Extinction Research Articles

Thermal homogenization of boreal communities in response to climate warming

Globally, rising temperatures are increasingly favoring warm-affiliated species. Although changes in community composition are typically measured by the mean temperature affinity of species (the community temperature index, CTI), they may be driven by different processes and accompanied by shifts in the diversity of temperature affinities and breadth of species thermal niches. To resolve the pathways to community warming in Finnish flora and fauna, we examined multidecadal changes in the dominance and diversity of temperature affinities among understory forest plant, freshwater phytoplankton, butterfly, moth, and bird communities. CTI increased for all animal communities, with no change observed for plants or phytoplankton. In addition, the diversity of temperature affinities declined for all groups except butterflies, and this loss was more pronounced for the fastest-warming communities. These changes were driven in animals mainly by a decrease in cold-affiliated species and an increase in warm-affiliated species. In plants and phytoplankton the decline of thermal diversity was driven by declines of both cold- and warm-affiliated species. Plant and moth communities were increasingly dominated by thermal specialist species, and birds by thermal generalists. In general, climate warming outpaced changes in both the mean and diversity of temperature affinities of communities. Our results highlight the complex dynamics underpinning the thermal reorganization of communities across a large spatiotemporal gradient, revealing that extinctions of cold-affiliated species and colonization by warm-affiliated species lag behind changes in ambient temperature, while communities become less thermally diverse. Such changes can have important implications for community structure and ecosystem functioning under accelerating rates of climate change.

Dental plate histology of †Ischyodus dolloi (Chondrichthyes, Holocephali), from Antarctica.

In contrast to other cartilaginous fishes (Chondrichthyes), the dentition of the Holocephali consists of six dental plates, four in the upper jaw (two vomerines and two palatines) and two in the lower jaw (mandibulars). While the microstructure of holocephalan dentition has been extensively studied in extant species, similar analyses in fossil taxa are less common. Here, we provide a detailed description and interpretation of the microanatomy and histology of dental plates of the extinct taxon †Ischyodus dolloi Leriche (Chimaeriformes: 'Edaphodontidae'). The study is based on two palatine and two mandibular plates from the Eocene of the Antarctic Peninsula. Our main objectives were to (1) identify the presence and distribution of different tissues; (2) analyze morphological diversity in hypermineralized structures (i.e., tritors) within the dental plates; (3) compare the microanatomy and histology of †I. dolloi with other living and fossil holocephalans; and (4) infer the sequence and mode of tissue formation within the plates. The dental plates are composed of an outer shell enclosing a framework of trabecular dentine, in which hypermineralized dentine (i.e., whitlockin) is deposited to form the tritors. Trabecular dentine becomes compacted by centripetal deposition of circumvascular dentine around vascular canals. The tritors exhibit two morphological types: tritoral rods (first report for 'Edaphodontidae') and tritoral pads. Additionally, a distinct tissue, which we term 'parallelitubular dentine', is formed in the aboral and symphyseal regions. Regarding the growth of dental plates, we identified a developmental pattern in which the full formation of tritors and complete compaction of trabecular dentine follows a mesial-to-lingual, oral-to-aboral, and labial-to-symphyseal sequence. This growth pattern aligns with the spatial order in which the dentinal tissues are progressively removed due to feeding-related wear.

Spatiotemporal patterns of diversity and diversity-stability relationships as a function of compounding disturbances and forest management

ContextConsistent with the diversity-stability hypothesis, high wildlife diversity has been associated with increased resilience and stability of ecosystem services and functions. Nevertheless, ecological non-stationarity associated with climate change challenges the concept of stability. Furthermore, ambiguity surrounding appropriate diversity metrics to use has hindered the ability of natural resource managers to leverage the potential benefits of biodiversity conservation.Objectives and methodsWe aimed to infer how diversity and compositional stability might be affected by multiple climate and disturbance stressors, including management activity.MethodsWe used a spatially explicit landscape succession model to predict spatiotemporal patterns of beta diversity for terrestrial vertebrates representing three trophic groups (herbivores, insectivores, and predators) over an 80-year time span.ResultsTrends in diversity were driven by species gains at higher elevations and species losses at lower elevations, however, species reorganization was modified by both mean species turnover (i.e. replacement of species across space) as well as management intensity. Higher species turnover was associated with greater among-site compositional stability and decreased local compositional change attributed to species losses for all trophic groups. Increasing management intensity further increased beta diversity across all elevations whereas decreasing management intensity led to spatial homogenization of herbivores and insectivores at low elevations. High management intensity also weakened naturally occurring diversity-stability relationships at larger spatial scales.ConclusionsIncreasing management intensity may be beneficial at lower elevations where projections anticipate species losses and homogenization. Additionally, conserving areas of high diversity will likely be important for promoting future compositional stability for trophic groups that support key ecological processes.

