Biology subjects

Svenning, J.-C.

Publications and source records attributed to Svenning, J.-C..

At least 19 recordsLinked to original sources

bioRxiv2026

Two decades of Novel Ecosystems: Literature analysis of topics, trends and connectivity

1. As human-driven climate change and other anthropogenic forces produce widespread impacts on biodiversity and ecosystem functioning, many ecosystems are shifting into unprecedented, novel states. The Novel Ecosystem Concept (NEC), formalized in 2006, was developed as an alternative framework for managing "novel ecosystems", human-altered systems that are challenging to restore to their historical state. In the years since, the NEC has been proposed as a broader lens for ecosystem management under ongoing global change. 2. We evaluated how the uptake and potential of the NEC have been realized over time using a bibliometric and linguistic toolkit. Using bibliometric data from the Web of Science, we clustered 40,914 applied ecology papers published between 2006 and 2025 into twenty research topics based on language use. We quantified the volume of NEC research within each topic, rates of publication over time, and cross-topic connectivity proxied by citations. 3. We found NEC research in most of the topics of applied ecology, particularly invasion biology, ecosystem services, soil research and studies of freshwater, urban and marine systems. In contrast, several major conservation-focused topics, including protected areas, threatened species, and human-wildlife interactions, contained little research with an explicit link to novel ecosystems. Publication rates increased across all topics, although growth slowed over time. At the same time, NEC research became more focused into ecosystem-specific topics, especially marine ecosystems. NEC research across different topics was well-connected by citations, with papers more likely to cite each other when they used similar language. 4. Overall, the NEC does not appear to have expanded beyond its origins in restoration to become a broadly applied framework across conservation and ecosystem management. Instead, the concepts behind the NEC have been integrated into restoration and management frameworks grappling with climate and other anthropogenic change, while "novelty" is emerging as a powerful quantitative variable for measuring ecological change over space and time. Our results highlight the potential value of bibliometric and linguistic tools to deconstruct the ecological literature to inform what we can, or should, do to intervene for benefit of nature and people.

ecology↗

bioRxiv2026

Density-dependent facilitation of livestock by small mammal ecosystem engineers

Small mammals and large herbivores have co-evolved in grasslands for millions of years, yet how they interplay remains unclear. Although large herbivores can significantly affect the smaller ones, the reversal effect is largely unknown. On the Qinghai-Tibetan Plateau, plateau pikas (Ochotona curzoniae) are often considered pests that compete with livestock at high densities. Using field experiments, we show that the presence of pikas facilitates weight gains of yaks (Bos grunniens) by improving vegetation composition at a moderate density level. Compared to the pika-present treatment, pika removal dramatically increased cover of the poisonous Stellera forbs by two-fold, reducing the abundance and protein content of palatable grasses and sedges, yak foraging efficiency, and yak weight gain by up to 42%. Notably, we found a humped relationship between yak weight gains and pika burrow densities in the pika-present plots; the facilitative effect of pikas on yaks was highest at about 200 burrows/ha, but shifted to a competitive effect at pika densities exceeding 400 burrows/ha. These results provide the first empirical evidence that maintaining a moderate density of small mammalian herbivores can benefit growth performance of livestock by improving vegetation composition. Our study highlights the significance of moderate populations of ecosystem-engineering small mammals in sustaining pastoral productivity in rangelands.

ecology↗

bioRxiv2025

Identifying the Levant as a potential contact and interbreeding zone for Neanderthals and modern humans

Timing of interbreeding between modern humans and Neanderthals has been subject of numerous studies but its geography remains largely unknown. Genetic evidence suggests three different interbreeding events: first in the Marine Isotope Stage (MIS) 7 ([~]250 to 200 ka), then in the MIS5 ([~]100 to 120 ka) and the final event in the MIS3 ([~]60 to 50 ka). Here, we used all known archaeological sites between 60-50 ka associated with Neanderthals and modern human presence and a set of paleoenvironmental data to reconstruct Neanderthals and modern humans habitat suitability using the Species Distribution Modeling (SDM) techniques. Assessing geographical overlap between the two species, we identify potential interbreeding zone. We found that the Levant was main potential interbreeding area of the third event. Previous research has identified the Zagros Mountains in Iran as a potential interbreeding zone during the second interbreeding event MIS5 ([~]100 to 120 ka). Compiling the results of this study to previous research can help us to better understand the dynamics of modern humans and Neanderthals interbreeding over both time and space. The two potential interbreeding areas have high priority for future research.

