Jens-Christian Svenning

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• PhD
• Professor (Full) at Aarhus University

Large herbivores (≥45 kg) fulfill key ecological functions. Since the Late Pleistocene megafauna diversity and abundances have declined sharply, with profound consequences for ecosystems. On this background the concept of trophic rewilding has emerged and is increasingly applied to restore natural disturbance regimes and trophic interactions, ultim...

Temperate forest plant diversity is declining despite increasing conservation efforts. The closed forest paradigm, emphasizing dense, continuous canopy cover, dominates current forest management strategies. However, this approach may overlook the historical role of large herbivores in maintaining semi-open forest conditions. Here we analyse the lig...

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 ag...

Urban trees provide numerous benefits, including improved air quality, reduced urban heat, and enhanced wellbeing for city dwellers. However, the distribution of these benefits is often uneven, with wealthy urban areas typically receiving greater advantages than poorer urban areas, highlighting a trend of green inequality in urban environments. The...

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 enhance...

As cities heat up and expand in area and population, urban forests offer a nature-based solution to enhance liveability and reduce rising temperatures in cities. However, urban forests are vulnerable to climate change and face costly establishment and maintenance challenges. Here we explore four key ecological and socioeconomic barriers to achievin...

One of the main objectives of ecological research is to enhance our understanding of the processes that lead to species extinction. A potentially crucial extinction pattern is the dependence of contemporary biodiversity dynamics on past climates, also known as “climate legacy”. However, the general impact of climate legacy on extinction dynamics is...

Human activities have transformed many wild and semiwild ecosystems into novel states without historical precedent. Without knowing the current distribution of what drives the emergence of such novelty, predicting future ecosystem states and informing conservation and restoration policies remain difficult. Here we construct global maps of three key...

Various authors have suggested that extinctions and extirpations of large mammalian herbivores during the last ca. 50,000 years have altered ecological processes. Yet, the degree to which herbivore extinctions have influenced ecosystems has been difficult to assess because past changes in herbivore impact are difficult to measure directly. Here, we...

Aim Pre‐degradation baseline conditions (references) provide crucial context for restoration actions. Here, we compare vegetation structure and its driving processes across the main pre‐agricultural references discussed for temperate Europe: the Last Interglacial and the early‐mid Holocene—before and after the arrival of Homo sapiens , respectively...

As cities heat up and expand in area and population, urban forests offer a nature-based solution to enhance liveability and reduce rising temperatures in cities. However, urban forests are vulnerable to climate change and face costly establishment and maintenance challenges. Here we explore four key ecological and socioeconomic barriers to achievin...

Questions Herbivores can exert strong top‐down control on vegetation structure and composition, which in turn can affect overall biodiversity and ecosystem processes. However, South American megafauna was largely driven to extinction in recent prehistory, and remaining species have suffered severe range reductions from human actions. The potential...

Environmental conditions are dynamic, and plants respond to those dynamics on multiple time scales. Disequilibrium occurs when a response occurs more slowly than the driving environmental changes. We review evidence regarding disequilibrium in plant distributions, including their responses to paleoclimate changes, recent climate change and new spec...

The extensive, prehistoric loss of megafauna during the last 50 000 years led early naturalists to build the founding theories of ecology based on already‐degraded ecosystems. In this article, we outline how large herbivores affect community ecology, with a special focus on plants, through changes to selection, speciation, drift, and dispersal, the...

Heavy Metals (HM) in soil pose a serious threat to environmental and public health, particularly in regions with extensive human activities. This study provides a comprehensive approach to evaluate the ecological and human health risks associated with eight key HM: copper (Cu), lead (Pb), nickel (Ni), chromium (Cr), zinc (Zn), cadmium (Cd), arsenic...

In European countries, raccoon dogs (Nyctereutes procyonoides) are believed to impact ecosystems and potentially threaten native species. In this study, the stomachs of 525 raccoon dogs culled in Danish wetlands were analysed and compared to 53 stomachs of adult raccoon dogs killed by vehicles, from the countryside. The stomach content was analysed...

