The Cañadón Asfalto Basin formed as part of the tectonic upheaval that accompanied the break-up of Gondwana, beginning in the Early Jurassic and continuing into the Late Cretaceous. North-westerly oriented half-grabens created isolated depocentres, and the Cerro Cóndor depocentre, in the middle Chubut River valley, preserves one of the most complete lacustrine successions of the period. The Cañadón Asfalto Formation itself is constrained between the Late Toarcian and Late Bajocian stages, an age anchored by biostratigraphically useful palynomorphs and a high-precision uranium-lead zircon date. At the Cañadón Lahuincó section, the team measured and sampled the succession bed by bed, collecting 51 outcrop samples of very fine-grained sandstones and siltstones for palynological processing using non-oxidative hydrochloric and hydrofluoric acids, a protocol chosen specifically to protect the natural colour and fluorescence of hydrogen-rich organic particles.

Palynofacies analysis, the technique at the heart of the study, examines the entire acid-resistant organic fraction of a rock rather than only the diagnostic spores and pollen grains. Each sample was quantified by counting a minimum of 500 particles under transmitted light microscopy, classifying them into structured organic matter such as palynomorphs, translucent and opaque phytoclasts, and unstructured amorphous organic matter. The researchers also assessed particle size, shape, colour, and fluorescence, and applied the thermal alteration index to gauge maturity. Cluster analysis using the Euclidean distance and unweighted pair group method grouped the samples into four distinct palynofacies types, designated PT-A through PT-D, plus one outlier sample whose organic matter had been baked by a thick andesite sill that intrudes the section. Total organic carbon measurements on 25 selected samples ranged from a mere 0.13 per cent to an impressive 11.96 per cent.

The sedimentological analysis revealed two complete depositional sequences, each telling a different chapter of the lake’s evolution. Sequence I, extending to about 197 metres above the base of the section, records a full transgressive-regressive cycle. Its lower part consists of fining- and thinning-upward cycles up to 10 metres thick, deposited when the lake was underfilled, meaning that water and sediment inflow could not keep pace with the accommodation space created by subsidence. In this state, lake levels fluctuated dramatically below the basin’s spill point, and marginal areas were periodically exposed, producing arid palaeosols and restricted water conditions that favoured phytoplanktonic productivity. The upper part of Sequence I flips the story: stacked coarsening-upward successions of littoral delta deposits indicate that the lake had transitioned to balanced-fill and ultimately overfilled conditions, in which the water level stabilised at the spill point and coastal progradation became possible.

Sequence II begins with an abrupt increase in accommodation, likely driven by renewed tectonic subsidence, and initially returns to underfilled conditions marked by shales interbedded with sandstones and thin limestones. The limestones, the authors interpret as punctuated episodes of lake restriction and alkaline waters during high-frequency regressive pulses. Then, at roughly 222 metres above the base, a sharp boundary marks what the researchers identify as a forced-regression surface, produced when the lake breached its spill point and entered fully overfilled conditions. Above this surface, thick coarsening-upward sandy cycles up to 30 metres record persistent progradation of littoral deltas into a freshwater lake, an overall progradational parasequence set that continues to the top of the measured section.

The palynological evidence maps beautifully onto this stratigraphic framework. Throughout the succession, land-derived material dominates, with phytoclasts making up between 31 and 100 per cent of the total organic assemblage, testifying to a strong terrestrial input into the basin. Yet the subtle shifts between this allochthonous plant debris and autochthonous algal material encode the climatic rhythm. Palynofacies types PT-A and PT-D signal wetter periods, when intensified rainfall drove extraordinary fluvial discharges, possibly including hyperpycnal flows, that swept high volumes of reworked terrestrial phytoclasts into the lake. PT-B, by contrast, marks drier intervals, and PT-C captures the transition between these opposing states. The ratio of equidimensional to blade-shaped opaque particles, a proxy for flow velocity, further supports this interpretation, with low values indicating distal accumulation from waning flows.

One of the most striking findings concerns the green colonial alga Botryococcus, whose well-preserved colonies with strong yellow fluorescence bloom in the assemblages during drier periods. Botryococcus is a tenacious coloniser of shallow, alkaline, oligotrophic to mesotrophic waters, equipped with desiccation-resistant walls and the ability to store large reserves of food, adaptations that allow it to survive conditions lethal to other algae. When evaporation outpaced runoff and the water body contracted, these algal blooms flourished, and their decay depleted oxygen in bottom waters, creating the dysoxic to anoxic conditions that allowed organic matter to be preserved with exceptional fidelity. The researchers note parallels with modern studies from southern Brazil, where algal dominance in lagoon sediments has been directly linked to twentieth-century drought episodes and falling water levels.

