The four species at the heart of the study, the long-tailed goral, the water deer, the Siberian roe deer and the wild boar, present a fascinating conservation puzzle. The endangered long-tailed goral depends on rugged, forested terrain and represents one of South Korea’s most closely monitored protected mammals. At the opposite end of the spectrum, water deer and wild boar thrive in human-modified environments, where their expanding ranges increasingly bring them into conflict with agriculture and peri-urban communities. Understanding how these ecologically contrasting animals coexist is central to community ecology and carries direct consequences for conservation planning and wildlife management.

Uljin County, spanning roughly 990 square kilometres within the Nakdongjungmaek mountain range, was a deliberate choice for the monitoring effort. The region’s terrain rises from sea level to 1,137 metres through narrow valleys and steep slopes, clothed in mixed forests of red pine and oak species such as Quercus variabilis and Quercus mongolica. Crucially, Uljin hosts the southernmost viable population of the long-tailed goral, making it a priority area for conservation-focused research. The temperate climate, with an average annual temperature of 12.5 degrees Celsius and 1,225 millimetres of precipitation, sustains year-round activity for all four species, allowing the researchers to capture seasonal variation in their movements.

The study design reflects a rigorous commitment to reducing bias. The research area was overlaid with a grid of 500 by 500 metre cells, and cameras were placed within 25 metres of each grid centroid where feasible, 52 cameras at site UJ1 and 30 at site UJ2. Reconyx HP2X infrared cameras were mounted on trees at heights of 80 to 100 centimetres, oriented parallel to the ground with a focal distance of at least three metres. Rather than using lures or baits, which can distort behaviour, the cameras were positioned along natural animal trails and operated continuously around the clock, capturing three images per trigger event without delay between successive detections.

To translate the raw photographic record into scientifically defensible data, the team applied a 30-minute independence rule, treating detections of the same species at the same camera as independent only when separated by at least half an hour. This threshold guards against pseudoreplication, the inflation of sample sizes caused by counting the same individual animal multiple times in quick succession. Survey effort totalled 29,850 functional camera-trap nights out of 30,410 scheduled nights, with 560 inactive nights accounted for by recorded downtime. The released files include a camera operation log, event-level records, station-level covariates and effort summaries, all harmonised to the GBIF Backbone Taxonomy for interoperability.

The species tally within the dataset itself reveals much about the relative abundance and detectability of each animal. The long-tailed goral dominated the record with 2,317 independent detections, followed by the water deer with 814, the Siberian roe deer with 808 and the wild boar with 684. Alongside each event, the researchers compiled station-level topographic covariates including elevation, slope, aspect and hillshade, derived from high-resolution NASADEM digital elevation data and processed with standard geospatial tools. An anthropogenic disturbance index, defined as the frequency of independent human detections at each station, was also computed to capture the intensity of human presence across the landscape.

To demonstrate the dataset’s analytical power, the authors provided two example workflows. The first applied single-species occupancy models, a standard technique for estimating the proportion of sites occupied by a species while accounting for imperfect detection. Detection histories were constructed at the station-by-season level, with season indicators and log-transformed effort in the detection component and covariates such as elevation, slope, human frequency and aspect in the occupancy component. Three candidate models were compared for each species using AICc. Notably, for the goral, a sensitivity check revealed that some occupancy parameters remained unstable and imprecise, a caution the authors emphasise: the analyses are demonstrations of reproducible workflows rather than definitive evidence of causal relationships.

The second workflow turned to the dimension of time. Using kernel density estimation of time-of-detection data, the researchers constructed continuous activity curves for each species and quantified pairwise similarity with the coefficient of overlap, employing the Delta4 estimator with 1,000 bootstrap replicates for uncertainty. The results, summarised in local clock time for the Asia/Seoul timezone, ranged from 0.653 to 0.840. The highest temporal overlap, 0.840, occurred between the long-tailed goral and the Siberian roe deer, suggesting these two species move through the forest on remarkably similar schedules. The lowest, 0.653, separated the water deer from the wild boar, hinting at more divergent daily rhythms.

Methodological care extended to how time itself was measured. Because civil clock time does not always align with actual sunrise and sunset, especially across seasons, the team complemented their clock-time analyses with a photoperiod-adjusted sensitivity analysis based on solar time, in which daylight and darkness were each standardised to twelve hours relative to site-specific sunrise and sunset times. They also reported diel-period summaries as rate-normalised detections per 100 hours, using civil twilight definitions, to correct for the unequal durations of day, night and the shorter crepuscular windows at dawn and dusk. The solar-time overlap estimates ranged from 0.633 to 0.819, closely mirroring the clock-time results and reinforcing the robustness of the temporal patterns.

The significance of this release extends well beyond the Korean Peninsula. Standardised, open-access occurrence data are increasingly recognised as critical infrastructure for biodiversity science, enabling researchers to balance the protection of endangered species against the management of over-abundant, conflict-prone wildlife. The dataset is archived under a CC0 waiver in the journal and available through the National Institute of Ecology’s EcoBank repository under a Korea Open Government License, with exact camera coordinates deliberately withheld and replaced by generalised site-level coordinates to safeguard the endangered goral from location disclosure. As the authors note, observational camera-trap data cannot alone identify the mechanisms driving coexistence; combining such records with GPS telemetry, dietary analysis and habitat measurements will be the next step. But for now, ecologists worldwide have a transparent, quality-controlled foundation on which to build, one year of forest life in one of East Asia’s most remarkable ungulate communities, freely available for reproducible science.

Subject of Research: Spatial occurrence and diel activity of four sympatric ungulate species in South Korean temperate forests assessed with a year-long camera-trap dataset

Article Title: A year-long camera-trap dataset for assessing spatial occurrence and diel activity of sympatric ungulates in South Korea

Article References: Jeon, J.-H., & Lim, A. (2026). A year-long camera-trap dataset for assessing spatial occurrence and diel activity of sympatric ungulates in South Korea. Biodiversity Data Journal, 14, Article e191556. https://doi.org/10.3897/bdj.14.e191556

Image Credits: AI Generated

DOI: 10.3897/BDJ.14.e191556

Keywords: camera trapping, ungulates, South Korea, diel activity, occupancy modelling, long-tailed goral, water deer, wildlife conservation, community ecology, open data, Uljin County, temporal overlap

The balsam woolly adelgid, first documented severely impacting areas within the park boundary in 1962, devastated the high elevation fir forests that define the skyline of the southern Appalachians. When the firs died, the canopy opened dramatically, flooding the understory with light and altering the cool, humid microclimate on which bryophytes depend. Because bryophytes make up the bulk of the ground cover and species richness in these high elevation zones, any shift in canopy structure reverberates through the entire community. The researchers asked whether these changes left a detectable fingerprint in the specimen record, and whether different management strategies applied to different peaks produced measurably different outcomes.

To answer these questions, the team compiled bryophyte specimen data collected in the park between 1913 and 2022, drawing records from the Consortium of Bryophyte Herbaria and the Global Biodiversity Information Facility and supplementing them with specimens not yet available through online portals. Species names were synonymized using Tropicos and current moss and liverwort classifications to account for a century of taxonomic change, and duplicate records and genus-level identifications were removed. Each specimen was georeferenced and assigned an elevation extracted in ArcGIS Pro, then grouped spatially by mountain peak: Kuwohi, formerly known as Clingmans Dome, Mt. Kephart, Mt. LeConte, and Mt. Sterling, each of which experienced a different management trajectory after the invasion.

The peaks tell contrasting stories. Mt. LeConte and Mt. Kephart received little to no adelgid management because their remoteness made strategy implementation impractical. Kuwohi was treated with both chemical and biotic controls, an approach that had a positive impact on the fir community. Mt. Sterling received the most aggressive intervention of all, including clear-cutting strips of trees to create a buffer zone alongside biotic controls, yet reports from the time indicate this combination was largely unsuccessful at slowing the invasion. The specimen data were then divided into three ecologically defined timespans: pre-adelgid from 1934 to 1962, post-adelgid from 1963 to 1999, and initial canopy recovery from 2000 to 2022, the period beginning when the first study documented fir canopy recovery in the park.

Because sampling effort varied enormously across decades, driven by extensive survey campaigns in some eras and sparse collecting in others, raw species counts were misleading. Uncorrected richness appeared to decline steadily through time across the peaks, but this pattern largely reflected disparities in collection intensity rather than genuine biological change. The researchers therefore applied rarefaction, a statistical technique that standardizes richness by randomly subsampling community data down to the lowest level of sampling effort being compared. They ran 9,999 rarefaction iterations for each timespan on each peak, reporting the percentage of iterations in which one timespan exceeded another, which allowed them to infer differences in rarefied richness with confidence.

