the impact of introduced predators, namely the red fox (Vulpes vulpes) and the feral cat (Felis catus). Recent studies suggest that Australia's top predator, the dingo (Canis dingo), may have a suppressive effect on fox populations but not on cat populations. The landscape of fear hypothesis proposes that habitat used by prey species comprises high to low risk patches for foraging as determined by the presence and ubiquity of predators within the ecosystem. This results in a landscape of risky versus safe areas for prey species. We investigated the influence of habitat and its interaction with predatory mammals on the occupancy of medium‐sized mammals with a focus on threatened macropodid marsupials (the long‐nosed potoroo [Potorous tridactylous] and red‐legged pademelon [Thylogale stigmatica]). We assumed that differential use of habitats would reflect trade‐offs between food and safety. We predicted that medium‐sized mammals would prefer habitats for foraging that reduce the risk of predation but that predators would have a positive relationship with medium‐sized mammals. We variously used data from 298 camera trap sites across nine conservation reserves in subtropical Australia. Both dingoes and feral cats were broadly distributed, whilst the red fox was rare. Long‐nosed potoroos had a strong positive association with dense ground cover, consistent with using habitat complexity to escape predation. Red‐legged pademelons showed a preference for open ground cover, consistent with a reliance on rapid bounding to escape predation. Dingoes preferred areas of open ground cover whereas feral cats showed no specific habitat preference. Dingoes were positively associated with long‐nosed potoroos whilst feral cats were positively associated with red‐legged pademelons. Our study highlights the importance of habitat structure to these threatened mammals and also the need for more detailed study of their interactions with their predators.

Late Quaternary Fossil Mammals from the Cayman Islands, West Indies

Abundant fossils of nesophontid lipotyphlan insectivores and capromyid rodents have been collected from late Quaternary deposits on the Cayman Islands, an island group separated by a major marine barrier from other Caribbean landmasses and isolated from anthropogenic impacts until the arrival of Columbus in 1503 CE. These collections have not previously been formally described. Using morphological and ancient DNA approaches, we document three new taxa of extinct endemic terrestrial mammals from this island group: Nesophontes hemicingulus (Grand Cayman and Cayman Brac), Capromys pilorides lewisi (Grand Cayman, Little Cayman, and Cayman Brac), and Geocapromys caymanensis (Grand Cayman and Cayman Brac). Morphometric comparisons with other extinct and living West Indian mammals indicate that the biogeographic origins of all three new taxa are from source populations on Cuba. Ancient DNA data indicate very low sequence divergence of Capromys pilorides lewisi from mainland Cuban C. pilorides (only 0.5% across the entire mitogenome). Using probabilistic analysis of existing and new radiometric dates, we calculate an estimated extinction date of 1700 CE (95% confidence interval = 1632–1774 CE) for the Cayman Brac Capromys population. This result suggests that at least one endemic Cayman terrestrial mammal population survived for well over a century following first European arrival in the Cayman Islands. The West Indies lost nearly all its species-rich late Quaternary land mammal fauna during the late Holocene due to direct or indirect human impacts, and this study provides a new baseline to understand the magnitude of human-caused mammal extinctions during the recent past.

Evidence that the functional extinction of small mammals facilitates shrub encroachment following wildfire in arid Australia

Woody shrub encroachment has been linked to environmental changes associated with pastoralism, such as fire regime shifts and overgrazing, throughout Earth's rangelands. Extinction of native fauna that are consumers of shrubs has also accompanied pastoralism in many areas; however fauna declines have rarely been considered as a driver of encroachment. Here we investigate the interacting impacts that wildfire and functional extinction of native granivorous rodents and a small introduced herbivore, the European rabbit (Oryctolagus cuniculus), have on shrub seedling density in the Strzelecki Desert, Australia. Using data from field surveys conducted following wildfires in 2012, we show that shrub seedling densities were higher at burned than unburned sites in areas where rodents and rabbits were rare. However, at sites where rodents and rabbits were common, seedling densities were higher at unburned than burned sites and rodent activity was greater on burned sites during an optimal recruitment period. Our results provide support for the hypothesis that post-fire shrub recruitment is facilitated by the extinction of small mammals which consume shrubs and their seeds. Our study suggests that “rewilding” of small mammal assemblages may provide a mechanism to curb shrub encroachment.