evolutionary biology↗

bioRxiv2025

TOWARDS CLIMATE-SMART REWILDING: AN INTEGRATED FRAMEWORK FOR BIODIVERSITY, CLIMATE CHANGE, AND SOCIETY

The UN Decade on Ecosystem Restoration and the Kunming-Montreal Global Biodiversity Framework aim to restore 30% of degraded ecosystems. Both the IPCC and IPBES highlight the crucial role of ecosystem restoration in addressing the interconnected crises of climate change and biodiversity loss. One key restoration strategy is rewilding, which enhances ecosystem complexity with minimal human intervention. While traditional rewilding strategies often focus on benefits for biodiversity, we propose a climate-smart rewilding framework as a new approach designed to deliver climate benefits alongside biodiversity restoration. This framework seeks to integrate biodiversity, climate change adaptation and mitigation, as well as socio-economic benefits and trade-offs. We illustrate how this framework can be utilized to identify areas across Europe where rewilding could increase carbon sequestration, enhance species abilities to adapt to the velocity of climate change, and maximize wildlife-watching benefits while minimizing the costs associated with livestock-wildlife conflict. Finally, we acknowledge some limitations of climate-smart rewilding, but we argue that its adaptability and low cost render it a promising solution to the challenges facing Europe and beyond.

ecology↗

bioRxiv2024

Trade-offs beget trade-offs: Causal analysis of mammalian population dynamics

Survival and reproduction strategies in mammals are determined by trade-offs between life history traits. In turn, the unique configuration of traits that characterize mammalian species give rise to species-specific population dynamics. The dependence of population dynamics on life history has been primarily studied as the relationship between population density and size-related traits. With the recent accumulation of genomic data, the effective population size (Ne) over million-year timescales has become quantifiable for a large proportion of mammal species. Using phylogenetic path analysis, we compared the dependence of population density and Ne on eleven traits that characterize mammalian allometry, diet and reproduction. We found variable impacts of traits on the two metrics of population dynamics across different classifications of mammalian species. For example, we found a negative association between brain size and both population density and Ne overall, but brain size was positively associated with Ne in carnivorans. Dietary specialization had a negative effect on population density, especially in ungulates. Ne of ungulates and primates was strongly affected by time to maturity and weaning age, respectively, highlighting the difference in reproductive strategy between these orders. The relationship between Ne and adult mass showed a gradient in association strength from cold to warm biomes. Together, our findings demonstrate that trade-offs not only characterize life-history evolution, but also extend across different metrics of population dynamics and vary among species groups. This challenges the static nature of the "energetic equivalence" rule and has major implications for selecting appropriate metrics for species conservation and restoration strategies.

evolutionary biology↗

bioRxiv2023

Preventing extinction in an age of species migration and planetary change

International and national conservation policies almost exclusively focus on conserving species in their historic native ranges, thus excluding species that have dispersed on their own accord or have been introduced by people. Given that many of these migrant species are threatened in their native ranges, conservation goals that explicitly exclude these migrant populations may overlook opportunities to prevent extinctions and respond dynamically to rapidly changing environmental and climatic conditions. Focusing on terrestrial mammals, we quantified the extent to which migration, in this case via introductions, has provided new homes for threatened mammal species. We then devised alternative scenarios for the inclusion of migrant populations in mainstream conservation policy with the aim of preventing global species extinctions and used spatial prioritization algorithms to simulate how these scenarios could change global spatial conservation priorities. We found that 22% of all identified migrant mammals (70 species) are threatened in their native ranges, mirroring the 25% of all mammals that are threatened. Reassessing global threat statuses by combining native and migrant ranges reduced the threat status of 23 species ([~]33% of threatened migrants). Thus, including migrant populations in threat assessments provides a more accurate assessment of actual global extinction risk among species. Spatial prioritization simulations showed that reimagining the role of migrant populations to prevent global species extinction could increase the importance of overlooked landscapes, particularly in central Australia. Our results indicate that these various and non-exhaustive ways to consider migrant populations, with due consideration for potential conservation conflicts with resident taxa, may provide unprecedented opportunities to prevent species extinctions. We present these alternatives and spatial simulations to stimulate discussion on how conservation ought to respond, both pragmatically and ethically, to rapid environmental change in order to best prevent extinctions.