The taphonomic contrast between lake stages proved equally revealing. During the underfilled stage, terrestrial palynomorphs are scarce and poorly preserved, a pattern the authors attribute less to the absence of vegetation nearby than to the hostile chemistry of the lake water, whose pH conditions likely destroyed sporopollenin, the resilient biopolymer forming spore and pollen walls. The robust walls of Botryococcus and plant cuticles survived where sporomorphs did not. In the balanced-fill stage, by contrast, sporomorph-rich assemblages with well-preserved grains appear, dominated by Classopollis pollen from the Hirmerellaceae, which reaches up to 85 per cent of the sporomorph group, alongside araucariacean and podocarpacean pollen whose distribution patterns help distinguish proximal delta-plain settings from more distal depositional environments.

The study also carries practical weight for petroleum geoscience. Kerogen in the analysed samples ranges from gas-prone Type III, dominated by terrestrial material, to mixed Type I/III in the algae-rich intervals, and thermal alteration indices between 2+ and 3− indicate an early to middle-mature, oil- and gas-prone stage. Given the predominance of Type III kerogen, the authors conclude that the Cañadón Asfalto Formation deposits at this locality represent a potential unconventional shale gas reservoir. More broadly, the work underscores that lacustrine basins cannot be treated as miniature oceans: their water levels, chemistry, and organic archives respond to climate with a sensitivity that marine systems rarely match. By reading the microscopic organic particles locked in Patagonian mudstones, geologists can now reconstruct, cycle by cycle, how a Jurassic lake breathed with the rhythm of ancient monsoons, and how those same rhythms determined which carbon was destined to become tomorrow’s energy resource.

Subject of Research: Palynofacies analysis and lacustrine sequence stratigraphy of the Jurassic Cañadón Asfalto Formation in Patagonia, Argentina

Article Title: Palynofacies and lacustrine sequence stratigraphy: a case example from the Jurassic Cañadón Asfalto Formation, Cañadón Asfalto Basin, Extra-Andean Patagonia, Argentina

Article References: Olivera, D. E., Zavala, C., Quattrocchio, M. E., Soreda, M. E., Scasso, R., & Yang, R. (2026). Palynofacies and lacustrine sequence stratigraphy: a case example from the Jurassic Cañadón Asfalto Formation, Cañadón Asfalto Basin, Extra-Andean Patagonia, Argentina. Journal of Micropalaeontology, 45(1), 335-357. https://doi.org/10.5194/jm-45-335-2026

Image Credits: AI Generated

DOI: 10.5194/jm-45-335-2026

Keywords: palynofacies, lacustrine sequence stratigraphy, Cañadón Asfalto Formation, Jurassic, Patagonia, Botryococcus, organic matter preservation, kerogen, total organic carbon, paleoclimate, underfilled lake, source rock

The study, published in the journal Climate of the Past, presents the first high-resolution, quantitative reconstruction of dust provenance in the EPICA Dome C ice core, one of the most celebrated climate archives on Earth. Led by Sibylle Boxho and Steeve Bonneville of the Université Libre de Bruxelles, the team analyzed rare earth element patterns in 279 samples of ancient dust spanning 33,700 to 2,800 years before present. Using a novel statistical unmixing algorithm called DEEPOT, they quantified for the first time exactly how much dust reached this remote inland site from each of the Southern Hemisphere’s major source regions, resolving changes on timescales of roughly a century.

The technical achievement lies in the chemistry of the lanthanoid series, the fourteen rare earth elements whose relative abundances act like a fingerprint for the rocks from which dust was derived. Traditional provenance work has relied on strontium, neodymium, and lead isotope ratios, but those methods demand relatively large sample masses, a serious problem at EPICA Dome C where dust fluxes plummeted by up to a factor of twenty-five from glacial to interglacial conditions. Rare earth element patterns, by contrast, capture multidimensional geochemical information from far smaller samples, and because the patterns of potential source areas differ subtly but consistently, a constrained least-squares model can decompose any measured dust sample into a weighted mixture of contributing sources.

To make the approach work, the researchers compiled a database of 245 rare earth element patterns from known dust source regions across the Southern Hemisphere: Patagonia and Tierra del Fuego, Central Western Argentina, the Puna-Altiplano Plateau, Southern Africa, Australia, New Zealand’s South Island, and the ice-free McMurdo Dry Valleys of Antarctica itself. Each ice core sample was then modeled as a linear combination of these end-members, with the constraint that all contributions must be positive, since physical proportions of dust cannot be negative. To guard against analytical uncertainty, the team ran 2,000 Monte Carlo simulations per sample, randomly perturbing measured concentrations within their error bars and recalculating the best-fit source mix each time. Only samples whose modeled patterns correlated strongly with the measurements, at a threshold corresponding to statistical significance, were retained, yielding 238 reliable reconstructions.