Interpreting the historical terrestrial vertebrate biodiversity of Cayman Brac (Greater Antilles, Caribbean) through collagen fingerprinting

Cayman Brac (Cayman Islands) lies within the Caribbean Islands Biodiversity Hotspot, an epicenter of high biodiversity and endemism. However, all endemic terrestrial mammals on the Cayman Islands are now extinct, following post-1500 AD human colonization of the islands. Introduced rodents and domesticated mammals now exclusively represent this facet of terrestrial fauna on the Cayman Islands, and are a likely cause of endemic species loss on the islands. Cayman Brac has numerous caves and rock fissures that offer protection to a naturally accumulated ensemble of vertebrate sub-fossil bone remains, documenting modifications in island biodiversity through the Holocene. In this study, we showcase the first molecular faunal survey undertaken on sub-fossil remains from the Cayman Islands, using collagen fingerprinting for taxonomic identification of the cave skeletal deposits collected from a single cave system, Green Cave on Cayman Brac. Collagen type (I) extracts from 485 bone fragments were analyzed to determine faunal identity and assemblage composition. A total of 76% of the collagen fingerprint-yielding samples were mammalian in origin, 67% of which were identified as invasive murid rodents. Here, we present mass spectral biomarkers for the endemic terrestrial mammal fauna of Cayman Brac, including the extinct capromyid rodents, Capromys and Geocapromys (Rodentia: Capromyidae), alongside commentary on the composition of the sub-fossil bone assemblage between the five distinct depositional chambers that comprise Green Cave. Collagen (I) provides a key service in taxonomic identification and mapping of macroevolutionary trends, and these results suggest a pivotal role for murid rodents in the competition and extinction of terrestrial endemic mammals from the Cayman Islands.

Mammal extinctions and the increasing isolation of humans on the tree of life.

A sixth great mass extinction is ongoing due to the direct and indirect effects of human pressures. However, not all lineages are affected equally. From an anthropocentric perspective, it is often purported that humans hold a unique place on Earth. Here, we show that our current impacts on the natural world risk realizing that expectation. We simulated species loss on the mammalian phylogenetic tree, informed by species current extinction risks. We explored how Homo sapiens could become isolated in the tree if species currently threatened with extinction disappeared. We analyzed correlates of mammal extinctions risks that may drive this isolation pattern. We show that, within mammals, and more particularly within primates, extinction risks increase with the number of known threat types, and decrease with geographic range size. Extinctions increase with species body mass, trophic level, and the median longitudinal extent of each species range in mammals but not within primates. The risks of extinction are frequently high among H. sapiens close relatives. Pruning threatened primates, including apes (Hominidae, Hylobatidae), from the tree of life will lead to our species being among those with the fewest close relatives. If no action is taken, we will thus not only lose crucial biodiversity for the preservation of Earth ecosystems, but also a key living reference to what makes us human.

Reconsidering mammal extinctions in the Pernambuco Endemism Center of the Brazilian Atlantic Forest: a critique

