Extinction in the Anthropocene.

Ecosystems have been modified by human activities for millennia, and insights about ecology and extinction risk based only on recent data are likely to be both incomplete and biased. We synthesize multiple long-term archives (over 250 archaeological and palaeontological sites dating from the early Holocene to the Ming Dynasty and over 4400 historical records) to reconstruct the spatio-temporal dynamics of Holocene–modern range change across China, a megadiverse country experiencing extensive current-day biodiversity loss, for 34 mammal species over three successive postglacial time intervals. Our combined zooarchaeological, palaeontological, historical and current-day datasets reveal that both phylogenetic and spatial patterns of extinction selectivity have varied through time in China, probably in response both to cumulative anthropogenic impacts (an ‘extinction filter’ associated with vulnerable species and accessible landscapes being affected earlier by human activities) and also to quantitative and qualitative changes in regional pressures. China has experienced few postglacial global species-level mammal extinctions, and most species retain over 50% of their maximum estimated Holocene range despite millennia of increasing regional human pressures, suggesting that the potential still exists for successful species conservation and ecosystem restoration. Data from long-term archives also demonstrate that herbivores have experienced more historical extinctions in China, and carnivores have until recently displayed greater resilience. Accurate assessment of patterns of biodiversity loss, and the likely predictive power of current-day correlates of faunal vulnerability and resilience, is dependent upon novel perspectives provided by long-term archives.

AimTo establish a chronology for late Quaternary avian extinction, extirpation and persistence in the Bahamas, thereby testing the relative roles of climate change and human impact as causes of extinction.LocationGreat Abaco Island (Abaco), Bahamas, West Indies.MethodsWe analysed the resident bird community as sampled by Pleistocene (> 11.7 ka) and Holocene (< 11.7 ka) fossils. Each species was classified as extinct (lost globally), extirpated (gone from Abaco but persists elsewhere), or extant (still resident on Abaco). We compared patterns of extinction, extirpation and persistence to independent estimates of climate and sea level for glacial (late Pleistocene) and interglacial (Holocene) times.ResultsOf 45 bird species identified in Pleistocene fossils, 25 (56%) no longer occur on Abaco (21 extirpated, 4 extinct). Of 37 species recorded in Holocene deposits, 15 (14 extirpated, 1 extinct; total 41%) no longer exist on Abaco. Of the 30 extant species, 12 were recovered as both Pleistocene and Holocene fossils, as were 9 of the 30 extirpated or extinct species. Most of the extinct or extirpated species that were only recorded from Pleistocene contexts are characteristic of open habitats (pine woodlands or grasslands); several of the extirpated species are currently found only where winters are cooler than in the modern or Pleistocene Bahamas. In contrast, most of the extinct or extirpated species recorded from Holocene contexts are habitat generalists.Main conclusionsThe fossil evidence suggests two main times of late Quaternary avian extirpation and extinction in the Bahamas. The first was during the Pleistocene–Holocene transition (PHT; 15–9 ka) and was fuelled by climate change and associated changes in sea level and island area. The second took place during the late Holocene (< 4 ka, perhaps primarily < 1 ka) and can be attributed to human impact. Although some species lost during thePHTare currently found where climates are cooler and drier than in the Bahamas today, a taxonomically and ecologically diverse set of species persisted through that major climate change but did not survive the past millennium of human presence.