Variation in prey availability over time shaped the extinction dynamics of sabertoothed cats.

The role of ecological interactions and abiotic factors in shaping macroevolutionary patterns has been extensively debated. Yet, the effect of predator-prey interactions on diversification dynamics is unclear. Here, we test the influence of predator-prey interactions in the diversification of saber-toothed cats, a subfamily of felids (Felidae: Machairodontinae) that developed a highly specialized morphology, the notoriously long upper canines. This morphology has been associated with a high degree of trophic dependence on large prey, which is assumed as one of the main reasons for the group's demise. To test the hypothesis that prey availability affected the diversification of sabertooths we examined whether shifts in speciation and extinction rates were linked with changes in the species richness of their potential prey clades. The only association we detected was between the increase in extinction rates of North American sabertooths and the decline in Equidae richness. However, when accounting for the prey richness per species, regardless of taxonomic affiliation of the prey, we found that the endpoint of most sabertooth taxa occurred when prey richness for that taxon was at its lowest. Our analyses then suggested that reduced prey richness was associated with increased extinction risk. These results support the hypothesis that the extinction of sabertooths was associated with the decline in megafauna, but extend it to more remote times, millions of years before their final demise, suggesting that prey availability contributed to drive the diversification dynamics of the group. More broadly, our findings highlight the importance of ecological interactions in shaping macroevolutionary patterns.

PlaceMyFossils: An Integrative Approach to Analyze and Visualize the Phylogenetic Placement of Fossils Using Backbone Trees.

In recent years, there has been a growing interest in using morphology to establish the placement of species on phylogenetic trees derived from molecular data. This is relevant in the case of recently extinct or fossil species, which are usually represented only by fragmentary morphology. In the latter case, constrained analyses using backbone trees have also proven helpful in evaluating the placement of fragmentary specimens on phylogenetic trees derived from morphological data. Consequently, several available phylogenetic programs now include functions to run constrained searches. However, a comprehensive evaluation of the obtained results is not readily available within existing analytical tools. Here, we present an integrated approach-PlaceMyFossils-specifically designed to (1) thoroughly evaluate the phylogenetic placement of given query species (especially fossils) on a reference tree, (2) determine which characters and character partitions are most relevant in defining the phylogenetic placement, (3) assess the confidence of the results, and (4) define the optimal analytical conditions to place the query species. PlaceMyFossils combines several analyses implemented as an interactive script for TNT (Tree Analysis Using New Technologies software), a popular-and free-phylogenetic software that is widely used in paleontological studies. Finally, we demonstrate the utility and investigate the performance of PlaceMyFossils compared to other available tools using two disparate empirical datasets drawn from conifers and dinosaurs. While primarily designed for working with fossils, this tool also holds great potential for advancing morphological and molecular systematics. It offers a powerful resource for empirical systematists aiming to integrate molecular and morphological data. This is particularly relevant given the growing interest in morphological evolution as a complementary perspective on evolutionary processes and the drivers of diversification.

High-quality genome of allotetraploid Avena barbata provides insights into the origin and evolution of B subgenome in Avena.

Avena barbata, a wild oat species within the genus Avena, is a widely used model for studying plant ecological adaptation due to its strong environmental adaptability and disease resistance, serving as a valuable genetic resource for oat improvement. Here, we phased the high-quality chromosome-level genome assembly of A. barbata (6.88 Gb, contig N50 = 53.74 Mb) into A (3.57 Gb with 47,687 genes) and B (3.31 Gb with 46,029 genes) subgenomes. Comparative genomics and phylogenomic analyses clarified the evolutionary relationships and trajectories of A, B, C and D subgenomes in Avena. We inferred that the A subgenome donor of A. barbata was Avena hirtula, while the B subgenome donor was probably an extinct diploid species closely related to Avena wiestii. Genome evolution analysis revealed the dynamic transposable element (TE) content and subgenome divergence, as well as extensive structure variations across A, B, C, and D subgenomes in Avena. Population genetic analysis of 211 A. barbata accessions from distinct ecotypes identified several candidate genes related to environmental adaptability and drought resistance. Our study provides a comprehensive genetic resource for exploring the genetic basis underlying the strong environmental adaptability of A. barbata and the molecular identification of important agronomic traits for oat breeding.