espanolSe ha calculado que, en los ultimos 500 anos, se han extinguido 21 mamiferos en el Centro de Endemismo Pernambuco. En el presente estudio, realizamos un examen critico de los datos aportados en las publicaciones cientificas historicas y recientes, y concluimos que el numero real de mamiferos extintos es de siete, lo que indica que la cifra anterior de 21 especies extintas es una sobrestimacion de aproximadamente 30%. Nuestra lista difiere de las publicaciones previas en que incluye especies aun existentes (n = 5) y excluye otras que nunca habian sido registradas en el Centro de Endemismo Pernambuco (n = 8). Asimismo, senalamos que, al elaborar listas de fauna extinta a escala regional, es necesario adoptar un planteamiento mas riguroso en relacion con los registros historicos y recientes, dado que las identificaciones erroneas y las suposiciones falsas podrian conducir a la perdida de credibilidad ante las partes interesadas y, en ultima instancia, ser negativas para la conservacion de especies. EnglishIn the last 500 years, there have been an estimated 21 mammal extinctions in the Pernambuco Endemism Center. We critically reviewed the published historical and recent literature records and concluded that the actual number of mammal species extinction was seven, indicating that the previous figure of 21 species lost is an overestimation of approximately 30%. Our checklist differs from previous publications by including species that are still extant (n = 5), and removing species that have never been recorded in the Pernambuco Endemism Center (n = 8). We point out that a more rigorous approach towards historical and recent records is needed when producing lists of regionally extinct fauna, given that the implications of misidentifications and false assumptions can potentially lead to loss of credibility by stakeholders and ultimately have a negative effect on species conservation.

Banning the Ivory Trade in Hong Kong

The date of 31 January 2018 marked the adoption in Hong Kong of a three-phased law banning trading in elephant ivory that will come into full effect on 31 December 2021. This follows the decision of mainland China outlawing this practice from 31 December 2017. These new ordinances, which derive from an international convention (CITES), are particularly adapted to these places as they represent (with Japan) the world’s principal destination of ivory, both legal and illegal, and have done so since the 1950s. This trade, and especially its illegal strand, threatens the survival of Africa’s elephants, whose ivory is regarded as precious. In Hong Kong, the movement of ivory is regularly in the news. July 2017 recorded the largest seizure of illegal ivory in the past 30 years (7.2tonnes). Early 2018 was also noteworthy on account of two events: on the one hand, the resignation of a member of the governmental consultative committee on endangered species (who is also an ivory trader), who had been selling illegal ivory, thus lending a whiff a scandal to the legislative process; and on the other hand, the killing in Nairobi of Esmond Bradley Martin, one of the leading experts on the trafficking of ivory. These national and international events, together with scientific studies and various other reports, have been part of the context of legislative reform in Hong Kong. They are an indication of the complex nature of the issues involved, as can be seen in the stormy legislative debates brought about by competing interests. Quite a number of local newspaper articles (in English and Chinese alike), as well as the (English-language) press in mainland China,have covered this reform by exposing the tensions, divergent points of view, and arguments of the protagonists. It might still appear, however, that there has been little discussion of certain points. The present article will highlight, through an analysis of the media’s treatment of the legislative reform process in Hong Kong, the political issues at stake in this ban, and in particular the grey areas of the public debate. It tries to break with the dichotomy “for” or “against” that are often typical of debates on the extinction of these emblematic mammals. In this press review I undertake a detailed analysis of local newspaper articles, essentially those of the English-language press. Of the 41 articles examined, I selected 21 on the basis of their relevance to legislative reform in Hong Kong and the diversity of their content. Two articles from the Chinese-language local press (selected from 28 articles), as well as six articles from the mainland’s English-language press (selected from 47 articles) serve to underscore this analysis. These articles were published between 2015 and July 2018, that is, from the announcement of the reform until its initial implementation. This article will refer to the timeline of the reform with respect to several key moments and questions that require particular attention.

The endangered northern bettong,Bettongia tropica, performs a unique and potentially irreplaceable dispersal function for ectomycorrhizal truffle fungi