ecology↗

bioRxiv2023

Distribution and extent of suitable habitat for geladas (Theropithecus gelada) in the Anthropocene

BackgroundClimate change coupled with other anthropogenic pressures may affect species distributions, often causing extinctions at different scales. This is particularly true for species occupying marginal habitats such as gelada, Theropithecus gelada. Our study aimed to model the impact of climate change on the distribution of suitable habitats for geladas and draw conservation implications. Our modelling was based on 285 presence locations of geladas, covering their complete current distribution. We used different techniques to generate pseudoabsence datasets, MaxEnt model complexities, and cut-off thresholds to map the potential distribution of gelada under current and future climates (2050 and 2070). We assembled maps from these techniques to produce a final composite map. We also evaluated the change in the topographic features of gelada over the past 200 years by comparing the topography in current and historical settings. ResultsAll model runs had high performances, AUC = 0.87 - 0.96. Under the current climate, the suitable habitat predicted with high certainty was 90,891 km2, but it decreased remarkably under future climates, -36% by 2050 and -52% by 2070. Whereas no remarkable range shift was predicted under future climates, currently geladas are confined to higher altitudes and complex landscapes compared to historical sightings, probably qualifying geladas as refugee species. ConclusionsOur findings indicated that climate change most likely results in a loss of suitable habitat for geladas, particularly south of the Rift Valley. The difference in topography between current and historical sightings is potentially associated with anthropogenic pressures that drove niche truncation to higher altitudes, undermining the climatic and topographic niche our models predicted. We recommend protecting the current habitats of geladas even when they are forecasted to become climatically unsuitable in the future, in particular for the population south of the Rift Valley.

ecology↗

bioRxiv2023

Megafauna diversity and functional declines in Europe from the Last Interglacial (LIG) to the present

Aim: to estimate European megafauna diversity and functional declines in the present compared to the nearest in time modern-analogue climate period prior to the worldwide diffusion of Homo sapiens. Location: Europe. Time period: Last Interglacial (LIG; ca. 127,000 years ago) to present. Major taxa studied: wild, large ([≥]10 kg) terrestrial mammals. Methods: we assessed the distribution of 48 European megafauna species during the LIG using hindcasting modelling and fossil records. Then, we estimated the decline in megafauna community diversity and potential trait-based functional effects from the LIG to the present, accounting for climate differences between the two periods. Results: from the LIG to the present, species richness and community biomass across Europe dropped by 74.3% ({+/-} 9.9% SD) and 96.7% ({+/-} 4.1% SD), respectively. Functional diversity dropped by 59.1% ({+/-} 11.8% SD) for herbivores and by 48.2% ({+/-} 25.0% SD) for carnivores, while trait-informed potential vegetation and meat consumptions dropped by 91.1% ({+/-} 7.4% SD) and 61.2% ({+/-} 17.2% SD), respectively. The loss in megafauna diversity and associated ecological processes were high everywhere, but particularly in western Europe for carnivores and in the East European Plain for herbivores. We found that potential megafauna richness and functional patterns in the two periods were near identical if only climate-driven differences were considered. Main conclusions: severe, size-biased defaunation has degraded megafauna assemblages and megafauna-mediated ecological processes across Europe from the LIG to the present. These patterns cannot be explained by climate differences between the two periods, thus were likely driven by the impact of prehistoric Homo sapiens. The results suggest that the structure of wild ecosystems of the present strongly deviates from the evolutionary norm, notably with decreased functional heterogeneity and decreased fluxes of biogeochemical compounds across the trophic networks, highlighting the importance of ambitious policies of megafauna community restoration to support ecosystems functioning.

