Northwestern Iberian Peninsula Research Articles

Percepción social y tendencia poblacional de mesocarnívoros y ungulados en el noroeste de la península ibérica

Mesocarnivores and ungulates were historically considered as harmful species to humans. Research into the relationship between the actual and perceived population abundance or trend can be useful in mitigating conflicts with these animals. In this work, the information on population trends (i. e. increasing, maintenance or decreasing abundance) obtained through semi-structured interviews with local people was contrasted with the data from a two-times-replicated camera-trap study, separated eight years between them, in the northwestern Iberian Peninsula. In general, we found a divergence between the two sources of information regarding the population trend in only two of the six species under study, red fox and wild boar. Specifically, camera-trap results showed a decrease in red fox catches, not reflected in the face-to-face interviews. On the contrary, face-to-face interviews indicated an increase in wild boar populations, not reflected in the camera-trap study. The findings of this study underscore the necessity of integrating different information sources to accurately assess the population dynamics of mesocarnivores and ungulates, thereby enabling informed management decisions.

Arqueología de las identidades locales. La producción de localidades en el noroeste peninsular en la Alta Edad Media

ABSTRACT The study of early medieval European localities and local identities has previously been approached from the perspective of the later emergence of 'classic' medieval towns and cities; the post-Roman centuries have been considered a formative, transitional, period in the emergence of the stable and well-organized settlements of the High Middle Ages. However, new findings and conceptual contributions have been made in recent years, allowing for a redefinition of the mechanisms involved in the creation and transformation of local identities. Drawing on concepts of the production of locality and communities of practice, this study aims to analyze some processes observed in northwestern Iberia to argue that local societies resorted to multiple mechanisms for aggregating and negotiating spatialized identities.

Hidden Archaeological Remains in Heterogeneous Vegetation: A Crop Marks Study in Fortified Settlements of Northwestern Iberian Peninsula

This study evaluates the effectiveness of multispectral imaging via Unmanned Aerial Systems (UAS), in combination with advanced digital image processing techniques, for the detection and mapping of archaeological sites within diverse landscapes. The research focuses on six case studies located in the northwest of the Iberian Peninsula, a region marked by complex vegetation patterns and varying topography. The primary objective is to assess the potential of these non-invasive remote sensing techniques in identifying crop marks associated with buried structures from ancient, fortified settlements. By means of Principal Component Analysis (PCA) and vegetation indices, the study aims to pinpoint areas of interest that may indicate the presence of archaeological features, while effectively distinguishing them from modern disturbances or natural terrain variations. The research encountered several challenges, including seasonal variations in crop conditions and recent land-use changes. The methodology successfully identified distinct archaeological features. In some instances, natural vegetation variability, typically seen as an obstacle, enhanced the visibility of crop marks, aiding in the detection of underlying structures. These results offer a cost-effective and scalable option for preliminary archaeological surveys, particularly in refining survey methodologies and guiding future excavation efforts aimed at uncovering and preserving ancient, fortified settlements in the region.

Airborne Alternaria Spores: 70 Annual Records in Northwestern Spain.

This study presents data on the concentration of Alternaria spores in the atmosphere of the northwestern Iberian Peninsula. A non-viable volumetric method was used to collect the samples, resulting in a database of 70 annual. When the annual averages for each locality are calculated, Ourense stands out with 2152 spores/m3, followed by Vigo and Lugo, while Santiago de Compostela recorded the lowest concentrations. Focusing on the total data for each locality, the main sporulation period started in May and ended in October in all localities, centered on a single phase, with an earlier onset and longer duration in Ourense and Vigo. The number of days with concentrations in excess of 100 spores/m3 was very low in Santiago de Compostela, Ourense, and Vigo and null in Lugo. Temperature was the meteorological parameter for which the highest statistical correlation was obtained in all locations, being favorable to the concentration of spores in the air. Temperature ranges favorable to the presence of airborne spores in the study area ranged from 25.5 to 31.2 °C. Based on the analysis of the data collected, it is concluded that Alternaria spore concentrations are low throughout most of the year.