Organisms that are highly connected in food webs often perform unique and vital functions within ecosystems. Understanding the unique ecological roles played by highly connected organisms and the consequences of their loss requires a comprehensive understanding of the functional redundancy amongst organisms. One important, yet poorly understood, food web is that between truffle-forming ectomycorrhizal fungi and their mammalian consumers and dispersers. Mammalian fungal specialists rely on fungi as a food source, and they consume and disperse a higher diversity and abundance of fungi than do mycophagous mammals with generalist diets. Therefore, we hypothesize that mammalian fungal specialists are functionally distinct because they disperse a set of fungal taxa not fully nested within the set consumed by the combined generalist mammalian community (i.e., functional redundancy of fungal dispersal is limited). Using high-throughput sequencing, we compared the fungal composition of 93 scats from the endangered fungal specialist northern bettong (Bettongia tropica) and 120 scats from nine co-occurring generalist mammal species across three sites and three seasons. Compared with other generalist mammals, B.tropica consumed a more diverse fungal diet with more unique taxa. This aligns with our hypothesis that B.tropica performs a unique dispersal function for ectomycorrhizal truffle fungi. Additionally, modelling of mammalian extinctions predicted rapid loss of food web connections which could result in loss of gene flow for truffle taxa. Our results suggest that this system is sensitive to the extinction of highly connected specialist species like B.tropica and their loss could have consequences for ectomycorrhizal truffle fungal diversity. This suggests that the conservation of fungal specialists is imperative to maintaining ectomycorrhizal fungal diversity and healthy plant-mycorrhizal relationships.

Extinctions of interactions: quantifying a dung beetle–mammal network

AbstractLoss of large‐bodied mammals across the globe through hunting, habitat degradation, and fragmentation is one of the most significant anthropogenic impacts on the environment. Cascading effects of these extinctions through ecosystems have been little studied, although correlative studies have revealed co‐extinctions in closely linked groups, with implications for ecosystem structure and function. Despite playing important roles in seed dispersal and hence seedling recruitment, mammals have been largely neglected in network studies. Similarly, the role of secondary seed dispersers, such as ants and dung beetles, has been largely unexplored. Most dung beetles rely on mammal feces for feeding and breeding and provide a suite of important ecosystem functions and services. While dung beetle community responses to environmental change have been widely investigated, studies quantifying the network of associations between dung beetle and mammal species are lacking. By developing the first quantitative mammal–dung beetle networks, we address several important knowledge gaps contributing to the understanding of how interactions in networks involving mammals and secondary insect seed dispersers are structured. We use the resulting quantitative interaction networks to model mammal species extinction scenarios to further explore the consequences for dung beetle populations, and the extent to which networks change the strength of interactions through resource switching. Dung beetle feeding and breeding networks did not differ significantly in structure and showed high nestedness and low levels of trophic specialization. Simulations suggested that mammal extinction scenarios based on mammal body mass and mammal dung volume will impact dung beetle populations to a greater extent than random scenarios of mammal loss. Thus, despite their generalist feeding preferences, realistic mammal extinction scenarios have the potential to negatively impact the dung beetle community, which may have consequences for ecosystem functioning.

Three flaws in defining a formal ‘Anthropocene’

The Anthropocene Working Group (AWG) of the Subcommission of Quaternary Stratigraphy of the International Commission on Stratigraphy is moving toward recommending that the start of a formally designated ‘Anthropocene’ epoch be placed in the middle-to-late 1900s. This article summarizes three objections to this possible action. First, major human alterations of Earth’s environment long preceded the 1900s: extinction of most Australian and American mammals; extensive deforestation of arable regions around the globe; creation of extensive anthropogenic wetlands for rice irrigation; and, in recent centuries, plowing of prairies and steppes for conversion to croplands. Second, the formal chronostratigraphic rules followed by the AWG reject any recognition of these early changes a priori: the very rapid pulse-like extinctions because they were ‘merely’ continent-wide, and forest clearance, rice irrigation, and prairie plowing because they developed time-transgressively. Third, the classical approach the AWG follows – adding subdivisions to the standard Geologic Column – is largely disregarded today among scientists working in the younger geologic record, as is apparent from the rare mention of the Pleistocene subdivisions in paleoclimate textbooks. For these reasons, the use of an informal, flexible ‘anthropocene’ is preferable to the constraints that would be imposed by defining a formal ‘Anthropocene’.