Drivers Of Extinction Research Articles

Simultaneous extinction of Madagascar's megaherbivores correlates with late Holocene human-caused landscape transformation

Reconstructing the dynamics and drivers of late Quaternary megafaunal extinctions requires direct radiometric date series that are assessed within probabilistic statistical frameworks. Extinction chronologies are poorly understood for many tropical regions, including Madagascar, which had a diverse, now-extinct Holocene large vertebrate fauna including a “megaherbivore” guild of endemic hippopotami and elephant birds. Madagascar's megaherbivores likely played vital roles in regulating ecosystem structure and nutrient cycling, but few direct dates are available for megaherbivore specimens identified to species level, with uncertainty over when and why different representatives of this guild disappeared. Here, we conduct a new investigation into Malagasy megaherbivore extinction dynamics, including 30 new AMS dates and 63 audited published dates. We use Gaussian-resampled inverse-weighted McInerny (GRIWM) analysis to estimate species-specific extinction dates for three elephant bird species (Aepyornis hildebrandti, Mullerornis modestus, Vorombe titan), eggshell representing Aepyornis or Vorombe, and two hippo species (Hippopotamus lemerlei, H. madagascariensis), and to estimate extinction dates for megaherbivore communities in different biomes. Megaherbivores persisted for millennia after first human arrival. Extinction date estimates vary significantly between biomes, with disappearance from dry deciduous forest over a millennium earlier than other biomes, possibly reflecting local variation in megaherbivore population densities or human pressures. However, megaherbivore communities including all elephant bird and hippo species persisted elsewhere across Madagascar until ∼1200-900 bp, when they collapsed suddenly. Extinctions are closely correlated in time with intensive conversion of forests to grassland at ∼1100-1000 bp, probably associated with a shift to agro-pastoralism and representing a radical change in sustainability of prehistoric human interactions with biodiversity.

The Dynamics of Diachronous Extinction Associated With Climatic Deterioration Near the Neogene/Quaternary Boundary

AbstractTo predict extinction, we must understand the processes leading to terminal population decline. Once a critical threshold of population size is reached, small environmental perturbations can push a species over the cliff‐edge to extinction, so the main drivers of extinction are the factors that cause the initial reduction in population size. Most studies of population decline leading up to extinction focus on modern species in a human‐dominated world. The drivers of population decline leading to non‐human mediated extinctions are less well known but changes in climate are arguably the most widely invoked mechanism. Here, we report data on >16,000 individuals of the planktonic foraminifer Globoconella puncticulata from six sites in the Atlantic Ocean along an 83 degree‐long latitudinal transect, over a 600,000‐years interval leading up to the species’ global extinction during the late Pliocene‐earliest Pleistocene intensification of Northern Hemisphere glaciation. We show changes in geographic range, abundance, and body size. We find that populations do not follow a North‐to‐South sequence in extinction as Earth cooled and developed large ice sheets in the high latitudes of the Northern Hemisphere. Instead, our results suggest that (a) populations are differentially adapted to local environmental conditions such as nutrient availability, (b) population dynamics in core populations differ from those at the edge of their range, and (c) individual population responses to external pressures are essential to understanding the drivers of global extinction. Our study demonstrates the potential to transform our understanding of extinction dynamics through spatially replicated sampling of the highly resolved marine microfossil record.

Ancient DNA from bulk bone reveals past genetic diversity of vertebrate fauna on Kangaroo Island, Australia

It is indisputable that much of Australia's modern biodiversity decline was triggered by European settlement. However, the driver(s) of pre-European extinctions and extirpations are more challenging to identify, particularly on islands where animals are faced with the additional pressures imposed by isolation. Kangaroo Island, South Australia, has been identified as a potential haven for the reintroduction of endangered animals, but the genetic relationship between reintroduction candidates on the mainland and their extinct relatives on Kangaroo Island is poorly understood. Here, we present a late Pleistocene to mid-Holocene genetic record from Kangaroo Island based on bulk bone metabarcoding of two thousand bone fragments excavated from Kelly Hill Cave. We detect 33 species of bird, reptile, fish and mammal and report additional intra-specific genetic diversity in Kangaroo Island's now extinct population of spotted-tailed quoll. Furthermore, we provide genetic evidence that the Eastern grey kangaroo formerly inhabited Kangaroo Island. Taken together, these data establish a more complete baseline of local biodiversity against which reintroduction programmes and bushfire recovery measures can be evaluated, which is more important than ever in light of the recent fires that devastated much of Kangaroo Island's flora and fauna.

