NW Spain Research Articles

When aposematism is not enough: Exotic Rattus rattus shows no mercy for carcasses of Salamandra salamandra in insular populations.

Predator-prey interaction is a major force driving natural selection. Yet, the identification of species preying on, or consuming, aposematic species is largely unknown. Here, I conduct a study evaluating the role of the exotic Rattus rattus as a consumer and possible predator of the aposematic and toxic Salamandra salamandra. I used camera traps to investigate the response of R. rattus towards S. salamandra carcasses in two insular populations, Ons and San Martiño (NW Spain), which show remarkable contrasting behaviour (nocturnal vs. diurnal activity) and demographic and phenotypic differences. This study unveils R. rattus consumes S. salamandra despite its aposematic colour pattern and toxicity. The high number of salamander carcasses consumed or taken by rats throughout each island (90%-100%) and the lack of other possible predator-prey interactions points to R. rattus as an efficient consumer of S. salamandra in these insular environments, which might exert a high predation pressure on both islands. Yet, the drivers underlying the behavioural and phenotypic differences in these insular populations should be further investigated.

Dating mortars and bricks of Santalla de Bóveda Monument (Lugo, NW Spain)

Santalla de Bóveda Monument (Lugo, NW Spain) is a small semi-buried building, under the Bóveda parish church, built in the 18th century, with an apsidal quadrangular floor plan, which was divided into three naves, a small vaulted apse and a rectangular floor plan vaulted, where paintings depicting birds and plant elements have been well preserved. The monument has aroused great interest since its discovery, but its chronology and functionality has always been the subject of controversy. Several hypotheses have suggested that the monument was built in the Roman period and some others around the 5h, 8th or 9th century AD. However, any direct evidence or absolute age has been provided until today. The stratigraphic analysis of the building suggests five constructive phases. Bricks and mortars of all phases were sampling to perform absolute dating techniques and to get a precise and accurate chronology. Radiocarbon dating of mortars and Optically Stimulated Luminescence (OSL) dating of bricks and mortars have been used to this purpose. A total of 34 samples were taken, being 20 used for luminescence (mortars and quartz aggregates) and 15 used for 14C ages (charcoal fragments of lime mortars). 5 brick samples were also dated by Thermoluminescence (TL). The obtained ages have allowed, for the first time, stablishing an accurate and precise chronology being the first phase assigned to the 4th Century AD. Alterations of the building and the vault paintings were performed in the early 7th century, while the construction of the second floor and occasional repairs were performed during the 10th-12th centuries.

A new species of the genus Biemna Gray, 1867 (Porifera: Biemnidae) from shallow waters of the Northwestern Iberian coasts

The genus Biemna currently includes fifty-eight valid species distributed worldwide with a wide depth range. In this paper, we describe a new species of this genus, Biemna begonae sp. nov., collected by scuba diving in two different locations on the Galician coast (NW Spain). The typical skeleton of this group is composed by megascleres arranged in a plumose or plumoreticulate fashion, with ectosomal skeleton constituted by brushes of choanosomal tracts and microscleres, including sigmata, commata and raphides. The habitus of the new species is a hemispherical cushion-shaped with numerous tubular projections emerging from the base, ending in oscules, and a general burgundy-red or whitish cream colour in live specimens. Spicules are styles, rare rhabdostyles, four size classes of sigmata, and raphides. The new species is compared morphologically with the other European representatives of the genus.

Preliminary screening of plant essential oils from an oceanic climate zone (NW Spain) for the control of equine cyathostomins

Cyathostomins (Strongylida: Cyathostominae) are gastrointestinal nematodes (GIN) that affect equines in many parts of the world. Due to anthelmintic resistance (AR), it is necessary to search for control alternatives. The objective of the study was to carry out a screening of 26 essential oils (EOs) from plants to determine in vitro their action on cyathostomins. Essential oils were obtained by hydro-distillation from leaves, flowers, fruits, and seeds of the selected species and used against the eggs of cyathostomins by means of the tests of egg hatching and larval motility inhibition. For each EO, different concentrations were prepared (250, 125, 62.5, 31.3, 15.6, 7.8, 3.9, 2.0, 1.0, 0.5 and 0.24 mg/mL). Oxfendazole at 2.5% mixed with closantel 5% was used as positive control, and PBS served as negative control. Cyathostomin eggs were obtained from feces of infected horses and infective larvae were recovered after coproculture. The in vitro test was carried out 36 h after the challenge with the EOs. The highest production of EOs was obtained from leaves of bay, eucalyptus, mallow, and basil, as well as from seeds of black pepper, coriander, cinnamon, anise, and peel of orange and cloves, cumin, and Lawson’s cypress. The oils extracted from laurel leaves, ground cinnamon, anise, cumin, and coriander seeds had a very high effect on cyathostomins eggs up to concentrations lower than 3.9 mg/mL. Therefore, in addition to the uses against other pathogens such as fungi and bacteria, some EOs might attain great importance as an alternative control strategy in the control of nematode eggs.