Interactions between invasive pests and pathogens in a native chestnut forest

The introduction in the same area of different invasive species can result in novel interactions, with unpredictable consequences. We carried out a study in Galicia (northwestern Iberian Peninsula) with the aim of clarifying the interactions between two invasive species Cryphonectria parasitica and Dryocosmus kuriphilus. In 2018, we selected five chestnut plots affected by both species. We compared trees affected only by the insect and trees affected by both the insect and the fungus with respect to attack level, gall characteristics, female size and fecundity, and concentrations of nitrogen, water and secondary metabolites. We also evaluated female preferences in a greenhouse assay. There were higher levels of attack in trees affected by both invaders. However, the greenhouse assay showed that ovipositing females do not preferentially choose trees attacked by the fungus. The presence of the fungus had no effect on the size, wall thickness, or hardness of D. kuriphilus galls, but larvae were smaller in trees also affected by the fungus. The fecundity of females was strongly related to the presence of chestnut blight; the number of eggs per female was almost double in trees affected by the fungus. There were no relations between blight and the nitrogen or water content in the galls, where the insects feed. There were also no effects of chestnut blight on the concentration of terpenes or phenols, but condensed tannins were higher in trees with chestnut blight. The higher tannins induced by chestnut blight may directly or indirectly benefit gall wasps. Positive relationships between condensed tannin concentration and reproductive performance of other gall makers were previously reported. Tannins can also improve the negative effects of environmental conditions inside the gall. Our results indicate that the presence of chestnut blight can increase the suitability of chestnut trees for the invasive insect, D. kuriphilus, through the increase in tannins due to the presence of the fungus.

Living in the Mountains. Settlement patterns in Northwestern Iberia during the Palaeolithic period

Living in the Mountains. Settlement patterns in Northwestern Iberia during the Palaeolithic period

A morphogenetic characterisation of a potentially dominant African marine species in Europe

Studying the early stages of the introduction of non-indigenous species (NIS) is crucial as it allows immediate management actions aimed at preventing NIS spread at a time when these actions are more likely to be effective. Recent species introductions present unique opportunities to study key aspects of the invasion process. However, comprehensive information on how and when NIS are first introduced remains rare. We assessed the characteristics of the introduction of a member of the widespread Pyura stolonifera species group (Chordata, Tunicata) in Europe. These ascidians are important bioengineer species that can attain amongst the highest benthic biomass per surface area ever reported. We collected introduced individuals on the coast of the northwestern Iberian Peninsula, an area with high shipping traffic and one of the world’s most important mussel farming regions. The specimens were analysed using taxonomic and genetic tools. Both field surveys and taxonomic analysis showed that one of the African members of the species group, Pyura herdmani, has recently been introduced to Europe and, although it does not yet form the large aggregates found in the native range, it is already well-established. Genetic data revealed that only the northwest African lineage of P. herdmani has been introduced to Europe. Considering the low dispersal capabilities of the early life-history stages of P. herdmani, the introduction of this species into Europe can only be explained via human mediated transport of NIS. In order to prevent any detrimental effects on both native biota and/or economically-important anthropogenic activities, regular monitoring of recent NIS introductions is urgently required.

A Systematic Approach to Map and Evaluate the Wildfire Behavior at a Territorial Scale in the Northwestern Iberian Peninsula

In the current context of extreme wildfires, understanding fire behavior at a territorial level has proven crucial for territory planning. This type of analysis is usually conducted by analyzing past wildfire statistics. In this study, we forego the past information related to wildfires and analyze, instead, the behavior of the entire territory in the face of wildfires. This allows for the distribution of ignition points to be systematized and for typical and atypical weather scenarios to be considered. This analysis relies on the use of wildfire simulation software. Ignition points used for the simulations were distributed using a systematic 1 × 1 km grid throughout the whole study area. Wildfires were simulated for each ignition point using eight different weather scenarios representing both typical and atypical weather conditions. The fire behavior on the territory was analyzed using rate of spread and intensity parameters for each simulated wildfire. It was observed that this territory is extremely prone to large wildfires both in typical and atypical weather conditions and that there is a tendency for extreme behaviors to develop. Some features were identified as prevention issues that ought to be addressed. This study develops a strategy to evaluate, in a systematic manner, the response of the territory to the threat of wildfires.