Demography reveals populational expansion of a recently extinct Iberian ungulate

Reconstructing the demographic history of endangered taxa is paramount to predict future fluctuations and disentangle the contributing factors. Extinct taxa or populations might also provide key insights in this respect by means of the DNA extracted from museum specimens. Nevertheless, the degraded status of biological material and the limited number of records may pose some constraints. For this reason, identifying all available sources, including private and public biological collections, is a crucial step forward. In this study, we reconstructed the demographic history based on cytochrome-b sequence data of the Pyrenean ibex (Capra pyrenaica pyrenaica), a charismatic taxon of the European wildlife that became extinct in the year 2000. Moreover, we built a database of the museum specimens available in public biological collections worldwide and genotyped a privately owned 140-year-old trophy from the Spanish Pyrenees to confirm its origin. We found that the population of the Pyrenean ibex underwent a recent expansion approximately 20,000 years ago, after which trophy hunting and epizootics triggered a relentless population decline. Our interpretations, based on the genetic information currently available in public repositories, provide a solid basis for more exhaustive analyses relying on all the new sources identified. In particular, the adoption of a genome-wide approach appears a fundamental prerequisite to disentangle the multiple contributing factors associated with low genetic diversity, including inbreeding depression, acting as extinction drivers.

Hunting practices and harvest of peccaries in the northern Paraguayan Dry Chaco

Overexploitation is a frequently cited driver of species extinction. Throughout the Neotropics, balancing traditional practices and the needs of local people with protection of rare or declining species is challenging, especially given low capacity for control by authorities. We conducted interviews with wildlife professionals and residents, along with a camera-based field survey of wildlife occurrence, to gain insight into recent population trends, relative abundance, and drivers of harvest for large mammals in the northern Dry Chaco of Paraguay including but not limited to, Defensores del Chaco National Park. Although the endangered Chacoan peccary (Catagonus wagneri) was preferred regardless of hunter motivation, harvests of all species appeared largely opportunistic, and limited to immediate family use due to a lack of market forces, and constraints on refrigeration capacity in the region. This pattern may soon change given rapid deforestation, and an associated and growing road network providing greater access both to wildlife resources and commercial bushmeat markets. Notably, public perception of abundance and trends for Chacoan peccary differed from professional opinions—likely due in part to greater use of areas along roads by C. wagneri compared to other, relatively more abundant species. This discordance may pose future challenges if harvest restrictions become a conservation necessity, especially during a process of essentially self-imposed voluntary limitations.

An analysis of the illegal bear trade in India

Throughout the range of bears in Asia, a combination of threats - loss of suitable habitat, increasing human conflict, illegal wildlife trade - are pushing bear populations towards extinction. But studies in Asia are showing that indiscriminate poaching and illegal trade are increasingly becoming the main driver of species extinctions. Here we examine seizure data and poaching incidents involving India’s bear species from 2009 to 2019 to assess the extent illegal wildlife trade is impacting bear populations in the country. The Wildlife Protection Society of India (WPSI) systematically collects data on poaching and seizures of protected species which is collated, categorised and stored in WPSI’s database on wildlife crime. Using this data, we assessed bear species impacted by trade, mapped out important trade and poaching hubs, and trade dynamics involving bears in India. Seizure data indicated the exploitation of Asiatic black bears for traditional medicine use while sloth bears were coveted for their skins. Poaching incidents predominantly involved sloth bears and steadily increased over the study period. However, it is unclear whether this is a result of targeted hunting of bears for trade, a threat possibly exacerbated by declining bear species elsewhere in Asia where demand still persists for bear gall bladder and parts; or in response to growing levels of human-bear conflict which is on the rise in India due to loss of suitable habitat and increasing human encroachment into forested areas. This study shows that despite being a strictly protected species in India, there is still a threat to bears from illegal trade. Greater effort is needed to protect bear habitat and reduce retaliatory killing of bears which impedes conservation efforts to reduce the illegal exploitation of bears for trade. Enforcement capacity and resources also need to be improved and must encompass intelligence-led investigations and cross-border cooperation between enforcement agencies to target buyers and traders. The trade in bears and their parts should be consistently monitored on a national scale to support effective law enforcement interventions and conservation initiatives to reduce the levels of poaching of bears in India.

