The argument rests on a striking gap in environmental surveillance. Water quality monitoring around the world routinely tracks bacterial indicators such as Escherichia coli and Legionella, along with enteric viruses, because these signal faecal contamination or acute failures in water treatment. Pathogenic free-living amoebae, however, are rarely included in any surveillance programme, despite living in exactly the environments that are already being sampled. The authors point out that conventional indicators primarily reflect contamination events, whereas amoebae integrate something far richer: the broader dynamics of microbial communities through their grazing behaviour and their remarkable ability to encyst. In other words, amoebae capture ecological information that bacteria and viruses alone cannot reveal, making them potential sentinels of ecosystem instability that public health systems have never learned to read.

The technical case for concern is grounded in amoebal biology. Free-living amoebae alternate between an active feeding stage called the trophozoite and a dormant, extraordinarily resistant cyst, with some genera such as Naegleria adding a temporary flagellate stage to the life cycle. The cyst stage allows both the amoeba and any bacteria it harbours internally to withstand desiccation, temperature fluctuations, ultraviolet radiation, chemical exposure, and standard disinfection procedures for prolonged periods. This persistence exceeds that of many free-living bacteria, and it creates a plausible pathway by which pathogens could survive harsh conditions and subsequently enter human-related environments. Climate-driven changes in temperature, precipitation, salinity, soil moisture, and ultraviolet radiation are likely to affect amoebic survival, encystment, and virulence, potentially increasing human exposure through soil disturbance, aerosols, recreational waters, and urban water systems, particularly in coastal zones and regions hit by extreme weather.

Perhaps the most provocative element of the argument concerns what amoebae do to the bacteria they encounter. Bacterial species have evolved mechanisms to survive digestion and persist within both trophozoite and cyst stages of their predators. By sheltering microorganisms from hostile conditions, amoebae facilitate horizontal gene transfer, promote microbial persistence, and contribute to the evolution of traits that enhance survival and virulence. Many microorganisms that resist amoebal digestion carry traits that also serve them well under stress, including antimicrobial resistance, increased biofilm formation, and improved tolerance to desiccation and temperature swings. The authors suggest that climate change may preferentially favour microorganisms that are pre-adapted to amoebal predation, and that the same adaptations that help bacteria survive inside a predator can also help them infect human hosts. This is the proposed mechanistic bridge between environmental change and emerging health risk.

The ecological stakes extend well beyond human disease. In soil ecosystems, Acanthamoeba species act as dominant bacterial grazers, consuming primary decomposers and releasing mineral nutrients sequestered within bacterial biomass, functioning as secondary decomposers in the soil food web. Amoebal grazing reshapes bacterial community composition and accelerates nutrient mineralisation, linking microbial turnover directly to soil fertility and carbon cycling. Recent work in soil microbial ecology has shown that protist-driven grazing enhances litter decomposition and increases microbial carbon flux, with the magnitude of these effects varying according to temperature. Because these processes are climate-sensitive, shifts in amoebal activity under warming conditions could influence soil function and microbial succession, with consequences for how carbon moves through ecosystems on a planetary scale.

The authors frame their argument within the One Health perspective, which recognises the health of humans, animals, plants, and the environment as interconnected, and within the emerging concept of the planetary microbiome: the interconnected microbial systems spanning soil, water, air, and host organisms that both shape and respond to planetary-scale ecological processes. Within this framework, amoebae occupy a peculiar position. They are ubiquitous, inhabiting soil, dust, air, and water, and they respond rapidly to changes in moisture, temperature, and nutrient availability, which makes them sensitive bioindicators of environmental instability. Shifts in their abundance, in the ratio of cysts to active trophozoites, and in their intracellular microbiota can be detected at the species or genus level, typically over seasonal timescales, offering a resolution that coarser microbial indicators cannot match.

Several pathogenic genera sharpen the urgency of the argument. Acanthamoeba species, Naegleria fowleri, Balamuthia mandrillaris, Sappinia pedata, Vahlkampfia species, Paravahlkampfia species, and Vermamoeba species can cause infections ranging from keratitis, a sight-threatening corneal disease, to fatal encephalitis. Rising temperatures may expand the geographic range of Naegleria fowleri, the so-called brain-eating amoeba, while changing moisture conditions may alter the behaviour of Acanthamoeba and Balamuthia in soil and dust. Salinity fluctuations impose osmotic stress on amoebae, and experimental evidence demonstrates differential growth responses among pathogenic genera under elevated salt conditions, suggesting that climate-driven hydrological change could restructure which amoebae thrive where. The authors are careful to note that these are plausible ecological links rather than direct causal relationships, and that environmental mediators likely modulate the outcomes, but the direction of the evidence is consistent enough to warrant systematic study.

What would it take to close the knowledge gap? The authors lay out a concrete research agenda. Experimental studies should link amoebal abundance, cyst prevalence, and intracellular microbiota to temperature, moisture, and land use, while climate-simulation systems could assess how warming and drying shift encystment and grazing behaviour. Multi-omic approaches, combining genomics, transcriptomics, and proteomics, should be applied to characterise the intracellular microorganisms carried by amoebae across different climates, with priority given to representative taxa such as Acanthamoeba, Naegleria, and Balamuthia and their internal microbiota. Useful metrics include the relative abundance of amoebae within total microbial or eukaryotic community reads, cyst prevalence, and detectable intracellular bacteria. Feasible detection methods range from microscopy with molecular confirmation to targeted quantitative PCR for key taxa and metagenomic screening, and seasonal sampling in coastal zones, urban water systems, and agricultural soils would capture climate-linked fluctuations over time.

The authors also propose that amoebae be incorporated into routine soil and water surveillance, particularly in regions experiencing sustained warming of more than 0.2 to 0.3 degrees Celsius per decade or marked precipitation variability exceeding 20 percent between years. Biosensor-based early warning tools for climate-sensitive hazards could provide a practical route to this goal, and the authors acknowledge that such approaches face limitations, including non-climatic drivers of amoebal ecology and technical constraints in detection, underscoring the need for simplified, comparable monitoring tools that can be deployed at scale. Systems that simulate future climate scenarios would additionally allow researchers to explore how amoebae influence microbial succession, biogeochemical cycling, and the persistence of opportunistic pathogens under conditions that have not yet arrived in the field.

The broader message is one of humility about what we know. To the authors’ knowledge, no global regulations currently address the presence of amoebae in environmental or built water systems, and no standardised prevention or disinfection protocols exist for them, even as their cysts shrug off the disinfectants that water utilities rely upon. As global temperatures rise and ecosystems transform, the microbial communities that underpin planetary health are changing in ways we are only beginning to measure, and the organisms that connect those changes to human exposure may be ones we have never thought to count. Incorporating free-living amoebae into planetary microbiome and One Health models, the authors argue, would provide a practical indicator system for tracking microbial responses to climate change, one that links the fate of soil carbon, the safety of drinking water, and the emergence of drug-resistant pathogens through a single, overlooked predator.

Subject of Research: The role of free-living amoebae in climate-driven microbiome dynamics and One Health

Article Title: Climate change and planetary microbiome: Are we overlooking free-living amoebae in climate-microbiome dynamics?

Article References: Siddiqui, R., Lloyd, D., & Khan, N. A. (2026). Climate change and planetary microbiome: Are we overlooking free-living amoebae in climate-microbiome dynamics?. PLOS Ecosystems, 1(1), e0000016. https://doi.org/10.1371/journal.pesy.0000016

Image Credits: AI Generated

DOI: 10.1371/journal.pesy.0000016

Keywords: free-living amoebae, climate change, planetary microbiome, One Health, Acanthamoeba, Naegleria fowleri, Balamuthia mandrillaris, soil ecology, water surveillance, encystment, horizontal gene transfer, antimicrobial resistance

The research team, led by Panpan Wu and Rong Mao of Jiangxi Agricultural University, set out to answer a question that has lingered in soil ecology for years: does the chemical form of nitrogen deposition change its effect on microbial necromass? Atmospheric nitrogen does not arrive in a single form. Industrial and agricultural activities release both inorganic nitrogen, dominated by ammonium and nitrate, and organic nitrogen compounds that travel through the atmosphere and settle onto forests. Earlier studies often treated these forms as interchangeable, or focused on just one. The subtropical forests of southern China, which receive some of the highest nitrogen deposition loads in the world, offered an ideal natural laboratory for testing whether form matters.