A new fossil species of Rhopalodia O. Müller (Bacillariophyceae, Rhopalodiales) from Mexico

A new species of Rhopalodia is described from fossil sediments from Mexico based on light and scanning electron microscope observations. The new Rhopalodia species has valve features that place it within the R. gibba group of the genus, including a raphe in a short keel on the dorsal side of the valve and girdle bands that have small extensions that clasp over the costate fibulae. The species is distinguished from R. gibba and other allied species by valve shape. This is the first extinct fossil species of Rhopalodia described outside of Europe.

Biotechnological Advances in Wildlife Conservation: Genetic Engineering, Cloning, Ecosystem Restoration, and Nanoparticle Applications

Biotechnology has become a revolutionary tool for wildlife conservation, offering novel approaches to counter the unprecedented challenges facing biodiversity today. This paper examines the application of biotechnology, specifically genetic engineering, cloning, and ecosystem restoration, to conserve endangered species and restore degraded ecosystems. Biotechnology, through genetic engineering, enables researchers to transfer disease resistance and reproductive enhancement into vulnerable species, allowing them to survive against global threats such as chytridiomycosis in amphibians. Additionally, it addresses inbreeding and genetic bottlenecks by reintroducing genetic diversity through gene editing and transgenic methods. Cloning, primarily through the use of SCNT, holds promise for the revival of extinct species and the preservation of genetic information. A prime example of the latter is the case of the Pyrenean ibex, which, despite its short-lived success, highlighted the promise that such technology holds and the ethical questions it raises. In addition to species-specific approaches, biotechnology plays a crucial role in restoring the ecosystem. Through genetic modification, stress-resistant plant varieties and beneficial microbial inoculants are engineered to restore degraded habitats, enhance soil fertility, and enable plants to withstand environmental stressors such as drought and salinity. These efforts support the recovery of degraded native ecosystems that have been impacted by urban development, deforestation, and global warming. While acknowledging the limitations and ethical issues, the article emphasises the importance that biotechnology plays as a complement rather than a replacement for conventional methods. Ultimately, by harnessing the power of science, conservation specialists can more effectively counteract biodiversity loss, making ecosystems healthier and the future more sustainable for wildlife.

Dietary Reconstruction of Pliocene–Pleistocene Mammoths and Elephants (Proboscidea) from Northern Greece Based on Dental Mesowear Analysis

Dental wear analyses of extinct animals offer key insights into their dietary preferences and in turn contribute substantially to palaeoenvironmental reconstructions, leading to more accurate interpretations about past ecosystems. This study employs dental mesowear analysis on Pliocene and Pleistocene elephants and mammoths from several localities in Northern Greece (Ptolemais Basin, Mygdonia Basin, Drama Basin, and the Neapolis-Grevena Basin), aiming to classify them into three main dietary categories (browsers, mixed-feeders, grazers) and investigate potential niche partitioning. The method relies on documenting the wear pattern of molar surfaces through angle measurements on the enamel ridges, which reflect the average annual diet of the examined taxon and in turn the annual ecological conditions of the studied area. Prior to the palaeodietary study and in order to ensure the taxonomic attribution of the examined specimens, a taxonomic review was conducted which confirmed the presence of the mammoths Mammuthus rumanus, Mammuthus meridionalis (southern mammoth), and Mammuthus trogontherii (steppe mammoth), and the European straight-tusked elephant Palaeoloxodon antiquus. Dental mesowear results indicate a grazing diet for M. (cf.) rumanus, a mainly browsing diet for M. meridionalis but mixed-feeding to grazing for the subspecies Mammuthus meridionalis vestinus, a grazing one for M. trogontherii, and a wide diet spectrum for P. antiquus, including browsing, mixed-feeding and grazing, depending on the locality. This study expands our knowledge on the palaeoecology of Greek proboscideans and further highlights the importance of mesowear analysis on proboscidean teeth for palaeodietary and palaeoenviromental inferences.

Review of evidence that foxes and cats cause extinctions of Australia's endemic mammals

Abstract Over half of Australia's threatened and extinct endemic mammal species have been attributed to introduced red foxes (Vulpes vulpes) and cats (Felis silvestris catus). But this claim has so far been based on expert opinion. We conducted a timeline analysis, systematic review, and meta-analysis to assess whether the attribution of decline and extinction to these predators is based on evidence. Records for 43.6% and 19.6% of populations did not confirm that extinctions occurred after fox and cat arrival, respectively. Most threatened species have been attributed to these predators without supportive population studies with data (76.1% of species attributed to foxes, and 79.7% to cats). The meta-analysis showed a negative correlation between threatened mammal and fox abundance for spatial but not for temporal correlations, and we found no evidence for a correlation with cats. We conclude that the hypothesis that foxes and cats cause extinctions has come to be accepted with little evidence.