Using conservation criminology to understand the role of restaurants in the urban wild meat trade

AbstractAt unsustainable rates and in illegal contexts, the wild meat trade is a driver of species extinction; it can also threaten ecosystem services, local food security and contribute to the risk of zoonotic disease spread. The restaurant and catering sectors are understudied groups in conservation, both with regards to the legal and illegal wild meat trade and particularly in urban areas. Restaurateurs are key actors between wild meat consumers and suppliers and thus play a central role in the supply chain. This study applied a crime science hot product approach to characterize: (a) restaurateur perceptions of urban wild meat consumption; (b) wildlife species most at risk in the urban wild meat trade; and (c) the differences between restaurants in Kinshasa (Democratic Republic of the Congo) and Brazzaville (Republic of the Congo). Through focus groups in both cities, participants affirmed that in urban centers wild meat is considered a luxury item and sign of wealth. Monkeys were seen as a hot product in both cities, but we found a greater variety of hot wild meat products in Brazzaville. When looking at the differences between the restaurant tier levels, middle‐tiered restaurants identified pangolin and antelopes as being hot products, rather than monkeys as with upper and lower‐tiered restaurants. By applying a hot product analysis, we identified the wild meat groups most likely to be targeted by the urban wild meat trade. Findings herein offer novel opportunities to better tailor and prioritize conservation interventions against illegal trade using design against crime or other crime prevention strategies.

Pesticide-induced multigenerational effects on amphibian reproduction and metabolism

Underlying drivers of species extinctions need to be better understood for effective conservation of biodiversity. Nearly half of all amphibian species are at risk of extinction, and pollution may be a significant threat as seasonal high-level agrochemical use overlaps with critical windows of larval development. The potential of environmental chemicals to reduce the fitness of future generations may have profound ecological and evolutionary implications. This study characterized effects of male developmental exposure to environmentally relevant concentrations of the anti-androgenic pesticide linuron over two generations of offspring in Xenopus tropicalis frogs. The adult male offspring of pesticide-exposed fathers (F1) showed reduced body size, decreased fertility, and signs of endocrine system disruption. Impacts were further propagated to the grand-offspring (F2), providing evidence of transgenerational effects in amphibians. The adult F2 males demonstrated increased weight and fat body palmitoleic-to-palmitic acid ratio, and decreased plasma glucose levels. The study provides important cross-species evidence of paternal epigenetic inheritance and pollutant-induced transgenerational toxicity, supporting a causal and complex role of environmental contamination in the ongoing species extinctions, particularly of amphibians.

Three-dimensional geometric morphometric analysis of the skull of Protoceratops andrewsi supports a socio-sexual signalling role for the ceratopsian frill.

Socio-sexual selection is predicted to be an important driver of evolution, influencing speciation, extinction and adaptation. The fossil record provides a means of testing these predictions, but detecting its signature from morphological data alone is difficult. There are, nonetheless, some specific patterns of growth and variation which are expected of traits under socio-sexual selection. The distinctive parietal-squamosal frill of ceratopsian dinosaurs has previously been suggested as a socio-sexual display trait, but evidence for this has been limited. Here, we perform a whole-skull shape analysis of an unprecedentedly large sample of specimens of Protoceratops andrewsi using a high-density landmark-based geometric morphometric approach to test four predictions regarding a potential socio-sexual signalling role for the frill. Three predictions—low integration with the rest of the skull, significantly higher rate of change in size and shape during ontogeny, and higher morphological variance than other skull regions—are supported. One prediction, sexual dimorphism in shape, is not supported, suggesting that sexual differences in P. andrewsi are likely to be small. Together, these findings are consistent with mutual mate choice or selection for signalling quality in more general social interactions, and support the hypothesis that the frill functioned as a socio-sexual signal in ceratopsian dinosaurs.