Cover: Devastation in Asheville, North Carolina, following the effects of Hurricane Helene, which caused billions of dollars of damage in the Southeast United States and other regions. In this issue’s “2024 State of the Climate Report,” an international team of scientists, led by Oregon State University’s William Ripple and Christopher Wolf, presen...

Plant communities are composed of species that differ both in functional traits and evolutionary histories. As species’ functional traits partly result from their individual evolutionary history, we expect the functional diversity of communities to increase with increasing phylogenetic diversity. This expectation has only been tested at local scale...

In Europe, various conservation programs adopted to maintain or restore biodiversity have experienced differing levels of success. However, a synthesis about major factors for success of biodiversity-related conservation programs across ecosystems and national boundaries, such as incentives, subsidies, enforcement, participation, or spatial context...

The Barro Colorado Nature Monument (BCNM) encompasses considerable variation in soils, topography, and forest age, presenting an excellent opportunity to explore their influences on tropical forest structure, dynamics, and composition. An extensive trail network provides access to this landscape, and many forest mensuration plots provide informatio...

The concept of the ecological niche is fundamental to understanding species distributions but it often overlooks the critical role of demography in shaping said distributions. Conversely, demographic theory has traditionally neglected how vital rates vary across environments, limiting our understanding of population dynamics across species’ ranges....

Changes in land use and climate directly impact species populations. Species with divergent characteristics may respond differently to these changes. Therefore, understanding species’ responses to environmental changes is fundamental for alleviating biodiversity loss. However, the relationships between land use changes, climate changes, species' in...

Aim People have strongly influenced the biosphere for millennia, but how their increasing activities have shaped wildlife distribution is incompletely understood. We examined how the distribution of European large (>8 kg), wild mammals has changed in association with changing anthropogenic pressures and climate change through the Holocene. Locatio...

The concept of the ecological niche is fundamental to understanding species distributions but it often overlooks the critical role of demography in shaping said distributions. Conversely, demographic theory has traditionally neglected how vital rates vary across environments, limiting our understanding of population dynamics across species’ ranges....

The concept of the ecological niche is fundamental to understanding species distributions but it often overlooks the critical role of demography in shaping said distributions. Conversely, demographic theory has traditionally neglected how vital rates vary across environments, limiting our understanding of population dynamics across species’ ranges....

The density of wood is a key indicator of the carbon investment strategies of trees, impacting productivity and carbon storage. Despite its importance, the global variation in wood density and its environmental controls remain poorly understood, preventing accurate predictions of global forest carbon stocks. Here we analyse information from 1.1 mil...

Hydropower is a rapidly developing and globally important source of renewable electricity. Globally, over 60% of rivers longer than 500 km are already fragmented and thousands of dams are proposed on rivers in biodiversity hotspots. In this Review, we discuss the impacts of hydropower on aquatic and semi-aquatic species in riverine ecosystems and h...

Since prehistory, humans have altered the composition of ecosystems by causing extinctions and introducing species. However, our understanding of how waves of species extinctions and introductions influence the structure and function of ecological networks through time remains piecemeal. Here, focusing on Australia, which has experienced many extin...

Our aim in the present article is to communicate directly to researchers, policymakers, and the public. As scientists and academics, we feel it is our moral duty and that of our institutions to alert humanity to the growing threats that we face as clearly as possible and to show leadership in addressing them. In this report, we analyze the latest t...

Large herbivorous mammals strongly influence vegetation structure by creating and maintaining open areas and causing disturbance within closed woody habitats. The herbivores alive today in Europe are only a small remnant of the large species that existed in high diversity and abundance before modern humans. The extinction of so many large herbivore...

Aim Wildlife populations are continuing to decrease worldwide. Understanding the ranking and distribution of drivers of species declines is crucial to enable targeted actions to counteract major threats. However, few studies have assessed the relative importance and geographic distribution of threats to biodiversity in China, even for high‐profile...

In recent decades, the integration of horses (Equus ferus) in European rewilding initiatives has gained widespread popularity due to their potential for regulating vegetation and restoring natural ecosystems. However, employing horses in conservation efforts presents important challenges, which we here explore and discuss. These challenges encompas...

Aim There is increasing interest in open‐ended restoration with the focus on restoring natural processes rather than static compositional goals. Here, we investigated vegetation dynamics in response to three decades of trophic rewilding with large herbivores in a recent anthropogenic, fertile 55‐km ² landscape on reclaimed marine sediments. This si...

