Simple food swaps could cut greenhouse gas emissions from household groceries by a quarter

New analysis shows potential contribution that different purchasing choices could make

GEORGE INSTITUTE FOR GLOBAL HEALTH

Switching food and drink purchases to very similar but more environmentally friendly alternatives could reduce the greenhouse gas emissions from household groceries by more than a quarter (26%), according to a new Australian study from The George Institute for Global Health and Imperial College London published today in Nature Food.1

Making bigger changes - like swapping a frozen meat lasagne for the vegetarian option - could push the reduction to as much as 71%.

To make this happen will require on-pack labelling of greenhouse gas emissions for every packaged food product so that consumers can make informed choices.

This is the most detailed analysis ever conducted on the environmental impacts of a country’s food purchasing behaviour, involving comprehensive data on greenhouse gas emissions and sales for tens of thousands of supermarket products, typical of the Western diet of many countries globally.

Lead author and epidemiologist Dr Allison Gaines, who conducted the analysis for The George Institute and Imperial College London, said, “Dietary habits need to change significantly if we are to meet global emissions targets, particularly in high-income countries like Australia, the UK, and US.

“But while consumers are increasingly aware of the environmental impact of the food system and willing to make more sustainable food choices, they lack reliable information to identify the more environmentally friendly options.”

Researchers calculated the projected emissions of annual grocery purchases from 7,000 Australian households using information on ingredients, weights and production life cycles in The George Institute’s FoodSwitch database and global environmental impact datasets. More than 22,000 products were assigned to major, minor and sub-categories of foods (e.g. ‘bread and bakery’, ‘bread’ and ‘white bread’, respectively) to quantify emissions saved by switching both within and between groups.

Making switches within the same sub-categories of foods could lead to emission reductions of 26% in Australia, equivalent to taking over 1.9 million cars off the road.2 Switches within minor categories of foods could lead to even bigger emission reductions of 71%.

“The results of our study show the potential to significantly reduce our environmental impact by switching like-for-like products. This is also something consumers in the UK could, and would probably like, to do if we put emissions information onto product labels," said Dr Gaines.

Dr Gaines added that the switches would not compromise food healthiness overall: “We showed that you can switch to lower emissions products while still enjoying nutritious foods. In fact, we found it would lead to a slight reduction in the proportion of ultra-processed foods purchased, which is a positive outcome because they’re generally less healthy,” she said.

The purchase analysis also showed that meat products contributed almost half (49%) of all greenhouse gas emissions, but only 11% of total purchases. Conversely, fruit, vegetables, nuts and legumes represented one quarter (25%) of all purchases, but were responsible for just 5% of emissions.

It is estimated that around one-third of global greenhouse gas emissions are attributable to the food and agriculture sector, and the combined health and environmental costs of the global food system are estimated to be 10-14 trillion USD (8-11 trillion GBP) per year.3,4,5 More than 12 million deaths per year could be prevented if the system transitioned to deliver healthy, low-emission diets.3

Prof Bruce Neal, Executive Director at The George Institute Australia and Professor of Clinical Epidemiology at Imperial College London, said that as a global community, we are taking too long to improve the sustainability of the food system, endangering the prospect of a net-zero future.

“There is currently no standardised framework for regulating the climate or planetary health parameters of our food supply, and voluntary measures have not been widely adopted by most countries. This research shows how innovative ways of approaching the problem could enable consumers to make a real impact,” he said.

“With this in mind, we have developed a free app called ecoSwitch, currently available in Australia, which is based on this research. Shoppers can use their device to scan a product barcode and check its ‘Planetary Health Rating’, a measure of its emissions shown as a score between half a star (high emissions) to five stars (low emissions).”

The George Institute plans to extend the ecoSwitch algorithm to integrate other environmental indicators such as land and water use, and biodiversity, and to introduce the tool to other countries.

“While ecoSwitch is a much-needed first step in providing environmental transparency for grocery shoppers, the vision is for mandatory display of a single, standardised sustainability rating system on all supermarket products,” concluded Prof Neal.