The absurdity of nature love through aviary bird-keeping

As mounting evidence highlights the human-driven extinction of avian species, reconnecting people with nature – particularly where birds are concerned – has become essential for engaging the public in conservation and the preservation of avian biodiversity. Paradoxically, heightened awareness of the benefits birds bring has fueled the rise of aviary bird-keeping for entertainment in Vietnam. This paper seeks to unravel the absurdity of bird keepers who claim to love nature and support conservation while engaging in practices that exploit and commodify birds for human interests. Through contrasting the values generated by birds in aviaries with those in natural habitats, the role of an eco-deficit culture – or, more fundamentally, humanity’s insatiable greed – in fostering this absurd form of ‘nature love’ is highlighted.

From Grasslands to Forblands: Year‐round grazing as a driver of plant diversity

Abstract Grazing by domestic herbivores is applied across Europe to combat the loss of light‐dependent, species‐rich communities due to encroachment by competitive woody and herbaceous plants. However, the billions of euros spent annually by the EU on grazing subsidies have failed to halt the loss of species in open habitats. We hypothesized that typical agri‐environmental, seasonal grazing fails to simulate the ecological effects of now‐extirpated, large, wild herbivores, which coevolved with these species‐rich communities. We conducted a survey of 30 semi‐natural sites, where grazing was either absent, seasonal, or year‐round, across a spectrum of abiotic conditions. We recorded plant species diversity and cover and used plant traits to assess taxonomic and functional responses. Year‐round grazing supported higher plant species richness and forb cover compared to seasonal or no grazing. Specifically, dormant‐season (winter) grazing pressure increased species richness and forb cover, superseding additional effects of growing‐season (summer) grazing pressure. Functional richness was similar across management types, likely due to higher plant trait similarity in year‐round grazed sites. Our results support that dormant‐season grazing plays a key role in weakening interspecific competition among plants and in enabling diverse forb communities to replace species‐poor grass dominance. Synthesis and applications. Our results indicate that typical, seasonal grazing may be counterproductive in terms of promoting plant diversity. We found the most effective management strategy for conserving species‐rich forb communities to be year‐round grazing. Our results urge a greater focus on the ecological and evolutionary mechanisms behind the relationship between large herbivores and plants, not least the balance between grasses and forbs. We advocate a shift in conservation strategies towards natural grazing, to halt the continued loss of species that depend on open and semi‐open, forb‐rich habitats such as grasslands, wetlands, and woodlands.

A Historical Misstep: Niche Shift to Specialisation Is Pushing Insular Ginger Towards an Evolutionary Dead End

ABSTRACTNiche specialisation is a double‐edged sword as it aids species in adapting to a particular environment but makes them more susceptible to environmental change, which may result in species extinction. Although it has long been debated whether niche specialisation necessarily falls into an ‘evolutionary dead end’, empirical evidence from a population genetics perspective remains scant, especially when comparing both ecological generalists and specialists simultaneously. In this study, we scrutinised two Taiwan endemic gingers (Zingiber pleiostachyum and Z. shuanglongense) to evaluate how their contrasting patterns in niche breadth evolution have shaped their evolutionary trajectories. We utilised a genome‐wide sequencing approach to investigate the demographic histories of each species, assess their maladaptation to future climate change, and estimate their mutational loads. Our results revealed distinct demographic histories between these two gingers. Z. shuanglongense, as the specialist, despite an initial increase during the Last Glacial Maximum (~22 Kya), has been subjected to a long‐term decrease in effective population size (Ne), while Z. pleiostachyum is on the contrary increasing, leading to a significantly larger current Ne. Furthermore, ecological specialists are much more vulnerable to future climate change and exhibit greater drift‐associated deleterious mutations compared to generalists, directly affecting species' fitness. This study strongly supports the idea that the transition in niche breadth towards specialisation will push Z. shuanglongense perilously close to extinction and also sheds light on species conservation within limited migratory space.