Provenance Studies of Natural Stones Used in Historical Buildings of the Peninsula de Barbanza, Galicia, Spain (North-Western Iberia)

Traditionally, the building stones used in the architectural heritage of Galicia (Spain) during the past were mainly extracted from quarries located in the surrounding areas of the historical buildings. Thus, a great variety of monuments were built with the same type of granite but with different degrees of weathering depending on local conditions, geological context (facies), and period of construction. The main purpose of this work is to evaluate the probable origin of the construction materials of six historical buildings on the Barbanza Peninsula, Galicia (Spain), based on the degree of weathering and petrographic-mineralogical characteristics. The evaluation was performed on six different samples of granite according to the geological context in outcrops of places where there are old quarries. We used X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), and petrographic microscopy (PM) to attempt to address whether the origin is really local to the Barbanza Peninsula or whether the stone was brought from more distant places, based on our knowledge of the geological context of the study area. Based on the chemical, textural, and mineralogical analyses obtained, the material used for construction has a local origin and comes from small quarries spread over a wide area within the Peninsula itself. Barbanza-type granite is the most abundant within the geological context of the area and also the most used as a construction material. Other types of granites identified are the Confurco Granite and other granitoids of the Noya complex. The Chemical Alteration Index (CIA) shows low to moderate weathering in the granites, fitting petrographic observations. In monuments, samples show higher concentrations of Na and K due to salt crystallization. They show microcracks due to extraction, cutting, and finishing processes and common alteration processes of the main minerals, such as sericitization of plagioclase and chloritization of biotite. This work consists of a multidisciplinary study focused on the geological perspective for the identification and preservation of historic quarries. Knowledge of the original material also presents a unique opportunity for the restoration and/or reconstruction of monuments, which allows for the maintenance of their conceptual and constructive homogeneity.

VNIR–SWIR reflectance spectroscopy as a nondestructive technique for compositional determination of archaeological talc samples with a machine learning approach

The material from which an archaeological piece is made provides a great deal of information regarding the society in which it was made; thus, any misidentification can lead to erroneous conclusions. The uniqueness of many of these pieces hinders their mineralogical analysis because the pieces cannot be damaged for sampling; therefore, errors in the classification of these materials are common. In the present study, we evaluate the suitability of the spectroradiometry technique in the analysis of two archaeological talc pieces. Both came from the Iron Age archaeological site of Peña del Castro (La Ercina, León) in the northwestern Iberian Peninsula. We compared the spectral curves of these 2 pieces with the spectral curves from 50 talc geological samples from different geographical sources, combining bulk and powdered samples. Our results show that spectral curves enabled the identification of the talc material in the powdered and bulk samples. Moreover, the absence of the talc characteristic features in other soft materials also used in antiquity enabled the detection of incorrect identification of the classified pieces. Even though our results cannot be used to define any absorption feature characteristic to establish the provenance of the material, in the present study, spectral analysis has been shown to be suitable as a nondestructive technique to mineralogically identify archaeological pieces.

