Search Results (37)

The Twaite shad (Alosa fallax Lacépède, 1800) is an endangered anadromous fish listed as Vulnerable on the IUCN Red List. In northern Catalonia (NE Iberian Peninsula), the species maintains a small reproducing population in the Fluvià River, while in the Ter River only sparse, irregular records exist and the status of the species has remained essentially unknown. This study aimed to assess the status of Twaite shad in the lower Ter River through a combined approach of scientific rod-and-reel fishing and eDNA analysis, with the specific objectives of confirming adult presence during the spawning season and detecting juveniles as evidence of effective reproduction. Water samples for eDNA analysis were collected at multiple sites along the lower Ter, across five sampling campaigns conducted between May and September 2025. Duplicate samples of mean 32 L each were filtered in situ and amplified using the MiFish 12S marker with twelve PCR replicates per site and sequenced using Illumina high-throughput technology at a 40 M read sequencing depth per sample. Complementary scientific fishing was carried out using a rod-and-reel technique with demonstrated effectiveness for Twaite shad, comprising five spring sessions (40 h of effort) and four autumn sessions (80 h of effort) at key habitat sites. The eDNA approach proved markedly more sensitive than conventional fishing. Notably, high-resolution eDNA confirmed the presence of the species below the Ullà weir, demonstrating its capacity to move upstream past the Torroella de Montgrí gauging station, most likely facilitated by elevated discharge events during spring. A confirmed eDNA detection in late August provides strong evidence of juvenile presence and, consequently, of effective reproduction in the Ter River. Conclusions: This study provides the first evidence that Twaite shad reproduce in the Ter River, confirming the existence of a previously undescribed breeding population. The eDNA approach demonstrated substantially greater sensitivity than conventional fishing methods for this cryptic migratory species. Priority actions include the identification of spawning grounds, the extension of eDNA surveys to reaches upstream of Ullà—now feasible given the current breach in the weir—and the genetic characterisation of this population to determine its origin, diversity, and potential introgression. Full article

In 2014, the Meteorological Service of Catalonia established systematic daily observations of anthropogenic clouds, defined in 2017 by08 the WMO as homogenitus. This initiative aimed to quantify the human contribution to cloud cover through direct observation. Since 2015, a comprehensive database of daily observations has been maintained at La Selva del Camp observatory (Spain). Using this 11-year dataset, two distinct analyses were performed. First, a statistical analysis focused on both high homogenitus clouds (contrails) from aircraft and low homogenitus clouds from a nearby chemical complex. To uncover the underlying periodicities of these phenomena, a Fast Fourier Transform (FFT) was applied to the monthly time series, revealing a dominant 12-month seasonal cycle alongside a significant long-term increasing trend. This analysis quantified average cloud cover and identified seasonal and annual trends spanning daily to interannual scales. Furthermore, the environmental impact of these persistent tracks was evaluated through a radiative forcing assessment, weighing the cooling albedo effect against longwave terrestrial radiation trapping. Second, the study examines ‘peak events’ where contrail coverage exceeded 2 and 3 oktas. Ultimately, this work connects multi-year visual observations with mathematical frequency spectra and energy budget assessments, providing a robust framework to evaluate the local climatic and radiative footprint of persistent anthropogenic cloudiness. Full article

Fluvial superfloods are geomorphologically significant episodes due to their enormous energy and extremely low recurrence in the geological record. Their rarity is particularly notable in areas far from the major continental glacial masses. Hydraulic constrictions in the Lower Ebro River gorges caused the accumulation of fluvial deposits, as floodwaters from the Ebro River were forced upstream into the tributary valleys of the Móra Basin. The most illustrative example is the Comte Creek, where two depositional units of different ages show upstream flood accumulations (extending up to ~4 km) with very high-energy sedimentary structures, followed by downstream reworking during backflow. Two-dimensional hydraulic simulations indicate that peak discharges reaching 385,000 m³·s⁻¹, with water depths of approximately 28 m in the confluence area, would have been required to transport sediments to the observed outcrop positions. Luminescence dating of the slackwater deposits indicates that the formative processes occurred during the latest Middle Pleistocene or the Last Interglacial (Eemian). Full article