The rarefied results revealed two distinct patterns. On Mt. Sterling and Mt. Kephart, rarefied alpha diversity increased from the pre-adelgid to the post-adelgid timespan, when the canopy would have been most open, and then declined during initial canopy recovery as the forest closed overhead. Kuwohi and Mt. LeConte showed no difference between the first two timespans but a sharp decrease in rarefied richness during recovery. This pattern of initial increase followed by decline matches what permanent plot studies of bryophytes have documented after canopy-opening disturbances, since increased light and downed wood create new niches that disappear again as the canopy closes and logs decay. Rarefied dissimilarity between timespans exceeded 0.5 for all comparisons across all four peaks, with Mt. Sterling and Mt. Kephart consistently showing the highest values, indicating that community composition has shifted substantially and has not simply returned to its pre-invasion state.

The most striking finding concerned species traits. Comparing the pre-adelgid and initial canopy recovery timespans for the high elevation group, the team classified each species as a substrate specialist occupying one substrate type, flexible occupying two, or a generalist occupying three or more, based on the Flora of North America. A chi-square analysis revealed that substrate specificity significantly differed between species that were lost, persisted, or newly appeared. Fewer generalists were lost and more generalists persisted than expected by chance, and generalists persisted significantly more often than specialists. This aligns with ecological theory and prior field studies: species capable of living on many substrates have more routes to survival and recolonization when disturbance reshapes the habitat, while specialists tied to transient resources such as downed logs, which proliferate after fir mortality but inevitably decay and vanish, face steeper odds.

Taxonomic patterns added further texture. Liverworts tended to be lost more often than mosses, a non-significant trend that echoes the literature documenting liverwort sensitivity to canopy opening. Several taxonomic orders, including Jungermanniales, Porellales, Hypnales, Grimmiales, Bryales, Pottiales, and Dicranales, showed significantly more species lost than new, driven by small numbers of newly appearing species against large numbers lost or persisting. The authors note that these apparent losses could guide targeted searches to determine whether species are truly gone or simply under-sampled, and that some new species may be climbing from lower elevations as climate change alters available niches at high elevation.

A crucial caveat runs through the analysis: the effects of the adelgid invasion and the effects of management cannot be strictly disentangled with these data. Mt. Sterling, which was clear-cut and heavily managed, and Mt. Kephart, which was unmanaged, showed remarkably similar patterns of rarefied richness and dissimilarity, suggesting that the invasion itself, possibly amplified by proximity between peaks, may have driven much of the change. Still, the comparison hints that aggressive canopy-altering practices like clear-cutting may have been more harmful to the bryophyte community than either leaving a peak unmanaged or using the chemical and biotic controls that succeeded on Kuwohi, which showed the lowest dissimilarity and nearly identical rarefied richness between the pre- and post-adelgid timespans. The authors suggest land managers may want to favor less extreme strategies when the goal is protecting the entire community.

Beyond the specific findings, the study carries a broader message for conservation. Permanent plots remain the gold standard for tracking community change, but they are prohibitively expensive and labor-intensive for many managed lands, leaving gaps in knowledge precisely where biodiversity is most at risk. GBIF documents more than 1.3 million preserved bryophyte specimens identified to the species level from the United States, collected from the 1800s to the present, and the southeast is among the most thoroughly surveyed regions. The authors argue that herbarium collections could serve as a substitute for permanent plots on lands with limited resources or expertise, enabling managers to evaluate the consequences of their decisions decades later. Future work should compare herbarium records directly with permanent plot data from the same areas and timespans, and expand sampling through field botany courses, collection forays, and bioblitz events, ensuring that the specimen record keeps growing rich enough to answer the ecological questions of tomorrow.

Subject of Research: Using bryophyte herbarium specimens to detect community change following the balsam woolly adelgid invasion in the southern Appalachians

Article Title: Detecting community changes in response to management practices using bryophyte herbarium specimens collected in the southern Appalachians

Article References: Shershen, E., & Budke, J. M. (2026). Detecting community changes in response to management practices using bryophyte herbarium specimens collected in the southern Appalachians. Natural History Collections and Museomics, 3, 1-22. https://doi.org/10.3897/nhcm.3.175897

Image Credits: AI Generated

DOI: 10.3897/nhcm.3.175897

Keywords: bryophytes, herbarium specimens, balsam woolly adelgid, Great Smoky Mountains, community ecology, rarefaction, invasive species, forest management, conservation, substrate specificity, liverworts, mosses

Comparing invertebrate communities across distant regions has always been fraught. Tropical rainforest spiders are poorly known taxonomically, many specimens in ecological samples belong to undescribed species, and the handful of species that do overlap between continents are often widespread invasives of little comparative value. The research team sidestepped much of this taxonomic barrier by working at the family level. Molecular phylogenetics has strengthened confidence that spider families are monophyletic, and with more than 52,000 described species distributed among 134 families, many of which have very broad geographic ranges, the presence and abundance of families offers a practical currency for comparing assemblage structure across the planet.

The deeper obstacle has always been methodology. The species-area relationship, one of ecology’s best-established principles, means that larger plots contain more taxa than smaller ones even when ecologically identical. Sampling intensity distorts diversity estimates in the opposite direction: heavily collected regions appear more diverse than undersampled ones regardless of biological reality. And the sampling methods themselves determine which animals are recorded at all. Existing standardized protocols developed by community ecologists solve these problems but demand intensive effort, typically one-hectare plots that cannot be exhaustively sampled in a tropical forest, plus resources, canopy access, and safe night work that most tropical researchers simply lack. The result is that most tropical sites have never been, and probably never will be, sampled in a way that permits rigorous comparison.

The Rapid Assessment Protocol, or RAP, developed by the first author threads between these extremes. After a site of interest is chosen, a 50-meter transect is run along the nearest trail, serving as an X axis with flags at 0, 12, 24, 36, and 48 meters. A compass determines the perpendicular Y axis running into the forest, beginning 24 meters from the trail to reduce edge effects, with possible plot centers at 24, 36, 48, 60, or 72 meters. Randomly selected coordinate pairs locate three 100-square-meter plots, each flagged out with a weighted rope marked at the 5.64-meter radius. Hazardous features such as streambeds or wasp nests disqualify a point, which is replaced by a new random draw. The entire 0.25-hectare site is thus sampled identically every time, with identical equipment and identical effort.

Within each plot, collectors spend one person-hour on aerial sampling, sweeping ground vegetation with canvas nets and beating or brushing trunks and shrubs with a horsehair brush onto one-square-meter sheets, and two person-hours on ground sampling, rapidly filling buckets with leaf litter and shaking it through a 35-centimeter geology sieve onto a sheet while teammates snatch the revealed spiders with aspirators and jars. The deliberate two-to-one bias toward litter sampling proved justified: pooled across all twelve plots, the single hour of aerial effort yielded 184 adult spiders from 20 families while the double ground effort yielded 151 adults from 21 families, meaning litter sieving accesses distinct taxa and roughly optimizes information gained per unit of time. All specimens were preserved in 50 percent propylene glycol, shipped to the Field Museum in Chicago, and identified to family by museum specialists, with only adults analyzed to guarantee accurate identifications.

The protocol was tested at two mature lowland rainforest sites on each continent. In Panama, the sites lay near the Panama Canal at roughly 70 meters elevation, one in Metropolitano National Park and the other in Soberania National Park, sampled by American university students on a travel course under an experienced field arachnologist. In the Democratic Republic of the Congo, both sites sat within the Yoko Forest Reserve near Kisangani, one a monotypic forest dominated by the canopy tree Gilbertiodendron dewevrei and the other a mixed forest with higher canopy diversity, sampled by Congolese students under the same protocol translated into French. Each site was completed in one to two days during dry seasons, with equipment carried in on transcontinental flights or rented canoes and motorcycles.

The samples yielded 350 adult spiders from 29 families, all araneomorphs. Panama dominated numerically, contributing 235 adults and 24 families against Congo’s 115 adults and 14 families. Five families together accounted for two-thirds of all adults: Theridiidae at 24 percent, Salticidae at 15 percent, Linyphiidae at 11 percent, Oonopidae at 10 percent, and Pholcidae at 7 percent, with every remaining family below 5 percent. The regional signatures diverged sharply. Theridiidae dominated Congo samples at over 36 percent, followed by Oonopidae and, notably, Thomisidae, a crab-spider family entirely absent from Panama. In Panama, jumping spiders of the family Salticidae led at 18.7 percent, followed by Theridiidae and Linyphiidae. Fifteen families appeared in Panama samples but not Congo samples, while only four were exclusive to Congo.