Application of quasi-empirical orthogonal functions to estimate wildfire impacts in northwestern Spain

Galicia (NW Spain) is one of the most fire-prone regions in Southern Europe. In the summer of 2022, a total of thirteen wildfires each exceeding 500 ha were reported in this area, with ten of these large fires occurring in the Ourense region. To study the impacts of wildfire smoke plumes on ambient air PM2.5 concentrations, a network of 18 PurpleAir monitors was deployed across the Galicia region during July and August 2022. The PM2.5 concentration data were then used as input to test the applicability of quasi-empirical orthogonal functions (QEOFs obtained with Positive Matrix Factorization (PMF)) to characterize the spatial variability of wildfire smoke impacts on air quality. HYSPLIT back-trajectory analysis and Concentration-Weighted Trajectory (CWT) models were implemented, and the results from these tools were combined with source contributions. As a result, 19 wildfires were identified and linked with peak ambient PM2.5 concentrations (>300 μg/m3 of PM2.5; 1-h mean). Specifically, the Folgoso do Courel fire emerged as a significant contributor to these high concentrations and played an important role in influencing a significant number of the identified factors. Moreover, the results also suggested that emissions from fires in Portugal reached the study area, contributing additional impacts on air quality. These results demonstrated that this approach was useful in identifying the emission source areas contributing to observed PM2.5 concentrations during wildfire events. The PM2.5 concentration maps resulting from the CWT analysis were also valuable in understanding the short- and long-term exposures to PM2.5 from wildfire smoke.

Opportunity of the NEGFRY Decision Support System for the Sustainable Control of Potato Late Blight in A Limia (NW of Spain)

The NEGFRY system is presented in this research work as a novelty strategy for the control of potato late blight in A Limia (NW Spain). The aim was to analyse the number of fungicide applications established by NEGFRY (Decision Support System, DSS) with respect to the routine calendars of this potato production area. This approach is in accordance with the requirements imposed by European policies, participating in more profitable and environmentally friendly agriculture. For this purpose, the relationships between the pathogen and the environmental conditions and epidemiological parameters were analysed in different plots compared to late blight infection in both Routine and DSS strategies. In addition, economic and environmental impacts of fungicide sprays were also analysed to check the adaptability of the decision support system to late blight in the area. Results confirmed that it is possible to reduce sprays following the NEGFRY model by more than 50% compared with Routine applications. Therefore, NEGFRY is a promising strategy to achieve lower footprint potato yields through a reduction in applied pesticides and water, lower gas emissions and less soil compaction due to a reduction in the number of tractor passes over the soil. The commitment to this strategy contributes to improving the economy of farmers, the health of the biodiversity, the environment and consumers, as well as to comply with demands of global economies in terms of more sustainable and resilient agriculture.

Wappleria tremoris gen. et sp. nov. the first representative of the insect order Caloneurodea in Spain (León, NW Spain) found in a Late Carboniferous forest

ABSTRACT We present a new genus and species of Caloneurodea from the Gzhelian (Stephanian B) of El Bierzo coalfield, in NW Iberian Peninsula (León, Spain) belonging to an uncertain family. Wappleria tremoris gen. et sp. nov. is described on the basis of a new specimen found in the Stephanian B strata of Casilda Mine, of Gzhelian age (Late Pennsylvanian, Late Carboniferous). The extinct order Caloneurodea (superorder Archaeorthoptera) is really scarce worldwide, it was previously found in the Carboniferous and Permian of Europe, North America, and Asia. This new specimen represents the first evidence of the order Caloneurodea from Spain, and the second record from the Iberian Peninsula, filling a gap in the Carboniferous palaeogeographical puzzle of this species in Europe. Little is known about the ecology and general biology of Caloneurodea. Nevertheless, Wappleria tremoris gen. et sp. nov. was found in close association with a rich palaeobotanical assemblage, dominated by pteridophytes, pteridospermatophytes, and gymnosperms, suggesting that W. tremoris could show a preference for forests under humid conditions.