Endemic Juniperus Montane Species Facing Extinction Risk under Climate Change in Southwest China: Integrative Approach for Conservation Assessment and Prioritization.

Simple SummaryClimate change is one of the most significant drivers of habitat loss and species extinction, particularly montane endemic species such as Juniper trees, which are restricted to unique habitats. Therefore, assessing the impact of climate change on the extinction risk of species is a promising tool or guide for species conservation planning. The loss in species habitat due to global warming indicates the level of extinction or endangerment. Predictions of suitable habitats are outputs from assessment analysis. This will help conservationists discover new populations of endemic species and help raise the awareness of local people to save and rescue these endangered species.Climate change is an important driver of biodiversity loss and extinction of endemic montane species. In China, three endemic Juniperus spp. (Juniperus pingii var. pingii, J. tibetica, and J. komarovii) are threatened and subjected to the risk of extinction. This study aimed to predict the potential distribution of these three Juniperus species under climate change and dispersal scenarios, to identify critical drivers explaining their potential distributions, to assess the extinction risk by estimating the loss percentage in their area of occupancy (AOO), and to identify priority areas for their conservation in China. We used ensemble modeling to evaluate the impact of climate change and project AOO. Our results revealed that the projected AOOs followed a similar trend in the three Juniperus species, which predicted an entire loss of their suitable habitats under both climate and dispersal scenarios. Temperature annual range and isothermality were the most critical key variables explaining the potential distribution of these three Juniperus species; they contribute by 16–56.1% and 20.4–38.3%, respectively. Accounting for the use of different thresholds provides a balanced approach for species distribution models’ applications in conservation assessment when the goal is to assess potential climatic suitability in new geographical areas. Therefore, south Sichuan and north Yunnan could be considered important priority conservation areas for in situ conservation and search for unknown populations of these three Juniperus species.

How do habitat amount and habitat fragmentation drive time-delayed responses of biodiversity to land-use change?

Land-use change is a root cause of the extinction crisis, but links between habitat change and biodiversity loss are not fully understood. While there is evidence that habitat loss is an important extinction driver, the relevance of habitat fragmentation remains debated. Moreover, while time delays of biodiversity responses to habitat transformation are well-documented, time-delayed effects have been ignored in the habitat loss versus fragmentation debate. Here, using a hierarchical Bayesian multi-species occupancy framework, we systematically tested for time-delayed responses of bird and mammal communities to habitat loss and to habitat fragmentation. We focused on the Argentine Chaco, where deforestation has been widespread recently. We used an extensive field dataset on birds and mammals, along with a time series of annual woodland maps from 1985 to 2016 covering recent and historical habitat transformations. Contemporary habitat amount explained bird and mammal occupancy better than past habitat amount. However, occupancy was affected more by the past rather than recent fragmentation, indicating a time-delayed response to fragmentation. Considering past landscape patterns is therefore crucial for understanding current biodiversity patterns. Not accounting for land-use history ignores the possibility of extinction debt and can thus obscure impacts of fragmentation, potentially explaining contrasting findings of habitat loss versus fragmentation studies.

Introduction to volcanism in Antarctica: 200 million years of subduction, rifting and continental break-up

Antarctica has undergone several important phases of volcanism throughout its long history. It was formerly at the heart of Gondwana but, from early Jurassic time ( c. 200 Ma), it commenced the prolonged process of disintegration, which resulted in the dispersal and final disposition of the southern hemisphere continents that we are familiar with today (Veevers 2012; Storey and Granot 2021 ). As a consequence, volcanism has been particularly important in its construction and it is geographically widespread, although mainly located within West Antarctica (Fig. 1). Its effects have frequently been felt far outside of the continent. For example, it has been a driver of global mass extinctions (Burgess et al. 2015; Ernst and Youbi 2017) and it has potentially driven Antarctica climatically, and by implication the world, both into and out of glacials (Bay et al. 2006; McConnell et al. 2017). Conversely, Antarctica's volcanoes may have played a pivotal role in helping Life not only to survive multiple glacial episodes during the past few tens of millions of years but to undergo species diversification on the continent in spite of the dramatic climate variations (Fraser et al. 2014). Eruptions from Mount Erebus also represent a significant point source of gases and aerosols to the Austral polar troposphere, including affecting the ozone layer (Boichu et al. 2011; Zuev et al. 2015). Some of Antarctica's active volcanoes also have the potential to have a significant impact on southern hemisphere aviation (Geyer et al. 2017). Finally, Antarctica contains the world's largest and longest-lived glaciovolcanic province. The glaciovolcanic sequences contain a detailed record of the terrestrial Antarctic ice sheet going back to nearly 30 Ma and that record is now beginning to be tapped (e.g. Smellie et al. 2009; Smellie and Edwards 2016; Wilch et al. 2021 ). Despite these …