Climate warming disproportionately impacts countries in the Global South by increasing extreme heat exposure. However, geographic disparities in adaptation capacity are unclear. Here, we assess global inequality in green spaces, which urban residents critically rely on to mitigate outdoor heat stress. We use remote sensing data to quantify daytime...

Motivation Terrestrial predators play key roles in cycling nutrients, as well as limiting prey populations, and shaping the behaviour of their prey. Prehistoric, historic and ongoing declines of the world's predators have reshaped terrestrial ecosystems and are a topic of conservation concern. However, the availability of ecologically relevant pred...

Extreme drought and intensification of land use pose substantial threats to ecosystem stability. However, existing studies that assess ecosystem stability focus primarily on the stability of aboveground net primary productivity (ANPP), while the stability of belowground net primary productivity (BNPP) is often not considered. Here, we examined the...

Survival and reproduction strategies in mammals are determined by trade-offs between life history traits. In turn, the unique configuration of traits that characterizes mammalian species gives rise to species-specific population dynamics. The dependence of population dynamics on life history has been primarily studied as the relationship between po...

Many species and ecosystems that diversified and adapted under consumer control in prehistoric times are nowadays highly threatened. Nature protection areas (PAs) form a major conservation strategy to avoid their losses. We argue that many PAs across Earth are in disequilibrium with current climatic conditions. At the same time, the main consumers...

The integrity of natural ecosystems, particularly in the Global South, is increasingly compromised by industrial contaminants. Our study examines the growth of plant species adapted to ecosystems impacted by heavy metal pollution, specifically focusing on their phytoremediation capabilities and tolerance to contaminants. The potential of pollution-...

Aims Long‐term climate stability, contemporary climate and environmental heterogeneity have been linked to bird diversity patterns through their direct impacts on diversification rate, as well as through their indirect effects on plant species richness, which could also directly and indirectly affect bird diversity. This study aimed to quantitative...

The fundamental value of universal nomenclatural systems in biology is that they enable unambiguous scientific communication. However, the stability of these systems is threatened by recent discussions asking for a fairer nomenclature, raising the possibility of bulk revision processes for "inappropriate" names. It is evident that such proposals co...

As a result of human activities, a considerable part of European vascular plants and their populations are non-native. Since the publication of previous studies summarizing the composition and structure of European alien flora, our knowledge has increased, and new alien plant inventories and updates to existing ones have been published. The aim of...

The Asiatic raccoon dog (Nyctereutes procyonoides) has successfully colonized Northern, Eastern, and Central Europe, following 20th century introductions. While subject to eradication campaigns, its ecological impacts remain incompletely understood and debated. This study aims to examine the habitat preference and movement patterns of raccoon dogs...

This study uses tooth meso- and microwear together with bone collagen stable isotope ratios (carbon (δ13C), nitrogen (δ15N), and sulphur (δ34S)) to investigate diet and human utilization of two middle Holocene (~ 5 ka cal B·P.) populations of wild horses, Equus ferus from northwest Europe. The results of the mesowear analysis places one population...

List of the 1543 additional coauthors. Co-authors who contributed revising translations are listed first. Then, the rest of the coauthors are listed according alphabetic order of countries/territories.

The emergence of alternative stable states in forest systems has significant implications for the functioning and structure of the terrestrial biosphere, yet empirical evidence remains scarce. Here, we combine global forest biodiversity observations and simulations to test for alternative stable states in the presence of evergreen and deciduous for...

Plot‐scale experiments indicate that functional diversity (FD) plays a pivotal role in sustaining ecosystem functions such as net primary productivity (NPP). However, the relationships between functional diversity and NPP across larger scale under varying climatic conditions are sparsely studied, despite its significance for understanding forest–at...

International and national conservation policies almost exclusively focus on conserving species in their historic native ranges, thus excluding species that have been introduced by people and some of those that have extended their ranges on their own accord. Given that many of such migrants are threatened in their native ranges, conservation goals...

