Organic amendments as a tool to restore soil microbial diversity after wildfires in native Mediterranean forests.

This article studies air quality in some of the most polluted medium-sized cities in Central and Southern Chile, which have experienced high levels of coarse and fine particulate matter pollution in recent years. Since air quality is much better in spring and summer, the study focused on the winter period (from April 1 to August 31) and between 2018 and 2023, corresponding to the pre- and post-COVID-19 pandemic. We analyzed the effect of the COVID-19 lockdown on air quality in ten urban areas declared saturated by air pollution. Elsewhere in the world, and during the same period, air quality improved due to a recession or decrease in human activity. This was due to the quarantine imposed on the global population when the WHO declared the SARS-CoV-2 pandemic. However, this study detected a possible increase in environmental pollution between 2020 and 2022 in all the cities studied. The possible causes of this phenomenon are investigated. Finally, it was observed that the population was exposed to poor air quality throughout the study period in the different cities studied, which could have had very detrimental effects on the population's health.

This study evaluated whether necrophagous arthropod assemblages, with emphasis on Calliphoridae (Diptera), differ among three sites in central Chile: Coastal (50 masl), Pre-mountain range (1000 masl), and High Andean (1800 masl). We analyzed differences in the abundance, richness, and community composition of arthropods associated with decomposed bait. Specimens were collected using carrion traps and active sampling. In total, 1240 specimens (predominantly insects) were obtained across three orders: Diptera (n = 1216), Hymenoptera (n = 22), and Neuroptera (n = 1). Within Diptera, the families recorded were Calliphoridae (n = 947), Muscidae (n = 118), Piophilidae (n = 77), Fanniidae (n = 44), Sarcophagidae (n = 15), Mycetophilidae (n = 8), Phoridae (n = 5), and Ulidiidae (n = 2). No significant differences were detected in total arthropod abundance or Calliphoridae abundance among sites. Necrophagous arthropod richness was highest at the Coastal and Pre-Andean sites. For Calliphoridae, no significant differences were observed among sites for the evaluated ecological parameters. Indicator taxa at the Coastal site included Braconidae (Hymenoptera) and the dipteran families Fanniidae and Muscidae. At the High Andean site, blowflies (Diptera: Calliphoridae), including Chrysomya albiceps, Compsomyiops fulvicrura, Lucilia cuprina, and Lucilia sericata, were identified as indicators. All Calliphoridae species sampled were confirmed as potentially forensically relevant for the region due to their necrophagous habits. Beyond documenting Calliphoridae across elevation, this study provides baseline data to support future work using this taxon to assess environmental impacts, characterize local trophic interactions, and inform forensic applications.

ABSTRACT Sweet cherry production relies heavily on managed and wild insect pollinators. Pollination success depends not only on the presence of flower visitors but also on their behaviour and traits. Although Chile is among the world's leading cherry producers, information on the diversity and pollination roles of insect visitors in its orchards remains scarce. In this study, we used video monitoring to assess the foraging behaviour of floral visitors in 16 conventional orchards in central Chile. In 2023, we recorded 3012 insect visits. Bees comprised 65% of visits, with honey bees ( Apis mellifera ) alone accounting for 64% and fewer than 1% for wild bees. Besides, 33% of the visits were attributed to flies—mainly Dilophus sp. (Bibionidae) and several syrphid species—and 2% to beetles. Bees spent the shortest time per flower, exhibited greater inter‐floral movement and contacted the stigma most frequently, behaviours associated with high pollination potential. In contrast, flies and beetles typically remained longer on flowers, moved little between them and often consumed floral resources without making contact with the stigma. These behavioural patterns suggest that hymenopterans are the most effective pollinators in these systems. Nevertheless, the high abundance of flies in the orchards may partly compensate for their limited pollination efficiency. Additionally, we found a significant positive relationship between body size and the likelihood of stigma contact, highlighting a key morphological trait associated with pollination effectiveness. The overall low diversity and small size of floral visitors in these conventional cherry orchards may explain why few of the species present have the potential to be effective pollinators. Promoting practices that enhance bee floral visitor diversity could increase the presence of alternative pollinators, reduce reliance on managed honeybees and contribute to more stable cherry yields.