Application of the Schmidt-hammer for relative-age dating of glacial and periglacial landforms in the Cantabrian Mountains (NW Spain)

A Schmidt hammer was applied for relative-age dating to 48 sites in 5 different massifs of the Cantabrian Mountains (NW Spain). The sample included glacial (moraines, erratics, and polished bedrock) and periglacial (rock glaciers, blockfields, and talus slopes) sites from the last glaciation to the present in different geomorphological contexts. The rebound (R) values agree with the morphostratigraphic reconstructions, showing progressively lower values for older deposits. Six stages from the Last Glacial Maximum to the present are inferred. The results differ according to the lithology: i) the quartzites showed higher R-values and very low weathering rates; ii) the granodiorites showed larger differences in R-values reflecting clearly age differences; iii) sandstones appear to be unsuitable for Schmidt hammer measurements in some areas; however, quartzite sandstones provide better results. The rock glaciers formed in different periods after deglaciation (i.e. just after the Last Glacial Maximum, Bölling/Allerød, Holocene), indicate a paraglacial dependence rather than climate-driven landforms. The sampled blockfields stabilized after the (almost) total deglaciation of the cirques, but their origin and significance in this mountainous area remain poorly understood.

First record of the semi-aquatic invasive plant Crassula helmsii in the Iberian Peninsula and its link to potential dispersal drivers

Aquatic neophytes are among the most harmful invasive species worldwide. Here we report the finding of the semi-aquatic invasive plant Crassula helmsii, naturalized in a freshwater reservoir that provides water to the large city of A Coruña, NW Spain. To better understand the extent and potential environmental correlates of C. helmsii invasion, we recorded the presence and frequency of C. helmsii in its emerged and floating mat forms at twelve sampling sites along the reservoir margins, and characterized the soil characteristics, plant community and environmental factors. Crassula helmsii is dispersed by fragmentation of the stems, potentially aided through shredding by local fauna such as the invasive crayfish Procambarus clarkii. We hypothesize that this could be a case of an invasional meltdown, when multiple invasive species facilitate one another and have synergistic effects on native ecosystems. The emerged form of C. helmsii was found in ten out of twelve sites with a mean cover value of 9.8 ± 10.4% (mean ± SD). We found no correlation between frequency of the emerged form of C. helmsii and abundance of Procambarus clarkii, but frequency of the emerged form of C. helmsii increased with higher soil nitrogen and vascular plant richness. We outline emergency actions for management of C. helmsii at this stage of the invasion, focusing on containment and avoiding spread to nearby water bodies.

Resin tapping of Atlantic pine forests: towards an optimized use of stimulant pastes over the season

Pine resin is a valuable non-wood forest product with an increasing interest in multiple industrial sectors. Resin-tapping activities also provide valuable ecosystem services in timber-oriented and highly productive pine forest of Atlantic regions, where little previous experience in resin-tapping is available. The objectives of this study were to determine the efficiency of different stimulant pastes and its variation with pine species, site conditions, seasonality and frequency of tapping interventions. We conducted parallel experiments using both conventional and micro-tapping techniques in mature pine stands in NW Spain. We tested four stimulants (control and Zeta, Cunningham and Salicylic pastes) and two groove frequencies (every 2 or 3 weeks). All stimulant pastes significantly increased resin yield compared to the control, being resin stimulation highly consistent across years, sites and species. In conventional resin tapping, resin yield was maximized with the Cunningham and Salicylic pastes while in micro-tapping Salicylic was the most outstanding stimulant treatment. According to the rapid decay of resin flow after wounding, total resin yield decreased with more spaced grooves. However, the reduction was low, and the global efficiency of the tapping operations are likely maximized with grooves applied every three weeks, which would allow increasing the number of tapped trees. Micro-tapping techniques were valuable for screening stimulant pastes and anticipating variation among sites in resin production. Altogether, the Salicylic paste is recommended, especially at the beginning of the resin campaign, when the effect of the pastes was maximized, and if tapping is conducted using closed atmospheres and containers.