The statistical treatment revealed a subtler picture than raw numbers alone. Non-metric multidimensional scaling of the four sites, using pooled aerial and ground data from three replicate plots each, found the overall ordination highly significant but no pairwise difference between any two sites, likely because three replicates per site limited statistical power. When the six plots per continent were pooled, however, the family-level assemblages of Congo and Panama separated significantly, at p equal to 0.0021, with 95 percent confidence ellipses showing little overlap. iChao1 richness estimators, which infer completeness from the ratios of singletons to doubletons and higher abundance classes, produced confidence intervals for the Congo sites of roughly 9 to 12 estimated families against 14 to 21 for Panama, with minimal overlap, lending independent support to the conclusion that the Panamanian sites harbor genuinely higher family-level richness accessible to ground-level sampling.

How much of this reflects biology rather than artifact? The authors treat abundance differences cautiously, since seasonality, humidity, and recent weather can all alter spider activity and catch even within dry seasons. Family richness is more robust but partly confounded by the larger Panamanian catch. Composition, however, is the hardest result to explain away: the proportional dominance of Theridiidae and Thomisidae in Congo and Salticidae in Panama is unlikely to be an artifact of sample size or weather, because dominant taxa drive ordination placement and their relative representation is comparatively stable. The authors also acknowledge the study’s limits. At least nine Panamanian families known from similar habitats, including all mygalomorphs, went unrecorded, and a pitfall study near Kisangani recovered 11 families absent from the Yoko samples, confirming that canopy dwellers, burrowers, and rare species fall outside the RAP’s reach. Of the 29 families sampled, only Anyphaenidae and Mysmenidae are likely absent from one of the two regions.

What the study delivers, above all, is proof of concept. Teams of inexperienced students, briefly trained and minimally equipped, produced replicated samples from randomly located plots of fixed size and fixed effort that supported ordination, richness estimation, and a statistically significant intercontinental comparison, all within days of fieldwork. As far as the authors know, this is the first time spider assemblages, as opposed to national species lists, have been compared between Africa and Central America, and standardized protocols made it possible. A definitive comparison of the two regions’ rainforests would need many more sites, better vegetation and site history data, and ultimately canopy sampling, which the RAP excludes for cost and safety reasons. But for conservation prioritization in a world where rainforest degradation continues apace, a protocol that trades exhaustive surveying for speed, replicability, and affordability may be exactly the tool the moment requires.

Subject of Research: A rapid assessment protocol comparing spider assemblages in lowland tropical forests of Congo and Panama

Article Title: Comparison of lowland tropical forest spider ( Araneae ) assemblages from Congo and Panama using a rapid assessment protocol

Article References: Draney, M. L., Juakaly, M. J.-L., Sierwald, P., & Milne, M. A. (2025). Comparison of lowland tropical forest spider (Araneae) assemblages from Congo and Panama using a rapid assessment protocol. African Invertebrates, 66(1), 133-150. https://doi.org/10.3897/afrinvertebr.66.138414

Image Credits: AI Generated

DOI: 10.3897/afrinvertebr.66.138414

Keywords: spiders, Araneae, tropical rainforest, Congo, Panama, biodiversity, rapid assessment protocol, community ecology, conservation, field methods, Comparison, lowland

The starting point of the framework is modern coexistence theory, which distinguishes two kinds of mechanisms that allow competing species to persist together. Equalizing mechanisms reduce fitness differences between species, slowing competitive exclusion, while stabilizing mechanisms increase competition within species relative to competition between them. Classic examples include resource partitioning among insects or prey switching by zooplankton. The authors argue that both kinds of mechanisms are often mediated by movement, and that movement itself is motivated and constrained by an animal’s energy state. Movement data alone, they note, frequently fails to predict coexistence patterns accurately without a mechanistic understanding of its causes and consequences.

Earlier theories have addressed pieces of this puzzle. The metabolic theory of ecology uses metabolic scaling laws to predict life-history traits, population growth rates and species interactions from body size and temperature, but it largely overlooks individual behaviour and plasticity. The pace-of-life syndromes hypothesis, and its extended version that incorporates behavioural traits such as movement, links physiological and life-history traits along a fast-slow continuum, yet these frameworks remain largely trait-based and emphasize species-level patterns over individual-level mechanisms. The new framework positions the energy budget—the total energy an animal acquires and allocates across maintenance, growth, reproduction and movement—as the central currency driving decisions about whether, how, when and where to move.

The mechanics of the framework begin at the level of the individual. As animals move through their habitats they acquire energy through foraging, while simultaneously expending energy on life processes, collectively termed field metabolic rate. The balance between intake and expenditure—positive, neutral or negative—determines whether reserves are built, maintained or depleted, and this internal state in turn shapes movement decisions. Movement itself is energetically costly, depending on mode, intensity, duration and environmental conditions, so movement both responds to and reshapes an animal’s energy landscape. Individuals may suppress activity under acute energy stress or reduce it through genetically encoded seasonal routines when food is predictably scarce.

Empirical examples illustrate how energetics can underpin coexistence. In bees, larger bumblebees with higher energy demands visit only flowers offering a high energy intake-to-cost ratio, while smaller honeybees are less selective, reducing direct competition between the species. In common blackbirds, migrants and residents allocate energy differently but maintain similar total expenditures, an equalizing mechanism that balances fitness outcomes. Among northern pikes, individuals with different behavioural types coexist by adopting distinct foraging strategies: opportunistic foragers incur higher movement costs but compensate with increased foraging success, leading to equal survival across types.

Stabilizing mechanisms can also be read energetically. As population density rises, energy balance declines through costs of fighting conspecifics, physiological stress and increased infection rates, reducing individual fitness and slowing population growth—a form of negative density dependence. Ontogenetic niche shifts offer another path: when a dominant competitor’s energy demands vary across life stages, direct interspecific competition is reduced, as observed in coexisting Trinidadian guppies and killifish. In the Yukon, snowshoe hares and squirrels cope with cold through contrasting adaptations—hares adjust metabolically by varying heart rate while squirrels rely on behavioural avoidance of low temperatures—producing temporal niche partitioning that mediates shared predation and supports coexistence in seasonally variable environments.

The movement side of the triangle spans all scales, from daily foraging to long-distance migration and dispersal. Dispersal connects to coexistence through the colonization–competition trade-off, migration can induce competition among migrants and between migrants and residents, and foraging movements mediate competition for spatio-temporally heterogeneous resources. Movement also produces mobile link effects: hares disperse seeds through endozoochory in agricultural landscapes, salmon transport nutrients uphill during spawning runs, and the whale pump moves nutrients from deep waters to the surface, enhancing productivity and shaping food web dynamics.

Energetic triggers of movement are strikingly concrete. In Sierra Nevada bighorn sheep, individuals with lower body fat reserves are more likely to migrate across greater elevational distances to reach richer forage, accepting increased predation exposure to reduce starvation risk. Griffon vultures show a flexible, hump-shaped response to hunger, increasing movement at moderate food deprivation but reducing it as starvation risk grows—a strategic shift from maximizing intake to minimizing expenditure. Golden-mantled ground squirrels double their body mass and triple their fat stores before hibernation, so that movement in this case facilitates future energy conservation. Juvenile coho salmon migrate daily between cold, food-rich waters and warmer areas to optimize digestion and growth, then time their seaward migration to when body size, abiotic factors and food availability align.

How animals move is equally shaped by energetics. Walking and running have a lower cost per unit time, while flying and swimming are more efficient per unit distance, but costs rise steeply with speed in swimming and flying while running costs increase more linearly. Starlings switch between walking and flying, weighing locomotion costs against foraging efficiency to maximize net energy gain. Some polar bears in the Southern Beaufort Sea have shifted from sea ice to land in response to ice loss, swimming more and expending more energy but gaining access to higher-quality foraging areas. In the Australian desert, banded stilts undertake rapid continent-wide movements to track ephemeral wetland resource pulses critical for breeding, illustrating the risks and costs of fully nomadic strategies.

From this integrated framework the authors derive testable predictions for a changing world. One holds that under resource scarcity, individuals that flexibly switch between intensive foraging and energy-saving modes will persist longer than inflexible ones, reshaping competitive interactions and community composition. Another predicts that in environments with fluctuating energy availability, species with higher energy demands or lower tolerance to deficits will abandon depleted patches more rapidly, driving shifts in community composition—an extension of the classic R* rule into dynamic, heterogeneous systems. A third predicts that interference competition among sympatric species will intensify as their metabolic niches increasingly overlap, since similar energy investment and movement traits raise encounter frequency and escalate stress, displacement and injury.