The experiment was conducted in a subtropical plantation, where the researchers applied three nitrogen treatments to field plots: ammonium chloride representing inorganic nitrogen, and urea and glycine representing organic nitrogen. They sampled soil at two depths, from zero to ten centimeters and from ten to twenty centimeters, and measured microbial necromass carbon using amino sugar biomarkers, molecules that persist in soil after microbial cells die and serve as fingerprints of fungal and bacterial remains. Alongside these measurements, the team tracked soil nutrient availability, microbial biomass, community composition, hydrolytic enzyme activities, and the mineralization of organic carbon into carbon dioxide.

The results were striking in their consistency. Despite the very different chemistry of the three compounds, all of them reduced soil microbial necromass carbon by similar magnitudes: ammonium chloride cut it by 20.7 percent, urea by 17.4 percent, and glycine by 20.1 percent. Just as notably, the total soil organic carbon content and the cumulative carbon dioxide emitted from the soil did not change. This decoupling is what makes the study so compelling. The overall carbon pool looked unchanged, yet a biologically meaningful and relatively stable fraction of it — the accumulated corpses of generations of microbes — had measurably declined. Necromass carbon is not a passive residue; it is a dynamic pool whose accumulation depends on the balance between microbial growth, death, and the recycling of dead cells by surviving organisms.

When the researchers separated the necromass into its fungal and bacterial components, a clearer picture emerged. The decline was driven almost entirely by reduced fungal necromass carbon, while bacterial necromass remained essentially unchanged after nitrogen addition. This distinction carries weight. Fungal cell walls are rich in chitin and other nitrogen-containing compounds, and fungal residues are generally considered more persistent and more important contributors to stable soil organic carbon than bacterial residues. Previous work has suggested that fungal necromass contributes disproportionately to soil organic carbon and is more sensitive to land-use intensity. A selective erosion of the fungal component therefore represents a loss of precisely the fraction of soil carbon that is best at sticking around.

Why would added nitrogen suppress fungal residue accumulation? The team’s measurements of the living community point toward a fundamental shift in microbial life-history strategy. Across all three nitrogen forms, microbial biomass actually increased, but the composition of the community changed, as indicated by rising ratios of fungi to bacteria and of gram-positive to gram-negative bacteria. These shifts suggest a move toward resource-conservative microbial characteristics — organisms that invest carefully, grow slowly, and recycle resources efficiently rather than building new biomass rapidly. In microbial ecology, this is often framed as a shift along a continuum from fast-growing, copiotrophic strategists to slow-growing, oligotrophic ones. When the community tilts conservative, the turnover of cells and the production of fresh residues slow down, and the existing necromass pool can be mined for nutrients faster than it is replenished.

The enzyme data add a second, complementary mechanism: intensified phosphorus limitation. Nitrogen addition enhanced the activities of both carbon-acquiring and phosphorus-acquiring enzymes, and increased the vector length and vector angle derived from ecoenzymatic stoichiometry, a widely used framework for diagnosing microbial resource limitation. In plain terms, the microbes were working harder to scavenge phosphorus from the soil while also ramping up carbon-degrading enzymes. Phosphorus is a notoriously scarce nutrient in highly weathered subtropical soils, and when nitrogen — the resource that was previously limiting — becomes abundant, demand for phosphorus intensifies. To obtain it, microbes may deploy enzymes that break down organic matter, including the very necromass residues that would otherwise accumulate. This creates a paradox: the added nutrient stimulates microbial activity while simultaneously destabilizing the carbon reservoir that microbial activity builds.

Further analysis by the team tied the decline in necromass carbon directly to these two threads — the community shift toward resource-conservative traits and the aggravation of phosphorus limitation. Together, they sketch a coherent mechanistic chain. Nitrogen arrives in whatever chemical form. The microbial community reorganizes, favoring conservative strategists and shifting the balance among functional groups. Phosphorus becomes the bottleneck. Enzymes are deployed to mine organic matter for scarce nutrients. Fungal residues, the most persistent building blocks of stable soil carbon, are consumed or fail to accumulate at their previous rate. The necromass pool shrinks, even as the bulk soil organic carbon and carbon dioxide emissions show no obvious change. It is a slow-motion rearrangement that standard carbon measurements would miss entirely.

The broader significance of the study lies in its message about form-independence. Because ammonium chloride, urea, and glycine produced nearly identical outcomes, the researchers conclude that atmospheric nitrogen deposition reduces the accumulation of soil microbial necromass carbon irrespective of its chemical form, acting through altered community composition and resource stoichiometry rather than through any compound-specific pathway. For modelers, this simplifies the challenge: nitrogen loads, not nitrogen speciation, may be the key variable to track when projecting soil carbon futures in nitrogen-polluted regions. For policymakers, it means that the growing organic nitrogen component of deposition — long understudied relative to inorganic forms — is not a benign alternative. It carries the same risk to the microbial carbon pump, the suite of processes by which living microbes convert plant carbon into persistent soil organic matter.

There are also cautionary notes for carbon sequestration strategies. Subtropical forests are among the most productive carbon sinks on Earth, and their soils hold enormous stores of organic carbon. Some proposed climate interventions involve fertilizing forests with nitrogen to boost tree growth and carbon uptake. This study suggests such approaches could carry an underappreciated cost below ground: while trees may grow faster, the microbial machinery that stabilizes carbon in soil may be quietly dismantled, with fungal residues — the glue of long-term soil carbon storage — eroding by roughly a fifth within the timeframe of the experiment. The work, supported by the National Natural Science Foundation of China, underscores a growing recognition in soil science that the fate of carbon in soils is written in the lives and deaths of microorganisms, and that human disruption of nutrient cycles rewrites that story in ways we are only beginning to measure.

Subject of Research: Effects of inorganic and organic nitrogen addition on soil microbial necromass carbon in a subtropical plantation

Article Title: Inorganic and organic nitrogen addition consistently reduces soil microbial necromass carbon in association with altered microbial community composition and intensified phosphorus limitation in a subtropical plantation

Article References: Wu, P., Li, W., Zhang, Y., Liu, Z., & Mao, R. (2026). Inorganic and organic nitrogen addition consistently reduces soil microbial necromass carbon in association with altered microbial community composition and intensified phosphorus limitation in a subtropical plantation. Plant and Soil. https://doi.org/10.1007/s11104-026-09106-1

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09106-1

Keywords: nitrogen deposition, microbial necromass carbon, soil organic carbon, subtropical forest, phosphorus limitation, microbial community composition, amino sugars, fungal necromass, enzyme activity, carbon sequestration, soil ecology, plantation

The research, led by Natascha V. Weinberger of the Hawkesbury Institute for the Environment at Western Sydney University together with colleagues at the University of Adelaide and partner institutions, set out to test whether multi-species AM fungal communities produce additive, synergistic, or antagonistic effects on tomato growth and disease resistance relative to their constituent single isolates. The team worked with tomato plants of the compact cultivar Micro-Tom, inoculating them with five individual AM fungal isolates or with six carefully designed community combinations, and then challenging half of the plants with Rhizoctonia solani, a devastating root pathogen responsible for damping-off and root rot in crops worldwide.

What makes the study methodologically distinctive is its use of high-throughput phenotyping. Rather than relying on a single endpoint harvest, the researchers grew their plants on the conveyor-belt imaging system at The Plant Accelerator, part of the Australian Plant Phenomics Network. Three cameras captured one top-view and two side-view RGB images of every plant daily, generating more than 3,300 observations per trait across the experiment. From these images the team derived the projected shoot area, a reliable proxy for aboveground biomass, and the absolute growth rate, which captures how quickly biomass accumulates between days. This temporal resolution proved crucial, because static endpoint measurements can mask the dramatic dynamics that unfold in the days immediately after a pathogen strikes.

The five isolates spanned two major AM fungal families with contrasting reputations. Funneliformis mosseae and two isolates of Rhizophagus irregularis belong to the Glomeraceae, a family previously associated with strong pathogen protection, while Gigaspora margarita and Scutellospora calospora belong to the Gigasporaceae, better known for promoting host growth. Prior work by the same group had classified F. mosseae and R. irregularis WFVAM 23 as effective at inducing so-called Mycorrhiza-Induced Resistance, or MIR, whereas the two Gigasporaceae isolates had been rated ineffective. The community treatments were built with these reputations in mind: a HIGH MIR pairing of the two protective isolates, a LOW MIR pairing of the two ineffective ones, a MIR plus GROWTH mix combining protection with growth promotion, a HIGH COL pairing of strong colonizers, an ISOLATES treatment mixing two strains of the same species, and a DIVERSITY treatment containing all five isolates.