Site Quality Models and Fuel Load Dynamic Equation Systems Disaggregated by Size Fractions and Vegetative States in Gorse and High Heath Shrublands in Galicia (NW Spain)

Compatible model systems were developed for estimating fuel load dynamics in Ulex europaeus (gorse) and in Erica australis (Spanish heath) dominated shrub communities at stand level. The models were based on intensive, detailed destructive field sampling and were fitted simultaneously to fulfill the additivity principle. The models enable, for the first time, estimation of the biomass dynamics of the total shrub layer, size fractions and vegetative stage, with reasonably good accuracy. The approach used addresses the high variability in shrub biomass estimates by using a site index (SI) based on biomass levels at a reference age of 10 years. Analysis of the effect of climatic variables on site index confirmed the preference of gorse for mild temperatures and the ability of high heath communities to tolerate a wider range of temperatures. In the gorse communities, SI tended to increase as summer rainfall and the mean temperature of the coldest month increased. However, in the heath communities, no relationships were observed between SI and any of the climatic variables analyzed. The study findings may be useful for assessing and monitoring fuel hazards, updating fuel mapping, planning and implementing fuel reduction treatments and predicting fire behavior, among other important ecological and biomass use-related applications.

Proposed spatial decision support system for delineating ecological corridors in green infrastructure planning constrained by lack of data: a case study in Galicia, Spain

In response to the constant loss of biodiversity in European ecosystems, which is partly due to the impacts of climate change, the European Commission urges member states to include Green Infrastructure (GI) in their land-use plans. However, although the European Commission establishes the fundamental principles to be applied, the ambiguity of some terms generates a certain degree of complexity regarding the delineation of GI elements, especially Ecological Corridors (ECs). Thus, a straightforward methodology for delineating GI elements is required. Here, we propose a Spatial Decision Support System (SDSS) that could help non-expert planners identify areas with a high potential to function as ECs and that could thus facilitate the inclusion of these areas in regional GI plans. Probability distribution maps were constructed by fitting a maximum entropy model (MaxEnt) to publicly available data on selected focal species. The maps were combined with other variables that negatively affect species mobility and later inserted in a graph theory tool to determine the least-cost path that would serve as the basis for delineating ECs. The method was applied to the design of an EC network in Galicia (NW Spain), and use of the system as a tool to help spatial decision-making was evaluated. Despite some limitations, the method yielded promising results that could help non-expert planners to establish the basis for delineating EC networks and other GI elements.

Recovery of fishery-stressed seagrass meadows is driven by improvements in wastewater management

As ecosystem engineers, seagrasses provide major benefits to coastal habitats worldwide. Nonetheless, their dynamics remain poorly understood in local areas. Three seagrass (Zostera noltei) meadows located within shellfish beds in Galicia (NW Spain) were selected to assess the intra and inter-annual changes in the habitats by considering the effects of harvesting, temperature and sewage pollution. Seagrass cover increased between April and October, when the sediment temperature ranged from 15 to 20 °C, while in terms of long-term dynamics there was a mean gain of 3 % year−1 between 2004 and 2023. Shellfishing caused mechanical disturbance within the meadows, but the seasonal changes in cover depended on temperature. However, we pointed out the built of new wastewater treatment plants since 1990 that improved water quality as the main driver of the long-term increase in seagrass cover. Environmental policies that enhance seawater quality and limit harvesting pressure are essential to maintain this positive trend.

Physicochemical Properties and Microbiome of Vineyard Soils from DOP Ribeiro (NW Spain) Are Influenced by Agricultural Management.

Agricultural management influences the soil ecosystem by affecting its physicochemical properties, residues of pesticides and microbiome. As vineyards grow crops with the highest incidence of pesticides, the aim of this study was to evaluate the impact of conventional and sustainable management systems of vineyards from DOP Ribeiro on the soil's condition. Samples from soils under three different management systems were collected, and the main soil physicochemical properties were evaluated. A selection of 50 pesticides were investigated by liquid chromatography with tandem mass spectrometry. The bacterial and fungal microbiomes were characterized through amplicon sequencing. The results show that organic agriculture positively influences soil pH and the concentration of some nutrients compared to conventional management. Our microbiome analysis demonstrated that transitioning from conventional to organic management significantly improves several BeCrop® indexes related to key microbial metabolism and soil bio-sustainability. Such a transition does not affect soil alpha diversity, but leads to a higher interconnected microbial network structure. Moreover, differential core genera and species for each management system are observed. In addition, the correlation of the microbiome with geographical distance is evidence of the existence of different microbial terroirs within DOP Ribeiro. Indeed, sustainable management leads to higher nutrient availability and enhances soil health in the short term, while lowering pesticide usage.