Late Quaternary megafaunal extinctions in India: How much do we know?

Understanding global patterns of late Quaternary megafaunal extinction is impeded by geographic variation in data quality and quantity. The magnitude, timing and drivers of megafaunal extinctions remain poorly understood for India, a region with a strong history of palaeontological research. We review available data for all putative extinct Indian megafaunal taxa with direct or indirect reported evidence of potential survival into the global “megafaunal extinction window” (from ∼50,000 years onwards). Assessment of late Quaternary megafaunal species richness is confused by multiple levels of taxonomic uncertainty, including the relationship of named Late Pleistocene taxa to extant taxa, and nomenclatural confusion over correct species names. There is sufficient evidence to recognise up to four genuine global megafaunal species-level extinctions in India during the Late Pleistocene: two proboscideans (Palaeoloxodon namadicus, Stegodon sp.), a hippopotamus (Hexaprotodon sp.), and possibly a horse (Equus namadicus). A fifth extinct megafaunal species, the Indian aurochs Bos [primigenius] namadicus, definitely persisted into the Holocene. Other Indian late Quaternary megafaunal species (Rhinoceros spp., Bubalus palaeindicus, Sus “palaeindicus”, Crocodylus palaeindicus) are likely to be synonyms of extant species. Reconstructing regional extinction dynamics is further impeded by chronological uncertainty; however, attempts to obtain new dates for vertebrate samples from six late Quaternary sites in five regions were unsuccessful. Accurate understanding of the dynamics of megafaunal extinctions in India will require robust taxonomic, chronological and palaeoecological data, and we encourage further investigation of the region’s rich late Quaternary record.

Victims of ancient hyperthermal events herald the fates of marine clades and traits under global warming.

Organismic groups vary non-randomly in their vulnerability to extinction. However, it is unclear whether the same groups are consistently vulnerable, regardless of the dominant extinction drivers, or whether certain drivers have their own distinctive and predictable victims. Given the challenges presented by anthropogenic global warming, we focus on changes in extinction selectivity trends during ancient hyperthermal events: geologically rapid episodes of global warming. Focusing on the fossil record of the last 300 million years, we identify clades and traits of marine ectotherms that were more prone to extinction under the onset of six hyperthermal events than during other times. Hyperthermals enhanced the vulnerability of marine fauna that host photosymbionts, particularly zooxanthellate corals, the reef environments they provide, and genera with actively burrowing or swimming adult life-stages. The extinction risk of larger sized fauna also increased relative to non-hyperthermal times, while genera with a poorly buffered internal physiology did not become more vulnerable on average during hyperthermals. Hyperthermal-vulnerable clades include rhynchonelliform brachiopods and bony fish, whereas resistant clades include cartilaginous fish, and ostreid and venerid bivalves. These extinction responses in the geological past mirror modern responses of these groups to warming, including range-shift magnitudes, population losses, and experimental performance under climate-related stressors. Accordingly, extinction mechanisms distinctive to rapid global warming may be indicated, including sensitivity to warming-induced seawater deoxygenation. In anticipation of modern warming-driven marine extinctions, the trends illustrated in the fossil record offer an expedient preview.