Smoothing Effects and Extinction in Finite Time for Fractional Fast Diffusions on Riemannian Manifolds

We study nonnegative solutions to the Cauchy problem for the Fractional Fast Diffusion Equation on a suitable class of connected, noncompact Riemannian manifolds. This parabolic equation is both singular and nonlocal: the diffusion is driven by the (spectral) fractional Laplacian on the manifold, while the nonlinearity is a concave power that makes the diffusion singular, so that solutions lose mass and may extinguish in finite time. Existence of mild solutions follows by nowadays standard nonlinear semigroups techniques, and we use these solutions as the building blocks for a more general class of so-called weak dual solutions, which allow for data both in the usual L1 space and in a larger weighted space, determined in terms of the fractional Green function. We focus in particular on a priori smoothing estimates (also in weighted Lp spaces) for a quite large class of weak dual solutions. We also show pointwise lower bounds for solutions, showing in particular that solutions have infinite speed of propagation. Finally, we start the study of how solutions extinguish in finite time, providing suitable sharp extinction rates.

Opportunities, research gaps, and risks in allogenic ecosystem engineer mimicry

AbstractIn an age of anthropogenically driven species loss and increasingly novel ecosystems, ecosystem engineer restoration is a process‐based approach to supporting ecosystem function. Many ecosystem engineers have low or declining population sizes. When feasibility and costs impede reintroduction of ecosystem engineers, an alternative may be artificial mimicry of ecosystem engineer structures. Research on mimicry of autogenetic ecosystem engineers, whose physical structure shapes habitat availability and complexity (e.g., tropical corals whose hard skeletons create complex reefs that provide habitat), spans many process scales. However, mimicry of allogenic ecosystem engineers, which shape habitat availability through their behavior (e.g., beavers building dams that influence hydrology), is less well explored. We reviewed the literature to examine the efficacy of artificial mimicry of allogenic ecosystem engineers and gaps in the research. Emerging findings suggest that artificial mimicry could restore physical processes, support focal species, alter biological communities, deliver benefits to landowners and ecosystems, and promote population recovery. However, some studies document the potential for unintended negative consequences for ecosystem engineers or species that use engineered structures or respond to environmental cues produced by engineered structures. Topics requiring additional research include assessing the efficacy of artificial structures as compared with natural structures, evaluating the scalability and cost‐effectiveness of mimicry projects, and investigating the potential for unintended consequences with mimicked structures.

Advancing medicinal plant agriculture: integrating technology and precision agriculture for sustainability.

To strengthen the agriculture sector, it is crucial to combine the efforts of industrialization (field mechanization and fertilizer production), technology (genome editing and manipulation), and the information sector (for the application of current technologies in precision agriculture). The challenge of modern sustainable agriculture is increasing agricultural output while using the least amount of resources and capital expenditure possible and considering the variables contributing to environmental damage. Different environmental factors adversely affect medicinal plant populations, leading to the extinction of these valuable medicinal species. These difficulties drew the attention of the international scientific community to farm sustainability and energy efficiency studies that put forth the idea of precision agriculture (site-specific crop management) in medicinal plants. It is a systems-based method that monitors and responds to changes in intra- and inter-field conditions for environmentally friendly and optimum crop output. Farming systems have significantly benefited from the visualization and morphological analysis of agricultural areas (both open fields and greenhouse experiments) using remote sensing technology, geographic information systems (GIS), crop scouting, variable rate technology (VRT), and Global Positioning System (GPS). These technologies form the backbone of the fourth agricultural technological revolution, Agriculture 4.0. This review concisely summarizes these innovative technologies' current use and potential future advancements in medicinal plants. The review is intended for researchers, professionals in medicinal plant cultivation, herbal medicine research, crop science, and related fields.

Embedding information flows within ecological networks.

Natural communities form networks of species linked by interactions. Understanding the structure and dynamics of these ecological networks is pivotal to predicting species extinction risks, community stability and ecosystem functioning under global change. Traditionally, ecological network research has focused on interactions involving the flow of matter and energy, such as feeding or pollination. In nature, however, species also interact by intentionally or unintentionally exchanging information signals and cues that influence their behaviour and movement. Here we argue that this exchange of information between species constitutes an information network of nature-a crucial but largely neglected aspect of community organization. We propose to integrate information with matter flow interactions in multilayer networks. This integration reveals a novel classification of information links based on how the senders and receivers of information are embedded in food web motifs. We show that synthesizing information and matter flow interactions in multilayer networks can lead to shorter pathways connecting species and a denser aggregation of species in fewer modules. Ultimately, this tighter interconnectedness of species increases the risk of perturbation spread in natural communities, which undermines their stability. Understanding the information network of nature is thus crucial for predicting community dynamics in the era of global change.