Preliminary Study on Yeasts Associated with the Production of "Tostado"-a Traditional Sweet Wine from Galicia (NW Spain).

Tostado is a traditional sweet wine from the Designations of Origins (DOs) of Ribeiro and Valdeorras in Galicia (NW Spain). The harvested grapes are air-dried and pressed to increase the concentrations of sugars, acids, and flavour compounds. Therefore, knowledge of the yeasts involved in fermentation under these conditions is essential to guarantee the quality and uniqueness of the valuable, distinctive, and expensive Tostado wines. Saccharomyces and non-Saccharomyces yeasts were identified using Wallerstein Laboratory (WL) Nutrient Agar and lysine plating, followed by polymerase chain reaction (PCR) amplification, enzymatic digestion, and sequencing. Saccharomyces cerevisiae isolates were further characterised at the strain level using mitochondrial DNA (mtDNA) restriction fragment length polymorphism (RFLP). Statistical analyses were also performed, including different diversity indices, Similarity Percentage (SIMPER) analysis, principal component analysis (PCA), neighbor-joining clustering, parsimony-phylogram, and network plot. In addition, the total acidity, volatile acidity, reducing sugars, and alcoholic strength by volume of the Tostado wines were analysed. A wide diversity of autochthonous yeasts was found, which were predominantly species of oenological relevance, such as Lachancea thermotolerans, Starmerella bacillaris, Hanseniaspora uvarum, Debaryomyces hansenii, Torulaspora delbrueckii, Pichia spp., and Saccharomyces cerevisiae from the must and paste stages of Tostado wine. In addition, 19 different S. cerevisiae strains were identified. This high yeast diversity, which changed from the early stages of fermentation, could contribute to the distinctive characteristics observed in Tostado wine. Characteristic and differentiating chemical and microbiological profiles were found as early as the pre-fermentation stages, which adds value to these special wines that have rarely been studied.

New problems for old vineyards: Mitigating the impacts of yellow-legged hornets (Vespa velutina) in a historical wine-producing area

Traditional small-sized vineyards are especially sensitive to different impacts, including the arrival of new pests. The adults of the yellow-legged hornet (Vespa velutina), an invasive alien species present in the Iberian Peninsula since 2010, feed on sugary foods, causing crop losses in vineyards. However, present management techniques for the control of V. velutina are limited, and they do not provide effective control in agricultural settings. This work aims to evaluate the use of an exclusion system in a traditional non-mechanized vineyard of a highly invaded area by V. velutina in NW Spain (Protected Geographical Indication of Betanzos, Galicia) as a method to mitigate the damage caused by hornets. Anti-hail nets were used in a factorial design experiment with groups of netted and unnetted vines of two white wine cultivars in order to address the vineyard production loss. In particular, we aim to 1) asses the effectiveness of anti-hail netting on preventing grape yield loss, 2) assess the impact of anti-hail netting on grape ripening and incidence of bunch fungal infection, and 3) study the potential relationship between the damage caused by V. velutina and grape fungal diseases. Results show that the tested exclusion system increases the crop yield, since it prevents effectively both the damage caused by hornets and birds. No significant correlation between the damage caused by V. velutina and the incidence of bunch fungal diseases was found in either cultivar. However, netting increased slightly the final sugar content in one of the cultivars, as well as the incidence of bunch fungal damage. We discuss the management implications of this exclusion method within the framework of agricultural land abandonment and the loss of traditional landscapes.