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JOURNAL

Nature Food

DOI

10.1038/s43016-024-00971-6 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Switches in food and beverage product purchases can reduce greenhouse gas emissions in Australia

ARTICLE PUBLICATION DATE

28-May-2024

 

Florida fossil porcupine solves a prickly dilemma 10-million years in the making

FLORIDA MUSEUM OF NATURAL HISTORY

 

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FORMER GRADUATE STUDENT NATASHA VITEK AND HER ADVISOR JONATHAN BLOCH CO-CREATED A COLLEGE COURSE FOR STUDENTS TO LEARN ABOUT PALEONTOLOGY WHILE GETTING HANDS-ON EXPERIENCE WITH A RARE 2 MILLION-YEAR-OLD PORCUPINE SKELETON.

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CREDIT: FLORIDA MUSEUM PHOTO BY JEFF GAGE

There’s a longstanding debate simmering among biologists who study porcupines. There are 16 porcupine species in Central and South America, but only one in the United States and Canada. DNA evidence suggests North America’s sole porcupine belongs to a group that originated 10 million years ago, but fossils seem to tell a different story. Some paleontologists think they may have evolved just 2.5 million years ago, at the beginning of the ice ages.

A new study published in the journal Current Biology claims to have reconciled the dispute, thanks to an exceptionally rare, nearly complete porcupine skeleton discovered in Florida. The authors reached their conclusion by studying key differences in bone structure between North and South American porcupines, but getting there wasn’t easy. It took an entire class of graduate and undergraduate students and several years of careful preparation and study.

“Even for a seasoned curator with all the necessary expertise, it takes an incredible amount of time to fully study and process an entire skeleton,” said lead author Natasha Vitek. While studying as a doctoral student at the Florida Museum of Natural History, Vitek teamed up with vertebrate paleontology curator Jonathan Bloch to create a college course in which students got hands-on research experience by studying porcupine fossils.

Ancient radiation gave rise to world’s largest rodents

Porcupines are a type of rodent, and their ancestors likely originated in Africa more than 30 million years ago. Their descendants have since wandered into Asia and parts of Europe by land, but their journey to South America is a particularly defining event in the history of mammals. They crossed the Atlantic Ocean — likely by rafting — when Africa and South America were much closer together than they are today. They were the first rodents to ever set foot on the continent, where they evolved into well-known groups like guinea pigs, chinchillas, capybaras and porcupines.

Some took on giant proportions. There were lumbering, rat-like animals up to five feet long, equipped with a tiny brain that weighed less than a plum. Extinct relatives of the capybara grew to the size of cows.

Porcupines remained relatively small and evolved adaptations for life in the treetops of South America’s lush rainforests. Today, they travel through the canopy with the aid of long fingers capped with blunt, sickle-shaped claws perfectly angled for gripping branches. Many also have long, prehensile tails capable of bearing their weight, which they use while climbing and reaching for fruit.

Despite their excellent track record of getting around, South America was a dead end for many millions of years. A vast seaway with swift currents separated North and South America, and most animals were unable to cross — with a few notable exceptions.

Beginning about 5 million years ago, the Isthmus of Panama rose above sea level, cutting off the Pacific from the Atlantic. This land bridge became the ancient equivalent of a congested highway a few million years later, with traffic flowing in both directions.

Prehistoric elephants, saber-toothed cats, jaguars, llamas, peccaries, deer, skunks and bears streamed from North America to South. The reverse trek was made by four different kinds of ground sloths, oversized armadillos, terror birds, capybaras and even a marsupial.

The two groups met with radically different fates. Those mammals migrating south did fairly well; many became successfully established in their new tropical environments and survived to the present. But nearly all lineages that ventured north into colder environments have gone extinct. Today, there are only three survivors: the nine-banded armadillo, the Virginia opossum and the North American porcupine.

New fossils catch evolution in the act

Animals that traveled north had to contend with new environments that bore little resemblance to the ones they left behind. Warm, tropical forests gave way to open grasslands, deserts and cold deciduous forests. For porcupines, this meant coping with brutal winters, fewer resources and coming down from the trees to walk on land. They still haven’t quite gotten the hang of the latter; North American porcupines have a maximum ground speed of about 2 mph.