Testing these predictions will require methodological integration. Controlled experiments, including treadmill studies with environmental complexity and mesocosms varying resource regimes, can quantify energy costs of movement and fitness outcomes. Field-based multi-sensor technologies recording accelerometry, heart rate and temperature allow estimation of field metabolic rates, increasingly scalable through tagging innovations and combinable with remote sensing to construct energy landscapes. Machine learning can infer energy expenditure from movement patterns in high-dimensional ecological datasets. Mechanistic simulation models then bridge scales from individual energetics to community dynamics, exploring causal pathways and forecasting responses to novel scenarios such as climate-driven resource shifts or species introductions, though their predictive power depends on high-quality empirical data for parameterization.

The stakes are considerable. Global change is reshaping energy landscapes—droughts, heatwaves, resource pulses and invasions alter not just resource availability but the energetic costs of acquiring it. Energetic mismatches may accelerate species turnover by filtering out individuals that cannot meet metabolic demands, and interaction networks may reorganize as movement patterns change, producing novel spatial and temporal overlaps. These transitions may not be gradual: thresholds may be crossed when energetic constraints are breached, triggering abrupt shifts in movement, competition or coexistence outcomes. By embedding energy fluxes and movement strategies within coexistence theory, the framework offers a mechanistic and predictive ecology of biodiversity—one in which it is not just how much energy is available, but how and when animals decide to pursue it, that determines who persists in fluctuating environments.

Subject of Research: Mechanistic links between animal energetics, movement behaviour and species coexistence in community ecology

Article Title: From metabolism to coexistence: Understanding animal movement and community dynamics through energy

Article References: Szangolies, L., Jeltsch, F., Halsey, L. G., & Gallagher, C. A. (2025). From metabolism to coexistence: Understanding animal movement and community dynamics through energy. Individual-based Ecology, 1, Article e151741. https://doi.org/10.3897/ibe.1.151741

Image Credits: AI Generated

DOI: 10.3897/ibe.1.151741

Keywords: animal movement, energetics, species coexistence, community ecology, movement ecology, ecophysiology, energy budget, metabolic theory, biodiversity, coexistence mechanisms, global change, individual-based ecology

The research team set out to evaluate species richness, endemism, and phylobetadiversity patterns across the entire physiographic province, which stretches from Cabo Corrientes in Nayarit to the Sierra de Chiconquiaco in Veracruz, between roughly 19°N and 21°N. The belt was forged over the last 19 million years through four major volcanic episodes, with the western section being the oldest and the eastern section the youngest. That asynchronous geological history has left a striking imprint: the west is dominated by semi-warm, subhumid climates, while the east is cooler and temperate, with vegetation ranging from tropical deciduous forests and xerophytic shrublands to oak and pine forests. The scientists expected these contrasts to shape which amphibian lineages thrive where.

To capture diversity at meaningful scales, the team overlaid the province with square grid cells ranging from a fine 0.125-degree resolution, suited to the small home ranges and limited dispersal of amphibians, up to the coarse 1-degree cells typical of macroecology. Very fine grids produced too many empty cells, while coarse ones washed out the region’s heterogeneity, so the analysis settled on 0.5-degree cells. After stringent quality filtering, 32,038 of 39,711 downloaded collection records were retained, representing 143 studied species in 36 genera. Among these were 92 species of frogs and toads in 27 genera, 50 salamander species in eight genera, and two caecilian species in a single genus, drawn from validated records in GBIF and a supertree of global amphibian relationships from which a maximum clade credibility tree was derived.

The results revealed a pronounced east-west asymmetry. Species richness in the eastern region ranged from 24 to 38 species per cell, whereas the western region held only one to 16 species per cell. Phylogenetic diversity also ranged widely, from 309 to 2,558, with high values in both subregions, although when standardized for species richness, most cells showed lower phylogenetic diversity than expected by chance, with just seven western cells exceeding expectations. The predicted split in lineage composition held firm: frogs and toads dominated the west, making up 86.3 to 100 percent of species there, while salamanders, which depend on cool, moist conditions, reached up to 60 percent of species in the east and were almost absent in the west.

Endemism told a subtler story. Values of both the endemism index and the phylogenetic endemism index were low across most of the belt, particularly in the west, with high concentrations confined to a handful of eastern cells. One eastern cell with exceptional phylogenetic endemism received only marginal coverage by Mexico’s Priority Terrestrial Conservation Areas, a gap the authors flag as a conservation concern. The near absence of overlap between cells of high richness and cells of high endemism matched one of the team’s core predictions and echoes a well-documented pattern across Mexico, where hotspots of different diversity facets rarely coincide.

Perhaps the most provocative finding concerns the forces structuring amphibian communities. Using phylogenetic community metrics including the phylogenetic diversity index, the net relatedness index, and the nearest taxon index, the researchers found that overdispersion, in which coexisting species are less closely related than expected by chance, is the dominant pattern across the belt. That signature points to ecological and biotic interactions, such as competition, as the primary drivers of community assembly, contradicting the expectation that habitat filtering would produce clusters of closely related species. In the west, a few cells did show positive values consistent with habitat filtering, and the net relatedness index was negative in the west and positive in the east, hinting at regionally distinct assembly rules within a single province.

Beta diversity, the turnover of species between sites, emerged as strikingly high. Sixty-nine percent of cells exhibited high taxonomic dissimilarity, especially in the east, and both taxonomic and phylogenetic beta diversity decomposed into a strong turnover component with low nestedness. That combination is consistent with patterns seen in other low-vagility taxa and in mountainous regions, and it supports the idea that species turnover reflects speciation and environmental specialization, whereas nestedness is tied to physiological constraints. In practical terms, nearly every grid cell harbors a distinct assemblage of lineages found nowhere else in quite the same combination, a mosaic that defies any single-site conservation strategy.

To identify the drivers behind these patterns, the team assembled nineteen predictor variables spanning contemporary bioclimatic conditions, historical climatic shifts since the Last Glacial Maximum about 21,000 years ago, and landscape features such as slope, evapotranspiration, aridity, vegetation greenness measured through satellite-derived NDVI, and soil temperature and moisture estimated from ERA5-Land and SMAP data. After removing collinear variables, eight predictors remained, all statistically significant across 1,000 randomizations. Differences in precipitation seasonality between the glacial period and today contributed most to explaining taxonomic beta diversity, while soil temperature was the leading factor behind species turnover on both taxonomic and phylogenetic facets. Geographic distance also correlated with both facets of beta diversity, underscoring dispersal limitation in these philopatric, moisture-dependent animals.

The explanatory power of the models was modest, explaining between 5.9 and 25.4 percent of the variance, a result the authors interpret honestly. Nestedness, in particular, is sensitive to grid-cell size, regional extent, and data resolution, and may reflect selective colonization, habitat nestedness, or disturbance. The team suggests that future work should incorporate landscape connectivity, geomorphology, and finer altitudinal stratification of records, since the rugged topography of the belt creates sharp gradients and barriers that coarse digital elevation models may not fully capture. Pleistocene refugia may also have played a role, allowing lineages with slow climatic niche evolution to persist in stable mountain environments and differentiate in place, a scenario consistent with the overdispersed communities observed.

The conservation implications are sobering. The study found little spatial congruence between the diversity facets it measured and Mexico’s existing Priority Terrestrial Conservation Areas, with many protected polygons encompassing cells with the lowest levels of beta diversity and turnover. This matters because 49 percent of the belt’s anuran species and 70 percent of its caudate species are currently listed in a risk category by the IUCN, many with extremely restricted distributions and specialized microhabitat requirements. When turnover dominates, the authors argue, preserving the region’s evolutionary history requires protecting many heterogeneous sites rather than a few species-rich ones. As climate change accelerates, they conclude, redefining the boundaries of priority areas with phylogenetic and beta diversity in mind may be the only way to safeguard the full breadth of the volcanic belt’s remarkable amphibian heritage.

