Overgrazing is threatening global drylands

Sheep on Green Grass Field
Photo Credit: Gökçe Gök

The positive effects of grazing by livestock and wild herbivores can turn negative as temperatures become warmer.

Grazing is a trillion-dollar industry, and is particularly important in drylands, which cover about 40 percent of Earth's land surface and support half of the world’s livestock. Livestock are critical for food, shelter and a source of capital, but changing climates threaten livestock production and the livelihoods of billions of people worldwide.

An international team of scientists has published a study in the journal Science today with the first global estimates of how grazing will affect ecosystem services across the world’s drylands. The research, led by the Dryland Ecology and Global Change group in Spain with collaborators from UNSW Sydney, shows that grazing by livestock and wild herbivores in drylands can have positive effects on ecosystem services, but these effects can turn negative as Earth’s temperature becomes warmer.

What Is: An Ecosystem

The Holocoenotic Nature of the Biosphere
Image Credit: Scientific Frontline / stock image

The Genesis of a Paradigm 

The concept of the ecosystem represents one of the most significant intellectual leaps in the history of biological science. It is not merely a label for a collection of living things, but a sophisticated framework that integrates the chaotic multiplicity of the natural world into a coherent, functional unit. To understand the ecosystem is to understand the fundamental architecture of life on Earth. This report provides an exhaustive analysis of the ecosystem concept, tracing its historical lineage, dissecting its thermodynamic and biogeochemical engines, exploring its diverse manifestations across the globe, and evaluating its resilience in the face of unprecedented anthropogenic pressure. 

Grassland Ecosystems Become More Resilient with Age

In diverse plant communities, evolution increases the division of labor between species over time.
Photo Credit: Alexandra Weigelt

Reduced biodiversity affects the stability of the entire ecosystem. A long-term experiment now shows that grassland plant communities with multiple species need about 10 years to adjust to each other and produce an even amount of biomass again.

Recent experiments have shown that the loss of species from a plant community can reduce ecosystem functions and services such as productivity, carbon storage and soil health. This reduced functioning may also destabilize the ecosystem in its ability to maintain ecosystem functions and services in the long term. However, assessing this is only possible if experiments can be maintained for a sufficient length of time.

Stable biomass production after 10 years

In a new study, researchers from the University of Zurich and colleagues from Leipzig and Jena analyzed the stability of plant biomass production over two decades in one of the longest-running grassland biodiversity experiments in the world, the Jena Experiment in Germany. After more than a decade, plant species in more diverse experimental communities complemented each other in producing stable biomass at the community level. At low plant diversity, by contrast, this “compensatory” effect was observed and community biomass varied much more from year to year. During the first decade of the experiment, species-rich communities had not yet stabilized because of large fluctuations in species populations. This long-term research shows that biodiversity plays an increasingly important role in stabilizing ecosystem productivity over time as plant communities mature.

Ecology: In-Depth Description

Photo Credit: Глеб Коровко

Ecology is the scientific study of the interactions between living organisms and their environment, including both living (biotic) and non-living (abiotic) components. Its primary goals are to understand the principles governing the distribution, abundance, and relationships of organisms, as well as the flow of energy and materials within ecosystems.

Apex predators in prehistoric Colombian oceans would have snacked on killer whales today

. Illustration of some of the apex predators in the Paja Formation biota with a human for scale.
Illustration Credit: Guillermo Torres, Hace Tiempo, Instituto von Humboldt.

Predators at the top of a marine food chain 130 million years ago ruled with more power than any modern species, McGill research into a marine ecosystem from the Cretaceous period revealed. 

The study, published in the Zoological Journal of the Linnean Society, reconstructs the ecosystem of Colombia’s Paja Formation, and finds it was teeming with marine reptiles reaching over 10 meters in length that inhabited a seventh trophic level.  

Trophic levels are the layers or ranks within a food chain that describe the roles organisms play in an ecosystem based on their source of energy and nutrients. Essentially, they help define who eats whom in an ecosystem. Today’s marine trophic levels cap at six, with creatures like killer whales and great white sharks. 

The discovery of giant marine reptile apex predators occupying a seventh trophic level underscores the Paja ecosystem’s unmatched diversity and complexity, offering a rare view into an evolutionary arms race among predators and prey. 

Map shows scale of ecosystem disturbance across Australia

The Human Industrial Footprint (HIF) map showing the varying levels of ecosystem disturbance.
Image Credit: University of Queensland

Scientific Frontline: Extended "At a Glance" Summary: Ecosystem Disturbance and Human Industrial Footprint Mapping

The Core Concept: Researchers have developed two high-resolution national datasets—the Human Industrial Footprint (HIF) and the Ecological Intactness Index (EII)—to precisely map the extent and intensity of human-driven ecosystem disturbance across the Australian continent.