BackgroundMicrobial communities in mining environments exhibit unique metabolic adaptations to extreme conditions, such as high metal concentrations and low pH. Their relatively low species complexity makes them an attractive model for fine-scale evolutionary analysis; nonetheless, genome-resolved metagenomic data from these environments are still scarce. Here, we employed genome-resolved metagenomics to analyze a high-quality Illumina-sequenced sample from the Cauquenes copper tailing in central Chile, one of the world’s largest and oldest copper waste deposits. We aimed to uncover the taxonomic composition, metabolic potential, and evolutionary pressures shaping this extremophile community.ResultsWe reconstructed 44 medium- and high-quality metagenome-assembled genomes (MAGs), predominantly from the phyla Actinomycetota, Pseudomonadota, and Acidobacteriota. Taxonomic analysis revealed limited species-level classification, with only five MAGs assigned to known species, highlighting the challenges of characterizing extreme environments. Functional profiling identified enhanced metabolic capabilities in sulfur and copper pathways, critical for survival in mining ecosystems. Using evolutionary analysis on mining MAGs using dN/dS ratios, we uncoverd strong negative selection on genes involved in sulfur, copper, and iron metabolism, indicative of a conservative evolutionary state. In contrast, genes under positive selection were linked to motility, biofilm formation, and stress resistance, suggesting adaptive mechanisms for resource acquisition and survival.ConclusionsOur study provides a metagenome-wide evolutionary analysis of mining MAGs, demonstrating that microbial communities in copper tailings are highly specialized, with conserved metabolic pathways under strong purifying selection. At the same time, the recovery of previously unclassified species of extremophiles expands the known biodiversity of mining ecosystems. These findings emphasise the challenges of leveraging these communities for biotechnological applications, such as biomining, due to their evolutionary constraints.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40793-025-00811-5.

Warming oceans are reshaping coastal ecosystems, yet the thermal sensitivity of many foundation macroalgae remains poorly constrained. Under SSP2-4.5, sea surface temperatures are expected to rise by ~2.7 °C by 2100, with unknown consequences for the canopy-forming kelp Lessonia spicata. We exposed thalli to control (15 °C) and warming (18 °C) conditions for 14 days to simulate near-future thermal scenarios, assessing photophysiology, oxidative stress and pigment composition. Warming caused marked declines in Fv/Fm and ETRmax and increased NPQmax, signaling reduced photochemical efficiency and enhanced thermal energy dissipation. Simultaneously, pigment concentrations decreased, ROS and MDA accumulated, and antioxidant capacity dropped, indicating rapid disruption of cellular redox homeostasis. Our results demonstrate that even modest warming consistent with mid-century projections triggers immediate photophysiological impairment and oxidative stress in L. spicata. These mechanistic insights highlight potential vulnerability of kelp forests in central Chile as ocean temperatures continue to rise.

The hyperarid-semiarid gradient of the western Andes, from the coastal Atacama Desert to central Mediterranean Chile, hosts exceptional plant endemism driven by paleoclimatic oscillations, rugged topography, and long-term isolation. Here, we use the columnar cactus genus Leucostele as a model to (1) quantify the influence of geographic isolation and topographic heterogeneity on genome-wide divergence, and (2) test whether zones of secondary contact foster genetic admixture. We genotyped 151 individuals from 20 populations of Leucostele using 9,397 SNPs to assess spatial genetic structure, isolation by distance, and the influence of terrain ruggedness and geographic isolation on admixture. Spatial ancestry analyses delineated ten latitudinal genetic clusters, with eight populations exhibiting > 75 % ancestry assignment to a single cluster and twelve showing varying degrees of admixture. Genetic differentiation increased with geographic distance, revealing strong isolation by distance across Atacama Desert to southern central Chile. Admixture, quantified as Shannon entropy, varied among populations and decreased significantly with both increasing terrain ruggedness and greater geographic isolation. Our study reveals that rugged topography and spatial isolation promote genomic divergence by limiting gene flow and fostering distinct genetic clusters while less rugged terrain facilitates secondary contact and admixture, showing that these barriers remain permeable and reproductive isolation is incomplete. This dual influence of topographic heterogeneity underpins the dynamic evolutionary mosaic observed across the coastal Atacama Desert-central Chile gradient.