Subject of Research: Environmental drivers of amphibian species richness, endemism, and phylobetadiversity in the Transmexican Volcanic Belt

Article Title: The role of environmental heterogeneity in the diversity of the amphibian fauna of the Transmexican Volcanic Belt

Article References: Gómora-Cercas, J., Martínez-Méndez, N., Díaz de la Vega-Pérez, A., & Mejía, O. (2026). The role of environmental heterogeneity in the diversity of the amphibian fauna of the Transmexican Volcanic Belt. Neotropical Biology and Conservation, 21(3), 223-243. https://doi.org/10.3897/neotropical.21.e187054

Image Credits: AI Generated

DOI: 10.3897/neotropical.21.e187054

Keywords: amphibians, Transmexican Volcanic Belt, biodiversity, phylogenetic diversity, beta diversity, endemism, biogeography, community ecology, conservation, climate, Mexico, salamanders

The loose equilibrium hypothesis is a refinement of classical equilibrium thinking in ecology. It predicts that biological assemblages will show modest, essentially random fluctuations from one year to the next, but that over longer periods they will not follow a directed trajectory away from a stable baseline condition. In other words, a community may jitter around its average composition, but it should not march steadily toward a new state unless something fundamental about the environment has changed. This idea matters because it offers a practical benchmark for detecting real ecological trouble: if a community departs directionally from its baseline, that pattern can signal disturbance, degradation, or a shift in environmental drivers rather than ordinary background variability.

Testing such an idea has historically been difficult because it requires long, consistent time series collected with identical methods across many sites. Most ecological datasets span only a few years, use inconsistent sampling designs, or cover single locations, making it hard to distinguish genuine directional change from sampling noise. The NEON stream program solves much of that problem. Since 2016, the network has deployed standardized protocols to sample the insects living on streambeds, the benthic macroinvertebrates that form the ecological backbone of small streams, at dozens of sites spanning wide gradients of climate, geology, and land use. The new analysis harnesses that infrastructure, using data from 2016 through 2023 at 21 stream sites to ask whether insect assemblages behave as the loose equilibrium hypothesis predicts.

The analytical approach is deceptively simple in concept but demanding in execution. For each stream, the researchers constructed a baseline assemblage condition and then quantified how the community moved through compositional space across successive sampling events. Random, non-directional movement among sampling events is the signature of loose equilibrium, while consistent directional movement away from the baseline indicates a departure from that state. Crucially, the team also expanded the traditional method, which typically relies on a single sampling season per year, by incorporating multi-season data. That expansion allowed them to ask a question that previous studies could not: does the season in which you sample influence whether a community appears to be in equilibrium?

The headline result is that loose equilibrium appears to be the norm. Seventeen of the 21 benthic insect assemblages exhibited random, non-directional change among sampling events, exactly the pattern the hypothesis anticipates. These communities fluctuated in composition from year to year, as real ecological communities always do, but their fluctuations did not accumulate into a sustained trend away from their starting point. For the vast majority of the streams examined, the loose equilibrium hypothesis held up under scrutiny, providing some of the strongest multi-site evidence to date that many stream insect assemblages are dynamically stable over nearly a decade of observation.

The four exceptions are where the story becomes especially interesting. Two assemblages showed directional movement away from their baseline condition, a pattern consistent with a genuine ecological transition. The remaining two displayed a different signature: directional movement away from the baseline followed by a return toward it, as though the community had been pushed off course and then recovered. Supplementary data on taxonomy, feeding behavior, and environmental conditions suggest that these four instances of directional change may represent responses to recent disturbances or to altered physicochemical habitat conditions at those sites. In other words, the deviations from equilibrium were not mysterious; they coincided with environmental changes that plausibly could reorganize an insect community, which is precisely what the loose equilibrium framework is designed to flag.

Beyond the equilibrium test itself, the study uncovered a striking seasonal dimension to stream insect dynamics. Distinct seasonal clusters, corresponding to spring, summer, and fall sampling periods, were detected for 13 of the 21 assemblages. This means that in most of these streams, the insect community sampled in spring looks measurably different from the community sampled in summer or fall, reflecting the seasonal life cycles of aquatic insects, in which emergence, reproduction, and recruitment are timed to temperature, flow regimes, and resource availability. Seasonal structure of this kind is well known to freshwater ecologists, but its interaction with long-term equilibrium dynamics had rarely been examined with data of this quality and breadth.

Within those seasonally clustered assemblages, the researchers found an even finer pattern. Eleven of the 13 clustered assemblages contained at least one significantly small cluster, indicating minimal interannual change within that particular season. A spring community, for example, might be nearly identical from one spring to the next even while differing sharply from the summer community at the same site. This tight seasonal repeatability suggests that each season imposes its own predictable environmental template, and the insects respond to that template with remarkable consistency. Such predictability, the authors argue, may be a mechanism that actively supports loose equilibrium rather than merely coexisting with it.

That mechanism forms the conceptual centerpiece of the paper. The researchers hypothesize that seasonally distinct yet predictable environments promote inter-seasonal consistency in assemblage structure, thereby constraining the opportunities for insect assemblages to shift far from their baseline condition. The logic runs as follows: if each season presents a reliable set of conditions, then the species adapted to those conditions reassemble reliably each year, and any drift that begins in one season is effectively reset when the next season’s template takes over. Strong seasonality, in this view, is not a source of instability but a stabilizing rhythm, a metronome that keeps communities tethered to their baselines even as individual years bring droughts, floods, and warm spells. This hypothesis reframes seasonality from a complicating nuisance in long-term monitoring into a potential pillar of community stability.

The implications extend well beyond stream insects. Equilibrium theory has anchored community ecology for a century, but critics have argued that the field’s core concepts are too loosely defined to be tested rigorously, and that apparent stability often dissolves when datasets lengthen or sampling designs improve. By tightening the loose equilibrium concept with a multi-season, multi-site analysis, this study gives ecologists a sharper tool for distinguishing healthy variability from genuine directional change, and it demonstrates that the tool works at continental scale using publicly available NEON data. As climate change alters flow regimes, temperatures, and disturbance frequencies in streams across North America, the ability to detect when an assemblage truly departs from its baseline, rather than merely fluctuating around it, will become increasingly valuable for anticipating future changes in benthic assemblage structure and for managing the freshwater ecosystems that depend on them. The study also offers a model for how large, standardized observatory networks can transform abstract ecological theory into testable, quantitative predictions, turning eight years of routine insect counts into a rigorous stress test of one of ecology’s central ideas about how nature holds together.

Subject of Research: Testing the loose equilibrium hypothesis using multi-season benthic insect assemblage data from National Ecological Observatory Network streams

Article Title: Tightening the loose equilibrium concept: New seasonal insights with benthic insect data from National Ecological Observatory Network streams

Article References: McGarvey, D. J., Parker, S. M., Esparra-Escalera, H. J., Vargas-López, N., Emer, L. K., Juarez, J. R., Secondine, V., Ortiz Muñoz, L. D., Bravo Ortiz, V., Reifsteck, A. R., Solliday, J., Turner, R. K., Presswood, D., Mendez, P. K., DeVivo, M., Meza Gonzalez, R., Romero, H. K., Aguirre, J., & Ondich, B. (2026). Tightening the loose equilibrium concept: New seasonal insights with benthic insect data from National Ecological Observatory Network streams. PLOS Ecosystems, 1(2), e0000037. https://doi.org/10.1371/journal.pesy.0000037

Image Credits: AI Generated

DOI: 10.1371/journal.pesy.0000037

Keywords: loose equilibrium, benthic macroinvertebrates, stream ecology, NEON, community ecology, equilibrium theory, seasonality, long-term monitoring, aquatic insects, ecological stability, baseline condition, disturbance

The research, led by Jinlong Gao and colleagues spanning the Chinese Academy of Sciences and partner institutions, examined a gradient of grazing-related disturbance across the meadow steppe, one of the most extensive grassland ecosystems in Eurasia. Grazing is among the most pervasive human-driven disturbances in grasslands worldwide, reshaping vegetation through defoliation, trampling, and the return of nutrients in dung and urine. Because livestock activity touches nearly every grassland on the continent, understanding how its intensity shapes biodiversity is not an academic curiosity; it is central to managing ecosystems that support herders, store carbon, and regulate water across vast regions.

Above the ground, the findings read like a textbook confirmation of the IDH. Plant communities responded to the disturbance gradient in a unimodal pattern, with diversity, biomass, and stability all peaking at intermediate levels of grazing-related disturbance. In other words, moderately grazed sites hosted the richest and most balanced plant assemblages, while both lightly disturbed and heavily disturbed sites fell short. This is precisely the hump-shaped relationship the hypothesis predicts, and it reinforces the long-standing management intuition that moderate grazing can sustain more diverse and more stable grassland vegetation than either strict exclusion or intensive use.