The faunal succession of Japanese Quaternary mammals is described within the stratigraphic framework provided mainly by KAMEI, KAWAMURA and TARUNO (1988). Descriptions are given separately for Hokkaido, Honshu-Shikoku-Kyushu and the Ryukyu Islands.In Hokkaido, Pleistocene mammalian remains are too scarce to provide a detailed faunal succession, but abundant remains of Holocene age suggest that the fauna was almost identical to that of the present day. Large mammals recorded for the Late Pleistocene are therefore considered to have been extinct by the Holocene.In Honshu-Shikoku-Kyushu, the Early Pleistocene fauna is of temperate forest type, and related to those of north China. Almost all the components are, however, assigned to extinct endemic species. The Middle Pleistocene fauna is characterized by the presence of extant species. In fact, they exceed half of the components in the middle Middle Pleistocene fauna, and are still more common in the later faunas. This fauna is also dominated by temperate forest elements and endemic species. Immigration from south China in the middle Middle Pleistocene is more limited than previously thought, and only a few forms migrated from north and northeast China in the late Middle Pleistocene. The Late Pleistocene fauna is basically identical with that of the Middle Pleistocene except for the absence of several extinct species and several exotic species which still survive in other regions. Although the fauna seems to have been isolated from those of the adjacent continent in the early Late Pleistocene, immigration of large herbivores from the northern part of the continent was recognized in the late Late Pleistocene. Most of the extinct and exotic species were eliminated from the fauna between 20, 000 and 10, 000 years BP, and thus the fauna became almost identical with that of the present day by the early Holocene.In the Ryukyu Islands, Early and Middle Pleistocene faunas are almost unknown, while Late Pleistocene and Holocene ones are relatively well recorded. The Late Pleistocene fauna is of insular type, and includes several species endemic to the islands. Some of them are extinct species. From the end of the Pleistocene to the Holocene, insularity of the fauna was enhanced by the extinction of major species and by extreme reduction in habitat areas of the survivors.

Human activity has dramatically accelerated both species extinctions and introductions, and the balance of these two processes is generally expected to reduce biodiversity and increase taxonomic homogenization. However, few tests of this hypothesis have been made. We tested whether new macroinvertebrate invaders in North American freshwaters can replace the recent loss of biodiversity, particularly focusing on molluscs. We found that both crustaceans and molluscs are overrepresented among endangered and recently extinct species, as well as among invaders. For molluscs, the number of recently extinct species (79 species) was more than twice that for exotic species (38 species). In addition, molluscan invaders are from different taxonomic families than recently extinct or endangered species. While most extinct and endangered molluscs are from streams and rivers, invaders preferentially colonize lakes and reservoirs. The impact of humans on species introductions and extinctions increases with spatial scale (from local to continental scales), resulting in the increased phylogenetic dissimilarity between introduced species and native communities. Construction of dams and alteration of the flow regimes of lotic systems will continue to lead to the extinction of native species, and promote the spread of invaders, resulting in a loss of biodiversity and taxonomic homogenization.

A simple quantitative approach is presented for determining the relative importance of climate change and human impact in driving late Quaternary megafaunal extinctions. This method is designed to determine whether climate change or human impact alone can account for these extinctions, or whether both were important, acting independently (additively) and/or synergistically (multiplicatively). This approach is applied to the megafaunal extinction in the Última Esperanza region of southern Chile. In this region, there is a complex pattern of extinction. Records of environmental change include temperature proxies and pollen records that capture the transition from cold grasslands to warmer, moister forests, as well as evidence of initial human arrival. Uncertainty in extinction times and time of human arrival complicates the analysis, as does uncertainty about the size of local human populations, and the nature, strength, and persistence of their impacts through the late Pleistocene and early Holocene. Results of the Ultima Esperanza analysis were equivocal, with evidence for climate- and human-driven extinction, with each operating alone or additively. The results depend on the exact timing of extinctions and human arrival, and assumptions about the kinds of pressures humans put on the megafauna. There was little evidence for positive synergistic effects, while the unexpected possibility of negative synergistic interactions arose in some scenarios. Application of this quantitative approach highlights the need for higher precision dating of the extinctions and human arrival, and provides a platform for sharpening our understanding of these megafaunal extinctions.