The headline result is strikingly clear. During the late Marine Isotope Stage 3, the Last Glacial Maximum, and Heinrich Stadial 1, roughly 65 to 75 percent of all dust deposited at Dome C came from Patagonia, with secondary contributions from New Zealand, Australia, Southern Africa, and the Puna-Altiplano. This dominance was remarkably stable, even as total dust flux began collapsing around 18,000 years ago. The explanation lies in the geography of the ice age world: the Patagonian Ice Sheet then stretched 2,090 kilometers along the Andes, grinding bedrock into fine glacial flour that braided rivers spread across vast outwash plains. With global sea level about 135 meters lower than today, an additional 763,000 square kilometers of continental shelf lay exposed, dry, and ready for the strong westerly winds to strip away.

New Zealand’s role emerged as a surprise. The country contributed an average of nearly 14 percent of dust at Dome C during the Last Glacial Maximum, making it the second-largest source, a finding that contrasts with earlier isotope-based studies that had argued against significant New Zealand input to East Antarctica. The researchers point to the extensive South Island ice sheet, an enlarged continental shelf of roughly 62,000 square kilometers, and cold, windy glacial conditions as factors that plausibly boosted New Zealand dust emissions to levels capable of reaching the deep interior of the continent. Modern trajectory modeling, they note, suggests New Zealand dust can still contribute between 14 and 32 percent of deposition at inland Antarctic sites.

Then, around 14,500 years ago, everything changed. The dust assemblage shifted decisively away from high-latitude glaciogenic sources toward lower-latitude ones. Patagonia’s share fell to an average of 43 to 53 percent during the Holocene, while Australia surged to become the second-most important supplier at 21 to 28 percent, the Darling Basin in particular. Southern Africa and the Puna-Altiplano each climbed to roughly 8 to 9 percent, and dust from the McMurdo Dry Valleys, essentially absent before 13,000 years ago, appeared as the Antarctic valleys deglaciated. The Holocene record also became far more variable, with source contributions fluctuating at high frequency in a way the stable glacial regime never did.

The drivers of this transition, the authors argue, were geological and hydrological rather than purely meteorological. The timing coincides with Meltwater Pulse 1A, a rapid episode of global sea-level rise that submerged vast tracts of the Patagonian and New Zealand continental shelves, permanently removing exposed, deflatable sediment from the wind’s reach. At the same time, the waning Patagonian Ice Sheet triggered a major reorganization of regional drainage: new channels opened, redirecting large portions of river catchments from the Atlantic to the Pacific, while rivers on the eastern flank of Patagonia shifted from braided to meandering forms. Together these changes starved the aeolian system of the fine sediment that had fed Antarctic dust for millennia. Crucially, the provenance shift was decoupled from the earlier, massive decline in total dust deposition between 18,000 and 15,000 years ago, which the researchers attribute instead to enhanced wet scavenging, rainout of particles along warmer, moister transport pathways.

Independent lines of evidence bolster the reconstruction. When the team converted their rare earth element-based source contributions into expected strontium and neodymium isotope ratios, the modeled values matched the sparse isotopic measurements from Dome C and other East Antarctic cores, clustering around less radiogenic signatures during the glacial period, consistent with fresh, mafic Patagonian and New Zealand lithologies, and drifting toward more weathered, radiogenic compositions in the Holocene as Australian and African inputs grew. Comparison with the EPICA Dronning Maud Land core, on the Atlantic side of the continent, revealed broadly synchronous millennial-scale changes but telling regional differences: the Atlantic-sector core received more Patagonian dust, while Dome C, deeper inland and in the Indian Ocean sector, received more Australian material, consistent with subtropical jet streams lofting low-latitude dust over the polar vortex during Rossby wave intrusions.

The broader significance extends beyond paleoclimate trivia. Mineral dust delivered iron to the Southern Ocean during glacial times, fertilizing marine productivity and helping draw down atmospheric carbon dioxide, so knowing precisely where that dust originated sharpens our understanding of the iron fertilization feedback that helped terminate ice ages. The study also demonstrates that sea-level rise and postglacial hydrological reorganization can durably rewire hemispheric dust cycles, a reminder that coastlines and river systems are active, threshold-sensitive components of the Earth system. As modern sea levels climb and hydrology shifts once again, the dust trapped in Antarctic ice offers a sobering preview of how quickly the planet’s connective tissue can be rearranged when the climate crosses a tipping point.