Long-term compositional and eruptive transitions in an early Miocene volcanic system, Central Chile (33°S)

Uncovering the relict periglacial landscapes of the central Chile Andes: Soil formation and polar desert features at 33°S

A new Upper Cretaceous bramble shark from central Chile reveals austral diversity among Weddellian echinorhinids

ABSTRACT Pre‐industrial forests are largely absent from environments long modified by humans, such as the Mediterranean region of central Chile. Around the capital, Santiago (33° S), the dominant vegetation is the “matorral,” characterised by shrubs, small trees, and succulents. However, colonial records indicate the presence of forests in this area. Here, we document for the first time the age, composition, and diameter distribution of a small remnant patch of primeval forest within the Río Clarillo National Park (RCNP), 45 km from Santiago. In this patch and in five surrounding matorral areas, we established 50 × 20 m plots, where we measured all trees with the diameter at breast height (DBH) > 5 cm. In the forest plot, we aged 36 trees using increment borers. The DBH showed an inverted J‐distribution, dominated by the shade‐tolerant Cryptocarya alba and Persea lingue (both Lauraceae) with individuals up to 1 m dbh and between 15 and 20 m tall. The basal area was 64 m 2 /ha, with 1140 trees/ha, and minimum ages ranged from 75 to 145 years. The matorral plots' trees were concentrated in smaller diameter classes (< 30 cm DBH), with an average basal area of 16.7 m 2 ± 6.5 m 2 . The forest exhibited characteristics of late‐successional stands and differed markedly from the surrounding matorral. The RCNP was first logged for charcoal in the mid‐20th century, much more recently than many other areas of central Chile. The physiognomy of this patch resembles descriptions from 19th and early 20th century scholars. We hypothesise that forests like this were once much more common in the landscape than previously thought, and that present‐day matorral represents an early successional forest maintained by recurrent human use. This patch represents a biological legacy from the past, provides a reference for long‐term ecological restoration, and is unique, irreplaceable, and of immense value for conservation.

Invasive forest pests are among the greatest threats to global forestry, causing substantial economic losses and disrupting ecosystem dynamics worldwide. The recent detection of the North American woodwasp Sirex obesus (Hymenoptera: Siricidae) in Brazilian pine plantations poses a serious risk to South America's 4.6 million hectares of commercial pine forests. Here, we present the first comprehensive assessment of its invasion potential across the continent, combining species distribution modeling with a multi-factor invasion risk index. Using occurrence records from the species' native range, we modeled climatic suitability across South America and addressed invasion risk by integrating bioclimatic suitability, host distribution, proximity to invaded areas, and wood trade volumes with Brazil. Our model predicts suitable climatic conditions in 48% of South American pine plantation areas, particularly in montane and high-altitude regions along the Andean corridor and central-eastern Brazil. The mean temperature of the driest quarter was the most influential predictor of suitability. The invasion risk index identified southern Brazil, northeastern Argentina, Argentine Patagonia, and central Chile as the regions most vulnerable to the establishment, due to the convergence of extensive pine plantations, favorable climate, and either proximity to infested areas or intense trade connections with Brazil. These findings provide a foundation for targeted surveillance and phytosanitary measures aimed at preventing further spread. Early monitoring in high-risk regions, combined with stricter inspections of wood products, will be critical to avoiding widespread establishment and severe economic impacts across South American forestry.

Wildfires pose a major environmental and societal challenge, due to their link with anthropogenic activities and changing climatic conditions. This study aimed to enhance our understanding of the drivers of wildfire occurrence across continental Chile by developing robust predictive models incorporating climatic, land cover, and anthropogenic variables. We leveraged geospatial data on historical fire events, infrastructure, fuels and weather, coupled with historical fire records through Random Forest binary models to ascertain the key drivers of ignition across four distinct ecological zones: North, Central Chile, South, and the Andes. Our analysis explored potential differences between arson and unintended fires within these regions. Model validation, assessed using the Area Under the Curve (AUC), revealed significant regional variations in predictive performance. The southern and northern zones exhibited higher predictive capacity, potentially due to less complex landscapes and fewer ignition sources compared to the densely populated and infrastructure- prone central zone, which showed the lowest AUC. The Andes region displayed intermediate performance. Our results indicated that anthropogenic factors, particularly the distance to power lines, roads, and the wildland-urban interface (WUI), were consistently among the most important predictors of wildfire ignition across the majority of the studied regions. This highlights the significant impact of human accessibility and infrastructure on fire incidence in Chile. In contrast, fuel-related and climatic variables, such as Dry Fuel Moisture Content (DFMC) and its anomaly, showed generally lower importance, although their influence increased notably in the southern zone. Partial dependence plots further elucidated the distinct ways in which these key variables influenced ignition probability across different regions and between arson and unintended fires. The findings emphasize the necessity of adopting region-specific approaches in wildfire modeling and prevention strategies, acknowledging the different interactions between natural and anthropogenic factors across Chile. This research provides a fundamental understanding for future advanced modeling and targeted risk management efforts. Future research should aim to incorporate more detailed socioeconomic data to further refine predictive models and inform effective risk mitigation strategies.