Below the ground, however, the story took an unexpected turn. Soil multitrophic communities, the combined assemblages of microbes, fungi, and the microscopic animals that feed on them and on each other, did not follow the same hump. Their alpha diversity, the diversity measured within a given site, was essentially insensitive to the disturbance gradient. No matter how hard the grassland was grazed, the number of soil life forms coexisting at a single location changed little. For a field that has often assumed aboveground rules transfer neatly to the soil, this is a consequential result.

Yet the soil communities were not indifferent to grazing; they simply responded along a different axis. Beta diversity, which captures how much community composition differs from place to place, peaked under moderate disturbance. At intermediate grazing intensity, soil communities across the landscape became most dissimilar from one another, suggesting that moderate disturbance reorganizes belowground life in ways that vary from site to site rather than uniformly reducing or enriching it. This spatial differentiation peaked exactly where plant diversity was highest, but the underlying mechanism and trajectory were clearly distinct.

The researchers also probed the architecture of the soil food web itself, mapping the networks of interactions among multitrophic communities. As disturbance increased, network complexity declined, and the character of the remaining connections shifted toward positive associations. In ecological terms, the intricate web of competition, predation, and antagonism that characterizes undisturbed soil gave way to simpler networks dominated by cooperation or mutual tolerance. The authors interpret this pattern as consistent with the stress-gradient hypothesis, the idea that as environmental stress intensifies, organisms increasingly rely on facilitation rather than competition to persist. Severe grazing, in this view, pushes soil communities into a reorganized, more cooperative state.

What could drive such a fundamental divergence between the visible and invisible halves of the grassland? The study points to a likely culprit: the flow of carbon from plants into the soil. Grazing reduces the biomass and productivity of vegetation, and the researchers found corresponding reductions in plant-derived carbon subsidies reaching belowground communities. Dissolved organic carbon, the labile carbon fraction that soil organisms readily consume, was lower under disturbance, and the remaining dissolved organic matter shifted toward more recalcitrant forms that are harder to decompose. In effect, heavy grazing starves the soil food web of its easiest energy source and forces it to subsist on tougher fare, a shift that plausibly explains both the reorganization of interactions and the changing spatial patterns of diversity.

This carbon mechanism matters far beyond the steppe. Soil multitrophic communities are the engines of decomposition, nutrient cycling, and carbon storage in grasslands, and their composition influences how much carbon these ecosystems lock away or release. If grazing decouples the response of plants from the response of soil organisms, then management strategies calibrated solely on vegetation, such as adjusting stocking rates to maximize plant diversity, may fail to safeguard the belowground processes that ultimately sustain the system. The study’s authors argue that their findings call for integrating belowground multitrophic dynamics into grassland resilience frameworks, particularly under global change, where shifting grazing regimes, altered precipitation, and rising temperatures will interact in ways that aboveground monitoring alone cannot anticipate.

The broader theoretical implication is equally provocative. The Intermediate Disturbance Hypothesis has been applied, debated, and tested across ecosystems from coral reefs to forests, and it has often been assumed to operate as a general law of biodiversity. By demonstrating that it holds for plants but not for soil multitrophic communities within the same landscape, the study delivers one of the clearest empirical demonstrations that disturbance responses are compartment-specific. The coupling between aboveground and belowground worlds, so often invoked in ecosystem science, is not automatic; disturbance can actively sever it, leaving plants and soil life marching to different ecological drumbeats.

For the Eurasian meadow steppe and the millions of hectares of grassland like it, the practical message is one of humility and nuance. Moderate grazing genuinely appears to be a sweet spot for plant diversity and stability, vindicating rotational and light-to-moderate stocking approaches. But the soil beneath those optimally grazed pastures is undergoing its own quiet transformation, with networks simplifying, communities differentiating, and carbon flows weakening in ways that no vegetation survey will reveal. As grasslands face intensifying pressure from livestock production and climate change, the study suggests that resilient management will require looking below the surface, treating the soil food web not as a passive mirror of the vegetation above but as a distinct and dynamic player with its own rules of response.

Subject of Research: Effects of grazing disturbance on aboveground plant and belowground soil multitrophic communities in the Eurasian meadow steppe

Article Title: Grazing-related disturbance decouples aboveground and belowground responses in the Eurasian meadow steppe

Article References: Gao, J., Wu, S., Wang, H., Chen, S., Wang, S., Xu, M., Pan, Q., Han, X., & Zhuang, X. (2026). Grazing-related disturbance decouples aboveground and belowground responses in the Eurasian meadow steppe. Communications Earth & Environment. https://doi.org/10.1038/s43247-026-04104-8

Image Credits: AI Generated

DOI: 10.1038/s43247-026-04104-8

Keywords: grassland ecology, grazing, Intermediate Disturbance Hypothesis, soil biodiversity, multitrophic communities, meadow steppe, dissolved organic carbon, stress-gradient hypothesis, community ecology, microbial ecology, ecosystem resilience, global change

The core of the work is a single, measurable quantity the authors call the competitive balance. In classic metapopulation theory, a species persists when its local extinction rate is lower than the so-called metapopulation capacity, typically captured by the largest eigenvalue of a dispersal kernel matrix. That logic works for a lone species, but in a community of many competitors, meeting the threshold is necessary yet not sufficient. The new framework shows that long-term persistence in an interacting metacommunity is instead governed by how a species’ competitive balance compares with those of all its neighbors—a collective property that emerges nonlinearly from the whole community rather than summing individual contributions.

What makes the approach practical is its refusal to demand data that ecologists rarely have. Mechanistic models of interacting communities usually require estimates of demographic rates, interaction coefficients and dispersal parameters, which are notoriously difficult to measure in species-rich ecosystems. Statistical tools such as species distribution models or population viability analyses are more data-friendly but often treat species in isolation. The Padova-led team sidestepped the problem by modeling the interaction–dispersal kernel entries as effectively random, drawn from a species-specific gamma distribution whose parameters can be inferred directly from spatial abundance patterns—the kind of coarse-grained census data that forest monitoring plots already collect.

The bridge between theory and data is a quantity called the vacancy-adjusted abundance, or VAA. For each species in a subplot, the VAA is the fraction of space it occupies divided by the locally unoccupied space. This normalization upweights patches that are nearly saturated, so the same relative space-use contributes differently depending on how crowded a site is. The result has a clear ecological reading: it rescales local occupancy to reflect a species’ effective colonization effort. Fitting the theoretical VAA distributions to empirical histograms yields two interpretable parameters per species—dispersal heterogeneity and effective dispersal strength—without any direct measurement of vital rates or interaction coefficients.

To validate the framework, the researchers turned to three spatially complete forest censuses: the Barro Colorado Island tropical plot in Panama, the Pasoh Forest Reserve plot in Malaysia and the Michigan Big Woods temperate plot in the United States. Each plot was partitioned into 50-meter square subplots, and the space used by each species was estimated using an established allometric relation between trunk diameter and crown area. The theory captured the diversity of distributional shapes across species with striking accuracy. In out-of-sample tests, parameters fitted on one half of a plot predicted the mean space-use of species in the other half with coefficients of determination of 0.97, 0.93 and 0.95 for the three datasets respectively.

The framework also outperformed ecological null models. Against a neutral negative-binomial model with community-level parameters, and against a species-specific variant matched in parameter count, the new theory achieved absolute goodness-of-fit consistent with a correctly specified model across all three forests, and beat the alternatives in relative comparisons. Perhaps most tellingly, the fitted parameters carried real biological signal: in the Barro Colorado Island data, gap-exploiting and intermediate tree species showed significantly higher dispersal heterogeneity than shade-tolerant species, consistent with the episodic local dominance that light-demanding trees achieve when canopy gaps open. Effective dispersal strength, by contrast, did not differ significantly between guilds.

The deeper payoff comes when the competitive balances of all species are computed from the fitted parameters. Although dispersal-related parameters varied widely among species in all three forests, the competitive balances themselves were tightly clustered around their mean. The theory predicts exactly this: a group of competing species can coexist as long as their balances are not too dissimilar, with full coexistence possible only within a limited region of balance space surrounding the equal-balance condition. Equal balance does not mean identical traits—simulations with species sharing the same balance but different dispersal strategies produced distinct abundances—so the narrow clustering reflects a community-wide trade-off rather than trait uniformity.

From this clustering, the team derived a vulnerability index: the distance between a community’s position in competitive-balance space and the critical boundary below which a given species cannot persist. A negative value signals persistence; a positive value means eventual competitive exclusion. Applied to the three forests, every analysed species fell safely below its threshold. More provocative was what the index revealed about rarity. Abundance and vulnerability were strongly correlated only near the extinction threshold; far from it, species with low average abundance were not necessarily in danger of competitive suppression. In simulations, species with positive vulnerabilities saw their stationary abundance collapse toward zero, but away from the threshold, abundances spread across a wide range, confirming that being rare does not automatically mean being doomed.