South American porcupines are equipped with a menacing coat of hollow, overlapping quills, which offer a substantial amount of protection but do little to regulate body temperature. North American porcupines replaced these with a mix of insulating fur and long, needle-like quills that can be raised when they feel threatened. They also had to modify their diet, which changed the shape of their jaw.

“In winter, when their favorite foods are not around, they will bite into tree bark to get at the softer tissue underneath. It’s not great food, but it’s better than nothing,” Vitek said. “We think this type of feeding selected for a particular jaw structure that makes them better at grinding.”

They also lost their prehensile tails. Although North American porcupines still like climbing, it’s not their forte. Museum specimens often show evidence of healed bone fractures, likely caused by falling from trees.

Many of these traits can be observed in fossils. The problem is there aren’t many fossils to go around. According to Vitek, most are either individual teeth or jaw fragments, and researchers often lump them in with South American porcupines. Those that are considered to belong to the North American group lack the critical features that would provide paleontologists with clues to how they evolved.

So when Florida Museum paleontologist Art Poyer found an exquisitely preserved porcupine skeleton in a Florida limestone quarry, they were well aware of its significance.

“When they first brought it in, I was amazed,” said Bloch, senior author of the study. “It is so rare to get fossil skeletons like this with not only a skull and jaws, but many associated bones from the rest of the body. It allows for a much more complete picture of how this extinct mammal would have interacted with its environment. Right away we noticed that it was different from modern North American porcupines in having a specialized tail for grasping branches.”

By comparing the fossil skeleton with bones from modern porcupines, Bloch and Vitek were confident they could determine its identity. But the amount of work this would require was more than one person could do on their own in a short amount of time. So they co-created a paleontology college course, in which the only assignment for the entire semester was studying porcupine bones.

“It’s the kind of thing that could only be taught at a place like the Florida Museum, where you have both collections and enough students to study them,” Vitek said. “We focused on details of the jaw, limbs, feet and tails. It required a very detailed series of comparisons that you might not even notice on the first pass.”

The results were surprising. The fossil lacked the reinforced bark-gnawing jaws and possessed a prehensile tail, making it appear more closely related to South American porcupines. But, Vitek said, other traits bore a stronger similarity to North American porcupines, including the shape of the middle ear bone as well as the shapes of the lower front and back teeth.

With all the data combined, analyses consistently provided the same answer. The fossils belonged to an extinct species of North American porcupine, meaning this group has a long history that likely began before the Isthmus of Panama had formed. But questions remain as to how many species once existed in this group or why they went extinct.

“One thing that isn’t resolved by our study is whether these extinct species are direct ancestors of the North American porcupine that is alive today,” Vitek said. “It’s also possible porcupines got into temperate regions twice, once along the Gulf Coast and once out west. We’re not there yet.”

Jennifer Hoeflich, Isaac Magallanes, Sean Moran, Rachel Narducci, Victor Perez, Jeanette Pirlo, Mitchell Riegler, Molly Selba, María Vallejo-Pareja, Michael Ziegler, Michael Granatosky and Richard Hulbert of the Florida Museum of Natural History are also authors on the paper.

North (left) and South (right) American porcupines have been on separate evolutionary trajectories for as long as 10 million years.

CREDIT

Florida Museum photo by Kristen Grace

JOURNAL

Current Biology

DOI

10.1016/j.cub.2024.04.069 

ARTICLE TITLE

An extinct north American porcupine with a South American tail

ARTICLE PUBLICATION DATE

27-May-2024

 

Salty soil sensitizes plants to an unconventional mode of bacterial toxicity

MAX PLANCK INSTITUTE FOR PLANT BREEDING RESEARCH

 

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CULTURE COLLECTION OF ROOT-ASSOCIATED BACTERIA

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CREDIT: STÉPHANE HAQUARD

Climate change, and specifically rising temperatures, will place a great strain on plant growth and will almost certainly impact plant production. One obvious consequence of a warmer climate is that plants in the field will require more irrigation. With more watering, however, also comes more salinity as in this way nutrient salts accumulate in agricultural soils. Climate change will also affect plant health through what it does to the communities composed of numerous microorganisms that live in intimate association with plant hosts. These communities make plants hardier in the face of stressful conditions and more resistant to pathogenic microbes. Thus, inoculation with defined bacterial communities as probiotics is an attractive strategy for safeguarding plant health. However, to ensure that these inocula are effective it is necessary to understand how bacteria and plants interact under different conditions.