Key Distinction/Mechanism: Unlike 30-year-old national models or generic global maps that omit region-specific operations, this spatial analysis achieves a 100-meter resolution that isolates and overlaps 16 distinct human pressures. This methodology allows for a highly accurate quantification of cumulative habitat loss, environmental strain, and landscape fragmentation.

Major Frameworks/Components:

• Human Industrial Footprint (HIF): A spatial model consolidating 16 specific environmental pressures—including mining, agriculture, public infrastructure, forestry plantations, roads, and human settlements—into a single metric of ecosystem disruption.
• Ecological Intactness Index (EII): A complementary dataset that evaluates and quantifies the resulting degree of habitat loss, baseline ecosystem quality, and physical fragmentation across the continent.
• Cumulative Strain Modeling: Utilizes a 100-meter resolution grid to calculate the compounding biological strain on environments where multiple distinct pressures (e.g., agricultural grazing intersecting with transportation infrastructure) overlap.

Marine heat waves disrupt the ocean food web in the northeast Pacific Ocean

Pyrosomes.
Photo Credit: Mark Farley, Hatfield Marine Science Center, Oregon State University.

Marine heat waves in the northeast Pacific Ocean create ongoing and complex disruptions of the ocean food web that may benefit some species but threaten the future of many others, a new study has shown.

The study, just published in the journal Nature Communications, is the first of its kind to examine the impacts of marine heat waves on the entire ocean ecosystem in the northern California Current, the span of waters along the West Coast from Washington to Northern California.

The researchers found that the biggest beneficiary of marine heat waves is gelatinous zooplankton – predominantly cylindrical-shaped pyrosomes that explode in numbers following a marine heat wave and shift how energy moves throughout the food web, said lead author Dylan Gomes, who worked on the study as a postdoctoral scholar with Oregon State University’s Marine Mammal Institute.

“If you look at single species interactions, you’re likely to miss a lot,” Gomes said. “The natural effects of a disturbance are not necessarily going to be straightforward and linear. What this showed us is that these heat waves impact every predator and prey in the ecosystem through direct and indirect pathways.”

The project was a collaboration by Oregon State University and the National Oceanic and Atmospheric Administration. Joshua Stewart, an assistant professor with the Marine Mammal Institute, mentored Gomes and co-authored the paper.

Smaller fish and changing food webs – even where species numbers stay the same

"Beyond the Numbers"
The hidden transition from ecosystems ruled by apex predators to those crowded by smaller, mid-level feeders.
Image Credit: Scientific Frontline

Scientific Frontline: Extended "At a Glance" Summary: Reorganization of Global Fish Food Webs

The Core Concept: Long-term global data indicates a widespread restructuring of marine and freshwater fish food webs, characterized by a shift toward smaller-bodied species and altered feeding relationships, even in ecosystems where overall species richness remains stable.

Key Distinction/Mechanism: Unlike traditional biodiversity metrics that rely primarily on species counts (richness), this ecological shift highlights underlying structural changes. Because the size of predators and prey governs feeding rules, the decline of large top predators and the rise of mid-level, generalist feeders create denser, more highly connected food webs. Ecosystem degradation is occurring via shifting biological traits and interactions rather than direct species loss.

Origin/History: The phenomenon was detailed in a massive global synthesis led by researchers from the German Centre for Integrative Biodiversity Research (iDiv), Martin Luther University Halle-Wittenberg (MLU), and Friedrich Schiller University Jena. By analyzing time-series data spanning up to 70 years across nearly 15,000 fish communities, the research team formally published their findings in Science Advances on February 24, 2026.

The many ways nature nurtures human well-being

Visitors leisurely enjoy an iris garden in Japan. Of all the pathways linking a single cultural ecosystem service to a single constituent of well-being captured from the academic literature, 86.3% represented positive contributions compared to just 11.7% negative contributions. 
Resized Image using AI by SFLORG
Credit: 2022 Nicola Burghall CC-BY-NC

A systematic review of 301 academic articles on “cultural ecosystem services” has enabled researchers to identify how these nonmaterial contributions from nature are linked to and significantly affect human well-being. They identified 227 unique pathways through which human interaction with nature positively or negatively affects well-being. These were then used to isolate 16 distinct underlying mechanisms, or types of connection, through which people experience these effects. This comprehensive review brings together observations from a fragmented field of research, which could be of great use to policymakers looking to benefit society through the careful use and protection of the intangible benefits of nature.