ecology↗

bioRxiv2023

Occurrence-based diversity estimation reveals macroecological and conservation knowledge gaps for global woody plants

Incomplete sampling of species geographic distributions has challenged biogeographers for many years to precisely quantify global-scale biodiversity patterns. After correcting for the spatial inequality of sample completeness, we generated a global species diversity map for woody angiosperms (82,974 species, 13,959,780 occurrence records). The estimated diversity demonstrated non-linear latitudinal and longitudinal patterns that were potentially related to region-specific biogeographic factors including current climate, paleoclimate, and topographical factors, while energy availability was the most important predictor at a global level. We identified the areas with potentially high species richness and rarity, but poorly explored, unprotected, and threatened by deforestation: they are distributed mostly at low latitudes across central South America, central Africa, subtropical China, and Indomalayan islands. These priority areas for botanical exploration would help to efficiently fill spatial knowledge gaps for better describing the status of biodiversity and improve the effectiveness of the protected area network for global woody plant conservation. TeaserBias-corrected diversity map based on occurrence records sheds new light on global macroecology and conservation of woody angiosperms.

ecology↗

bioRxiv2023

The evolutionary history of spines: a Cenozoic arms race with mammals

The role of mammal herbivory in plant evolution is largely unrecognised. Spines on stems are a common and important feature found in [~]9% of eudicot woody plant species worldwide. Spines evolved independently multiple times during the Cenozoic. The timing and extent of spiny plant diversification varied among continents, pointing towards continental rather than global drivers. Spine evolution is closely related to radiation of extant ungulates and extinct ground sloths, rather than climate variation. Diversification began in the Paleogene in herbivore species-rich Eurasia and North America, emerging later in the Neogene in species-poorer South America, Africa and Australia. Spiny lineages expanded their ecological footprint over non-spiny plants, mainly through intercontinental migrations, indicating that spines likely provided a competitive advantage with increasing, and novel, mammal herbivory pressure.

evolutionary biology↗

bioRxiv2022

Socioeconomics and biogeography jointly drive geographic biases in our knowledge of plant traits: a global assessment of the Raunkiaerian shortfall in plants

The traits of plants determine how they interact with each other and their environment, constituting key knowledge for diverse fields. The lack of comprehensive knowledge of plant traits (the "Raunkiaerian shortfall") poses a major, cross-disciplinary, barrier to scientific advancement. Spatial biases in trait coverage may also lead to erroneous conclusions affecting ecosystem management and conservation planning. Thus, there is an urgent need to assess the spatial completeness of plant trait data, understand drivers of geographic biases, and to identify solutions for filling regional gaps. Here, we leverage a comprehensive set of regional species checklists for vascular plants and trait data for 2,027 traits and 128,929 plant species from the TRY database to assess trait data completeness across the globe. We show that trait data availability in TRY is associated with socioeconomic and biological factors influencing sampling likelihood: trait completeness was positively associated with mean species range size, research expenditure, and human population density and negatively associated with endemism and vascular plant species richness. Integration of a second, regional trait database (AusTraits) more than doubled trait completeness for the continent covered, indicating that the creation and integration of regional databases can rapidly expand trait completeness. Plain Language SummaryThe traits of plants determine how they interact with each other and their environment. Our knowledge of plant traits is incomplete, limiting scientific advancement as well as our ability to manage ecosystems and plan conservation actions. We show that there are large biases in trait data availability which are associated with both biological factors (range size, endemism, species richness) and socioeconomic factors (research expenditure, human population density). We also show how regionally-focused efforts can help rapidly expand trait data availability.

ecology↗

bioRxiv2022

Identifying the potential for sustainable human wildlife coexistence by integrating willingness to coexist with habitat suitability models