Due to the dramatic biodiversity crisis, it is crucial to understand how people perceive biodiversity. Knowledge of how thoughts are organized around this concept can identify which ideas are best to focus on biodiversity conservation information campaigns. The primary aim of the present study was to identify social representations of the German public regarding the concept of biodiversity and its loss using a free word association test. Furthermore, unique association networks were analyzed. For this purpose, data collection was performed in September 2021 in Germany using an online questionnaire to assess participants' associations with the prompt "biodiversity" (n = 131) and "biodiversity loss" (n = 130). Additionally, we used the social network software Gephi to create biodiversity (loss) association networks. The five most commonly mentioned associations for biodiversity were "animal," "plant," "nature," "human," and "flower." For biodiversity loss, the five most commonly mentioned associations were "species extinction," "climate change," "plant," "insect," and "bee." Neither "land use change" nor "invasive species," as key drivers of biodiversity loss, were present in social representations of the German public. A difference was observed in the total number of mentioned associations between biodiversity and biodiversity loss. For both, the associations "plant" and "animal" were related. However, participants associated specific taxa only with animals, such as "insects" and "birds." For plants, no specific taxa were named. Based on the network analysis, the most commonly mentioned word pairs for biodiversity and biodiversity loss were "plant - animal" and "species loss - climate change," respectively. Based on our statistical network analysis, these associations were identified as the most central associations with the greatest influence in the network. Thus, they had the most connections and the function of predicting the flow in the network. In sum, the public's multifaceted views on biodiversity and its loss, as well as the aforementioned central associations, hold great potential to be utilized more for the communication and education of biodiversity conservation. In addition, our findings contribute to the scientific community's understanding of social representations and perceptions of biodiversity and its loss.

The Ecuadorian Andes in northwestern South America are well known for being among the hot spots of global vascular plant diversity due to their complex topography (uplift of the mountain chain), varying climatic conditions and different vegetation types. Despite its high biodiversity level, the Ecuadorian Andes represent a most threatened and poorly studied landscape. Especially the páramo and mountain ecosystems are subject to overgrazing, burning, cultivation and deforestation caused by the expansion of human activity during the last decades. The knowledge of palaeoecology and landscape dynamics is important in order to understand past processes that played a major role in the development of the ecosystems and Ecuadorian landscapes of today. Nevertheless only a limited number of palaeoecological studies are available from the Ecuadorian Andes. This thesis presents palynological analyses carried out at three different sites in the central and southern Ecuadorian Andes region to better understand the past vegetation changes, climate and fire dynamics as well as human impact since the late Pleistocene. The analysis of the sediment core El Cristal, located on the eastern slope at the Protective Forest Corazón de Oro in southeastern Ecuador reveals changes in the vegetation distribution, climate, fire regime and human impact since late Pleistocene. During the late Pleistocene mountain forest was the main vegetation type. In particular, there is evidence of a Polylepis forest which does not occur today. Nevertheless there is also evidence of relatively high proportion of páramo, which suggest that an open mountain forest occupied the region. The presence of páramo taxa during the late Pleistocene, points to an upper forest line (UFL) at a markedly lower elevation. The transition from the late Pleistocene to the early mid-Holocene was characterized by mountain forest and a stable proportion of páramo vegetation. However, after ca. 4000 cal yr BP, the Polylepis forest decreased, probably because of an increase in fire frequency. During the mid- to late Holocene the composition of the vegetation changed. The mountain forest was less frequent and the páramo vegetation expanded. Higher proportions of Asteraceae and Muehlenbeckia/Rumex (since ca. 1380 cal yr BP) reflect landscape disturbance probably by human impact. Fires were recorded throughout the late Pleistocene but were more frequent during the wetter late Holocene, which suggests that they were of anthropogenic origin. The pollen record from Cajanuma valley, in the western slope at the Podocarpus National Park, southern Ecuador, reveals environmental changes since the late Glacial. During the late Glacial, herb páramo rich in Poaceae, Cyperaceae and Gentianaceae covered the area. The UFL occurred at a much lower elevation than today. The early to mid-Holocene is characterized by partial replacement of treeless páramo by a mountain forest (Symplocos taxa), which moves into higher elevations where it is today. During the mid- to late Holocene there is evidence of a vegetation change. The páramo re-expanded with the dominance of Poaceae and high presence of Huperzia and Cyatheaceae. During the late Holocene páramo was the main vegetation type that covered the area. Fires became frequent since the late Holocene. The Anteojos valley pollen record, which is located in the western slope at the Llanganates National Park, central Ecuadorian Andes, yields a detailed environmental reconstruction of the past ca. 4100 years. Páramo vegetation had a dominant and stable occurrence in the study area (Poaceae, Cyperaceae and Asteraceae); especially between ca. 4100 to 3100 cal yr BP. Between ca. 3100 to 2100 cal yr BP páramo decreased followed by a slight expansion of mountain forest (Moraceae/Urticaceae, Trema, Celtis and Macrocarpaea). From ca. 2100 cal yr BP to the present páramo once again became more frequent with stable occurrence of mountain forest taxa. Low frequencies of fires were evidenced throughout the record but there is evidence of a slight increase during ca. 4100 to 3100 cal yr BP.