Do you ever feel the need for a bit of fresh air to energize yourself, or to spend time in the garden to relax? Aside from clean water, food and useful raw materials, nature provides many other benefits that we might overlook or find it hard to grasp and quantify. Research into cultural ecosystem services (CESs), the nonmaterial benefits we receive from nature, aims to better understand these contributions, whether they emerge through recreation and social experiences, or nature’s spiritual value and our sense of place.

Hundreds of CESs studies have explored the connections between nature and human well-being. However, they have often used different methods and measurements, or focused on different demographics and places. This fragmentation makes it difficult to identify overarching patterns or commonalities on how these intangible contributions really affect human well-being. Better understanding them could aid real-world decision-making about the environment, which could benefit individuals and the wider society.

Loss of nature costs more than previously estimated

Photo Credit: Christian Heitz

Researchers propose that governments apply a new method for calculating the benefits that arise from conserving biodiversity and nature for future generations.

The method can be used by governments in cost-benefit analyses for public infrastructure projects, in which the loss of animal and plant species and ‘ecosystem services’ – such as filtering air or water, pollinating crops or the recreational value of a space – are converted into a current monetary value.

This process is designed to make biodiversity loss and the benefits of nature conservation more visible in political decision-making.

However, the international research team says current methods for calculating the values of ecosystem services “fall short” and have devised a new approach, which they believe could easily be deployed in Treasury analysis underpinning future Budget statements.

Their approach, published in the journal Science, takes into consideration the increase in monetary value of nature over time as human income increases, as well as the likely deterioration in biodiversity, making it more of a scarce resource.

Urban birds prefer native trees

Urban great tits prefer native trees for breeding
Photo Credit: Sandra Alekseeva

Small passerine birds, such as blue and great tits, avoid breeding in urban areas where there are many non-native trees. Chicks also weigh less the more non-native trees there are in the vicinity of the nest. This is shown in a long-term study from Lund University in Sweden.

City trees contribute to several important ecosystem services such as lowering local temperature and purifying air but are also homes to birds and insects. Vegetation, especially trees, is the primary managed biological component of a city’s ecosystem. It is therefore important to understand the consequences of our planning of parks and green spaces. To find out how different types of trees affect birdlife, a research team, led by Lund University, monitored 400 nest boxes in five parks in the Swedish city Malmö over a seven-year period.

The results, now published in the scientific journal, Oecologia, show that native trees – defined in the study as species that have been in the ecosystem for at least 700 years – provide more resources and are preferred by urban birds.

New rapid method to predict effects of conservation actions on complex ecosystems

From left: Dr Matthew Adams, Sarah Vollert, Professor Drovandi
Photo Credit: Courtesy of Queensland University of Technology

A new way to analyze the effects of conservation actions on complex ecosystems has cut the modelling time from 108 days to six hours, QUT statisticians have found:

• Some conservation efforts backfire, eg eradicating feral cats could lead to rabbit explosion

• Modeling predicts the cascading effects through species in a complex ecosystem, but is computationally slow

• New method cuts prediction time from 3.5 months to six hours

PhD researcher Sarah Vollert, from the School of Mathematical Sciences and the QUT Centre for Data Sciences, said it was impossible to predict exactly how conservation actions would affect each species.

“Though well-intentioned, conservation actions have the potential to backfire,” Ms. Vollert said.

“For example, if decision-makers decide to eradicate feral cats, it could lead to explosive populations of their prey species, like rabbits.

“Uncontrolled rabbit populations could then have devastating effects on the vegetation, destroying the habitat native species need to survive.

Rare glimpse at understudied ecosystem prompts caution on deep-sea mining

Some of the animals identified in the deep-sea that spend their life in the benthic boundary layer.
Photo Credit: Gabrielle Ellis

Scientific Frontline: Extended "At a Glance" Summary: The Abyssal Benthic Boundary Layer

The Core Concept: The abyssal benthic boundary layer is an enormous, poorly understood marine region located just a few meters above the global ocean seafloor. It hosts a dynamic community of tiny organisms, such as zooplankton, snails, bivalves, and barnacles, forming a crucial and interconnected component of the broader deep-sea ecosystem.

Key Distinction/Mechanism: Unlike the historical assumption that the deep abyss is a largely static environment, the benthic boundary layer is highly responsive to seasonal changes. The ecosystem is driven by the varying levels of organic material (food) sinking from the productive surface waters above, resulting in stark structural changes to the biological community between spring and fall.