Prehistoric and Early Roman Period Goldwork from Northwestern Iberia: An Analytical Study of Artefacts from the Archaeological and Historical Museum of A Coruña

This article presents the results of a topographical and analytical study using hh-XRF of 22 gold and gilded objects from the Archaeological and Historical Museum of A Coruña (Galicia, Spain). They are highly representative of the northwestern Iberian goldwork from the Chalcolithic (third millennium BC) to the early Roman period (first century AD). This study contributes to our knowledge of the production techniques used in those periods, as well as their evolution over time. The collection includes some of the most representative types in this area, such as Early Bronze Age “sheet collars” and torcs from the Second Iron Age. In the case of torcs, new data are provided on one of the formally best-documented types (the Artabrian type) and on those known as “Baroque torcs” that are characteristic of the final moments of this goldsmith tradition. While pieces from the Chalcolithic and Early Bronze Age were made with alluvial gold, the torcs from the Late Iron Age contain variable amounts of silver and copper. Also detected is the frequent use of cores made of less precious metals, which were subsequently given a golden appearance using gilding techniques. The new data are discussed in light of our current knowledge of NW Iberian goldwork, one of the most representative of this craft tradition in Western Europe for those periods.

Complementarity of offshore energy resources on the Spanish coasts: Wind, wave, and photovoltaic energy

The complementarity of the solar, wind, and wave energy resource in hybrid offshore platforms has the potential to increase productivity and reduce the variability in the energy output that a single type of energy source can generate. In this study, ERA5 reanalysis is used to calculate wind, solar and wave energy resources in Spanish potential locations for offshore platforms. The results indicate that wind energy presents the largest energy resource for all Spanish offshore regions, followed by photovoltaic energy. However, taking in count the “drought periods” (periods in which no energy is obtained from any of the analysed technologies), wave energy presents an opportunity to provide a continuous flow of energy, especially in the northwestern Iberian Peninsula and the Canary Islands. The evaluation of the complementarity of the three energy sources shows that the use of hybrid platforms would not only increase energy production but also reduce variability. In terms of energy production, wind energy along with solar energy are the largest energy generators. But in terms of minimizing variability, wave energy along with solar photovoltaic energy are the most important. Thus, this study is paving the way to introduce multiple energy converters on hybrid platforms as a pathway toward more powerful and sustainable energy production.

Potentially toxigenic phytoplankton patterns in the northwestern Iberian Peninsula

The Galician estuaries are Europe’s foremost supplier of mussels, generating millions of euros annually and offering substantial employment opportunities for its population. One of the most critical threats to shellfish production is the occurrence of harmful algal blooms (HABs), contaminating bivalves with phytotoxins. To successfully tackle this problem, there needs to be a collaborative effort between the scientific community and decision-makers to establish a dynamic and effective monitoring system. This could enable early warnings and preventive actions to avert the loss of millions of tons of shellfish. Remote sensing, despite its limitations, requires commitment and effort by experts to devise effective methods for detecting target optical constituents mixed with other undesired target but that exhibit strong signals. Therefore, the essential necessity arises to identify approaches for mitigating the shortcomings of the undertaken efforts. The objective of this study is to assess the main environmental drivers of potential harmful genera (Pseudo-nitzschia, Dinophysis, Alexandrium, and Gymnodinium) in the Rías Baixas from 2015 to 2022, developing regression-based models and customizing Generalized Additive Models (GAMs) to investigate their spatial-temporal dynamics. Risk-susceptible bloom zones were identified in the river mouth of the Ría Pontevedra and from the center to offshore of the Ría Vigo. Early upwelling events triggered peaks in chlorophyll-a (Chl-a), driving Dinophysis grazing on phytoplankton communities mainly dominated by diatoms, flagellates, and ciliates. Subsequently, the upwelling intensity favoring Pseudo-nitzschia or Alexandrium minutum growth as larger diatoms declined. A. minutum exhibited elevated incidence over the past five years. Gymnodinium catenatum presented a rare occurrence across the three studied estuaries, which limited the assessment of its spatial dynamics in the region. This study emphasizes the need to integrate remote sensing evaluation of high-risk bloom areas (July to September), in-situ cell count collection, and enhanced efforts for forecasting future critical occurrences of HABs.