When the researchers analyzed growth in the absence of the pathogen, the results largely defied the simple logic that more fungi should mean more benefit. Only one community, the MIR plus GROWTH combination of F. mosseae and G. margarita, consistently outperformed both of its constituent single isolates, qualifying as synergistic and showing the highest absolute growth rate during the early phase of the experiment. Three other mixtures behaved additively, tracking the intermediate or lower range of their components. Strikingly, the HIGH MIR pairing and the five-species DIVERSITY community performed closest to the weakest individual isolate, an antagonistic outcome suggesting that competition among fungi for root colonization sites, or shifts in how plants allocate carbon to their partners, can erode the benefits that each species provides alone.

The disease experiments produced the study’s biggest surprise. Five of the six community treatments reduced the biomass losses caused by Rhizoctonia solani compared with non-mycorrhizal infected controls. The HIGH MIR community, combining the two previously validated protective isolates, delivered synergistic protection, with pathogen-challenged plants reaching biomass levels comparable to uninfected controls. But the real shock came from the LOW MIR community, which paired the two Gigasporaceae isolates previously classified as incapable of inducing resistance. Together, these two individually ineffective fungi protected tomato plants almost as completely as the best protective pairing, allowing infected plants to match the biomass of their uninfected counterparts.

This outcome demolishes the intuitive hypothesis that combining two effective isolates yields strong resistance while combining two weak ones yields none. The community effect, the authors conclude, is not simply an average of individual performances. Complex interactions such as competition, resource partitioning, and possibly the timing of root colonization appear to shape the final result in ways that single-isolate screening cannot capture. Even the ISOLATES treatment, mixing two strains of the same R. irregularis species, showed an unexpected burst of accelerated growth immediately after pathogen addition, a transient compensatory response visible only in the daily growth-rate data and invisible in final biomass figures.

The temporal dimension added further nuance. The researchers observed that the most successful community owed its high final biomass to rapid early growth rather than late-stage acceleration, while antagonistic communities showed depressed growth rates in the later phases of the experiment. Immediately after pathogen inoculation, almost all communities conferred some degree of protection, but the magnitude and duration of that protection varied widely. The MIR plus GROWTH community, despite its impressive performance without the pathogen, suffered an immediate and near-complete cessation of growth once Rhizoctonia arrived, revealing that its resistance mechanism was profoundly ineffective at maintaining post-infection growth. A fungus combination that excels in comfort can collapse under attack.

The authors are candid about the limitations of their work. Endpoint colonization assessments confirmed successful fungal establishment but likely underestimated earlier colonization because AM fungal structures naturally decline in mature roots, and early colonization dynamics were not directly measured. The simplified sand-and-soil growth medium, the specific set of isolates, and the controlled greenhouse environment all mean the findings may not translate directly to field soils with their far richer microbial communities. High functional variability within and among AM fungal species, and the sensitivity of outcomes to inoculum propagation and environmental conditions, further caution against overgeneralization. The researchers also note that mixed inoculations are often dominated by a single fungal species, meaning plant responses may reflect the dominant taxon rather than the collective contribution of the community.

Nevertheless, the implications for agriculture are substantial. Commercial mycorrhizal inoculant products are typically developed and marketed on the strength of single-isolate performance data, yet this study demonstrates that such data are an unreliable guide to how products containing multiple species will behave. For glasshouse tomato production, where targeted use of AM fungi could support plant health and reduce fungicide dependence, the message is that community composition, not just diversity, determines function, and that promising combinations must be tested as communities, under pathogen pressure, and over time. The study also carries a broader ecological lesson: in the root zones of our crops, the whole is genuinely different from the sum of its parts, and sometimes two fungi that fail alone succeed spectacularly together.

Subject of Research: Effects of multi-species arbuscular mycorrhizal fungal communities on tomato growth and resistance to the root pathogen Rhizoctonia solani

Article Title: Community-level AM fungal interactions lead to unexpected growth and disease outcomes in tomato

Article References: Weinberger, N. V., Cibils-Stewart, X., Brien, C., Jewell, N., Berger, B., Cavagnaro, T. R., Salomon, M. J., Zhang, H., Plett, J. M., & Powell, J. R. (2026). Community-level AM fungal interactions lead to unexpected growth and disease outcomes in tomato. Plant and Soil. https://doi.org/10.1007/s11104-026-08655-9

Image Credits: AI Generated

DOI: 10.1007/s11104-026-08655-9

Keywords: arbuscular mycorrhizal fungi, tomato, Rhizoctonia solani, mycorrhiza-induced resistance, high-throughput phenotyping, fungal communities, plant-microbe interactions, biological control, Glomeraceae, Gigasporaceae, plant pathology, soil ecology

The study, led by soil ecologist Franciska de Vries of the University of Amsterdam together with colleagues across Europe, set out to answer a question that had largely been overlooked. Much of the existing literature assumes that climate change will gradually accelerate the spread of antibiotic resistance genes in the environment, as warmer and wetter conditions favour microbial growth and the exchange of genetic material. But climate change does not arrive only as a slow, steady warming. It also delivers sudden shocks: heatwaves, droughts, floods and freeze-thaw cycles that hit ecosystems with little warning. What those abrupt extremes do to the resistance repertoire of soils was, until now, poorly understood.

De Vries explains that many people simply do not realise how important soils are as reservoirs of both antibiotics and resistance genes. Most of our antibiotic classes were originally discovered in soil-dwelling microorganisms, and the same soils harbour an enormous diversity of genes that confer resistance to those compounds. In the soil, she notes, a kind of war is constantly underway: bacteria produce antibiotics and simultaneously defend themselves against them with resistance genes. Understanding how climate disturbances perturb this equilibrium is therefore not an abstract ecological curiosity but a question with direct implications for public health.

The research unfolded in two phases. In the first, the team wanted to establish a general picture of how soil organisms respond to extreme weather. Soils, De Vries points out, perform functions that society depends on, not least the sequestration of carbon dioxide from the atmosphere. If extreme events impair those functions, the consequences extend far beyond the microbial community. To probe this, the researchers collected soils from across the breadth of Europe, from Iceland to Greece and from Sweden to Spain, and even from the Russian steppe. The samples were then subjected to a battery of simulated extremes in climate chambers: severe drought, flooding, alternating frost and thaw, and a short but intense heatwave.

One of the most striking results of this first phase was how predictable the responses turned out to be. The researchers could forecast, with considerable accuracy, how a given soil would react to a given extreme. The logic, De Vries says, is quite straightforward: hot soils can withstand heat better than cold and wet soils of the kind found in Sweden, Iceland and the Netherlands. Soils from warm, dry countries are already accustomed to heat and drought, and their communities of bacteria and fungi remain relatively stable even when conditions turn extreme. In cold, wet soils, by contrast, the organisms are disrupted far more quickly. Those soils lose their functions, such as carbon storage, more easily under heat and drought, and it is precisely these historically cool, damp regions that are warming most rapidly. The Netherlands, with its wet climate and accelerating heat extremes, exemplifies the vulnerability.

With that foundation in place, the team moved to the second phase, a new collaboration employing fresh DNA techniques to ask a sharper question: what do these extreme conditions do to the type and quantity of antibiotic resistance genes in soils, and are those effects also predictable? The answer differed sharply depending on the kind of extreme. Droughts, floods and freeze-thaw periods caused only mild changes in the resistance repertoire, and those changes were reasonably predictable from climate and soil type. The microbial communities bent under the stress but did not fundamentally alter their genetic defences.

Heatwaves were another matter entirely. Of all the extremes tested, heatwaves produced the least predictable responses, and the bacteria visibly struggled. According to De Vries, under heatwave conditions the bacteria exchange fewer resistance genes and produce fewer antibiotics. That was very surprising, she says: just like plants, the microorganisms go into survival mode. And crucially, after the extreme has passed, those genes do not grow back quickly. The temporary suppression of the resistance repertoire is not a rapid rebound; the microbial community needs time to rebuild its arsenal of antibiotics and defensive genes once temperatures return to normal.