Brown trout (Salmo trutta) populations at the southern edge of the species’ distribution are increasingly exposed to interacting climatic, biotic, genetic, and anthropogenic pressures. This study provides an integrative assessment of the drivers of variation in brown trout density, biomass, and size structure across six Mediterranean river basins in Catalonia (NE Iberian Peninsula), based on long-term standardized electrofishing surveys (2016–2025; 88 sites). Generalized linear mixed models revealed that mean summer temperature, genetic introgression from hatchery-derived Atlantic lineages, and the density of introduced fish species were the most consistent negative predictors of total density, biomass, and juvenile abundance (<120 mm FL). Hydrological and nutrient variables showed comparatively weak or non-significant effects relative to thermal and biotic predictors. Fishing regulations significantly influenced the biomass and density of larger trout (>220 mm FL), with lower values in harvest-allowed sections, whereas total density was less responsive to regulation. These findings indicate that Mediterranean brown trout populations are primarily constrained by thermal conditions, genetic integrity, and biological invasions, with implications for conservation and fishery management under ongoing climate warming. Full article

The 2025 fire season in Portugal was marked by large fires, underscoring the vulnerability of the forested areas to fire. The study analyzes the main meteorological conditions during a critical period of fire activity and addresses the following question: Why can the northeast (NE) weather pattern be so critical for fire danger in Portugal? Fire severity in the Arouca wildfire, the largest fire of the period, was estimated using a methodology that integrates foundation vision models with computer vision algorithms. ECMWF analyses and convection-permitting Meso-NH simulations are used to examine large-scale circulation and the mesoscale environment, respectively. Synoptic-scale analysis revealed the Azores anticyclone centered slightly northwest of the Iberian Peninsula (IP), with its eastern sector directly affecting the northern IP under north/northeast winds. The hectometric-scale simulation demonstrated that orographically enhanced wind gusts over the northern Portuguese mountains substantially intensified near-surface fire-weather conditions when the winds were nearly easterly. Furthermore, strong low-level winds and atmospheric stability constrained vertical plume growth, favoring horizontal smoke transport. In addition, the study highlights that Arouca’s fire had 88% of its area affected with moderate to high severity. Overall, the results demonstrate that the interaction between large-scale NE circulation and local orography plays a decisive role in amplifying fire danger in northern Portugal, emphasizing the need for high-resolution atmospheric modeling to identify fire-prone regions under specific synoptic patterns. Full article

Loess–palaeosol sequences (LPSs) are continuous records of palaeoenvironmental and palaeoclimatic conditions during the Quaternary. This study includes 17 LPS located in the NE of the Iberian Peninsula, irregularly distributed, associated with different river basins: the Ebro Basin, the Mora Basin, and the Ter sub-basin. The soils developed on these loess deposits present a loam–sandy texture, coarser than the typical loess, ochre in colour, with variable thickness (1–12 m), calcareous composition (20–45% CaCO₃ eq.), very low or null organic matter (OM), and basic pH. These deposits have been classified as desert LPS, whose pedogenesis is mainly associated with the redistribution of calcium carbonate and, in some cases, gypsum. Several methodologies have been applied to determine their mineralogical, physical, and chemical characteristics and date them by luminescence techniques. In addition, some relevant pedofeatures (porosity, CaCO₃, gypsum, etc.) have been characterised in detail. The aims of the present study have been to know the pedogenic development of the LPS by defining the main soil-forming factors that have affected them in order to associate these factors with the characteristic palaeoclimatic and palaeoenvironmental conditions reported in this area over time and to improve the understanding of soil evolution. Full article

The Costa Brava, a Mediterranean coastal strip spanning ca. 250 km (in NE Spain), is a hotspot of plant invasions. To address this issue, the LIFE medCLIFFS project was launched to improve the management of invasive species along sea cliffs in the region. The initial phase of the project involved designing more than 100 transects distributed across the coastline, each 1 km in length, which were to be monitored by volunteers. During the fieldwork for transect design, we identified a total of 126 alien species. This is a substantial number, considering that the observations were confined to the transect areas. Notably, among the 126 observed taxa, 24 represented floristic novelties: 7 were new to the Costa Brava, 7 to the province of Girona, 4 to Catalonia, 1 to Spain, 1 to the Iberian Peninsula, and 4 to Europe. Additionally, we provide information on other alien taxa that, although not novel for the study area, could be significant for control and management efforts. These observations provide a foundation for compiling a comprehensive catalog of the alien flora of the Costa Brava. Full article

Different giant and very large hail events have occurred in Catalonia (NE of the Iberian Peninsula) in the last three years, with stones ranging between 8 and more than 10 cm in diameter. These sizes have not occurred in this area in at least thirty years. This research analyzed all those events with at least one severe hail register (more than 2 cm diameter) in the region for 2013–2023. The present study considered large volumes of high reflectivity in weather radar 3D fields at high tropospheric levels (more than 10 km). The goal was to determine if high reflectivity cores (over 55 dBZ) occurred at those levels before or during the hail-fall. The main question was whether this radar signature could reveal the occurrence of very large or giant hail. The 55 dBZ volumes occurred and were maintained over 10 km between six and sixty minutes in a high percentage of large-hail cases. However, giant hail cases did not present the maximum duration of high reflectivity at high levels as was initially expected. Full article