Unveiling Local Power Through Microhistory: A Multidisciplinary Analysis of Early Modern Husbandry Practices in Casaio and Lardeira (Ourense, Spain)

Abstract Following the proposal for the special issue, the aim of this study is to reflect on the potentialities and setbacks of a micro-historical approach to the archaeological record. This will be done by analysing the local organization of Early Modern husbandry in a territory in northwestern Iberia, where investigations have been carried out since 2017. I will apply the theoretical background of microhistory to four specific archaeological sites to delve into the social structuring and power relationships among the different agents involved in stockbreeding in the territory. In this regard, I will argue that one of the most compelling contributions of microhistory is to delve into the deep connection between the systemic and the quotidian, between structure and agency. However, this connection is not always straightforward and visible in the sources, and thus a deep theoretical and methodological background becomes necessary to understand questions such as how power was conceived and articulated at the local level and in daily life.

Estimating spatial variability of baseline isoscapes from fish isotopic signatures at the community level

One of the main limitations in the application of stable isotopes to marine trophic ecology is obtaining a reliable baseline upon which to calculate isotopic enrichment. Isotopic baselines are variable in space and time, influenced by several environmental factors such as terrestrial runoff, oceanic currents or primary production, and thus, investigating their patterns of variability is essential to gain confidence in the estimates of trophic position based on isotopic signatures. We here propose a multispecies and multitrophic approach to study baseline isoscapes for nitrogen (δ15N) and carbon (δ13C), which we test on the demersal community of the Northwestern Iberian Peninsula. Using a set of 372 isotopic data of 11 demersal fish species sampled during autumn, we modelled the spatial variability of the isotopic baseline (for δ15N and δ13C separately) by removing the biological effect of species identity and individual length. Using the residuals of these models, which represent the isotopic baseline anomalies, we investigated the effect of environmental variables in driving the observed spatial patterns. Our results identify clear and consistent spatial patterns for the δ13C isotopic baseline. This isoscape achieved the lowest values in the westernmost part of the study area (Galician coast) increasing towards the east (Cantabrian Sea). This spatial pattern was mostly driven by primary production and organic matter in the sediment, reflecting the influence of upwelling intensity in the δ13C isotopic baseline over the study area. Baseline isotopic anomalies of δ15N, on the other hand, did not show clear spatial patterns, suggesting that for this isotopic baseline spatial patterns at the regional scale might not be as consistent. Our study brings forward the potential of multispecies isotopic data for approximating the environmental isotopic baselines for the whole ecosystem.

The influence of databases enrichment using local macroinvertebrate genetic references for metabarcoding based biodiversity studies in river monitoring

Water resources play a vital role in sustaining ecosystems, human life, food security, and biodiversity. However, these resources currently face serious threats caused primarily by human activities. Because of that, European Union have mandated that all its member states monitor the ecological status of their water bodies. One of the most commonly used bioindicator groups for routine river biomonitoring is benthic macroinvertebrates, which rely mainly on morphological identification at the family level and the use of diverse indices to estimate the ecological status of the river ecosystem. The morphological approach has certain limitations, and metabarcoding is now considered an alternative technique for biodiversity studies and biomonitoring of surface waters. However, the efficacy of this approach depends on the comparison of sequencing data with genetic databases, which are often incomplete and geographically biased. In this study, we collected 92 macroinvertebrate samples from rivers in the northern Iberian Peninsula to identify all possible species and generate new DNA sequences for the COI-5P region. The objectives were to perform region-specific enrichment of reference databases for the geographical area of northern Spain and to assess the impact, before and after this strategy, on the taxonomic assignments used for ecological status inference in metabarcoding samples. The results showed that 21% of morphospecies lacked reference sequences in the BOLD or GenBank databases, indicating that a significant number of macroinvertebrate species in the northwestern Iberian Peninsula lack reference sequences in major genetic databases. Enriching the BOLD databases with new sequences led to the detection of an average of 17.25 more BINs (species-assimilable gene cluster) and 1.54 more IBMWP taxa (river ecological status indicator macroinvertebrate taxa) per sample, causing changes in the ecological status determination for 16% of the samples, which clearly shows that improving the databases with local species sequences could enhance the detection and identification of new IBMWP taxa, potentially impacting ecological status inference from molecular data. Additionally, a historical analysis of Iberian macroinvertebrate addition in the BOLD database using public BOLD records revealed an asymptotic trend that can be partially mitigated by region-specific enrichment. These results indicate that a local biota sequencing effort can considerably improve metabarcoding results rather than waiting for a gradual improvement of genetic databases. In conclusion, we advocate for a creation an Iberian freshwater macroinvertebrate checklist and then the initiation of a coordinated effort for sequencing any unsequenced species from the region.