Geography, it turned out, was the single most important indicator of how a soil’s resistance genes respond to extremes. Where the soil comes from, De Vries explains, matters more than what extreme weather is unleashed upon it. Wet soils find it much harder to cope with drought and heat, whereas the researchers observed much larger quantities of resistance genes in countries such as Greece and Spain. This means that the baseline climate of a region, rather than the specific disturbance it experiences, largely determines both the size of the resistance gene pool and the way it shifts under stress. For modellers and risk assessors, that is a valuable simplification: knowing where a soil is from tells you a great deal about how it will behave.

At first glance, the headline finding might sound like a rare piece of good news about climate change. If heatwaves temporarily reduce the number of resistance genes circulating in soils, could extreme heat actually help contain the environmental reservoir of antibiotic resistance? De Vries is emphatic that this interpretation would be a mistake. The same heat and drought that suppress the resistance genes are simultaneously causing significant damage to soils and ecosystems, degrading functions such as carbon sequestration and disrupting communities that took millennia to assemble. A short-lived dip in resistance gene abundance does nothing to remove the underlying health risks of antibiotic resistance, which remain a global concern regardless of what the weather does. The dip is a symptom of microbial distress, not of a safer environment.

What the study does offer is a clearer map of where the risks actually lie. As De Vries concludes, we now know that climate extremes do not always affect antibiotic resistance in the same way, and that knowledge makes it easier to predict where the real risks are concentrated and to tailor policy and monitoring to particular soils and regions. Warm, dry soils with naturally high resistance gene loads may need different surveillance than cold, wet soils that are newly exposed to heat extremes they have never evolved to tolerate. The research, published in the Proceedings of the National Academy of Sciences as an experimental study, thus reframes the conversation about climate change and antibiotic resistance: the relationship is neither uniformly negative nor uniformly benign, but contingent on geography, soil history and the character of the disturbance. In the hidden war beneath our feet, the weather decides when the fighting pauses, but the landscape decides who is fighting in the first place.

Subject of Research: The effects of extreme climatic events on antibiotic resistance genes in European soils

Article Title: Heatwaves inhibit antibiotic resistance in soils, but at a price

Article References: Heatwaves inhibit antibiotic resistance in soils, but at a price. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: antibiotic resistance, soil bacteria, heatwaves, climate extremes, soil ecology, resistance genes, drought, carbon sequestration, University of Amsterdam, Europe, PNAS, microbiology

The research, led by Guoliang Sha of Lanzhou University together with colleagues from several Chinese institutions and Yudi M. Lozano of the Arid Zones Experimental Station in Spain, surveyed 63 alpine meadow sites spread across the Qinghai–Tibet Plateau. At each site, the team used a paired design, comparing the vegetation and soil directly beneath shrub canopies with adjacent open meadow plots that lacked shrub cover. This pairing allowed the researchers to isolate the local effect of shrub presence from the broader environmental conditions of each site, while the wide geographic spread captured a natural gradient of precipitation from drier to wetter portions of the plateau.

The central question was deceptively simple: how do shrub-associated habitat differences and rainfall jointly influence ecosystem multifunctionality, the capacity of an ecosystem to deliver multiple functions simultaneously, such as productivity, nutrient cycling, and carbon storage? Ecosystem multifunctionality has become a key concept in ecology because single functions can be misleading; a grassland might maintain high plant growth while quietly losing soil fertility or decomposition capacity. To capture this complexity, the team measured eleven distinct ecosystem functions at each site and combined them into a single multifunctionality index.

But the researchers went a step further by adopting a trait-based response–effect framework. The idea is that certain traits of organisms act as responses, changing predictably when the environment changes, while other traits act as effects, driving changes in ecosystem processes. If a trait both responds to an environmental driver and influences ecosystem functions, it can serve as a mechanistic bridge linking climate change to ecosystem outcomes. The team quantified this bridge at two trophic levels at once: aboveground, using community-weighted plant traits including plant height, specific leaf area, and leaf dry matter content; and belowground, using functional traits of soil nematodes, the microscopic roundworms that are among the most abundant animals on Earth, including body size, biomass, and the colonizer–persister value that indicates where a nematode species sits along a spectrum from rapid colonizers to slower-growing, more sensitive species.

The results revealed a consistent signature of shrub presence. Habitats beneath shrubs had significantly taller plants and higher specific leaf area, a trait associated with fast growth and efficient light capture, than the paired open habitats. Belowground, the shrub-associated soils harbored nematodes with wider bodies, greater biomass, and higher colonizer–persister values, suggesting a soil fauna community shifted toward larger, more persistent organisms under the moderating microclimate and improved resource conditions that shrubs create. These findings align with a well-documented pattern in which shrubs act as nurse plants in harsh environments, buffering temperature extremes, trapping wind-blown nutrients, and enriching the soil beneath their canopies.

Crucially, however, the strength and even the direction of these shrub effects depended on where a site sat along the precipitation gradient. The positive difference in specific leaf area between shrub and open plots grew larger toward wetter sites, indicating that shrubs amplify fast-growth traits most strongly where water is plentiful. Meanwhile, the difference in leaf dry matter content, a trait linked to tissue toughness and conservative resource use, reversed direction across the gradient. This precipitation-dependent reversal is a striking illustration that the ecological consequences of shrub encroachment are not uniform: the same shrub can push the understorey plant community in opposite functional directions depending on how much rain falls at its location.

When the team connected these traits to ecosystem multifunctionality, a clear hierarchy emerged. Plant traits were significantly associated with the aggregate index of ecosystem multifunctionality, meaning that shifts in community height, leaf economics, and related characteristics tracked closely with how well the meadows performed their combined functions. The nematode traits told a different story. Although the soil worms responded clearly to both shrub presence and precipitation, their measured traits showed no detectable association with aggregate multifunctionality. The researchers describe this as a decoupling between response and effect roles: nematode traits are useful indicators of environmental change, but the particular traits measured here do not appear to translate into changes in the overall functioning of these ecosystems.

This decoupling carries practical weight. Soil nematodes are increasingly promoted as bioindicators because they are abundant, easy to sample, and sensitive to disturbance, and previous work has linked nematode communities to nutrient cycling and plant growth. Yet the new findings suggest that, at least for predicting how alpine meadow multifunctionality responds to shrub encroachment and shifting rainfall, aboveground plant traits may be the more reliable signal. For monitoring programs on the plateau, this implies that measuring the functional composition of the vegetation could yield more actionable forecasts than expanding belowground trait sampling, though the authors note the result applies to the nematode traits they measured rather than to soil fauna more broadly.

The study also speaks to a larger debate about what shrub encroachment means for the world’s grasslands. Globally, woody plant encroachment is intensifying under climate change across tundra and savanna biomes, and its consequences range from beneficial facilitation in harsh, dry environments to losses of grassland biodiversity and grazing value elsewhere. By showing that the functional fingerprint of shrubs on the understorey changes with precipitation, the Qinghai–Tibet study helps explain why encroachment produces such divergent outcomes in different regions. In wetter meadows, shrubs may amplify resource-acquisitive plant communities with different functional consequences than in drier ones, and the associated soil conditions shift accordingly.

For the roof of the world, the message is one of interconnected change. Rainfall, shrubs, leaves, and soil life form a chain of cause and effect, and the strongest link in that chain runs through the plants. As precipitation regimes continue to shift across high Asia, the functional traits of meadow vegetation, more than the traits of the nematodes in the soil, will likely determine whether these ecosystems keep delivering their full portfolio of services, from forage production to carbon storage, for the herders and wildlife that depend on them.

Subject of Research: How shrub encroachment and precipitation affect ecosystem multifunctionality in alpine meadows through plant and nematode traits

Article Title: Plant traits and soil conditions link shrub presence and precipitation to ecosystem multifunctionality in alpine meadows

Article References: Sha, G., Chen, S., Chen, J., Wang, J., Liu, Z., Song, H., Cui, H., Zhang, A., Yang, Z., Zhao, X., Xia, W., An, L., Zhang, J., Yu, X., Xiao, S., & Lozano, Y. M. (2026). Plant traits and soil conditions link shrub presence and precipitation to ecosystem multifunctionality in alpine meadows. Plant and Soil. https://doi.org/10.1007/s11104-026-09035-z

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09035-z

Keywords: ecosystem multifunctionality, plant traits, nematode traits, shrub encroachment, precipitation, alpine meadows, Qinghai–Tibet Plateau, soil ecology, grassland ecology, trait-based ecology, Plant and Soil, climate change

The conventional method for assessing mycorrhizal colonization, known as the gridline intersect method, has remained the standard for decades. It requires fixing, dyeing and microscopically examining host plant roots to determine the percentage of root length containing fungal structures such as mycelia, vesicles and arbuscules. The approach is not only time-consuming, laborious and costly, but also prone to error, since staining can color root cortex vessels in ways that mimic false mycorrhizal structures. More fundamentally, the method cannot distinguish between natural, neutral and even parasitic symbiotic relationships, and it ignores entirely the question of fungal effectiveness, that is, whether the colonization actually improves the plant’s performance. Earlier attempts to find alternatives, including the magnified intersections method and the detection of mycorrhiza-specific isozymes, improved objectivity but still fell short of quantifying the functional benefits of the partnership.