Leishmania infantum is a zoonotic protozoan parasite distributed worldwide that is transmitted by phlebotomine sandflies. Dogs are the main reservoir for human infections. However, in recent years, the capacity of lagomorphs to contribute to Leishmania transmission has been confirmed. The present study aimed to assess Leishmania spp. exposure and infection in lagomorphs and sympatric domestic dogs in NE Spain. Sera from European hares, European rabbits, and rural dogs were tested for antibodies against L. infantum using an in-house indirect ELISA. PCR analysis targeting Leishmania spp. was performed in spleens from L. europaeus. Antibodies against Leishmania spp. were detected in all the species analyzed. Total sample prevalence was significantly higher in O. cuniculus (27.9%) than in L. europaeus (2.0%). Results of the PCR were all negative. The present study expands knowledge about Leishmania infections in free-ranging lagomorphs in the Iberian Peninsula, suggesting a more important role of O. cuniculus in the study area. Given the strong correlation between lagomorph densities and human leishmaniasis outbreaks in Spain, the high rabbit and human densities in NE Spain, and the high Leishmania spp. seroprevalence in rabbits, it becomes imperative to establish surveillance programs for lagomorphs in this region. Full article

Peri-urban regions, especially in the Mediterranean, face challenges like farmland loss due to urban pressure. This study emphasizes retail stores as strategic focal points for evaluating societal, economic, and production systems. It hypothesizes that analyzing retail stores in agricultural areas provides insights into traded and cultivated agrobiodiversity. Using the Baix Llobregat Agrarian Park (Catalonia, NE Iberian Peninsula) as a case study, this research examines different food retailers from short and conventional food supply chains. Results indicate variations in plant diversity, origin, and seasonality among different retail stores. Farmers’ markets exhibit higher intraspecific diversity, contributing to local agrobiodiversity conservation. This study observes temporal changes in farmers’ markets, highlighting shifts influenced by socioeconomic factors and climate change perceptions. Finally, this research underscores certain strategies to promote sustainable peri-urban local food systems and preserve agrobiodiversity, offering valuable insights into food supply chain dynamics in peri-urban agricultural regions. Full article

Groups with morphological stasis are an interesting framework to address putative cryptic species that may be hidden behind traditional taxonomic treatments, particularly when distribution ranges suggest disjunct and environmentally heterogeneous biogeographic patterns. New hypotheses of delimitation of evolutionary independent units can lead to the identification of different biogeographic processes, laying the foundation to investigate their historical and ecological significance. Jasione is a plant genus with a distribution centered in the Mediterranean basin, characterized by significant morphological stasis. Within the western Mediterranean J. gr. crispa species complex, J. sessiliflora s.l. and allied taxa form a distinct group, occupying environmentally diverse regions. At least two ploidy levels, diploid and tetraploid, are known to occur in the group. The internal variability is assessed with phylogenetic tools, viz. GMYC and ASAP, for species delimitation. The results are compared with other lines of evidence, including morphology and cytology. The fitting of distribution patterns of the inferred entities to chorological subprovinces is also used as a biogeographical and environmental framework to test the species hypothesis. Despite the scarcity of diagnostic morphological characters in the group, phylogenetic delimitation supports the description of at least one cryptic species, a narrow endemic in the NE Iberian Peninsula. Moreover, the results support the segregation of a thermophilic group of populations in eastern Iberia from J. sessiliflora. Ploidy variation from a wide geographical survey supports the systematic rearrangement suggested by species delimitation. Taxonomic reorganization in J. sessiliflora s.l. would allow ecological interpretations of distribution patterns in great accordance with biogeographical regionalization at the subprovince level, supporting geobotanical boundaries as a framework to interpret species ecological coherence of cryptic lineages. These results suggest that species differentiation, together with geographic isolation and polyploidization, is associated with adaptation to different environments, shifting from more to less thermophilic conditions. Thus, the recognition of concealed evolutionary entities is essential to correctly interpret biogeographical patterns in regions with a complex geologic and evolutionary history, such as the Mediterranean basin, and biogeographical units emerge as biologically sound frameworks to test the species hypothesis. Full article