The explanation lies in spatial strategy. Holding mean abundance constant, the researchers found a significant negative partial correlation between the spatial heterogeneity of a species’ space-use distribution and its vulnerability across all three datasets. Two Barro Colorado species made the point vividly: Prioria copaifera and Pterocarpus rohrii differ in total stem count by only about two percent, yet the former’s much more heterogeneous spatial distribution gives it a lower vulnerability. Intuitively, a heterogeneous dispersal strategy lets a species carve out spatial niches where it is hard to displace, trading some overall abundance for local strongholds. This trade-off between abundance, its spatial variability and vulnerability may be a key mechanism sustaining the coexistence of many species in the same forest.

The authors are careful about limits. The vulnerability index predicts final outcomes, not the timescales over which species approach them, and transient dynamics varied substantially in simulations. At very low abundances, demographic randomness will matter, and the framework cannot disentangle local competition from facilitation, both of which are folded into the inferred kernel parameters. Still, the applications are tantalizing: the same machinery could probe how an invasive species with a particular competitive balance might reconfigure a community, or whether suppressing a single species would trigger cascading exclusions like dominoes. An open-source package, vulntool, implements the core calculations. For a field racing to anticipate a potential mass extinction, the message is quietly radical: to know which species are truly at risk, look not just at how many individuals remain, but at how variedly they spread themselves across the landscape.

Subject of Research: A statistical-physics framework quantifying species vulnerability to competitive exclusion in metacommunities using spatial abundance data

Article Title: Dispersal diversity buffers species vulnerability to local extinction

Article References: Bernardi, D., Nicoletti, G., Padmanabha, P., Suweis, S., Azaele, S., Levin, S. A., Rinaldo, A., & Maritan, A. (2026). Dispersal diversity buffers species vulnerability to local extinction. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-026-03195-y

Image Credits: AI Generated

DOI: 10.1038/s41559-026-03195-y

Keywords: community ecology, metacommunity, dispersal, competitive exclusion, species vulnerability, coexistence, statistical physics, forest plots, biodiversity, spatial ecology, dynamical mean-field theory, conservation

The research, led by Facundo X. Palacio of Argentina’s Museo de La Plata and CONICET, tested whether a simple photogrammetric framework known as the pinhole camera model can produce reliable estimates of bird morphology from field photographs. The model describes how a three-dimensional scene is projected onto a two-dimensional camera sensor: light from a point in the scene passes through the aperture and maps to a corresponding point on the sensor, so the physical size of an object relates proportionally to its size in the image, its distance from the camera, and the focal length of the lens. In other words, if you know how far away the bird is and what lens you used, you can convert pixels into millimeters.

That idea had already proven itself on large mammals. Researchers using camera traps estimated the size of reindeer with a mean relative error of roughly minus nine percent, and similar approaches have been applied to leopards and other terrestrial species. But large animals are forgiving subjects. Small, mobile, wary creatures like birds pose a far harder problem: they flee, hide in dense vegetation, perch high in the canopy, and present constantly changing angles to the lens. Earlier attempts hinted at promise—one team estimated bill, head, tarsus, and body length in free-ranging chickens with estimates that did not differ from a one-to-one relationship with true values—yet those tests involved a single large-bodied species at short distances. A stereo-camera study of kiwi achieved remarkable accuracy on taxidermied specimens in daylight but produced biases exceeding twenty percent on live birds at night.

To find out whether the method could survive contact with real fieldwork, the team first built a controlled experiment. Four Neotropical species spanning roughly 25 to 300 grams—House Sparrow, Rufous-bellied Thrush, Campo Flicker, and Chimango Caracara—were represented by museum-mounted specimens posed in lifelike positions. Using a Canon DSLR with a 70–300 mm lens fixed at 1.50 meters on a tripod, the researchers photographed each specimen from three horizontal distances (3, 5, and 7 meters), eleven different heights along a ladder, and four orientations relative to the focal plane: 0, 20, 40, and 60 degrees. In total, 580 photographs were captured, with reference values established from images that included a metric scale. The design deliberately mirrored the geometry of real birdwatching: the distances chosen match those at which observers typically encounter birds.

The results were strikingly patterned. Under optimal conditions, with the specimen parallel to the focal plane, body and wing length showed the lowest biases—between one and six percent and one and nine percent respectively—while tarsus and bill length fared somewhat worse, at five to twelve and two to fifteen percent. When the researchers fitted generalized least squares models to explain the absolute relative bias, the three predictors—distance, viewing angle, and elevation angle—accounted for nearly all the variability, with pseudo-R-squared values between 0.974 and 0.995. The dominant factor was the angle of the bird relative to the focal plane: the further a bird rotated away from parallel, the more its projected length shrank, a classic foreshortening effect. Distance, counterintuitively, had only weak and variable effects, and moderate distances of three to ten meters actually emerged as a sweet spot, balancing geometric distortion against image resolution.

The trait differences have a logical anatomical basis. Bills and wings are typically fully exposed on a perched bird, making their outlines easy to trace in an image. The tarsus, by contrast, is often partially hidden by feathers at the joint with the tibia, forcing observers to guess where the structure begins. Body length is harder still, because it must be measured along a bird’s natural, often curved posture rather than the relaxed, flattened position used in museum protocols. The authors therefore recommend prioritizing bill or wing length when measuring birds photographically, and they note that the tarsus also showed the lowest repeatability across repeated photographs of the same individuals—an intraclass correlation of 0.73, compared with 0.94 for body length, 0.81 for wing length, and 0.80 for bill length.

Then came the real test. Over ten surveys between July and November 2024 in the talares forests and Ligustrum-invaded woodlands of the Parque Costero del Sur Biosphere Reserve in Buenos Aires province, the team photographed 99 individual birds from 37 species, recording the horizontal distance to each bird with a tape measure and its elevation angle with a clinometer. Mean shooting distance was about 9.5 meters, ranging from 1.55 meters for a Mottle-cheeked Tyrannulet to over 39 meters for a White-tipped Dove. Because capturing the same wild birds to verify measurements was impractical, the photographic estimates were benchmarked against two independent references: the global AVONET morphological database and caliper measurements of museum specimens of the same species from the Museo de La Plata collection.

The correlations were strong across the board. Photographic estimates correlated with AVONET values at 0.84 for tarsus length up to 0.92 for bill length, and with museum measurements at 0.82 to 0.95, all highly significant. Uncorrected estimates mostly fell below the one-to-one line—a systematic underestimation expected from foreshortening—but the relative ranking of species was preserved. That preservation matters enormously for community ecology, because many functional diversity metrics depend on the relative positions of species in trait space rather than their absolute values. When the researchers computed functional richness and functional divergence for their photographed assemblage and compared them against 500 bootstrap assemblages simulated from AVONET, the observed values fell comfortably within the simulated distributions, suggesting that photo-based trait data can reproduce community-level patterns.

The team also applied a trigonometric correction, dividing measured lengths by the cosine of the body’s inclination angle to compensate for out-of-plane rotation. The correction brought estimates closer to the one-to-one relationship on average, though with greater variability, and the authors caution that it is an approximation rather than a full three-dimensional reconstruction. A single two-dimensional image collapses depth information, so different combinations of yaw and pitch can produce indistinguishable projections, and the rotation angle of the whole body does not necessarily match the effective projection angle of each individual structure. Their practical advice: photograph birds as parallel to the focal plane as possible, at low elevation angles, from moderate distances, and take two or three shots of the same individual to average out error.

The implications reach well beyond ornithological curiosity. Photogrammetry could open morphological research to raptors, parrots, and other taxa that are difficult or risky to capture, and to environments like dense cities where trapping is impractical. The same geometry can quantify prey items carried to nests, as demonstrated in seabird diet studies, or measure the architecture of conspicuous but inaccessible structures like Rufous Hornero oven nests—all without handling a single feather. The authors are candid about the caveats: four experimental species cannot represent the full diversity of bird form, photographic sampling may favor bolder or more exposed individuals, and body length from a photo is an approximation of the standard total length rather than an equivalent. But the core message stands. With nothing more than a camera, a tape measure, and a clinometer, ecologists can now measure the birds they see—no nets required.