Global biodiversity is disappearing at an alarming rate. Habitat loss, fragmentation, habitat degradation, direct pressures like hunting and other extractive human uses are all contributing to the loss of biodiversity, which in turn are leading to the loss of vital ecosystem services. Different conservation strategies have been proposed for arresting this loss of biodiversity in tropical countries, through establishment of protected areas of various types. In India, a model based on ‘wildlife preservation’ under state ownership of protected areas is predominant. However, alternative models based on community ownership and sustainable resource use by local people are also being advocated for preserving biodiversity. However, a practical problem in evaluating such broad, generic alternative models of wildlife is that these are not locally context-specific or sufficiently evidence-based. We examined human impacts on different forms of biodiversity under different levels of local access, degree of state protection and legal and illegal resource extraction regimes in a conservation landscape in Nagarahole, southern India. We applied current and rigorous sampling, modeling and estimation approaches to assess the status of three components of biodiversity, namely plants, birds and mammals, across three ecologically similar areas that differed only in terms of access and human impact characteristics. Different levels of human disturbance and environmental variables altered species composition, richness, diversity and abundance of plants, birds and mammals. These impacts were generally negative on a wide range of taxonomic groups. Estimated values of species richness and abundance of plants and birds were higher for highly protected and moderately protected areas compared to least protected areas. Strict protected areas were particularly important for galliformes and omnivores, while moderately protected areas were important for insectivores, granivores and insecti-frugivores, amongst birds. We also showed that the loss of bird guilds have serious consequences on seed dispersal, forest growth and regeneration. Abundance estimates for terrestrial mammals were substantially higher for highly protected and moderately protected areas. These differences were particularly evident for arboreal mammals. Decline in mammalian abundance recorded in the present study are likely to have cascading effects on overall structure and functioning of these forests. Through these results, we discuss the relevance of the ‘wildlife preservation’ approach to conserving varied forms of biodiversity particularly within human-dominated landscapes of India.

Connectance indicates the robustness of food webs when subjected to species loss

Climate change and humans are proposed as the two key drivers of total extinction of many large mammals in the Late Pleistocene and Early Holocene, but disentangling their relative roles remains challenging owing to a lack of quantitative evaluation of human impact and climate-driven distribution changes on the extinctions of these large mammals in a continuous temporal-spatial dimension. Here, our analyses showed that temperature change had significant effects on mammoth (genus Mammuthus), rhinoceros (Rhinocerotidae), horse (Equidae) and deer (Cervidae). Rapid global warming was the predominant factor driving the total extinction of mammoths and rhinos in frigid zones from the Late Pleistocene and Early Holocene. Humans showed significant, negative effects on extirpations of the four mammalian taxa, and were the predominant factor causing the extinction or major extirpations of rhinos and horses. Deer survived both rapid climate warming and extensive human impacts. Our study indicates that both the current rates of warming and range shifts of species are much faster than those from the Late Pleistocene to Holocene. Our results provide new insight into the extinction of Late Quaternary megafauna by demonstrating taxon-, period- and region-specific differences in extinction drivers of climate change and human disturbances, and some implications about the extinction risk of animals by recent and ongoing climate warming.