Determinants of Tubastraea coccinea invasion and likelihood of further expansion in the northern Gulf of Mexico

Invasive species have large economic and ecological impacts and are the leading driver of extinction for both plants and animals worldwide. In the USA, coral reefs, which provide $3.4 billion per year in ecosystem services, are impacted by invasive marine species. One such species is Tubastraea coccinea, which was the first scleractinia to invade the western Atlantic and recently has spread to natural reefs within the northern Gulf of Mexico (GoM). We document this recent invasion by compiling occurrence records, develop a species distribution model identifying important determinants of invasion, and project potential range expansion. Our results indicate T. coccinea currently is distributed along the GoM coast from the Florida Keys to southern Texas, with documented localities clustered ≈ 100 km off the Louisiana coast and ≈ 200 km off the Texas coast, and sparsely distributed elsewhere. Our species distribution model identified five environmental factors that together contribute > 99% to the overall model. These factors include two surface variables (mean pH and mean calcite, contributing ≈ 40%) and three benthic variables (maximum current velocity, minimum iron, and minimum dissolved oxygen, contributing ≈ 60%). Our model suggests potential habitat for range expansion is distributed mainly within the western portion of the northern GoM, with the highest probabilities of occurrence (0.8 < P < 1.0) clustered along the Texas and Louisiana coasts between 88 and 97° W (near the border between states).

Major volcanic eruptions linked to the Late Ordovician mass extinction: Evidence from mercury enrichment and Hg isotopes

Abstract The Late Ordovician mass extinction (LOME) was the second most severe Phanerozoic biodiversity crisis. While environmental deterioration and oceanographic changes associated with the Hirnantian glaciation have been frequently invoked as potential extinction drivers, recent evidence for a large igneous province eruption at that time has challenged this prevailing view. As such, the triggering and killing mechanisms of the LOME remain debated. Here we report mercury (Hg) concentrations, isotopic compositions, Hg/total sulfur (Hg/TS), and Hg/total organic carbon (Hg/TOC) in Late Ordovician limestone/black shale alternations from two successions in South China and Laurentia that straddled the paleoequator. Our results, in both areas, show multiple Hg enrichments before and during the LOME, suggesting a global, or at least a widespread increase in environmental Hg loading. The initial Hg enrichments occur in the mid-upper Katian units and are followed by additional Hg anomalies in the lower Hirnantian strata that coincide temporally with the first pulse of the LOME. Extremely high levels of Hg, Hg/TS, and Hg/TOC, with maximum values of 737 ng g−1, 633 ng g−1 Hg/wt% TS, and 167 ng g−1 Hg/wt% TOC, respectively, represent ~3–13 × background values, indicating increased Hg input to the ocean. The absence of mass-independent fractionation of Hg isotopes in the Hg-enriched intervals suggests a volcanic source for the observed Hg anomalies. The temporal coincidence of Hg anomalies with the extinction horizon in both continents suggests that extensive and widespread volcanism may have had global climatic and ecological impact, and was a primary trigger for prolonged and synergetic deterioration of Late Ordovician environment such as climate changes, ocean acidification, and anoxia, causing the LOME.

Using environmental DNA and occupancy modelling to estimate rangewide metapopulation dynamics

We demonstrate the power of combining two emergent tools for resolving rangewide metapopulation dynamics. First, we employed environmental DNA (eDNA) surveys to efficiently generate multiseason rangewide site occupancy histories. Second, we developed a novel dynamic, spatial multiscale occupancy model to estimate metapopulation dynamics. The model incorporates spatial relationships, explicitly accounts for non-detection bias and allows direct evaluation of the drivers of extinction and colonization. We applied these tools to examine metapopulation dynamics of endangered tidewater goby, a species endemic to California estuarine habitats. We analysed rangewide eDNA data from 190 geographically isolated sites (813 total water samples) surveyed from 2years (2016 and 2017). Rangewide estimates of the proportion of sites that were occupied varied little between 2016 (0.52) and 2017 (0.51). However, there was evidence of extinction and colonization dynamics. The probability of extinction of an occupied site (0.106) and probability of colonization of an unoccupied site (0.085) were nearly equal. Stability in site occupancy proportions combined with nearly equal rates of extinction and colonization suggests a dynamic equilibrium between the 2years surveyed. Assessment of covariate effects revealed that colonization probability increased as the number of occupied neighbouring sites increased and as distance between occupied sites decreased. We show that eDNA surveys can rapidly provide a snapshot of a species distribution over a broad geographic range and, when these surveys are paired with occupancy modelling, can uncover metapopulation dynamics and their drivers.