Amaranthus cruentus Genotypes Exhibit Higher Seed Yield and Yield Stability than Amaranthus hypochondriacus Genotypes Across Four Environments in Central Chile

Rivers are under intense anthropogenic pressure, leading to increases in water temperature and changes in physicochemical properties, which threaten aquatic biota. Understanding how these environmental changes affect heat tolerance in freshwater organisms is critical for assessing the status of wild populations and predicting their vulnerability under global warming scenarios. Here, we studied how body mass and heat tolerance, measured by thermal death time (TDTs) curves under normoxic and hypoxic conditions, vary among populations of the Chilean pencil catfish Trichomycterus areolatus inhabiting a Mediterranean river in central Chile. We detected significant differences in fork length, body mass and Fulton’s condition factor among populations, with fish from reference sites being significantly larger and in better condition. Although heat tolerance did not differ among populations, we found a strong effect of body mass under both normoxic and hypoxic experimental conditions. Simulations combining laboratory-derived TDTs with field-recorded water temperatures suggest that the window of vulnerability occurs at lower temperatures but over longer exposures, indicating that heat stress has chronic effects on T. areolatus. Accordingly, the cumulative survival simulation using the warmer season records is predicted to be lower in river sections with reduced levels of dissolved oxygen. While our results did not show population level differences in thermal tolerance per se, the significant effect of individual body mass may translate into varying vulnerability among populations, given their marked differences in body mass distribution. These findings highlight how the interplay between water quality, body condition and heat tolerance shapes the vulnerability of T. areolatus populations to warming. Thus, an integrated perspective is essential to properly assess the impact of global warming on wild freshwater populations.

ABSTRACT In February 2024, central Chile experienced one of the deadliest wildfire disasters in its history, with over 136 fatalities, thousands of homes destroyed, and extensive environmental damage. This paper analyzes the contributing factors, impacts, and lessons from the Valparaíso mega-fire, situating it within broader climatic, ecological, and governance contexts. Global warming has increased the frequency and severity of extreme weather events, including heat waves and droughts. Chile is not immune to the increase in these extreme events. In addition, the El Niño episode amplified natural atmospheric variations, leading to warmer-than-usual conditions during the summer, which happened with the 2023–2024 El Niño when the mega-fire took place on February 2-4, 2024. The meteorological factors leading to the heat wave event and the favorable conditions for spreading forest fires (the 30-30-30 rule) were accurately forecast five days before, providing early warnings. Despite significant advancements in early warning systems and emergency alerts, the response to the 2024 fire revealed critical limitations in preparedness, particularly in wildland-urban interface areas. This event shows the vital need for proactive fire-forest management from the high-level authorities to residents to minimize its i mpact and to adapt strategies to address the growing threat of climate-induced wildfires.