From previous experiments, co-corresponding author Hacquard who is based at the Max Planck Institute for Plant Breeding Research in Cologne, Germany, and his colleagues knew that approx. 95% of the bacteria found in plant microbiota are either neutral or beneficial in one-on-one interactions with thale cress plants. A small number, however, are detrimental when grown together with plants under laboratory conditions, among them Pseudomonas brassicacearum R401, a Gram-negative bacterium found in soil that is a dominant member of the plant microbiota. Surprisingly, though, when this bacterium was grown together with plants under natural soil conditions, no disease was observed. This suggests that the bacterium requires specific conditions to cause disease on soil-grown plants.

Some previous reports had shown that salt stress can facilitate bacterial infection of plants. Indeed, when the scientists applied salt, they found that plant growth was negatively affected in the presence of the R401 strain. Many Gram-negative bacteria cause virulence by injecting disease-causing proteins directly into the host cell cytoplasm. However, inspection of the R401 genome failed to reveal any genes encoding this injection apparatus. Further, many pathogenic bacteria overgrow on their plant host and deploy strategies to dampen plant immune responses. Again, R401 was doing neither of these things. 

 

To understand how the R401 strain causes disease on soil-grown plants facing salt stress, Hacquard and his group teamed up with the natural product group of Till Schäberle at the Justus-Liebig-University and the Fraunhofer Institute for Molecular Biology and Applied Ecology in Giessen. Together the researchers identified genes that showed similarity to genes from related bacteria that encode phytotoxic metabolites. They isolated the predicted metabolite, which they termed brassicapeptin, and mutated one of the core genes required for its synthesis. This mutation was sufficient to turn R401 into a plant-beneficial bacterium. 

Strikingly, once they had the compound in hand, the scientists could show that brassicapeptin is by itself enough to cause plant disease in concert with high salt conditions. Further, brassicapeptin was not only toxic for thale cress plants but also for tomato plants experiencing salt stress, as well as for other microbes. The researchers could show that the molecule, which is composed of a fatty acid tail linked to amino acids, can form pores in plant membranes. This could explain why the molecules toxicity becomes apparent when plants are facing salt stress.

Till Schäberle is excited by the possibilities this study throws up for improving crop health: “It is important that we learn more about how the natural products produced by microbes influence plant physiology. This will allow us to design effective biologics for crop protection.” 

Stéphane Hacquard found remarkable that “a single bacterial molecule can at the same time sensitize plants to osmotic stress, promote bacterial capability to colonize roots and impede growth of bacterial and fungal competitors.” 

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JOURNAL

Nature Communications

DOI

10.1038/s41467-024-48517-5 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Physiochemical interaction between osmotic stress and a bacterial exometabolite promotes plant disease

ARTICLE PUBLICATION DATE

28-May-2024

Asian forests show excellent resilience despite rising disturbances from climate change and human activities

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

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EVERGREEN NEEDLELEAF FOREST IN THE SUNSHINE

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CREDIT: YIYING ZHU

Since 1850, global temperatures have been steadily rising. Human activities have significantly increased the emissions of greenhouse gases into the atmosphere, exacerbating the greenhouse effect and global warming. Forests in Asia have faced numerous challenges from climate change and human activities, threatening their stability and ecological functions. However, detailed studies on forest disturbances and their responses in this region are limited. 

Ecologists from Beijing Forestry University and the Institute of Atmospheric Physics, China, conducted a comprehensive analysis of forest disturbances and resilience using satellite remote sensing data in a new study. The associated paper has recently been published in Atmospheric and Oceanic Science Letters.

Forest ecosystems absorb about 33% of the carbon dioxide from human-related emissions, which is vital to climate-change mitigation and adaptation. However, frequently occurring climate extremes and human activities have considerably threatened the resilience of forests. The study employed the Breaks For Additive Seasonal and Trend (BFAST) method, an effective tool for detecting abrupt changes in time series data, to analyze the Enhanced Vegetation Index time series across East Asia, South Asia, and Southeast Asia. By identifying disturbances and quantifying forest resilience, the research sheds light on the dynamics of forest ecosystems in response to various external pressures.