Subject of Research: Quantitative reconstruction of Southern Hemisphere dust provenance in Antarctic ice during the last glacial-interglacial transition

Article Title: Quantifying Southern Hemisphere dust sources during the Last Glacial-Interglacial Transition using rare earth elements in the EPICA Dome C ice core

Article References: Boxho, S., Vanderstraeten, A., Mattielli, N., Laruelle, G. G., Bory, A., Gabrielli, P., & Bonneville, S. (2026). Quantifying Southern Hemisphere dust sources during the Last Glacial-Interglacial Transition using rare earth elements in the EPICA Dome C ice core. Climate of the Past, 22(9), 1655-1674. https://doi.org/10.5194/cp-22-1655-2026

Image Credits: AI Generated

DOI: 10.5194/cp-22-1655-2026

Keywords: EPICA Dome C, ice core, dust provenance, rare earth elements, Last Glacial Maximum, Patagonia, Australia, Puna-Altiplano, sea-level rise, Southern Hemisphere circulation, last deglaciation, Climate of the Past

The challenge the researchers set out to solve is a familiar one in aeolian geomorphology. Traditional approaches, such as drift potential calculations and mobility indices, do a good job of describing wind-driven sediment transport at a given moment, but they offer limited ability to forecast whether dunes will migrate or become fixed over time. That gap matters increasingly in a changing climate, where shifts in wind regimes, precipitation patterns, and storm frequency may alter dune behavior with real consequences for ecosystems, roads, and homes. Complex numerical simulations could in principle fill the gap, but they demand data and expertise that many coastal regions simply do not have.

Toffani and Casadío turned instead to binomial logistic regression, a statistical technique that predicts the probability of a binary outcome, coded as zero or one, from a set of continuous predictor variables. First developed in the early 1980s, the method has been applied successfully to landslide susceptibility, soil mapping, and vegetation dynamics, yet its use for coastal dune mobility remained notably limited. The elegance of the approach lies in its ability to fold multiple climatic variables, including wind speed, precipitation, and large-scale atmospheric indices, into a single probabilistic framework that outputs a forecast probability of dune activation rather than a static description.

The natural laboratory for the study was the northern coast of the San Matías Gulf, stretching roughly 180 kilometers from the mouth of the Negro River to San Antonio Oeste. The region is a cold semi-arid environment where strong westerly winds blow hardest during the austral summer, exacerbating the aridity created by the Andean rain shadow. Its dunefields are remarkably varied: the Bahía Creek–Caleta de los Loros system extends over 36 kilometers with active dunes up to 16 meters high migrating east-northeast at 6 to 10 meters per year, while dunes near El Cóndor advance at around 7 meters per year. The area is also home to thousands of residents and a booming tourist trade, with Las Grutas alone averaging 118,000 visitors annually between 2006 and 2023, making dune encroachment a genuine practical concern.

To build their model, the researchers drew on hourly meteorological records from two stations, Viedma Aero and San Antonio Oeste Aero, covering the standard 1991 to 2020 reference period. Wind speeds and directions were normalized to a standard height of 10 meters, and winds exceeding 6.17 meters per second were flagged as capable of transporting sand, a threshold calculated from local grain sizes using Bagnold’s classic equations for the onset of saltation. From these data the team computed drift potential values and combined two established mobility measures, the Tsoar and Lancaster indices, into a new integrated index they dubbed TsoLa. Dunes were coded as active only when both indices simultaneously indicated mobility and the resultant drift direction aligned with the coast’s general eastward migration pattern.

The statistical screening was rigorous. Temperature, potential evapotranspiration, and soil moisture were excluded because of multicollinearity, while wave height, cattle populations, and the Southern Oscillation Index were dropped because they added little predictive power. What survived was a lean trio of predictors: monthly average wind speed, total monthly precipitation, and the Southern Annular Mode, or SAM, the dominant mode of extratropical climate variability in the Southern Hemisphere. When SAM is positive, the westerly wind belt contracts poleward and mid-latitude conditions turn warmer and drier; when it is negative, storm tracks shift north and the study region around 40 degrees south experiences stronger, stormier weather.

The results were strikingly consistent across both study sites. Wind speed emerged as a positive predictor of dune migration, with coefficients of 0.64 at San Antonio Oeste and 0.32 at Viedma, while both precipitation and SAM carried negative coefficients, meaning higher rainfall or a positive SAM phase reduces the probability of migration. In practical terms, the model suggests dune movement becomes unlikely when monthly precipitation exceeds 150 millimeters, when wind speeds fall below 20 kilometers per hour, or when SAM values are high. The models achieved area under the ROC curve values of 0.77 and 0.78, comfortably above the 0.5 threshold of random guessing, and correctly classified between 73 and 77 percent of observations in training and test datasets. A bootstrap analysis of 1,000 resamples confirmed that all three predictors had stable, statistically significant effects.