Satellite remote sensing has become an important tool for monitoring and evaluating the impacts of drought. In this study, a modeling framework aimed at estimating the time series of evapotranspiration (ET), a key variable for drought monitoring, at a regional scale is presented. A two-source energy balance (TSEB) model was used concurrently with Terra/Aqua MODIS data and the ERA5 atmospheric reanalysis dataset. The modeling framework is based on the SEN-ET scheme to calculate the surface energy balance of the soil-canopy-atmosphere continuum and estimate ET at 1 km spatial resolution. The model was applied for the whole Iberian Peninsula, and it was evaluated with a pistachio orchard flux tower data in Lleida (NE Iberian Peninsula). Preliminary daily ET evaluation results for the Terra dataset showed an RMSE, MBE, and R² of around 1.43 W·m⁻², −1.27 W·m⁻², and 0.56, respectively, and for the Aqua dataset were 1.05 W·m⁻², −0.84 W·m⁻² and 0.48, respectively within 100 days in 2022. Ongoing evaluation is being carried out on two forested watersheds as well as mountain meadows and semi-arid vegetation flux towers. Full article

The hailstorm of 30 August 2022 in the NE of Catalonia (NE of the Iberian Peninsula) produced the largest hail size, with diameters exceeding 10 cm. Furthermore, hail occurrence exceeded 2 cm in fourteen days and 4 cm in seven days during August 2022. The size and the days number constituted new records in Catalonia for at least the last 30 years. The analysis has compared the thermodynamic values derived from the sounding of Barcelona with the climatic data for 1998–2022 (25 years of data). This fact has allowed the selection and evaluation of different thermodynamic parameters’ behaviour during hail days in Catalonia. In this research, the precipitable water mass provided the best results as a hail forecaster. Second, the study has evaluated if the different parameters have a significant trend during the study period. The answer is yes in all cases, but some parameters presented a stepped rise while others increased smoothly. Finally, the research has analysed if the parameter values during August 2022 were extraordinary compared with the rest of the period. In this case, the thermodynamic parameters nature was well correlated with the hail size and occurrence maximums of August 2022. Full article

In the climate change context, wildfires are an increasing hazard in the Mediterranean Basin, especially those triggered by lightning. Although lightning activity can be predicted with a reasonable level of confidence, the challenge remains in forecasting the thunderstorm’s probability of ignition. The present work aims to characterise the most suitable predictors to forecast lightning-ignited wildfires. Several ERA5 parameters were calculated and compared for two different samples, thunderstorm episodes that caused a wildfire (n = 961) and ordinary thunderstorms (n = 1023) that occurred in Catalonia (NE Iberian Peninsula) in the 2006–2020 period. Lightning wildfires are mostly associated with dry thunderstorms, characterised by: weak-to-moderate Mixed-Layer Convective Available Potential Energy (MLCAPE, 150–1100 J kg⁻¹), significant Dew Point Depression at 850 hPa (DPD₈₅₀, 3.3–10.1 °C), high Most-Unstable Lifted Condensation Level (MULCL, 580–1450 m) and steep 500–700 hPa Lapse Rate (LR, −7.0–−6.3 °C). Under these conditions, with relatively dry air at lower levels, thunderstorms tend to be high-based, the rain evaporating before reaching the ground and lightning occurring without significant rainfall. Specifically forecasting the probability of LIW occurrence would be of great assistance to the forest protection tactical decision-making process, preparing for “dry” thunderstorm days where multiple ignitions can be expected. Full article

The main goal of this study was to analyze the reproductive patterns of edible dormouse (Glis glis) populations in the northeast of the Iberian Peninsula using an 18-year period of data obtained from nest boxes collected between 2004 and 2021. The average litter size in Catalonia (Spain) was 5.5 ± 1.60 (range: 2–9, n = 131), with litter sizes between 5 and 7 pups as the more frequent. The overall mean weight in pink, grey and open eyes pups was 4.8 g/pup, 11.7 g/pup and 23.6 g/pup, respectively. No differences in offspring weights between sexes were found in any of the three age groups. Maternal body weight was positively associated with mean pup weight, whereas no correlation between the weight of the mothers and litter size was found. The trade-off between offspring number and size was not detected at birth. Regarding litter size variation across the geographic gradient (and their climatic gradient associated) from the southernmost populations of the Iberian Peninsula located in Catalonia to the Pyrenees region in Andorra, no evidence to suggest that geographic variables affect litter size was found, discarding (1) an investment in larger litters to compensate shorter seasons related to higher altitudes or northern latitudes, and (2) variation in litter size related to weather changes (e.g., temperature and precipitation) along latitudinal and/or altitudinal gradients. Full article