"20% of forests in Asia's low and middle latitudes experienced disturbances between 2000 and 2022, with Southeast Asian countries being particularly affected. Despite these challenges, 95% of the forests showed robust resilience and recovered from disturbances within a few decades. Notably, forests with greater disturbance magnitude exhibited stronger resilience; they tend to have faster recovery rates compared to forests with lower disturbance magnitude," says the first author, Yiying Zhu, an ecology master at Beijing Forestry University. "This is good news for adapting to future extreme events due to climate change or human activities."

"Almost half of the forest disturbances were caused by commodity-driven deforestation, and the average recovery time for a forest ecosystem to return to its pre-disturbance state was 16.2 years," explains Prof. Hesong Wang, a global change ecology researcher at Beijing Forestry University. "The land-use changes resulting from human activities have a profound impact on forest ecosystems, and we need to have a deeper understanding of ecosystem recovery to mitigate the damage to forests."

"Applying satellite remote sensing in monitoring and managing forest ecosystems is essential for us to elucidate the relationship between disturbances and forest recovery," adds A/Prof. Anzhi Zhang, an associate professor from the Institute of Atmospheric Physics, China, another coauthor of the paper. "Satellite remote sensing provides valuable insights for sustainable forest management practices in the region, and should be employed throughout the globe."

In conclusion, this research underscores the excellent resilience of Asian forests after disturbances, as revealed by satellite remote sensing data. By elucidating the spatial and temporal patterns of forest dynamics, the study contributes to advancing our knowledge of forest ecology and informs conservation strategies for preserving forest ecosystems.
 

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JOURNAL

Atmospheric and Oceanic Science Letters

DOI

10.1016/j.aosl.2024.100511 

ARTICLE TITLE

Satellite remote sensing reveals overwhelming recovery of forest from disturbances in Asia

Turning carbon dioxide into useful chemicals

German junior research group investigates how to convert carbon dioxide using sunlight

UNIVERSITY OF OLDENBURG

 

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LARS MOHRHUSEN'S JUNIOR RESEARCH GROUP AIMS TO DEVELOP NEW CATALYSTS FOR THE CONVERSION OF CARBON DIOXIDE. THE CATALYST SAMPLES (LIKE THE SQUARE GREY PLATE IN THE MIDDLE OF THE HOLDER) ARE EXAMINED IN VACUUM CHAMBERS USING VARIOUS ANALYTICAL METHODS.

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CREDIT: UNIVERSITY OF OLDENBURG / MARCUS WINDUS

Harnessing the power of the sun to convert carbon dioxide into useful chemicals is the goal of a new junior research group at the University of Oldenburg. The international team led by chemist Dr Lars Mohrhusen will adopt a double-sustainable approach: it aims to develop precious-metal-free catalysts that use sunlight to chemically activate this relatively inert greenhouse gas. The Federal Ministry of Education and Research (BMBF) has approved 2.6 million euros in funding for the project Su2nCat-CO2 over the next six years as part of its funding programme SINATRA (for junior research groups focused on “Artificial Photosynthesis” and the “Use of Alternative Raw Materials for Hydrogen Production”).

Commenting on the project, Prof. Dr Ralph Bruder, President of the University of Oldenburg, said: “The new junior research group’s work is aimed at finding inexpensive and durable materials to replace the precious metal catalysts currently in use. The BMBF's funding commitment acknowledges the University of Oldenburg’s extensive interdisciplinary expertise in the fields of catalysis and nanomaterials and underlines the great importance of this research for society.”

Catalysts without precious metals

Mohrhusen and his team will focus on developing catalyst materials based on readily available and inexpensive components such as titanium dioxide. The aim is to find highly energy-efficient ways to convert the greenhouse gas carbon dioxide into compounds such as methanol, formaldehyde or ethylene which can be used by the chemical industry in the manufacture of plastics or synthetic fuels, for example. “The conversion of substances like carbon dioxide generally involves precious-metal-containing catalysts, which often require high pressure and high temperatures during operation,” Mohrhusen explains. In addition to the large amounts of energy required to create the right conditions to trigger a reaction, these materials often have the disadvantage of being expensive and not particularly durable. Impurities in the gas feed, for example, can easily “poison” the catalyst material so that it becomes less active over time, the chemist points out.