The integration of Geographic Information System (GIS) methodology within a phylogenetic and statistical framework provides a background against which to evaluate the relationship between biogeographic changes and evolution in the fossil record. A case study based on patterns in Middle and Late Devonian phyllocarids (Crustacea) illustrates the usefulness of this integrated approach. Using a combined approach enhances determination of rates of biodiversity change and the relationship between biogeographic and evolutionary changes. Because the interaction between speciation and extinction rates fundamentally determines biodiversity dynamics, and speciation and extinction rates are influenced by the geographic ranges of component taxa, the relationship between biogeography and evolution is important. Furthermore, GIS makes it possible to quantify paleobiogeographic ranges.Phylogenetic biogeography resolved patterns of both vicariance and geodispersal and revealed that range expansions were more abundant than range contractions in Devonian phyllocarids. In addition, statistical tests on GIS-constrained species ranges and evolutionary-rate data revealed a relationship between increasing species' ranges and increases in both speciation and extinction rates. Extinction rate, however, increased more rapidly than speciation rate in the phyllocarids. The pattern of extinction rate increasing faster than speciation rate in the phyllocarids may illuminate aspects of the Late Devonian biodiversity crisis in particular, and protracted biodiversity crises in general.

Biodiversity crunch

To understand the current biodiversity crisis, it is crucial to determine how humans have affected biodiversity in the past. However, the extent of human involvement in species extinctions from the Late Pleistocene onward remains contentious. Here, we apply Bayesian models to the fossil record to estimate how mammalian extinction rates have changed over the past 126,000 years, inferring specific times of rate increases. We specifically test the hypothesis of human-caused extinctions by using posterior predictive methods. We find that human population size is able to predict past extinctions with 96% accuracy. Predictors based on past climate, in contrast, perform no better than expected by chance, suggesting that climate had a negligible impact on global mammal extinctions. Based on current trends, we predict for the near future a rate escalation of unprecedented magnitude. Our results provide a comprehensive assessment of the human impact on past and predicted future extinctions of mammals.

After the launch of the Global Assessment of the Intergovernmental Platform for Biodiversity and Ecosystem Services (IPBES) in May 2019, the message that 1 million species are threatened with extinction made headlines in news and social media across the world. These headlines also resulted in critical responses that questioned the credibility of this number and – by extension – the Global Assessment report and the institution of IPBES. In this article, we – as two authors of the Global Assessment – draw lessons from the GA about how to represent biodiversity in assessments and how biodiversity knowledge can inform effective and legitimate actions that contribute to conservation as well as equity, justice, and human well-being. Specifically, we highlight the inherent multiplicity of meanings and definitions of biodiversity to reflect on the limitations of using species richness and extinction as proxies for biodiversity and biodiversity loss. It is crucial to communicate clearly and in a balanced way that biodiversity loss is broader than species extinction, and how this broader loss of biodiversity jeopardises human wellbeing irrespective of whether species die out. Consequently, the post-2020 biodiversity framework will require multiple targets around not only species extinction but also broader biodiversity loss and human well-being.

We investigate changes in small-mammal richness and diversity in southwestern Europe (Iberian Peninsula) during the late Pleistocene–Holocene transition in order to evaluate whether they follow a climatic pattern or are predominantly determined by human impact, especially after the emergence of agriculture in the Neolithic period. We selected 6 late Pleistocene and Holocene sites that correspond to 18 different layers dated to between ca. 22 and 3 kyr B.P. Using indices of species richness and evenness diversity, we show that climate played an important role at some sites during the late Pleistocene and at the beginning of the Holocene, in that the richness and diversity of small mammals were closely related to the mean annual temperatures and landscape changes, and varied according to the different climatic fluctuations detected (Heinrich Event 1, Bolling-Allerod, and Preboreal-Boreal). However, at the beginning of the mid-Holocene, the small-mammal richness and diversity no longer seem to follow any kind of climatic pattern, and the observed changes in some studied sites are more closely related to human activities. By contrast with similar studies carried out in other parts of the world, the changes in diversity in the Iberian Peninsula do not seem to follow a constant pattern during the late Pleistocene and beginning of the Holocene. Some of the changes detected appear to be related to climate (late Pleistocene), and others appear to be related to human influence (Holocene) on the landscape.