Climate change aggravates bog species extinctions in the Black Forest (Germany)

AbstractAimBogs and transition mires in Central Europe have undergone tremendous changes in the last decades, declining in spatial extent and favourable conservation status. However, species extinctions have been documented only rarely because of a lack of reliable floristic data. Here, we assessed species losses of bog complexes and analysed their potential drivers.LocationBlack Forest, Germany.MethodsWe made use of the unique situation that the majority of bogs in the Black Forest (124 sites) had been systematically surveyed from 1972 to 1980 and resurveyed the flora of the same sites between 2017 and 2020. In addition, we included further data from the preceding decades.ResultsOut of 88 species for which we compiled site occupancy data, two species went extinct in the whole study area and 37 decreased from 1972 to 2020, losing on average 33% of their initial frequency. In contrast, 46 species displayed a positive trend. While decreasing species were characteristic of raised bogs, moorland ponds and base‐rich mires, increasing species were typical of poor mires, fens and wet meadows. Species losses were higher at low elevation, pointing to increasing temperature increase and decreasing precipitation as main drivers of extinction, while habitat area, distance to the nearest site and land use played no significant role. The mean altitude at which extinctions of populations occurred increased with time. Assuming a continuation of the observed negative trends for declining bog species, our models predict the extinction of further ten species by 2045.Main ConclusionOur study highlights the value of systematic and comprehensive past biodiversity surveys to assess biodiversity change. We demonstrated that low‐mountain habitats have already suffered biodiversity loss as a result of climate change. There are only limited management options against rising temperatures and decreasing precipitation.

Environmental drivers of megafauna and hominin extinction in Southeast Asia.

Southeast Asia has emerged as an important region for understanding hominin and mammalian migrations and extinctions. High-profile discoveries have shown that Southeast Asia has been home to at least five members of the genus Homo1-3. Considerable turnover in Pleistocene megafauna has previously been linked with these hominins or with climate change4, although the region is often left out of discussions of megafauna extinctions. In the traditional hominin evolutionary core of Africa, attempts to establish the environmental context of hominin evolution and its association with faunal changes have long been informed by stable isotope methodologies5,6. However, such studies have largely been neglected in Southeast Asia. Here we present a large-scale dataset of stable isotope data for Southeast Asian mammals that spans the Quaternary period. Our results demonstrate that the forests of the Early Pleistocene had given way to savannahs by the Middle Pleistocene, which led to the spread of grazers and extinction of browsers-although geochronological limitations mean that not all samples can be resolved to glacial or interglacial periods. Savannahs retreated by the Late Pleistocene and had completely disappeared by the Holocene epoch, when they were replaced by highly stratified closed-canopy rainforest. This resulted in the ascendency of rainforest-adapted species as well as Homo sapiens-which has a unique adaptive plasticity among hominins-at the expense of savannah and woodland specialists, including Homo erectus. At present, megafauna are restricted to rainforests and are severely threatened by anthropogenic deforestation.

Human carnivory as a major driver of vertebrate extinction

Although a considerable part of the anthropogenic impacts on other species has been caused by our habit of eating other animals, little attention has been given to understanding and quantifying how human carnivory threatens biodiversity globally. Herein we review the anthropogenic threats to 1000 species randomly selected among more than 46,000 vertebrate entries in the IUCN Red List database. We identified the following mechanisms by which human carnivory (i.e., our habit of feeding on other animals and related products) negatively affects the world's vertebrates: two mechanisms related to predation (predation and bycatch), two to competition (prey depletion and persecution), one to biohazards (any negative impacts caused by livestock or alien species whose introduction is linked to human carnivory), four to environmental changes (destructive harvesting practices, livestock, agriculture, and climate change), and a miscellaneous category for processes more indirectly connected with our high trophic position. Our conservative estimate, which does not include livestock impacts via agriculture and climate change, reveals that about one-quarter of the world's vertebrates are threatened by at least one mechanism related to human carnivory, and that this proportion is higher than that attributable to other leading causes of biodiversity decline including agriculture, forestry, infrastructure, pollution, invasive species, energy production and mining, fire regime and water systems modifications, and climate change. Our results suggest that human carnivory is the major driver of the current biodiversity crisis, and we hope our findings may contribute to raise awareness about this fundamental yet overlooked aspect of human ecology.