Late Quaternary Supernovae In Earth History

Abstract Supernovae (SNe) may have affected Earth's atmosphere during Late Quaternary (50 ka-present) time and be detectible in cosmogenic isotopic records. Supernova remnants (SNRs) at distances < 2.3 kpc provide a revised chronology of SNe and predicted hard photons received by Earth. Calculated fluences assume X-ray and γ isotropic emissions of 4 × 1049 erg within 2 y. Such are compatible with high energy observations of extragalactic SNe. Earlier values may be unrealistically small given current knowledge. The radiation events associated with nearby SNR are compared to dated records of terrestrial environmental changes. Eight SNe may have produced hard photon fluences of 1–6 × 1024 erg on the terrestrial disc; they were at distances ≤ .6 kpc. The Vela SN (.29 kpc) produced the highest fluence, at ∼13 ka. Its predicted environmental effects include abruptly elevated atmospheric 14C, reductions in upper atmosphere O3 and CH4, increased solar UVB at Earth's surface, possible cooling of the global climate, selective animal extinctions, increased wildfires, and Pt-group dust deposition. All are recorded in terrestrial records commencing at 12.76 ka and the start of the Younger Dryas cold period. Several thousand years earlier, the Hoinga SN (∼.35 kpc, ∼15 ka) may have caused a single year 30‰ Δ14C rise at 14.32 ka and the Older Dryas cool period. The 14C production dropped to its previous level by 14.23 ka but a subsequent increase occurred 14–13.9 ka and may record the arrival of associated cosmic radiation. Δ14C events at 9.126, 7.209, 2.764, 2.614, 1.175 ka, and .957 ka were apparently global and each have plausible SNe candidates of appropriate distances and ages. The nearest SNe appear to be associated with the largest isotope anomalies.

Nature-based solutions could offset coastal squeeze of tidal wetlands from sea-level rise on the U.S. Pacific coast

In this study, we explored the opportunities for tidal wetland landward migration in response to sea-level rise on the Pacific Coast of the United States. By employing a systematic spatial approach, we quantified the available space for wetland migration with sea-level rise across 61 estuarine drainage areas. Although many of the existing tidal wetlands are small patches, our analyses show that 63% of the estuaries lacked the landward migration space needed to replace current tidal wetland extent, thereby threatening a wide range of protected species and ecosystem services. Developed lands and steep topography represent common barriers to migration along the Pacific coast, especially in central and southern California. The available wetland migration space consists primarily of agriculture, pasture, and freshwater wetlands, with most of the area available for migration occurring in just a few watersheds. In most watersheds tidal wetland migration would only occur with human intervention or facilitation. The greatest amount of area available for wetland migration was in the San Francisco Bay-Delta and Columbia River estuaries, together accounting for 58% of all available migration space on the Pacific Coast. Nature-based solutions to reduce tidal wetland loss from sea-level rise can include restoration in suitable areas, removal of barriers to tidal wetland migration, and elevation building approaches. Tidal wetland restoration opportunities could increase area by 59%, underscoring it as a plausible approach to prevent tidal wetland loss in those estuaries and a viable Nature-based solution. 54% of estuaries building elevations of existing tidal wetlands may be the most feasible approach needed. Our analyses illustrate the importance of management efforts that use Nature-based approaches to prevent tidal wetland ecosystem and species loss over the coming decades from sea-level rise.

Global impoverishment of natural vegetation revealed by dark diversity.

Anthropogenic biodiversity decline threatens the functioning of ecosystems and the many benefits they provide to humanity1. As well as causing species losses in directly affected locations, human influence might also reduce biodiversity in relatively unmodified vegetation if far-reaching anthropogenic effects trigger local extinctions and hinder recolonization. Here we show that local plant diversity is globally negatively related to the level of anthropogenic activity in the surrounding region. Impoverishment of natural vegetation was evident only when we considered community completeness: the proportion of all suitable species in the region that are present at a site. To estimate community completeness, we compared the number of recorded species with the dark diversity-ecologically suitable species that are absent from a site but present in the surrounding region2. In the sampled regions with a minimal human footprint index, an average of 35% of suitable plant species were present locally, compared with less than 20% in highly affected regions. Besides having the potential to uncover overlooked threats to biodiversity, dark diversity also provides guidance for nature conservation. Species in the dark diversity remain regionally present, and their local populations might be restored through measures that improve connectivity between natural vegetation fragments and reduce threats to population persistence.