Sarcoptic mange (SM), caused by the mite Sarcoptes scabiei, is a globally distributed disease affecting a broad range of hosts and posing a potential threat to wildlife. However, its full ecologic impact remains unclear. This study investigates SM occurrence in two native fox species (Lycalopex spp.) in rural central Chile, exploring its association with macrohabitat types, land covers, domestic dogs, and human presence. Fieldwork was conducted across three rural sites (<56 km apart), representing distinct macrohabitats: exotic monoculture tree plantations (Alto Colorado) and two native Mediterranean coastal forest sites, La Estrella (thorn shrubland) and Callihue (sclerophyllous forest). At each site, 10 camera traps were deployed within 100-ha grids for 13 mo. Foxes were detected in all stations, and individuals showing lesions consistent with SM (SM-foxes) were found in 24 of 30 stations, accounting for 329 of 3,140 fox images (10.4% observed prevalence). Domestic dogs were recorded at 28 stations, detected up to 7.9 km from human settlements. In our fine-scale approach, foxes, SM-foxes, and dogs were present across all macrohabitats and land covers, tending to be more abundant in native landscapes. The occurrence of SM was weakly associated with human presence and, to a lesser extent, with domestic dogs, the latter of which nonetheless remain the most plausible original source of SM in the region. In general, SM occurrence, foxes, and domestic dogs were more frequent closer to human settlements and farther from urban areas, reflecting a complex association with human presence. Human settlements were not consistently related to altered macrohabitats such as exotic plantations. Sarcoptes scabiei circulation is probably maintained through both direct and indirect contact, involving occasional spillover from dogs, prey, and infected carcasses. These findings underscore the importance of rural areas as hotspots for dogs-fox interactions and highlight the relevance of understanding fine-scale pathogen dynamics for wildlife conservation.

Ants (Hymenoptera: Formicidae) are a diverse and ecologically important group of social insects that play crucial roles in ecosystems worldwide. In this study, we aim to identify the community of ant species present in two important fruit crops of Central Chile. Ants were sampled from January to March in three cherry orchards and three vineyards, using standard pitfall traps to sample above-ground, and subterranean pitfall traps to sample below-ground. We found in total seven species of ants, three native and four introduced, with Strumigenys silvestrii Emery, 1906 being the first record of Attini species for central Chile. The introduced Hypoponera eduardi (Forel, 1894) was the most frequently sampled species, while the invasive Linepithema humile (Mayr, 1868) was found in only two sites. The ecological or functional roles of these species within the Chilean agroecosystems deserve further investigation.

The African clawed frog Xenopus laevis is invasive on four continents, and is recognized as one of the invasive amphibians that generates the greatest impacts in the ecosystems it invades. Although its diet has been studied in its native habitat and invaded areas, its trophic role is still unclear, especially in the communities it invades. We studied the diet of X. laevis , and looked at its stable isotope signatures and its bioaccumulation of heavy metals, to gain a better understanding of its trophic role. The diet was found to consist mainly of aquatic invertebrates, with some consumption of the native fish Cheirodon pisciculus . The isotope analysis revealed that the assimilation of prey by X. laevis is unrelated to the most-consumed item. Xenopus laevis occupied a high trophic position in its own stream and was segregated from fish in by its use of trophic resources. Despite its high trophic position, only biomagnification of copper and zinc was found in relation to some prey, but not manganese or arsenic.

ABSTRACT Aim To investigate how the El Niño‐Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) influence zooplankton diversity and community structure in the central Chile coastal upwelling system, focusing on long‐term changes in species composition and abundance under shifting climatic conditions. Location Eastern South Pacific off central Chile, covering an area of approximately 38,500 km 2 . Time Period 2003–2020. Major Taxa Studied Zooplankton, with emphasis on dominant groups such as copepods, jellyfish, radiolarians, siphonophores and cladocerans. Methods We analysed an 18‐year time series of zooplankton abundance and composition. Partial Canonical Correspondence Analysis (pCCA) examined relationships between zooplankton groups, the PDO and environmental variables (sea surface temperature, dissolved oxygen, wind). Threshold Indicator Taxa Analysis (TITAN) identified taxa characteristic of warm (PDO+) or cold (PDO–) phases, clarifying their roles as either sensitive or tolerant indicators of climatic shifts. Results Warm phases (PDO+) were dominated by jellyfish, siphonophores and pteropods, whereas cold phases (PDO–) favoured radiolarians and cladocerans. Copepods, the most abundant group, exhibited notable fluctuations across climate phases. Zooplankton diversity showed an ‘in‐phase’ response to climatic oscillations, indicating strong links between decadal‐scale climate regimes and ecosystem dynamics in this productive upwelling region. Main Conclusions Our findings underscore the sensitivity of marine zooplankton communities to climate variability, with distinct PDO phases exerting significant influence on zooplankton composition and diversity. Recognising key indicator taxa in warm versus cold periods is crucial for ecosystem management and developing indicator‐based monitoring programs. Continued long‐term surveys will be essential to anticipate future shifts in marine biodiversity under ongoing climate change.