Mohrhusen's team plans to investigate two different types of hybrid catalyst materials in model systems. For this they will create combinations of titanium dioxide and semi-metal nanoparticles as the first class of materials, and organic structures on oxide surfaces as the second. In the next step, the researchers will use various techniques to characterise the systems at the atomic level– a process which typically requires ultra-high vacuum conditions. Both material classes will be photocatalysts, meaning that they become catalytically active when exposed to light. Their exposure to sunlight generates charge carriers – negatively charged electrons and positively charged “vacancies”, so called “holes” – which can then react chemically with carbon dioxide. “On the basis of these model catalysts we aim to gain a detailed, atomic-level understanding of which material properties enhance the reactivity as well as the stability of these systems," says Mohrhusen. This can be very difficult under the technical conditions that prevail in large reactors, he explains.

Tests in microreactors

In a third sub-project the team plans to design micro reactors to test the model catalysts under more realistic conditions. This will involve bringing the catalyst materials into a gas atmosphere – a combination of carbon dioxide, hydrogen and water, for example – in a special chamber and simultaneously irradiating them with light. The researchers will analyse the formation of reaction products during the process and can also examine the catalyst materials for structural changes caused by the reaction once the tests have been completed.

Mohrhusen studied chemistry at the University of Oldenburg, where he earned his bachelor's degree in 2014 and his master's in 2016. He also completed his PhD in Oldenburg in 2021, in the Nanophotonics and Surface Chemistry group led by Prof. Dr Katharina Al-Shamery. As a postdoc, he has spent around three years in total conducting research at Harvard University (USA) and Aarhus University (Denmark).

The Friedrich-Alexander-Universität Erlangen-Nürnberg, Leiden University (the Netherlands), Aarhus University (Denmark), the University of Florida (USA) and the two companies Evonik and Leiden Probe Microscopy are supporting Mohrhusen's project as associated partners. The BMBF’s funding line for junior research groups enables outstanding early-career researchers to set up their own research groups and work on innovative projects while advancing their careers on the path to a professorship or other leading academic positions.

 

Biodiversity in the margins: Merging farmlands affects natural pest control

A new study published in the Journal of Applied Ecology demonstrates how the diversity and abundance of arthropods decrease when hedgerows and field margins covered by wild grass and flowers are removed.

XI'AN JIAOTONG-LIVERPOOL UNIVERSITY

 

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TRADITIONAL CHINESE SMALLHOLDER FIELDS ARE IRREGULARLY SHAPED AND SEPARATED BY AREAS OF HEDGEROWS, WILD GRASS, AND FLOWERS. USING LARGE-SCALE MACHINERY IN THESE FARMLANDS IS DIFFICULT, SO THERE IS LOW AGRICULTURAL OPERATION EFFICIENCY. AS A RESULT, A GROWING PROPORTION OF CHINA'S TRADITIONAL FARMLANDS ARE RAPIDLY CHANGING AS FARMERS CONSOLIDATE LAND TO IMPROVE EFFICIENCY.

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CREDIT: MARKUS RAAB

A new study published in the Journal of Applied Ecology demonstrates how the diversity and abundance of arthropods decrease when hedgerows and field margins covered by wild grass and flowers are removed.

Researchers from the UK, Netherlands and China studied 20 rice fields in China for six years to see how the changing agricultural landscape affects the diversity and abundance of rice pests and their natural enemies, as well as the effect on rice yield.

Traditional Chinese smallholder fields are irregularly shaped and separated by areas of hedgerows, wild grass, and flowers. Using large-scale machinery in these farmlands is difficult, so there is low agricultural operation efficiency. As a result, a growing proportion of China's traditional farmlands are rapidly changing as farmers consolidate land to improve efficiency.

However, the grassy margins and flowering vegetation between the traditional smallholder rice fields provide a habitat for the natural enemies of rice pests such as spiders and ground beetles. 