The new approach flips the problem on its head. Rather than counting fungal organs inside roots, Jahan and Nassiri-Mahallati measured the eco-physiological consequences of symbiosis in the plant itself. Their reasoning was straightforward: if the fungus genuinely benefits its host, that benefit should reveal itself in improved growth, better resource capture and higher yield. By measuring a comprehensive suite of plant and soil traits in inoculated and non-inoculated maize, and then applying mathematical modeling to the resulting data, the researchers could trace exactly which plant functions the fungi enhanced and by how much. This multidisciplinary framework draws together plant ecophysiology, soil ecology, multivariate statistics and mathematical modeling into a single analytical pipeline that goes beyond observation to causal understanding.

The evidence base came from two years of field experiments conducted at the research farm of Ferdowsi University of Mashhad, in the semi-arid Kashaf River watershed of northeastern Iran, where mean annual precipitation is just 252 millimeters. The experiments followed a split-plot arrangement within a randomized complete block design with three replications, spanning four different cropping systems ranging from high-input to ecological management. Maize seeds of the single cross 704 cultivar were coated with powdered inoculum containing propagules of two fungal species, Rhizophagus intraradices and Funneliformis mosseae, at a concentration of one million colony-forming units per gram, while control seeds were left uninoculated. The team then measured everything from leaf area index, dry matter yield and seed yield to maximum photosynthesis rate, leaf chlorophyll content via SPAD readings, canopy temperature, plant phosphorus content, specific root length, soil respiration and the chlorophyll fluorescence ratio Fv/Fm.

Analysis of variance confirmed that mycorrhizal inoculation significantly affected nearly every trait measured, with mycorrhizal plants showing significantly higher values than their non-mycorrhizal counterparts for maximum photosynthesis rate, leaf area index, dry matter, seed yield, plant height, stem diameter, soil respiration, specific root length, root colonization, SPAD readings and plant phosphorus. But the real innovation lay in what came next. Confirmatory factor analysis divided the fourteen measured variables into two coherent groups, which the researchers named on eco-physiological grounds. The first factor, containing leaf area index, SPAD readings, dry matter, root colonization and stem diameter, was labeled the resource capture construct. The second, comprising specific root length, plant height, maximum photosynthesis rate, canopy temperature, cob number, seed yield, plant phosphorus, soil respiration and Fv/Fm, was named the resource utilization construct. The reliability of both constructs was confirmed by Cronbach’s Alpha values of 0.77 and 0.74 respectively, exceeding the conventional threshold of 0.70.

With the two latent constructs established, the team employed structural equation modeling, a statistical technique that tests networks of hypothesized causal relationships against observed covariance patterns. SEM has grown increasingly popular in ecology since 2000 precisely because it can partition direct and indirect effects along multiple pathways, something regression and analysis of covariance cannot achieve when the goal is understanding biological mechanisms. The fitted model proposed a causal path running from resource capture to resource utilization, with the capture construct driving the utilization construct and both jointly shaping final yield. The model’s goodness of fit was assessed through several indices: a normalized chi-square of 2.33, comfortably within the accepted range of one to three, and a coefficient of determination of R squared equal to 0.37, which by the classification standards of Hair and colleagues falls within the good range of 0.25 to 0.50.

That R squared value carries the study’s headline finding: thirty-seven percent of the total variance in maize performance can be explained by resource capture and utilization through the mycorrhizal collaboration. In other words, the direct advantages of AMF symbiosis, quantified through the eco-physiological machinery of the plant, account for a substantial and now measurable share of what makes an inoculated crop thrive. The standardized path coefficients revealed which traits mattered most. Leaf area index showed a direct effect of 0.888 on the resource capture construct, meaning that a one standard deviation increase in capture translates into a 0.888 standard deviation increase in leaf area. Dry matter showed a squared multiple correlation of 0.718 with resource utilization, indicating that the construct explains nearly seventy-two percent of dry matter variation. Stem diameter ranked highest after leaf area and dry matter at 0.707, reflecting its role in the vascular transport of assimilates between sources and sinks.

The placement of root colonization and SPAD readings within the resource capture construct proved particularly telling. From an eco-physiological standpoint, mycorrhizal colonization of roots increased leaf chlorophyll content, which in turn plays an essential role in capturing and utilizing radiation in the photosynthetic system. Plant height correlated strongly with specific root length, canopy temperature and leaf area index, defining the canopy architecture that governs how efficiently a crop intercepts sunlight. The analysis also showed that the effect of AMF on yield was largely indirect, mediated through increases in leaf area and plant height rather than acting directly on yield itself. Meanwhile, the negative effect of resource utilization on specific root length, a coefficient of minus 0.534, is consistent with a well-known trade-off: when fungal hyphae effectively extend the root’s absorption network, the plant can afford to invest less in its own root length per unit of soil volume.

The practical implications extend well beyond maize. Because the method relies on farm-measured traits rather than laboratory microscopy, it can in principle be applied to most crop plants, with results varying by plant species, fungal species and environmental conditions. The authors suggest that identifying the plant characteristics involved in symbiosis makes it possible to manage and strengthen them, improving final performance. As an agroecological management tool, for example, farmers could synchronize the timing of maximum leaf area index with the long sunny days of summer by adjusting planting density, planting date, irrigation and fertilization, thereby maximizing the efficiency of the photosynthetic system when radiation capture is at its peak. The approach could also help quantify the effects of inputs and treatments on yield formation across different cropping systems, since structural equation modeling works on correlation and variance-covariance matrices that can pool data across management regimes.

The study does carry caveats. The experiments evaluated the effect of two exogenous fungal species on the plant, not the entire indigenous AMF community in the soil, and native fungi could not be eliminated from the field, so the reported functions rest on exogenous measurements alone. The RMSEA value of 0.169, while above the commonly cited cut-off of 0.06, is considered mediocre in models with small samples and few variables, where the index tends to inflate; the authors note that chi-square provides a sufficient measure of model accuracy in such cases. Still, the broader vision is ambitious: a fast, reliable and low-cost method to identify causal paths and quantify symbiotic efficacy, giving farmers, advisors, researchers and policymakers a practical foundation for deploying mycorrhizal technology across agroecosystems. At a time when phosphorus fertilizers face supply restrictions, rapid fixation in soils, high costs and pollution concerns, a tool that measures exactly what fungi contribute to crop productivity, while pointing the way to reduced inputs, cost and labor, may prove one of the more quietly revolutionary developments in sustainable agriculture.

Subject of Research: Quantifying the eco-physiological benefits of arbuscular mycorrhizal fungal symbiosis with maize using structural equation modeling

Article Title: Discovering and quantifying the eco-physiological advantages of plant-soil-Arbuscular Mycorrhizal Fungi (AMF) system: a promising eco-math-statistical modelling approach

Article References: Jahan, M., & Nassiri-Mahallati, M. (2025). Discovering and quantifying the eco-physiological advantages of plant-soil-Arbuscular Mycorrhizal Fungi (AMF) system: a promising eco-math-statistical modelling approach. Discover Ecology, 1(1), Article 2. https://doi.org/10.1007/s44396-025-00001-0

Image Credits: AI Generated

DOI: 10.1007/s44396-025-00001-0

Keywords: arbuscular mycorrhizal fungi, maize, symbiosis, structural equation modeling, eco-physiology, resource capture, resource utilization, sustainable agriculture, soil ecology, phosphorus uptake, crop yield, agroecology

The research, led by Ariel Levi Simons along with Christopher Timlin-Broussard, Avicka Willis, and Jerelyn Lee, tackles one of the most persistent blind spots in urban ecology. Fungi underpin nearly every terrestrial ecosystem, decomposing organic matter, cycling nutrients, forming mycorrhizal partnerships with plants, and even acting as pathogens that shape community structure. Yet despite this ecological centrality, fungi remain chronically understudied in biodiversity monitoring, and their responses to urban stressors have been documented far less thoroughly than those of birds, mammals, or flowering plants. The new study demonstrates that publicly archived community science data can begin to close that gap at a spatial scale no single research project could achieve.