Validation against the real world came from nearly four decades of satellite and aerial imagery. The team digitized dune fronts in images spanning 1985 to 2023, placing reference points every 50 meters along each dune crest and measuring perpendicular distances between successive front positions. In the Viedma area, average migration rates ranged from 2.92 to 10.12 meters per year and correlated strongly with wind intensity values, with a correlation coefficient of 0.84. In San Antonio, migration was slower, between 2.51 and 6.01 meters per year, and showed little correlation with wind, likely because limited sand supply and encroaching vegetation, rather than wind energy alone, control movement there. Vegetation cover in the San Antonio area has in fact surged from 16 percent in 1961 to 60 percent in 2021, a greening trend the authors link to weakening winds and a trend toward more positive SAM values.

That contrast between the two dunefields carries an important lesson: geology matters. Viedma’s proximity to the Negro River mouth provides abundant sand that feeds large transverse dunes whose migration tracks wind capability closely, while San Antonio’s narrower beaches deliver a more limited sediment budget. The authors argue that integrating such geomorphological context into predictive models is essential, and they suggest that future refinements could incorporate higher-resolution vegetation indices, buoy-based wave data, better livestock records, and estimates of monthly sediment supply. They also note that lagged effects of El Niño events, which influence regional precipitation by up to 50 millimeters, deserve further study with properly calibrated time lags.

What makes the study resonate beyond Patagonia is its accessibility. Every input, from weather station records to the SAM index published by the British Antarctic Survey, is freely available, and the R scripts and datasets are posted in a public Zenodo repository. Because the framework relies on standard meteorological observations, it can be adapted to other coastal and inland aeolian systems with minimal modification, offering a scalable pathway for integrating climate forecasting with geomorphic hazard assessment. For coastal communities watching dunes advance toward their roads and homes, the message is empowering: the data needed to anticipate the next phase of dune activity may already be sitting in the nearest weather station’s archive.

Subject of Research: Statistical forecasting of coastal dune mobility using meteorological data and climate indices in northeastern Patagonia

Article Title: Forecasting coastal dune mobility: a logistic regression model driven by meteorological data and climate indices

Article References: Toffani, M., & Casadío, S. (2026). Forecasting coastal dune mobility: a logistic regression model driven by meteorological data and climate indices. Earth Surface Dynamics, 14(5), 801-820. https://doi.org/10.5194/esurf-14-801-2026

Image Credits: AI Generated

DOI: 10.5194/esurf-14-801-2026

Keywords: coastal dunes, dune mobility, logistic regression, aeolian geomorphology, Patagonia, Southern Annular Mode, wind erosion, climate indices, remote sensing, coastal management, sediment transport, Earth Surface Dynamics

The Burrowing Parrot, Cyanoliseus patagonus, is no ordinary bird. It breeds in colonies dug into soft sandstone and limestone cliffs known as barrancas, and the colony near El Cóndor, beside the Río Negro estuary, is the largest known colony of any parrot species on Earth. Stretching 18.1 kilometers along the coast, it holds roughly 71 percent of the global breeding population, with long-term monitoring between 1998 and 2019 recording between 22,000 and 41,000 active nests. Understanding what these birds eat is therefore not a niche question of natural history; it is central to the survival of the majority of the species.

Historically, Burrowing Parrots were thought to feed mainly on the native vegetation of the Monte and Espinal ecoregions: seeds and fruits of chañar, caldén, algarrobo trees, berries of native shrubs such as Lycium, Discaria and Schinus, and grasses of the arid scrubland. Early naturalists, including W. H. Hudson in 1923 and Alexander Wetmore in 1926, described a diet rooted firmly in Patagonia’s native flora. The new study, published in The Science of Nature, tells a very different story. Of 202 valid plant molecular operational taxonomic units, or MOTUs, identified in the parrots’ droppings over the annual cycle, only 13 percent corresponded to native plants. Fully 40 percent were introduced species, with a further 4.5 percent presumed introduced, 12 percent ornamental garden plants, and 6.9 percent cultivated crops and pastures.

The methodology behind these numbers is a textbook example of modern molecular scatology. Between January and December 2021, the researchers collected 220 fresh fecal samples from the roosting flocks — 20 per month, except February, when the parrots mysteriously abandon the village roost. DNA was extracted from 178 samples using a stool kit optimized with bead-beating homogenization and extended incubation. Two primer sets were then amplified: one targeting the second internal transcribed spacer (ITS2) of plant nuclear ribosomal DNA, and a second targeting Bilateralia, the group that includes all animals with bilateral symmetry, to detect parasites and other animal DNA. The libraries were sequenced on an Illumina MiSeq with 250-base-pair paired-end reads.