Major Frameworks/Components:

• Organic Matter Flux: The dependence of the deep-sea benthic community on the downward transfer of organic material from the surface ocean.
• Temporal Dynamics: The significant seasonal variations in the community structure of deep-sea zooplankton based on surface productivity.
• Larval Dispersal Pathway: The boundary layer functions as a critical transit zone and habitat for the larvae of wide-ranging abyssal species before they settle on the seafloor.
• Anthropogenic Disruption: The mechanisms by which deep-sea mining harms the ecosystem, including ambient water removal, sediment plumes that interfere with filter-feeding, and the removal of polymetallic nodules that serve as essential settling habitats for larvae.

Dry grass: Research project explores the effect of multi-year drought on grasslands

As a dry spell stretches from months to years, grasslands can adapt — to a point.
Photo Credit: Scientific Frontline / Heidi-Ann Fourkiller

A recent paper in the journal Science, “Drought intensity and duration interact to magnify losses in primary productivity,” explores how moderate and extreme droughts affect grasslands around the world. The paper has more than 180 international co-authors, with Binghamton University Assistant Professor of Ecosystem Science Amber Churchill among them.

Known as a distributed network, research projects of this type call upon collaborators to perform the same experiments locally, Churchill explained.

“The idea is that everyone uses the same methodology, but each local site is independently responsible for the maintenance of their site, data collection and ongoing measurements,” she said. “Often, individual sites will collect data in addition to the core project’s data.”

The experiment measured productivity, or how much plant biomass grows in a year. Less rain typically means less productivity, but the long-term picture is complicated by a number of factors. For one, not all grasslands are created equal; they come in a variety of types, with varying precipitation levels. Removing 10% of rainfall in an arid grassland is the equivalent of removing 40% of the precipitation in a wetter ecosystem, according to the research.

New study reveals how Ethiopia’s hyenas combat climate change, save money and prevent disease

Image Credit: Scientific Frontline

Scientific Frontline: Extended "At a Glance" Summary: Ecological Role of Urban Hyenas

The Core Concept: Spotted hyenas and other native scavengers in Mekelle, Ethiopia, function as essential components of the urban ecosystem by consuming thousands of tons of discarded organic meat waste. This natural scavenging acts as a vital ecosystem service, positioning these predators as accidental "eco-warriors" within high-density human settlements.

Key Distinction/Mechanism: Unlike traditional conservation models that assume large carnivores require vast, human-free natural environments to thrive, this phenomenon demonstrates a mutually beneficial coexistence in an urban setting. The scavengers actively clear organic waste from roadsides and open spaces before it can decompose, thereby preventing the release of greenhouse gases and eliminating breeding grounds for disease.

Origin/History: The findings stem from a recent study led by Dr. Gidey Yirga at the University of Sheffield's School of Biosciences. Researchers surveyed over 400 households to quantify urban waste generation, discovering that approximately 1,058,200 animals are slaughtered domestically each year in Mekelle, resulting in massive quantities of roadside meat waste.

Island-wide field surveys illuminate land-sea connections in Mo‘orea

Mo'orea, French Polynesia, is surrounded by a diverse and vibrant coral reef ecosystem.
Photo Credit: Christian John

A massive, multi-year scientific expedition led by researchers from the University of California, Santa Barbara and collaborating institutions, including the University of Hawai‘i (UH) at Mānoa, determined that land use on tropical islands can shape water quality in lagoons and that rainfall can be an important mediator for connections between land and lagoon waters. These findings provide vital information for ecosystem stewards facing global reef decline. Their findings were published recently in Limnology and Oceanography.

“This study is pretty groundbreaking in terms of its scale,” said Christian John, lead author of the study and postdoctoral scholar at the University of California, Santa Barbara. “We looked at algal tissue nutrients, water chemistry, and microbial communities at almost 200 sites around the island of Mo‘orea, French Polynesia, and we repeated this sampling over multiple years.”

“The links between land and sea are dynamic and complex, so it’s a topic that has remained elusive to science,” said Mary Donovan, co-author and faculty at the Hawai‘i Institute of Marine Biology in the UH Mānoa School of Ocean and Earth Science and Technology. “It took a dream team to pierce through that complexity. We brought together a group of interdisciplinary thinkers, from students to senior investigators, across at least five major institutions to tackle this immense challenge.”

Forest Resilience Linked with Higher Mortality Risk in Western U.S.