The Water Quality Index (WQI) is a primary metric used to evaluate and categorize surface water quality which plays a crucial role in the management of fresh water resources. Machine Learning (ML) modeling offers potential insights into water quality index prediction. This study employed advanced ML models to get potential insights into the predict...

Aim Species occurrence data are valuable information that enables one to estimate geographical distributions, characterize niches and their evolution, and guide spatial conservation planning. Rapid increases in species occurrence data stem from increasing digitization and aggregation efforts, and citizen science initiatives. However, persistent qua...

Brief introduction: What are microclimates and why are they important? Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystem...

Human-induced global changes, including anthropogenic climate change, biotic globalization, trophic downgrading and pervasive land-use intensification, are transforming Earth's biosphere, placing biodiversity and ecosystems at the forefront of unprecedented challenges. The Anthropocene, characterized by the importance of Homo sapiens in shaping the...

Restoring wild communities of large herbivores is critical for the conservation of biodiverse ecosystems, but environmental changes in the twenty-first century could drastically affect the availability of habitats. We projected future habitat dynamics for 18 wild large herbivores in Europe and the relative future potential patterns of species richn...

Recent climate change has effectively rewound the climate clock by approximately 120 000 years and is expected to reverse this clock a further 50 Myr by 2100. We aimed to answer two essential questions to better understand the changes in ecosystems worldwide owing to predicted climate change. Firstly, we identify the locations and time frames where...

Ecosystem response to climate change is complex. In order to forecast ecosystem dynamics, we need high-quality data on changes in past species abundance that can inform process-based models. Sedimentary ancient DNA (sedaDNA) has revolutionised our ability to document past ecosystems' dynamics. It provides time series of increased taxonomic resoluti...

Trophic rewilding is gaining rapid momentum as a means of restoration across the world. Advances in research are elucidating the wide‐ranging effects of trophic rewilding and megafauna re‐establishment on ecosystem properties and processes including resilience, nutrient cycling, carbon sequestration, productivity and plant richness. A substantial g...

Across the last ~50,000 years (the late Quaternary) terrestrial vertebrate faunas have experienced severe losses of large species (megafauna), with most extinctions occurring in the Late Pleistocene and Early to Middle Holocene. Debate on the causes has been ongoing for over 200 years, intensifying from the 1960s onward. Here, we outline criteria t...

Freshwater megafauna, such as sturgeons, giant catfishes, river dolphins, hippopotami, crocodylians, large turtles, and giant salamanders, have experienced severe population declines and range contractions worldwide. Although there is an increasing number of studies investigating the causes of megafauna losses in fresh waters, little attention has...

Human‐induced species declines and extinctions have led to the downsizing of large‐herbivore assemblages, with implications for many ecosystem processes. Active reintroduction of extirpated large herbivores or their functional equivalents may help to reverse this trend and restore diverse ecosystems and their processes. However, it is unclear wheth...

The density of wood is a key indicator of trees’ carbon investment strategies, impacting productivity and carbon storage. Despite its importance, the global variation in wood density and its environmental controls remain poorly understood, preventing accurate predictions of global forest carbon stocks. Here, we analyze information from 1.1 million...

The desert ecosystem of the Qinghai–Tibet Plateau (QTP) is an important component of China's desert ecosystem. Studying the mechanisms shaping the taxonomic, phylogenetic, and functional beta diversity of plant communities in the QTP desert will help us to promote scientific conservation and management of the region's biodiversity. This study inves...

Megafauna (animals ≥45 kg) have probably shaped the Earth’s terrestrial ecosystems for millions of years with pronounced impacts on biogeochemistry, vegetation, ecological communities and evolutionary processes. However, a quantitative global synthesis on the generality of megafauna effects on ecosystems is lacking. Here we conducted a meta-analysi...

Large mammalian herbivores (megafauna) have experienced extinctions and declines since prehistory. Introduced megafauna have partly counteracted these losses yet are thought to have unusually negative effects on plants compared with native megafauna. Using a meta-analysis of 3995 plot-scale plant abundance and diversity responses from 221 studies,...

Young-of-the-year fish communities are widely used as bioindicators of various environmental disturbances. This study was conducted from 1997 to 2015 and aims to develop fish trait–based indices of changes in the temperature regime and eutrophication of water bodies in the Dnipro River basin. We identified fish traits that significantly correlate w...