The bioinformatic pipeline was equally rigorous. Reads were quality-trimmed with TRIMMOMATIC, merged with FLASH, de-replicated and screened for chimeras with USEARCH, and clustered into MOTUs. Each MOTU was then matched against the NCBI GenBank nucleotide database using BLASTn, with stringent thresholds: sequences had to be at least 190 base pairs long, with matches above 98 percent identity and an e-value below 0.00001. Species-level assignments required matches above 99.5 percent with consistent quality metrics across all retained hits. Negative extraction controls and PCR-grade water controls showed no contamination, and a dedicated gap analysis confirmed that the reference libraries were adequate: 69 percent of native plant species in the region have reference sequences in GenBank, rising to 97 percent at the genus level — sufficient given that 85 percent of the recovered MOTUs could be assigned to genus or better.

The seasonal patterns that emerged were striking. The parrots consumed 77 plant taxa during the breeding season, 172 during the post-breeding period, 72 in winter and 70 during pre-breeding — a statistically significant difference, with dietary diversity peaking just after the chicks fledge. This post-breeding explosion in dietary breadth coincides with the period when most plants in the region produce fruits and release seeds, and it is a critical window for juvenile survival, as young parrots must build up reserves before the harsh Patagonian winter. Non-metric multidimensional scaling and permutational multivariate analysis of variance revealed considerable overlap in diet across breeding, post-breeding and pre-breeding stages, but far less overlap with winter, when the birds turn to plants such as white spruce, velvet grass, perennial ryegrass and other introduced and ornamental species that are absent from the diet at other times of year.

Could the dominance of introduced plants be an artifact of sampling location? The researchers considered this carefully. Because samples were collected in the evening at the village roost, the diet might theoretically be biased toward items eaten near El Cóndor, where the landscape is most heavily modified. But several lines of evidence argue against it. Observations over five breeding seasons show the parrots flying over fields near the village without stopping to feed, and previous tracking studies show they forage between 58 kilometers northwest and 66 kilometers northeast of the colony. Moreover, digestive transit studies in parrots — corn-fed budgerigars empty their entire digestive tract within 26 hours — indicate that the DNA detected in evening droppings most likely reflects a full day of foraging, not just the last hours.

The most plausible explanation, the authors argue, is environmental degradation. Since the 1970s, a combination of increased rainfall and aggressive land clearing has transformed the region. In the Patagones department, natural vegetation that covered 65 percent of the land in 1975 has been reduced to an estimated 20 to 29 percent; in just three years, from 2015 to 2018, more than 216,000 hectares were cleared. In Adolfo Alsina department, home to El Cóndor, nearly 49,000 hectares were cleared between 1986 and 2006. Such landscape-scale disturbance disrupts native plant communities and opens the door to alien species. The parrots, it appears, are switching from a diet historically based on Monte and Espinal plants to one now dominated by introduced species — either a remarkable display of behavioral flexibility, or a warning sign of a suboptimal strategy that could undermine the persistence of the world’s largest parrot colony. A persistent La Niña event before and during the study may also have reduced the availability of native plants, though the authors caution that a single year of sampling cannot establish causation, and multi-year research is essential, especially as La Niña events are expected to become more frequent under climate change.

The study also delivered an unexpected bonus: a parasitological survey conducted entirely from droppings. Using the Bilateralia primer, the team identified 31 animal MOTUs, including four parasite families never before recorded in the digestive tracts of Burrowing Parrots: Gongylonematidae, which infects the oral cavity of birds and can cause starvation and death; Hymenolepididae and Onchobothriidae, both tapeworm groups previously unknown in parrots — Onchobothriidae had never been reported in any bird; and Capillariidae, thin nematodes known from captive parrots. The Gongylonematidae finding is particularly intriguing. During the 2020–2021 breeding season, at least 1,050 adult parrots died at El Cóndor — compared with the 20 to 30 typically found dead each year — and veterinary experts suspected infection rather than starvation as the primary cause. The authors stress that they can only speculate about a connection, but the possibility of a widespread Gongylonematidae infection driving that mortality event now demands investigation.

For decades, Burrowing Parrots were persecuted as agricultural pests, blamed for damage to maize, sunflowers, wheat and fruit orchards. The evidence tells a more nuanced story: systematic evaluations found that the birds affected only 0.1 to 0.4 percent of the sunflower harvest, leaving wheat and maize undamaged, and the species has been removed from Argentina’s pest-control lists. The new data reinforce this picture — cultivated plants made up just 6.9 percent of the diet, and official agricultural statistics suggest these mostly correspond to forage pastures of oats and barley rather than standing crops. As the clearance of the Monte continues and the El Cóndor colony concentrates the vast majority of the world’s Burrowing Parrots, the authors call for close monitoring of both population size and diet. The droppings collected under those Patagonian power lines have done more than reveal a menu; they have documented a dietary revolution in real time, flagged nine plant species newly introduced to the region, and possibly left a molecular clue to a mass mortality that still awaits explanation.