To measure urbanization, the team turned to the National Land Cover Database, which classifies every 30-meter pixel of the continental United States by the fraction of its area covered by surfaces impervious to water flow. This metric serves as a proxy for the hallmark of urban development: sealed ground. When rain cannot infiltrate soil, nutrient flows are disrupted, runoff accelerates, and groundwater recharge plummets. Previous research has shown that surface runoff can double when just 10 to 20 percent of a landscape is paved, and that groundwater recharge in urbanized areas can drop by as much as half. For soil-dwelling organisms, these hydrological upheavals fundamentally alter the resource base on which communities depend.

The fungal observations came from the Global Biodiversity Information Facility, or GBIF, an open archive where community scientists and researchers deposit species records. The researchers extracted every fungal occurrence recorded in California between 2015 and 2024, an initial haul of more than 342,000 records. After filtering to retain only species-level identifications, the dataset still contained nearly 300,000 occurrences, overwhelmingly contributed by human observers. Each record was then assigned to an ecological guild, or trophic mode, using the FUNGuild tool, sorting the fungi into pathotrophs, saprotrophs, and symbiotrophs. Ambiguous assignments and low-confidence classifications were discarded, leaving roughly 180,000 occurrences with clear ecological roles.

Working with opportunistically collected data requires statistical care, because sampling effort varies wildly across space and time. The team addressed this by estimating sample coverage for each putative assemblage, defined as all occurrences within a single imperviousness pixel in a given year and trophic mode, using the iNEXT framework. Only assemblages meeting coverage thresholds of 70, 80, or 90 percent were retained for analysis, a stringent filter that reduced the dataset to between roughly 1,700 and 499 assemblages and about 10,000 occurrences at the strictest threshold. Species richness, the study’s measure of alpha diversity, was then estimated by tracking the asymptotic behavior of richness against sampling effort, with rare species weighted equally to guard against undercounting.

The results paint a nuanced picture. For saprotrophic fungi, the decomposers that break down dead organic matter, estimated richness declined significantly with increasing impervious coverage, though the signal emerged clearly only at the strictest 90 percent coverage threshold. Notably, most of this decline appears to occur as soon as any impervious surface is recorded in the immediate vicinity, suggesting that even modest sealing of the ground may push fungal communities past an ecological threshold. However, when the researchers compared assemblages in areas with and without any impervious cover using nonparametric rank-sum tests, the difference in richness did not reach statistical significance, a reminder of how sensitive such analyses are to sample size and distributional skew. The data were heavily skewed toward unpaved areas, with skewness values rising from 1.64 before filtering to 1.87 after, reflecting a well-documented tendency of community scientists to record species in natural areas rather than city centers.

The more striking and consistent finding concerned beta diversity, the variation in community composition from place to place. For both saprotrophic and symbiotrophic fungi, the dispersion of beta diversity, measured as the average distance of assemblages from a group centroid in Jaccard dissimilarity space, declined significantly with increasing impervious coverage across all coverage thresholds. When assemblages from paved and unpaved areas were compared directly, the declines in dispersion were highly significant, with p-values as low as 10 to the power of negative 15 for saprotrophs and 10 to the power of negative 7 for symbiotrophs. In plain terms, fungal communities in paved landscapes are significantly more similar to one another than those in unsealed habitats, a signature of biotic homogenization. Pathotrophic fungi showed no such pattern, though the authors caution that the small number of recorded occurrences makes it impossible to distinguish a true ecological signal from a statistical artifact.

Why would urbanization flatten the differences between fungal communities? The authors propose ecological filtering as a central mechanism. The mechanical and chemical disturbances associated with development, from soil compaction to heavy metal runoff from roads, impose a narrow set of stresses that only a subset of species can tolerate. Land conversion disrupts the intricate architecture of mycorrhizal networks, while the urban heat-island effect alters temperature and rainfall regimes known to drive fungal richness. Compounding this, urbanization transforms plant communities, replacing native vegetation with a cosmopolitan suite of non-native ornamentals, and each plant community carries its own fungal symbionts. The massive transport of soil that accompanies construction may further homogenize underground communities by mixing propagules across regions. The result is a distinctly urban fungal flora, filtered from a once-diverse regional pool.

The study also underscores both the promise and the pitfalls of community science as a biodiversity monitoring tool. The fungal records were dominated by two phyla, Ascomycota and Basidiomycota, and by saprotrophic and symbiotrophic species, biases that mirror the tendency of amateur mycologists to document mushrooms with conspicuous, easily identified fruiting bodies. Microscopic fungi, aquatic chytrids, and arbuscular mycorrhizal Glomeromycota barely registered. Seasonal fruiting patterns were also obscured by the annual aggregation of records. Yet the sheer volume of data, growing year over year, proved sufficient to test the study’s central hypotheses at the scale of an entire US state, something previously feasible only with intensive DNA-based surveys.

Looking ahead, the authors argue that the era of molecular monitoring is poised to transform fungal conservation. Environmental DNA sampling can resolve species that never produce visible mushrooms, detecting microscopic inhabitants of soil that escape human observation entirely, and fungal datasets are expected to expand rapidly in both volume and taxonomic resolution. As urban land cover continues its global expansion, the California findings offer a warning and a template: the invisible kingdom beneath our feet responds to pavement in measurable ways, and with the right tools, we can now track it. Whether that tracking translates into protection for urban soil communities remains one of the defining ecological challenges of the century ahead.

Subject of Research: Effects of impervious urban surfaces on fungal richness and beta diversity in California

Article Title: Evidence for Reductions in Fungal Richness and Beta Diversity Dispersion Associated With Impervious Surfaces in California

Article References: Simons, A. L., Timlin‐Broussard, C., Willis, A., & Lee, J. (2026). Evidence for Reductions in Fungal Richness and Beta Diversity Dispersion Associated With Impervious Surfaces in California. Ecology and Evolution, 16(10), Article e74448. https://doi.org/10.1002/ece3.74448

Image Credits: AI Generated

DOI: 10.1002/ece3.74448

Keywords: urbanization, fungi, biodiversity, impervious surfaces, community science, GBIF, beta diversity, mycology, California, ecological homogenization, soil ecology, citizen science

The research team, led by Rojen Singh Thounaojam of Manipur University, spent the entirety of 2018 sampling earthworms and soils at two contrasting forest sites in the Imphal region. Site I was a reserved mixed forest in Imphal West district, while Site II was a community-protected mixed forest in Imphal East. Both sit within a subtropical monsoon climate that delivers an average annual rainfall of 1325.7 millimeters, with a wet season from June to October, a hot summer from March to May, and a cool, dry winter from November to February. The soils at both sites were sandy loam, and the vegetation included familiar subtropical trees such as Lithocarpus dealbatus, Gmelina arborea, Pinus kesiya, and Schima wallichii.

The sampling protocol was deliberately rigorous. Each month, the researchers demarcated six random plots of one square meter at each site, and within each plot they excavated four soil monoliths measuring 25 by 25 by 30 centimeters. Over the year, this yielded 72 quadrats per site, with earthworms extracted by digging and hand-sorting following the standard Tropical Soil Biology and Fertility method. Specimens were preserved in formalin and identified under stereo zoom microscopes using established taxonomic keys. Alongside the biological sampling, the team recorded soil temperature in situ each month, measured pH in soil-water suspensions, and determined moisture content gravimetrically.

What emerged from this year-long effort was a community profile that surprised the researchers. Site I harbored seven earthworm species belonging to six genera and four families, while Site II supported five species in four families. The Megascolecidae family dominated the species lists at both sites. Shannon diversity indices of 1.29 at Site I and 1.17 at Site II indicated modestly higher diversity at the reserved forest. But the headline result concerned the exotic component of the community: at Site I, exotic species made up more than 74 percent of the earthworm community, with P. corethrurus alone accounting for 62.37 percent. At Site II, the single exotic species present, P. corethrurus, constituted 38.65 percent of the community, second only to the native Drawida nepalensis at 45.89 percent.