Subject of Research: Photogrammetric estimation of bird morphological traits from field photographs using the pinhole camera model

Article Title: Measuring Bird Morphology From Field Photographs

Article References: Palacio, F. X., Elso, E., & Montalti, D. (2026). Measuring Bird Morphology From Field Photographs. Ecology and Evolution, 16(10), Article e74422. https://doi.org/10.1002/ece3.74422

Image Credits: AI Generated

DOI: 10.1002/ece3.74422

Keywords: photogrammetry, pinhole camera model, bird morphology, morphometrics, ornithology, field photography, functional diversity, AVONET, non-invasive methods, community ecology, trait measurement, Ecology and Evolution

The research addresses one of the most perplexing puzzles in marine science, known as the ‘missing plastic’ paradox. Ocean-input models predict far more microplastic floating at the sea surface than scientists actually find there, suggesting that most plastic sinks. Marine sediments are now recognized as the principal global sink, potentially sequestering 70 to 90 percent of all plastic entering the ocean. Dense polymers such as polyethylene terephthalate and polyvinyl chloride sink directly, while buoyant polymers like polyethylene and polypropylene are dragged down after biofouling — the accumulation of microbial films — increases their density. Yet the seafloor is not a dead end. Once particles arrive, the fate of burial, resuspension, or transfer up the food chain is governed by the organisms living in the sediment, and that is where nematodes take center stage.

To probe this hidden role, a team led by Flávia Juliana Lobato de França and Giovanni Amadeu Paiva dos Santos of the Universidade Federal de Pernambuco in Brazil, together with Anna-Maria Vafeiadou and Tom Moens of Ghent University in Belgium, ran two independent microcosm experiments using sediment from Cupe Beach in Ipojuca, Pernambuco, Brazil. Each experiment used glass beakers holding 400 grams of sediment — a blend of natural live sediment and defaunated sediment that had been frozen and thawed to remove animals while preserving much of the native microbial community. The worms were exposed to fluorescent polystyrene microspheres just one micrometer in diameter, a size chosen to mimic the bacterial prey that many deposit-feeding nematodes naturally consume. Exposure densities spanned 10³, 10⁵, and 10⁷ particles per milliliter of sediment, with the lowest reflecting levels found in moderately polluted coastal sediments and the higher tiers representing plausible future scenarios. One experiment ran for nine days, with sampling at days three, six, and nine; the other stretched to thirty days, with sampling at days fifteen and thirty.

The results were strikingly conditional. Ingestion was detected exclusively in the highest-density treatment. In the short-term experiment, a total of 4,452 particles were quantified across 13 of the 52 nematode genera identified, and the community’s gut burden nearly doubled between day three and day nine, rising from an average of 294 to 581 particles. Most particles accumulated in the intestine rather than the pharynx, with the posterior gut holding significantly more than the anterior region — a pattern consistent with the posterior intestine serving as the principal site of retention and transit. In the long-term experiment, total uptake was far lower, just 571 particles across ten genera, and did not increase significantly with exposure time, hinting at a dynamic equilibrium in which particles are rapidly ingested and egested rather than stored indefinitely.

Even more revealing was who was doing the eating. In the short-term experiment, a single genus, Daptonema — which made up more than 87 percent of the community’s relative abundance — accounted for 89.9 percent of all ingested particles, averaging roughly ten particles per individual. Other genera such as Rhynchonema, Marylynnia, Viscosia, and Theristus collectively contributed about eight percent. Daptonema is a non-selective deposit-feeder with an opportunistic, r-selected life strategy, classified as a colonizer-persister group 2 organism, and its dominance of the sequestration function perfectly matched the researchers’ hypothesis that fast-living, indiscriminate feeders with wide buccal cavities would be the main gateways for microplastic entry into the benthic food web. In the long-term experiment, where the starting community was structurally very different and Daptonema was nearly absent, the sequestration role shifted to a consortium of four genera — Rhynchonema, Latronema, Marylynnia, and Theristus — which together carried over 91 percent of ingested particles. These were functionally more diverse taxa, dominated by more K-selected, persistent life strategies, yet all shared fairly wide buccal cavities.

That anatomical detail appears to be a fundamental constraint. Selective deposit-feeders, which possess tiny or absent buccal cavities, showed minimal to no ingestion, and previous work has demonstrated that microplastic uptake is only possible when the buccal cavity exceeds the particle diameter by a factor of roughly 1.3. Body size mattered too: across both experiments, the researchers found significant positive correlations between individual and community biomass and the number of ingested particles, suggesting that larger worms, with higher feeding rates and larger gut volumes, are more efficient sequestrators. In the short-term trial, Daptonema’s individual biomass correlated strongly with its particle load, while in the long-term trial total community biomass correlated with total ingestion, indicating that the sequestration function had become distributed across the community’s collective biological mass rather than concentrated in one taxon.

The most counter-intuitive finding, however, concerned harm rather than uptake. The most severe community-level impacts — reduced nematode density and biomass — occurred at the lowest and intermediate plastic densities, precisely where no ingestion was detected. In the 10³ particles per milliliter treatment, Daptonema’s abundance collapsed to less than 17 percent of the community by day three, and nematode densities remained significantly below control levels throughout the short-term experiment. The researchers propose several possible explanations, including a behavioral avoidance response that exhausts the animals metabolically, a hormetic stress reaction in which low doses trigger stronger effects than high ones, or adverse effects mediated by direct physical contact with particles — polystyrene microspheres have previously been shown to inhibit nematode reproduction even without detectable ingestion. At the highest density, by contrast, Daptonema persisted at control-like abundances while simultaneously functioning as the community’s principal biological sink, a striking decoupling of the sequestration function from direct ecological harm.

Long-term exposure told a different story again. Chronic exposure consistently lowered nematode density across all treatments, and the community lost 16 of its 37 genera between days fifteen and thirty, although much of that loss occurred in the control microcosms as well, pointing to experimental bottling effects. The dominance structure shifted transiently: at day fifteen, the control was dominated by Chromadorella, while the highest-density treatment was co-dominated by Rhynchonema, Latronema, and Theristus. Crucially, in the long-term experiment the researchers found a complete decoupling between community structure and sequestration function — none of the standard diversity metrics correlated with total ingestion, suggesting that under chronic exposure, the identity and traits of the taxa present, rather than their abundance or diversity, determine how much plastic the community processes.

So how much does any of this matter for the ocean’s plastic budget? The team ran a back-of-the-envelope calculation assuming a realistic intertidal community of about 1,000 nematodes per 10 square centimeters, all non-selective deposit-feeders carrying roughly ten particles each, all eventually eaten by predators. In a sediment volume containing 10⁷ particles per milliliter, such a community would transfer about 1.1 × 10⁴ particles to higher trophic levels out of a total sediment load of 2 × 10⁸ — less than one percent. The quantitative importance of nematode gut storage for trophic transfer therefore appears very limited. But the authors caution against complacency. Gut loads at any instant are a minute fraction of total throughput, since many nematodes pass gut contents in minutes to hours, and if gut enzymes dislodge or modify pollutants adsorbed to plastic surfaces, the cumulative pollutant exposure could exceed what gut loads suggest by one or two orders of magnitude.

The study paints the seafloor not as a passive graveyard for plastic but as an active biological processing zone, where the smallest and most abundant animals continuously encounter, ingest, and transform microplastic particles. The sequestration function is conditional, dependent on a high-contamination threshold well beyond most currently recorded sediment loads, and its identity shifts over time from opportunistic specialists to a more diverse, persistent consortium. The authors acknowledge the limitations of using a single polymer type and particle size in simplified microcosms, and they call for validation under natural conditions, experimental tests of trophic transfer and its consequences for carbon assimilation in higher consumers, and assessments of how different polymer shapes and sizes alter these pathways. As plastic production continues and coastal sediments near urban and industrial zones already approach the densities tested here, the humble nematode may prove to be a small but telling barometer of how the ocean’s largest waste problem plays out at its smallest scale.

Subject of Research: Microplastic sequestration and community-level effects of microplastic exposure in marine nematodes

Article Title: Community dynamics and functional traits drive microplastic sequestration by marine nematodes

Article References: de França, F. J. L., Silva, R. B. D., França, D. A. D. A., Frasson, I. D., Silva, G. A. X. D., Rodrigues, M. E. L., Pessoa, G. L., Vafeiadou, A.-M., Moens, T., & dos Santos, G. A. P. (2026). Community dynamics and functional traits drive microplastic sequestration by marine nematodes. Discover Oceans, 3(1), Article 16. https://doi.org/10.1007/s44289-026-00125-5

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00125-5

Keywords: marine nematodes, microplastics, benthic sediments, meiofauna, functional traits, missing plastic paradox, polystyrene microspheres, buccal cavity morphology, trophic transfer, community ecology, Daptonema, ocean plastic pollution