Subject of Research: Seasonal diet composition of Burrowing Parrots revealed by DNA metabarcoding of fecal samples

Article Title: Using next-generation sequencing to unravel the diet composition of Burrowing Parrots over the annual cycle

Article References: Masello, J. F., Failla, M., Leder, C. V., & Quillfeldt, P. (2026). Using next-generation sequencing to unravel the diet composition of Burrowing Parrots over the annual cycle. The Science of Nature, 113(5), Article 119. https://doi.org/10.1007/s00114-026-02159-3

Image Credits: AI Generated

DOI: 10.1007/s00114-026-02159-3

Keywords: Burrowing Parrot, DNA metabarcoding, next-generation sequencing, diet composition, Patagonia, El Cóndor colony, molecular scatology, introduced plants, environmental degradation, parasites, Psittaciformes, La Niña

The answer, published in the journal Regional Environmental Change, is a study in contrasts. The kelp itself, it turns out, is still there, in densities that statistically match those recorded more than five decades earlier. But the living community woven around those forests has been quietly rewritten. An invasive sea anemone that did not exist in Patagonian waters in 1972 now smothers hard surfaces across sheltered sites, covering up to 88.4 percent of the seafloor in places. The region’s commercially harvested sea urchin has crashed by as much as 90 percent, its remaining individuals measurably smaller than their ancestors. And one widespread, long-lived urchin species appears to have vanished almost entirely from the study region.

The comparison is possible because of an extraordinary scientific legacy. In 1972, ecologist Paul Dayton sailed aboard the research vessel Hero as part of one of the first quantitative expeditions to describe kelp forest ecology across the breadth of Patagonia. His work, published in the mid-1980s, established the region’s forests as functionally unique—shaped by exposure gradients and largely free of the human disturbance that had transformed kelp ecosystems in the Northern Hemisphere. Dayton’s coordinates, transect designs and written descriptions became a frozen snapshot of a baseline world. In February 2026, a team led by Albert Pessarrodona of the University of Western Australia, working with Rewilding Chile’s Patagonian Megatransect initiative, relocated five of those original forests and replicated the historical sampling with remarkable fidelity, laying the same 25-meter transects along the same isobaths in the shallow subtidal zone.

The expedition surveyed twelve sites in total, spanning a dramatic environmental gradient that begins inside the Aysén fjord, threads through the channel networks of the Chonos Archipelago, and ends at fully wave-exposed oceanic islands. At each site, divers counted and measured kelp holdfasts—the root-like anchors of the plants—while a second diver tallied every mobile invertebrate larger than 2.5 centimeters. Kelp were classified into recruits, juveniles and adults using the same holdfast-diameter criteria Dayton had applied. Herbivore densities were quantified across three depth strata using quadrats, and the cover of every sessile organism was estimated with point-intercept methods. The statistical machinery brought to bear on the comparison was thoroughly modern: generalized linear mixed models with Gamma and Tweedie distributions, site treated as a random effect, and a 5,000-resample bootstrap to generate empirical confidence intervals where historical raw data were incomplete.

The headline finding on the kelp itself was reassurance. Adult giant kelp densities did not differ significantly between 1972 and 2026, and the community patterns across the fjord-to-ocean gradient closely matched the historical descriptions. At offshore sites, the dynamics remained what ecologists call top-down: grazing by the red sea urchin Loxechinus albus, the dominant herbivore by biomass, shapes where kelp can persist, carving urchin barrens at depth and confining forests to shallow boulder tops where wave exposure limits urchin access. Toward the sheltered inner fjord, the rules change. There, abiotic stress—freshwater runoff, low salinity, summer nutrient depletion—suppresses kelp growth, producing stunted, dwarfed plants barely three meters long, and non-consumptive interactions such as competition for space take center stage. The fjord’s shallow surface layer, with salinity dipping as low as 0.6 practical salinity units, excludes grazers that cannot tolerate the brackish conditions, so forests exist near the fjord head entirely devoid of herbivores.