Estimating illegal catches in data-poor S-fisheries: Insights from multispecies shellfish poaching in galician small scale fisheries

The opaque nature of illegal, unreported, and unregulated (IUU) fishing means that the data on catches are scarce or unreliable, making it difficult to estimate the volume of illegal fishing and the number of individuals who practice it. In this work, we develop the use of quantification methods for IUU fishing in data-poor fisheries and provide estimates for the main shellfish species exploited in S-fisheries in Galicia (NW Spain). To make the estimates, we use a model whose primary input is the Confiscations per unit of policing effort (CPUPE) index, which relates the sanctions imposed for poaching, estimated poaching, and confiscations carried out by the Enforcement Forces. The estimates for the period 2012–2020 are 660.2 t of illegal catches of different species and an average number of 1,766.2 poachers/year. These estimates provide evidence that makes it possible to analyse tendencies in illegal fishing, to establish assessment baselines and to highlight potential improvements in the fight against IUU fishing in small-scale fisheries.

Urban pluvial flood modelling in the absence of sewer drainage network data: A physics-based approach

1D/2D dual drainage models have become one of the most useful tools in the study of urban pluvial floods. However, such models require information about the sewer network that is not always readily available. In this study we present a physics-based approach for assessing urban pluvial floods, with the aim of overcoming the common situation of having limited information on the sewer system. The method proposed involves the use of available open-access information within a virtual sewer network generation tool. This realistic approach allows for the implementation of 1D/2D dual drainage models, such as the recently developed Iber-SWMM model. Results obtained from four storm events using a virtual sewer network in Iber-SWMM were compared with those derived using data from the actual sewer network in a coastal town located in NW Spain. These results revealed that the proposed approach can reasonably represent the sewer network's drainage capacity during pluvial floods, especially compared to other simplified approaches, like the rainfall reduction method. The proposed approach also accounts for the sewer network transport capacity and the impact of overflows when a sewer’s capacity is exceeded. Hence the study confirms the significant effect of these processes on the magnitude of pluvial flooding in urban areas. The methodology is shown to be robust, and can be applied to any urban settlement in which no proper record of the sewer network is available.

Age and growth analysis of Loliginidae squid paralarvae in the NW Spanish coast using statolith increment counts

Knowledge of recruitment to a fishery is particularly important in short-lived species, like most cephalopods, in which there is a complete turnover of individual every 1 or 2 years. In this study, age, body length, statolith length and growth rates of loliginid paralarvae (Alloteuthis media, A. subulata and Loligo vulgaris) were determined to evaluate the form of the growth curve and differences between species and hatching seasons. A total of 222 paralarvae collected in zooplankton samples along the Galician coast (NW Spain) were used to determine relationships between dorsal mantle length (DML), statolith length (SL) and the number of increments (NI)) deposited in the statolith. The paralarvae of L. vulgaris were between 1 and 35 days old, while both Alloteuthis species ranged in age from 1 to 54 days. Generalised additive models (GAMs) revealed non-linear growth in DML, with L. vulgaris exhibiting higher DML-at-age than Alloteuthis species. The best parametric model fit for these data was obtained using exponential regressions. The SL–NI relationship also differed between species, with L. vulgaris having larger statolith length at age. The paralarvae of L. vulgaris and A. media had two well-differentiated hatching peaks, one in late spring-early summer (beginning of the upwelling season) and another peak in late autumn (end of the upwelling season). Alloteuthis subulata had an earlier hatching peak in spring than in the other two loliginid species—and the second peak in autumn was barely visible, possibly because this species occurs further north in areas not sampled in autumn.

Dating and Characterising the Transformation of a Monastic Landscape. A Multidisciplinary Approach to the Agrarian Spaces of Samos Abbey (NW Spain)

ABSTRACT This paper explores the potential of a multidisciplinary approach to understand landscape evolution over the last 1200 years around an important monastic centre, Samos Abbey, in northwest Iberia. Our objective is to test whether or not landscape transformations here – in particular terracing related to agriculture – can be linked to the agency of the monks. Our landscape study combined analysis of written sources with archaeological survey and test-pitting, including OSL profiling and dating of seven earthworks, with pollen and geochemical analysis of three of them. It has been possible to detect at least four main phases of landscape transformation in the immediate surroundings of Samos Abbey. The mid-seventeenth century saw the most recent and visible transformations, partly overprinting earlier landscapes changes from the Iron Age, eighth–ninth and thirteenth centuries AD. The data suggest that landscape transformation had already begun in this area centuries before the abbey was created, but the presence of this power centre from the early Middle Ages resulted in intensive use of the territory over the last twelve centuries.