Persistence of large mammals in the Anthropocene depends on human willingness to coexist with them, but this is rarely incorporated into habitat suitability or conservation priority assessments. We propose a framework that integrates human willingness-to-coexist with habitat suitability assessments to identify areas of high potential for sustainable coexistence. We demonstrate its applicability for elephants and rhinos in the socio-ecological system of Maasai Mara, Kenya, by integrating spatial distributions of peoples willingness-to-coexist based on Bayesian hierarchical models using 556 household interviews, with socio-ecological habitat suitability mapping validated with long-term elephant observations from aerial surveys. Willingness-to-coexist was higher if people had little personal experience with a species, and strongly reduced by experiencing a species as a threat to humans. The sustainable coexistence potential framework highlights areas of low socio-ecological suitability, and areas that require more effort to increase positive stakeholder engagement to achieve long-term persistence of large herbivores in human-dominated landscapes.

ecology↗

bioRxiv2022

Worldwide late-Quaternary population declines in extant megafauna are due to Homo sapiens rather than climate

The worldwide loss of large animal species over the past 100,000 years is evident from the fossil record, with climate and human impact as the most likely causes of megafauna extinctions. To help distinguish between these two scenarios, we analysed whole-genome sequence data of 142 species to infer their population size histories during the Quaternary. We modelled differences in population dynamics among species using ecological factors, paleoclimate and human presence as covariates. We report a significant population decline towards the present time in more than 90% of species, with larger megafauna experiencing the strongest decline. We find that population decline became ubiquitous approximately 100,000 years ago, with the majority of species experiencing their lowest population sizes during this period. We assessed the relative impact of climate fluctuations and human presence on megafauna dynamics and found that climate has limited explanatory power for late-Quaternary shifts in megafauna population sizes, which are largely explained by Homo sapiens arrival times. As a consequence of megafauna decline, total biomass and metabolic input provided by these species has drastically reduced to less than 25% compared to 100,000 years ago. These observations imply that the worldwide expansion of H. sapiens caused a major restructuring of ecosystems at global scale.

evolutionary biology↗

bioRxiv2022

Quantifying the Human Cost of Global Warming

The costs of climate change are often estimated in monetary terms1,2 but this raises ethical issues3. Here we express them in terms of numbers of people left outside the human climate niche4 - defined as the historically highly-conserved distribution of relative human population density with respect to mean annual temperature (MAT). We show that climate change has already put [~]8% of people (>500 million) outside this niche. By end-of-century (2080-2100), current policies leading to around 2.7 {degrees}C global warming5-9 could leave one third (21-42% or 2-4 billion) of a future 9.5 billion population outside the niche. Limiting global warming to 1.5 {degrees}C could halve this exposure, reducing it by [~]1.5 billion people. For the two countries with the most people affected - India and Nigeria - reducing global warming from 2.7 to 1.5 {degrees}C results in a >6-fold decrease in the population exposed to unprecedented temperatures, MAT [≥]29 {degrees}C. The lifetime emissions of [~]3.5 global average citizens today (or [~]1.2 average US citizens) expose 1 future person to MAT [≥]29 {degrees}C by end-of-century. That person comes from a place where emissions today are around half of the global average. These results highlight the need for more decisive policy action to limit the human costs and inequities of climate change.

ecology↗

bioRxiv2021

Using recent baselines as benchmarks for megafauna restoration places an unfair burden on the Global South

The potential for megafauna restoration is unevenly distributed across the world, along with the socio-political capacity of countries to support these restoration initiatives. We show that choosing a recent baseline to identify species indigenous range puts a higher burden for megafauna restoration on countries in the Global South, which also have less capacity to support these restoration initiatives. We introduce the Megafauna Index, which considers large mammals potential species richness and range area at country-level, to explore how the responsibility for megafauna restoration distributes across the world according to four scenarios using various temporal benchmarks to define species indigenous range - current, historical (1500AD), mid-Holocene and Pleistocene. We test how the distribution of restoration burden across the world correlates to indicators of conservation funding, human development, and governance. Using a recent or historical baseline as a benchmark for restoration puts a higher pressure on African and southeast Asian countries while lifting the responsibility from the Global North, where extinctions happened a long time ago. When using a mid-Holocene or Pleistocene baseline, new opportunities arise for megafauna restoration in Europe and North America respectively, where countries have a higher financial and societal capacity to support megafauna restoration. These results contribute to the debate around benchmarks in rewilding initiatives and the ethical implications of using recent baselines to guide restoration efforts. We suggest that countries from the Global North should reflect on their responsibility in supporting global restoration efforts, by increasing their support for capacity building in the South and taking responsibility for restoring lost biodiversity at home.