Yet the apparent stability of the kelp itself conceals a subtler warning. Mean adult holdfast diameter was significantly larger in 2026—21.6 centimeters versus 13.6 in 1972—suggesting that today’s forests are dominated by older cohorts, a demographic signature that in other regions has preceded collapse. Recruit densities, meanwhile, were higher in the historical surveys, though the authors caution this likely reflects seasonal timing differences between the November historical sampling and their February expedition rather than a genuine decadal decline in reproduction. In the sheltered inner fjord, kelp populations run on an annual or semi-annual cycle, vanishing each late summer and persisting through a microscopic phase, an adaptation to the nutrient-poor, stratified waters that follow summer warming. Offshore, bathed in nutrient-rich subantarctic water, populations are perennial and reproduce year-round. These life-history differences, the study argues, reveal the fundamental role of geomorphology and oceanography in structuring the entire ecosystem.

The clearest footprints of global change appeared in the animals living among the kelp. Loxechinus albus, the target of the world’s largest sea urchin fishery—roughly 30,000 tons per year in the Aysén region alone—declined by 59 to 90 percent across the depths examined at the historical sites. Depth-specific averages that once ranged from 0.6 to 101 individuals per square meter in 1972 now span just 0.8 to 20. Maximum body sizes have shrunk from more than 10 centimeters to 7.5, a pattern classically associated with intense fishing pressure that removes the largest, oldest individuals. Independent stock assessments indicate standing stocks have fallen 45 to 51 percent since the late 1990s, and the bootstrapping analysis showed that the overwhelming majority of historical density values—between 80 and 94 percent depending on depth—fell outside the contemporary range of variation. Intriguingly, the surveys suggest offshore kelp forests may now be more extensive than Dayton reported, plausibly because reduced urchin grazing has loosened the top-down control that once constrained them—a cascade with consequences no one yet fully understands.

Equally striking is the fate of Pseudechinus magellanicus, a small, long-lived, opportunistic urchin that was ubiquitous in the 1970s at average densities of 1.7 to 30.1 individuals per square meter. In 2026, it was recorded at only four of twelve sites, at densities of essentially zero. Because this species is not commercially harvested, the mechanism behind its disappearance remains a mystery, though the researchers speculate that reduced recruitment—or populations living at the edge of their geographic range—may be involved. Its functional role, grazing on drifting kelp fragments from cryptic refuges in holdfasts and crevices, may already be quietly absent from the system.

Then there is the anemone. Metridium senile, a plumose filter-feeder native to the North Atlantic and North Pacific, first appeared in Chilean Patagonia in 2005. Two decades later, it is common at all but three of the surveyed sites, colonizing gravel, kelp fronds and even the surfaces of mobile invertebrates, and reaching peak cover in the sheltered channels and inner fjord. Its distribution appears governed by physics: oscillatory wave turbulence at exposed sites deforms its tentacle crown and cripples its feeding efficiency, while the low-salinity surface layer of the Aysén fjord falls below its known tolerance of roughly 15 to 37.5 practical salinity units, excluding it from the shallowest inner-fjord habitats. Where conditions suit it, however, it dominates—likely competing with native filter feeders including mussels, barnacles and a rich diversity of indigenous anemones. The study found no simple relationship between anemone cover and kelp recruitment or urchin density, but the authors warn that impacts may be most severe in the annual, sheltered kelp populations that depend on microscopic life stages to persist, and they flag potential effects on commercially important resources.

The broader lesson is one that marine ecologists have learned repeatedly around the world: the canopy can look intact while the forest’s inner machinery is being dismantled. Patagonia’s kelp forests have persisted through five decades of intensifying pressures—industrial fisheries, the explosive expansion of salmon aquaculture, marine invasions, and increasingly extreme climatic events—and the region’s relative climatic stability has likely buffered them from the declines seen elsewhere. But persistence of the foundation species is not the same as health of the ecosystem. The authors argue that protecting these globally significant forests will require conserving not just the kelp itself, but the ecological processes, connectivity and environmental conditions that underpin their resilience. In a region where long-term monitoring has been nearly impossible due to sheer remoteness, this rare half-century resurvey delivers both reassurance and alarm: the forests are still standing, but the fingerprints of the Anthropocene are now pressed firmly into every square meter of the seafloor beneath them.

Subject of Research: Long-term ecological change in Patagonian giant kelp forests assessed by resurveying sites first studied in 1972

Article Title: Footprints of global change in Patagonian kelp forests after half a century

Article References: Pessarrodona, A., Palacios, M., Kaminsky, J., Mora-Soto, A., Dayton, P. K., & Hüne, M. (2026). Footprints of global change in Patagonian kelp forests after half a century. Regional Environmental Change, 26(4), Article 194. https://doi.org/10.1007/s10113-026-02680-1

Image Credits: AI Generated

DOI: 10.1007/s10113-026-02680-1

Keywords: giant kelp, Macrocystis pyrifera, Patagonia, kelp forests, sea urchins, invasive species, Metridium senile, Loxechinus albus, Chile, fjords, marine conservation, historical ecology