The ecology of P. corethrurus helps explain its success. First described in 1857 by the German naturalist Fritz Müller from Santa Catarina State in Brazil, and believed to have originated in the Guiana Shield region of South America, the species is now one of the most widely distributed tropical earthworms on Earth. According to the Drilobase database, as of July 2025 it had been recorded in tropical, subtropical, and Mediterranean zones across dozens of countries on four continents. In India, it was first reported from Kerala in 1910, likely introduced through human activity associated with cassava or rubber plantations. It has since spread to nine of India’s fifteen agro-climatic zones and to eight states in Northeast India alone.

Several biological traits make this worm a formidable invader. It tolerates an exceptionally broad range of soil conditions and climates, reproduces continuously with high fecundity and hatching success, develops quickly, and can even reproduce by parthenogenesis, meaning a single individual can found a population without a mate. In the Manipur forests, the species showed remarkable spatial and temporal versatility: it was found throughout the year, in every season, and at soil depths of up to 30 centimeters, whereas most other species were confined to the upper 10 centimeters of soil and many appeared only during the rainy season. Notably, the researchers recorded P. corethrurus active at soil temperatures as low as 15 degrees Celsius, below the previously reported minimum of 17 degrees for other parts of Northeast India.

The statistical analysis reinforced the importance of climate in structuring these communities. Soil moisture and soil temperature showed significant positive correlations with every recorded species at both sites, with correlation coefficients generally ranging from about 0.69 to 0.86, while soil pH was negatively correlated with earthworm abundance. Earthworm populations peaked during the rainy season, when elevated moisture and moderate temperatures create ideal conditions for activity and reproduction. Earthworms breathe through their skin, so moisture is a critical constraint on their distribution, and the optimal soil temperature for the species recorded in this study fell between 20.21 and 24.26 degrees Celsius, within the broader 20 to 30 degree range reported for tropical and subtropical earthworms.

Why does the dominance of an exotic worm in an undisturbed forest matter? Earthworms are ecosystem engineers, and established populations of P. corethrurus have been shown elsewhere to alter soil physical structure, modify biogeochemical processes, and reshape plant and microbial communities. By accelerating leaf litter decomposition and mixing soil in the upper layers, invasive earthworms can strip away the litter layer, increase soil bulk density, and reduce soil carbon content, carbon-to-nitrogen ratios, and cation exchange capacity, ultimately degrading forest soil fertility. The density of P. corethrurus is often inversely correlated with the density of other earthworm species, and previous studies have documented the displacement of native earthworms following the establishment of exotic populations. The Manipur findings suggest a real risk that native species at these sites could decline over time.

Yet the story is not one of inevitable defeat for the natives. The native Drawida nepalensis maintained high population densities even in communities dominated by exotics, and it was the most abundant species at Site II, where natives predominated. A parallel pattern has been reported in pineapple plantations in West Tripura, where the native Drawida assamensis outcompeted P. corethrurus, apparently thanks to superior survival and competitive ability. Endogeic earthworms, which live within the soil rather than on its surface, are also known to be the most resistant ecological group to disturbance. These observations hint that some native lineages may possess the competitive arsenal to coexist with, or even resist, the invader, although the researchers caution that long-term coexistence may ultimately depend on how much habitat modification the exotic species causes.

How the worm reached these protected forests remains a question of pathways rather than capability. Earthworms disperse on their own less than 10 to 15 meters per year, so human-mediated transport is almost certainly responsible. Cocoons and worms can hitchhike in soil on vehicle tires, in potted plants, in streams and surface water, or on birds and mammals. In Manipur specifically, the authors point to a worrying and largely unregulated trend: the booming use of exotic earthworms, particularly Eisenia andrei and Eisenia fetida, for vermicomposting, with little ecological oversight or public awareness of the risks of escape and establishment. The team calls for immediate policy formulation, monitoring protocols, and public education to protect native soil biodiversity. As the invasion of P. corethrurus proceeds even in undisturbed forests, the study stands as a warning that no ecosystem, however pristine, is automatically safe from a determined, parthenogenetic, climate-tolerant invader moving quietly beneath our feet.

Subject of Research: Invasion of protected subtropical forests in Northeast India by the exotic earthworm Pontoscolex corethrurus

Article Title: Assessment of Pontoscolex corethrurus, an exotic earthworm, in contrasting protected subtropical forest habitats in North-East India

Article References: Thounaojam, R. S., Singh, K. B., Singh, T. B., Keisham, S., & Singh, T. B. (2025). Assessment of Pontoscolex corethrurus, an exotic earthworm, in contrasting protected subtropical forest habitats in North-East India. Discover Ecology, 1(1), Article 10. https://doi.org/10.1007/s44396-025-00010-z

Image Credits: AI Generated

DOI: 10.1007/s44396-025-00010-z

Keywords: Pontoscolex corethrurus, invasive species, earthworms, soil biodiversity, Manipur, Northeast India, Indo-Burma biodiversity hotspot, subtropical forest, soil ecology, ecosystem engineers, vermicomposting, species invasion

The recognition arrives at a moment when soil ecology is moving from the margins of biology toward the center of conversations about climate, food security and biodiversity loss. Soils are among the most species-rich habitats on Earth, and the organisms that inhabit them drive processes on which nearly all terrestrial life depends. Ashwood’s book takes readers on a vertical descent through the soil profile, beginning at the surface with plant litter and ending in the deep subsoil, introducing along the way what he describes as some of the world’s strangest inhabitants and the essential roles they play in nutrient cycling, agriculture and carbon storage.

Ashwood is a soil scientist with a research background in earthworm ecology who quickly broadened his interests to encompass the full diversity of soil invertebrates. He is also a passionate macrophotographer, and that visual obsession with the hidden majority of life runs through his approach to writing. In response to the award, he said he really enjoys science communication, telling anyone who will listen about the wonders of life belowground, often with the help of his macrophotography, and that this strong desire to pass on his love of soil ecology to as broad an audience as possible is what ultimately led him to write the book.

The judging panel emphasized the book’s success in making an invisible world legible. Hefin Jones, one of the judges for the prize, described it as an engaging and accessible exploration of soil biodiversity and its importance to ecosystems and human society, noting that its major strength lies in Ashwood’s ability to communicate complex ecological processes through vivid descriptions of the largely unseen organisms that sustain soils. Fellow judge Ken Thompson said there are jaw-dropping facts on every page and that Ashwood’s narrative is greatly enlivened by his personal encounters with soil life, adventures that lend the text an immediacy and excitement making it an entertaining read.

Understanding why a popular book on soil deserves ecology’s book prize requires appreciating just how much is happening beneath a single step. A handful of grassland soil can contain billions of microorganisms and hundreds of invertebrate species spanning bacteria, fungi, protists, nematodes, mites, springtails, enchytraeids, earthworms and insect larvae. These organisms form a food web that decomposes organic matter, restructures mineral particles, regulates the flow of water and gases, and determines how much carbon is locked away versus released back to the atmosphere. Decomposition alone, the sequential breakdown of dead plant material by fungi, bacteria and their invertebrate grazers, is the process that returns nutrients locked in litter to forms that plant roots can absorb, effectively powering every forest and grassland on the planet.

The structural engineers of this underworld are the ecosystem engineers, a term most famously associated with earthworms, the group in which Ashwood began his research career. Earthworms ingest mineral soil and organic debris, mix them in their guts, and excrete casts that alter soil aggregation, porosity and microbial activity. Their burrows create macropores that channel rainfall into the profile, reducing surface runoff and erosion while giving roots low-resistance pathways to depth. Different ecological groups of earthworms occupy distinct niches, from litter-dwelling surface species to deep-burrowing anecic forms that pull organic matter down into permanent vertical burrows, and their combined activity can transform the physical architecture of an entire soil profile within years.

Below the reach of most earthworm activity lies the subsoil, the zone Ashwood’s book treats as its final destination. Subsoils are typically lower in organic matter and oxygen but enormously important as reservoirs of mineral nutrients, as sites of long-term carbon stabilization, and as habitats for specialized microbial communities adapted to scarcity. Carbon that reaches depth through leaching, root death or the transport of fine particulate organic matter can persist for centuries to millennia when protected on mineral surfaces or inside stable aggregates. The organisms that govern whether carbon is respired to carbon dioxide or stabilized in place are therefore directly implicated in one of the central feedbacks of the global climate system, which is a large part of why soil biodiversity has become a priority for researchers and policymakers alike.