Dr Yi Zou, from Xi'an Jiaotong-Liverpool University (XJTLU) and corresponding author of the study, says: "Hedgerows and field margins are frequently removed during the land consolidation procedure to create larger, rectangular fields and install concrete irrigation channels to facilitate the use of larger machinery.

"Our study suggests that removing these habitats negatively affects arthropod communities."

Enemies in abundance

The team collected 141,587 individual arthropods made up of 80 taxonomic families. They found that traditional farmland supported a significantly higher abundance and diversity of rice pests' natural enemies than consolidated land, but there were no significant differences in the number of rice pests or rice yield.

Dr Zou says: "Land consolidation removes the natural vegetation of traditional farmlands that can provide nesting habitats and food sources for the natural enemies of rice pests.

"But there is a lot we still don't know, such as how land consolidation affects different groups of rice arthropods. Long-term monitoring and detailed assessment of land consolidation is still needed."

The research group also sprayed half of each field with insecticide. They found that its application decreased the diversity and abundance of pests and natural enemies in both consolidated and traditional fields. However, where crops were not sprayed with insecticide, there was a 10.8% decrease in rice yield.

The study provides support for agri-environmental measures (AEM) – environmentally friendly agricultural practices such as using flowering plants in field margins. AEM can be an effective way to increase farmland biodiversity and mitigate the negative impact of land consolidation. They have been widely implemented in Europe but are hardly used in China.

Dr Zou says: "Our agricultural biodiversity monitoring in this study serves as a critical tool for assessing the impacts of land consolidation and the effectiveness of AEM on biodiversity. These measurements are needed before proposing land management recommendations for an appropriate AEM.

"As a result of our findings, we recommend the implementation of AEM or re-establishing field margin vegetation during the consolidation process to mitigate the potential negative effects on rice arthropod biodiversity."

Dr Jenny Hodgson, a co-author from the University of Liverpool, says: "This study is noteworthy because of the quality of its data and the breadth of influential factors we were able to investigate. It has been really interesting to disentangle the effects of farmland consolidation, of pesticide application and of seminatural habitat beyond the farm."

Profit margins

The team also acknowledges that biodiversity is not a farmer's only concern.

Dr Shanxing Gong, who graduated from XJTLU, now a postdoctoral researcher at Peking University and lead author of the study, says: "The trade-off between biodiversity improvements with labour efficiency, yield and pest control is a balance that has to be finely tuned to ensure maximum profitability, and these factors will always need to be considered.

"While we did not observe a direct correlation between the increase in the number of rice pests and the reduction of their natural enemies due to land consolidation, further investigation into the effectiveness of natural enemies in biological pest control is necessary before implementing AEM strategies."

The researchers also found no decrease in rice yield in traditional fields compared to consolidated farmland.

Dr Gong says: "The impact of AEMs on yield depends on many factors, including agricultural management intensity, soil fertility and pesticide application, that all need to be taken into account when assessing their suitability for land management."

The team includes researchers from XJTLU, Jiangxi Academy of Sciences, Jiangxi Agricultural University, China Agricultural University, and Beijing Forestry University, China; Wageningen University & Research, the Netherlands; and the University of Liverpool, UK.

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JOURNAL

Journal of Applied Ecology

DOI

10.1111/1365-2664.14671 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Land consolidation impacts the abundance and richness of natural enemies but not pests in small-holder rice systems

ARTICLE PUBLICATION DATE

28-May-2024

COI STATEMENT

The authors declare no conflict of interest. YZ is an Associate Editor of Journal of Applied Ecology, but took no part in the peer review and decision-making processes for this paper.

Land consolidation impacts the abundance and richness of natural enemies but not pests in small-holder rice systems 

 

Locations of the 20 study sites with focal rice fields (a) and examples of landscapes dominated by traditional (b) and consolidated fields (c). Consolidated / traditional sites refer to the consolidation status of the experimental rice field changed during the six experimental years.

S. Gong et al,. (2024). Land consolidation impacts the abundance and richness of natural enemies but not pests in small-holder rice systems,. Journal of Applied Ecology. DOI:10.1111/1365-2664.14671 https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.14671

CREDIT

Yi Zou (XJTLU)