Questions Does the non‐native evergreen Chinese windmill palm ( Trachycarpus fortunei ) affect native plant community and forest regeneration in deciduous forests? Are effects modulated by soil moisture? What are the implications for forest management and nature conservation? Location Broadleaved deciduous low‐elevation forests on the southern slo...

Trees are pivotal to global biodiversity and nature’s contributions to people, yet accelerating global changes threaten global tree diversity, making accurate species extinction risk assessments necessary. To identify species that require expert-based re-evaluation, we assess exposure to change in six anthropogenic threats over the last two decades...

Preserving and restoring terrestrial ecosystems is crucial to halting the collapse of life on Earth. To guide global conservation and restoration efforts, we present a comprehensive map, encompassing all ecosystems, revealing the Earth's potential tree, short vegetation, and bareground cover accounting for various land management scenarios such as...

This article focuses on hunter-gatherer impact on interglacial vegetation in Europe, using a case study from the Early Holocene (9200–8700 BP). We present a novel agent-based model, hereafter referred to as HUMLAND (HUMan impact on LANDscapes), specifically developed to define key factors in continental-level vegetation changes via assessment of di...

Climate warming, often accompanied by extreme drought events, could have profound effects on both plant community structure and ecosystem functioning. However, how warming interacts with extreme drought to affect community‐ and ecosystem‐level stability remains a largely open question. Using data from a manipulative experiment with three warming tr...

Fires significantly affect the structure and diversity of vegetation. Natural recovery of vegetation after fires in the Chornobyl Exclusion Zone is of special interest because of its status as a nuclear disaster area. This is the first assessment of the potential for natural regrowth of forest and post-fire succession after the catastrophic fires...

The concept of novel ecosystems has been discussed for over more than a decade to describe ecosystems that have an altered species composition and function, such that the community has crossed a threshold forbidding a return to its historical state. While spatial and temporal community compositional change has been well studied in biogeography, stu...

The worldwide extinction of megafauna during the Late Pleistocene and Early Holocene is evident from the fossil record, with dominant theories suggesting a climate, human or combined impact cause. Consequently, two disparate scenarios are possible for the surviving megafauna during this time period - they could have declined due to similar pressure...

Aim Reconstructing megafauna diversity in the past before anthropogenic impacts is crucial for developing targeted restoration strategies. We estimated the diversity and functional decline of European megafauna in the present compared with the nearest in‐time climate period analogue to the present but prior to the worldwide diffusion of Homo sapien...

Forests are a substantial terrestrial carbon sink, but anthropogenic changes in land use and climate have considerably reduced the scale of this system¹. Remote-sensing estimates to quantify carbon losses from global forests2–5 are characterized by considerable uncertainty and we lack a comprehensive ground-sourced evaluation to benchmark these est...

Climate change will cause substantial vegetation shifts across the world. Africa may face varying dynamics such as tree decline, savannization, and woody encroachment due to rising temperatures and rainfall changes. This study examines the potential effects of climate change on Kenyan vegetation and vegetation shifts for 2050 and 2100, employing a...

The extent of vegetation openness in past European landscapes is widely debated. In particular, the temperate forest biome has traditionally been defined as dense, closed-canopy forest; however, some argue that large herbivores maintained greater openness or even wood-pasture conditions. Here, we address this question for the Last Interglacial peri...

Background Climate change coupled with other anthropogenic pressures may affect the extent of suitable habitat for species and thus their distributions. This is particularly true for species occupying high-altitude habitats such as the gelada (Theropithecus gelada) of the Ethiopian highlands. To explore the impact of climate change on species distr...

for species and thus their distributions. This is particularly true for species occupying high-altitude habitats such as the gelada (Theropithecus gelada) of the Ethiopian highlands. To explore the impact of climate change on species distributions, Species Distribution Modelling (SDM) has been extensively used. Here we model the current and future...

Ecosystem response to climate change is complex. In order to forecast ecosystem dynamics, we need high-quality data on changes in past species abundance that can inform process-based models. Ancient DNA has revolutionised our ability to document past ecosystems' dynamics. It provides time-series of increased taxonomic resolution compared to microfo...