Agriculture sits at the sharp end of these processes. Soil fauna and microbes underpin the fertility of farmland by mineralizing nitrogen and phosphorus, suppressing pathogens, improving water-holding capacity and building the aggregate structure that resists compaction. Intensive tillage, monoculture and agrochemical pressure can simplify belowground communities, and a growing body of research links that simplification to declining soil health. Books that translate this science for a general audience perform a function that technical literature cannot, building the public understanding and political will needed to treat soil as a living resource rather than an inert growing medium. The Marsh Ecology Book of the Year has a history of rewarding exactly this kind of influential communication, and the judges’ comments suggest Ashwood’s combination of rigorous content and personal narrative continues that tradition.

The prize itself reflects an unusual and durable model of partnership between a learned society and a charitable funder. The Marsh Charitable Trust supports a wide range of recognition schemes across conservation, culture and the arts, and 2026 marks the 30th anniversary of its collaboration with the British Ecological Society. Awarded to the book judged to have exerted the greatest influence on the science of ecology in any two-year period, the Marsh Ecology Book of the Year has become one of the most visible honors for ecological writing, and The World Beneath Our Feet is its 21st winner. Ashwood will receive the award in person during a ceremony at the BES Annual Meeting, which runs from 14 to 17 December 2026 in Birmingham and will bring together more than 1,500 ecologists to discuss the latest advances across the whole discipline.

For a field whose subject matter is literally underfoot, soil ecology has long struggled for visibility against charismatic megafauna and distant ecosystems, which makes this award more than a ceremonial pat on the back. It signals that the scientific community regards the communication of belowground biology as central to ecology’s public mission at a time when soils are being lost to erosion, degradation and sealing far faster than they can form. Ashwood’s descent from litter layer to subsoil offers readers a narrative structure for a world they will never see with the naked eye, populated by organisms whose quiet work cycles nutrients, feeds crops and stores carbon. If the judges are right that jaw-dropping facts crowd every page, the book may do for the soil what earlier classics of nature writing did for oceans and rainforests: make the invisible both vivid and worth fighting for. The World Beneath Our Feet is published by Hodder Press, with cover design by Holly Ovenden.

Subject of Research: Soil ecology and the recognition of popular science writing on soil biodiversity through the British Ecological Society's Marsh Ecology Book of the Year award

Article Title: The World Beneath Our Feet wins the British Ecological Society Book of the Year 2026

Article References: The World Beneath Our Feet wins the British Ecological Society Book of the Year 2026. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: soil ecology, soil biodiversity, British Ecological Society, Marsh Ecology Book of the Year, Frank Ashwood, earthworms, nutrient cycling, carbon storage, decomposition, ecosystem engineers, science communication, subsoil

The research was led by scientists from the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences together with collaborators, and it tackled the problem at a scale rarely attempted for soil fauna. The team conducted their fieldwork across Southwest China and Thailand, an extraordinary environmental gradient that stretches from the high elevations of the Tibetan Plateau, through the rugged Hengduan Mountains, and down into the humid tropical lowlands. Using a nested sampling design, the researchers collected approximately 700 soil samples from seven undisturbed forest plots, each spanning 400 by 400 meters. The plots represented three distinct forest types: two coniferous forests, two broadleaf forests, and three tropical rainforests. Within each large plot, smaller 40 by 40 meter grids served as the finest sampling units, allowing the team to examine nematode communities simultaneously at local, landscape, and regional scales.

This hierarchical design matters because ecological patterns are notoriously scale-dependent. A process that dominates community assembly at one meter may be irrelevant at one kilometer, and vice versa. By nesting fine-grained grids inside large forest plots, and by spreading those plots across a montane transect spanning thousands of meters of elevation, the researchers could watch the drivers of nematode diversity shift as the lens zoomed out. As first author Wang Wenting explained, examining nematode communities along this transect uncovered how the forces structuring soil animal diversity change across spatial scales, a perspective that single-site studies simply cannot provide.

What the team found in the soil was remarkable in its own right. Across the seven forests, they identified 209 nematode genera belonging to five feeding types: herbivores that pierce plant roots, bacterivores that consume bacteria, fungivores that graze on fungal hyphae, omnivores with broader diets, and predators that hunt other soil animals. Each feeding group represents a different branch of the soil food web, so changes in their diversity ripple through decomposition, nutrient mineralization, and even plant health. Among all the forest types examined, tropical rainforests supported the highest nematode diversity, reinforcing the idea that these species-rich ecosystems are not just hotspots for visible life like birds and trees, but also for the microscopic majority living underground.

The central analytical question was how nematode diversity relates to the diversity of the plant communities above. Ecologists distinguish between different components of biodiversity, and the study focused on several of them. Alpha diversity describes the variety of species within a single local site, gamma diversity captures the total variety across an entire region, and beta diversity measures turnover, meaning how different the plant communities are from one location to another. When the researchers compared these metrics, a consistent pattern emerged: nematode alpha diversity and gamma diversity both increased with plant beta diversity across most feeding types. In other words, forests composed of a shifting mosaic of different plant species harbored richer and more varied nematode communities than forests where the vegetation was more uniform.

This finding has profound implications for conservation. It suggests that the benefits of plant diversity do not stop at the soil surface. Different plant species produce different root architectures, leaf litter chemistries, and rhizosphere environments, and each of these creates distinct microhabitats and food resources for soil organisms. When plant communities turn over from one patch to the next, they generate a heterogeneous underground landscape in which many nematode species can coexist. Conversely, simplifying vegetation, whether through monoculture plantations, selective logging that removes key species, or other forms of habitat homogenization, may silently erode the diversity of soil fauna even when the forest canopy still looks intact. Maintaining a mosaic of different plant communities, the authors conclude, is critical for safeguarding the hidden biodiversity beneath our feet.

The second major discovery concerned nematode body size, and it revealed an unexpected subtlety in how these animals move through their world. Dispersal, the movement of organisms from one place to another, is a fundamental process in ecology, and body size is often assumed to influence how far a species can travel. For soil nematodes, which are aquatic animals in the sense that they live in water films and depend on moisture for movement, dispersal tends to happen over short distances, through soil pores, or passively via wind, water, and larger animals. The researchers asked which aspect of body shape, length or width, best predicts how nematode communities assemble across the landscape.

The answer was body width, not length. Nematode body width emerged as a key trait influencing community assembly, presumably because wider animals have more difficulty squeezing through narrow soil pores and water films, limiting how far they can disperse and how readily they colonize new habitats. Body length, by contrast, had little effect on assembly processes, with one notable exception: random changes in community composition known as ecological drift. This distinction suggests that dispersal limitation in nematodes is governed by the physical geometry of the soil environment, which filters organisms according to their girth rather than their overall size. Two nematodes of identical length but different widths may face very different dispersal barriers, and this trait-mediated filtering helps explain why some nematode genera are widespread across a landscape while others remain confined to particular patches of soil.

Taken together, the two findings paint a coherent picture of how underground biodiversity is organized. At large scales, the turnover of plant species from one location to another sets the template, creating the environmental variety that nematode communities exploit. At finer scales, the body width of each nematode genus determines how easily it can move through the soil matrix to reach those habitats, shaping which species coexist where. Aboveground and belowground biodiversity, the study demonstrates, are tightly linked through the turnover of plant species across the landscape, a coupling that ecologists have long suspected but rarely documented with such spatial rigor for soil fauna.

The broader message is one of urgency and opportunity. As Yang Xiaodong of XTBG noted, protecting ecosystems and biodiversity is not just about conserving plants; it is about safeguarding the invisible majority of life beneath our feet. Soil organisms are increasingly recognized as essential allies in climate regulation, food production, and ecosystem resilience, yet they remain largely absent from mainstream conservation planning. This study provides a concrete, actionable principle: preserve and restore the diversity and spatial turnover of plant communities, and the microscopic food webs below will follow. As forests across the tropics and mountains of Asia face mounting pressure from land-use change, the humble nematode offers a powerful reminder that the fate of the smallest animals is woven into the fate of the largest forests, and that protecting one means protecting the other.

Subject of Research: Soil nematode biodiversity and its drivers across forest landscapes

Article Title: Plant turnover and body size shape soil nematode diversity across landscapes

Article References: Plant turnover and body size shape soil nematode diversity across landscapes. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: soil nematodes, plant diversity, beta diversity, dispersal limitation, body size, tropical rainforest, soil ecology, biodiversity conservation, Tibetan Plateau, Hengduan Mountains, PNAS, ecological drift