ecology↗

bioRxiv2021

Undersampling correction methods to control γ-dependence for comparing β-diversity between regions

Measures of {beta}-diversity are known to be highly constrained by the variation in {gamma}-diversity across regions (i.e., {gamma}-dependence), making it challenging to infer underlying ecological processes. Undersampling correction methods have attempted to estimate the actual {beta}-diversity in order to minimize the effects of {gamma}-dependence arising from the problem of incomplete sampling. However, no study has systematically tested their effectiveness in removing {gamma}-dependence, and examined how well undersampling-corrected {beta}-metrics reflect true {beta}-diversity patterns that respond to ecological gradients. Here, we conduct these tests by comparing two undersampling correction methods with the widely used individual-based null model approach, using both empirical data and simulated communities along a known ecological gradient across a wide range of {gamma}-diversity and sample sizes. We found that undersampling correction methods using diversity accumulation curves were generally more effective than the null model approach in removing {gamma}-dependence. In particular, the undersampling-corrected {beta}-Shannon diversity index was most independent on {gamma}-diversity and was the most reflective of the true {beta}-diversity pattern along the ecological gradient. Moreover, the null model-corrected Jaccard-Chao index removed {gamma}-dependence more effectively than either approach alone. Our validation of undersampling correction methods as effective tools for accommodating {gamma}-dependence greatly facilitates the comparison of {beta}-diversity across regions.

ecology↗

bioRxiv2020

Extinctions have strongly reduced the mammalian consumption of primary productivity

Herbivorous mammals are important for natural ecosystems even today, but how much stronger would there effects be without human-linked extinctions and extirpations? The ranges of many mammal species have contracted and numerous species have gone extinct due to human pressures, so herbivore impacts in even seemingly natural ecosystems likely deviate from their pre-anthropogenic state. However, such effects remain poorly understood and often unrecognized. To address this issue, we here quantified and mapped plant consumption by all terrestrial mammals in natural areas based on both current and estimated natural ranges. We then compared the estimated consumption rates to current plant net primary productivity, and summarised the results for global ecosystem types both broadly and in the wildest remaining natural areas around the world (the Last of the Wild). We found that wild mammals consume 7.3% (95% interquantile range: 0.85% - 26%) of net primary productivity in current natural areas, and that this would be much higher in the absence of extinctions and extirpations, namely 13% (95% interquantile range: 1.7% - 40%), i.e., a >50% higher consumption rate. Marked human-linked declines in herbivory were seen even in the wildest remaining natural areas, where mammals now consume a mean of 9% (95% interquantile range: 2.2% - 26%) of plant primary productivity, which is only 60% of no-extinction level. Our results show that mammalian herbivores naturally play an important part in ecosystems at a global scale, but that this effect has been strongly reduced by extinctions and extirpations.

ecology↗

bioRxiv2020

Species packing and the latitudinal gradient in local beta-diversity

The decline in species richness at higher latitudes is among the most fundamental patterns in ecology. Whether changes in species composition across space (beta-diversity) contribute to this gradient of overall species richness (gamma-diversity) remains hotly debated. Previous studies that failed to resolve the issue suffered from a well-known tendency for small samples in areas with high gamma-diversity to have inflated measures of beta-diversity. Here, we provide here a novel analytical test, using beta-diversity metrics that correct the gamma-diversity and sampling biases, to compare beta-diversity and species packing across a latitudinal gradient in tree species richness of 21 large forest plots along a large environmental gradient in East Asia. We demonstrate that after accounting for topography and correcting the gamma-diversity bias, tropical forests still have higher beta-diversity than temperate analogs. This suggests that beta-diversity contributes to the latitudinal species richness gradient as a component of gamma-diversity. Moreover, both niche specialization and niche marginality (a measure of niche spacing along an environmental gradient) also increase towards the equator, after controlling for the effect of topographic heterogeneity. This supports the joint importance of tighter species packing and larger niche space in tropical forests while also demonstrating the importance of local processes in controlling beta-diversity.

ecology↗