A new study assesses decades of U.S. forest health data, revealing a twist in Western U.S. forest fate amid climate change — higher ecosystem resilience is linked with higher mortality risk
Photo Credit: Sarah Ardin

A forest’s resilience, or ability to absorb environmental disturbances, has long been thought to be a boost for its odds of survival against the looming threat of climate change.

But a new study suggests that for some Western U.S. forests, it’s quite the opposite.

In the journal Global Change Biology, researchers have published one of the first large-scale studies of U.S. forest land exploring the link between forest resilience and mortality.

The study is based on more than three decades of satellite image data used for assessing forest resilience, and more than two decades of ground observations of forest tree death across the continental United States.

The results show that while high ecosystem resilience correlates with low mortality in eastern forests, it is linked to high mortality in western regions.

“It’s a surprising finding. … It was widely assumed that greater forest resilience indicates lower mortality risk, but this relationship hadn’t been rigorously evaluated at such a large scale until now,” said Xiaonan Tai, assistant professor of biology at New Jersey Institute of Technology and the corresponding author.

Biodiversity 'time machine' uses artificial intelligence to learn from the past

Experts can make crucial decisions about future biodiversity management by using artificial intelligence to learn from past environmental change, according to research at the University of Birmingham.

A team, led by the University’s School of Biosciences, has proposed a ‘time machine framework’ that will help decision-makers effectively go back in time to observe the links between biodiversity, pollution events and environmental changes such as climate change as they occurred and examine the impacts they had on ecosystems.

In a new paper, published in Trends in Ecology and Evolution, the team sets out how these insights can be used to forecast the future of ecosystem services such as climate change mitigation, food provisioning and clean water.

Using this information, stakeholders can prioritize actions which will provide the greatest impact.

Principal investigator, Dr Luisa Orsini, is an Associate Professor at the University of Birmingham and Fellow of The Alan Turing Institute. She explained: “Biodiversity sustains many ecosystem services. Yet these are declining at an alarming rate. As we discuss vital issues like these at the COP26 Summit in Glasgow, we might be more aware than ever that future generations may not be able to enjoy nature’s services if we fail to protect biodiversity.”

Biodiversity loss happens over many years and is often caused by the cumulative effect of multiple environmental threats. Only by quantifying biodiversity before, during and after pollution events, can the causes of biodiversity and ecosystem service loss be identified, say the researchers.

How fires, storms, and bark beetles will shape the future of Europe’s forests

Forests in southern and western Europe are especially at risk, while the economic, climatic and ecological impacts extend far beyond regional borders
Photo Credit: Rupert Seidl / TUM

Scientific Frontline: Extended "At a Glance" Summary: Future Forest Disturbances in Europe

The Core Concept: By 2100, the total area of European forests damaged by climate-driven disturbances—such as wildfires, storms, and bark beetles—is projected to substantially increase, potentially doubling under severe global warming scenarios.

Key Distinction/Mechanism: While routine tree mortality is a natural component of forest regeneration, this emerging paradigm is defined by an unprecedented scale of destruction driven by climate change, fundamentally altering ecosystem trajectories rather than simply recycling older canopy growth.

Major Frameworks/Components:

• AI-Driven Simulation Modeling: The researchers employed an artificial intelligence model trained on 135 million data points derived from forest simulations.
• High-Resolution Spatial Analysis: Multi-decadal satellite data covering 13,000 European locations enabled the simulation of future disturbances down to a single-hectare resolution.
• Climate Scenario Mapping: Projections were calculated based on varying degrees of global warming, ranging from an optimistic 2°C limit to scenarios exceeding 4°C.

New Insights into Ecosystem Functions

The mastermind behind the new statistical method: mathematician and statistician Anne Chao from National Tsing Hua University in Taiwan. Here she is in the university forest of the University of Würzburg on an experimental test plot.
Photo Credit: Simon Thorn/JMU

A DFG research group led by the University of Würzburg has developed a method that makes it possible to analyze the relationship between biodiversity within and between ecosystems and the multifunctionality of entire landscapes.

Ecosystems fulfil a number of vital tasks: They store carbon, clean polluted water, pollinate plants and so on. How well an ecosystem can fulfil these tasks depends largely on its biodiversity, i.e. the variety of plants, animals and microorganisms that live in it. Until now, scientists have only been able to understand the exact nature of this relationship at a local level, for example in relation to individual forest areas, meadows and ponds. The DFG (German Research Foundation) research group BETA-FOR, led by the University of Würzburg (JMU), has now succeeded in developing a statistical method that for the first time can also analyze the contributions of biodiversity between local ecosystems to the multifunctionality of entire landscapes.