A new genus and species of deep-sea Coralliidae (Octocorallia) from the northeastern Atlantic, the first polymorphic octocoral genus with a membranous-stolonate colony growth form

During bathyal samplings undertaken by the Spanish Institute of Oceanography, a new genus and species of trimorphic Coralliidae was collected from the Avilés Canyon System, the Le Danois Bank (Bay of Biscay) and the Galicia Bank (north and northwestern Iberian Peninsula, northeastern Atlantic). Mollecorallium aenigmaticum gen. nov., sp. nov. is described and illustrated, including a molecular study. It has retractile autozooids within small mounds, and an abundance of radiates and crosses morphologically very similar to those occurring typically in species from other genera of the family with a calcareous axis of cemented sclerites. However, the new species is exceptional in lacking an axis, growing instead as small membranous and stolonal colonies, and in having mesozooids in addition to siphonozooids. According to our molecular study, the new genus herein proposed is strongly supported by the phylogenetic distance from soft-coral and gorgonian growth form genera in the family. Despite the notable biodiversity of the octocoral bathyal fauna of the Bay of Biscay and nearby areas, new species are discovered whenever exceptional sites such as submarine canyons and seamounts are sampled.

Predator and pollinator? An invasive hornet alters the pollination dynamics of a native plant

Invasive vespids are able to disrupt native species assemblages, modify ecological dynamics, and degrade ecosystem services. However, it is often difficult to quantify such effects within invaded ranges, principally due to the complexity of interactions, and a lack of comparative pre-invasion controls. In this study, we thus examine the effects of an invasive hornet, Vespa velutina, upon native species densities and pollination in a major food plant, Hedera hibernica. Using the highly heterogeneous distribution of V. velutina in a coastal area of the northwestern Iberian Peninsula, we assessed the impact of differing hornet abundance on insect diversity, flower visitation frequency, and predator-prey interactions. We then examined resultant effects upon the pollination success of H. hibernica, in the form of fruit and seed set. Our results demonstrated that in areas with high V. velutina abundance, the floral visitation frequencies and durations of insect pollinators were significantly altered. Effects varied widely across insect families, reflected in the differing predation success rates of V. velutina upon various native pollinators, in tandem with competitive exclusion. Interestingly, V. velutina was itself a frequent floral visitor, becoming the most common nectar forager in areas where it was abundant. In spite of this, H. hibernica reproductive success was significantly degraded in these areas, resulting in reduced seed set. As such, V. velutina appears to have multidirectional effects upon pollination services, first as an insect predator, and second as a nectar competitor and pollinator. Crucially, our findings suggest that V. velutina is an inferior pollinator when compared to the native species that it displaces, resulting in a net reduction in pollination efficacy, and hence reproductive success in H. hibernica. This study thus reveals the profound effects of an invasive vespid on native species through both competitive and predatory interactions.

Nestedness Patterns of Amphibian Assemblages in Northwestern Iberia along an Altitudinal Gradient: Implications for Conservation

Nestedness Patterns of Amphibian Assemblages in Northwestern Iberia along an Altitudinal Gradient: Implications for Conservation

Relationship of seasonal variations in drip waterδ13CDIC,δ18O, and trace elements with surface and physical cave conditions of La Vallina cave, NW Spain

Abstract. Cave-monitoring studies clarify the climatic, surface vegetation, and karst processes affecting the cave system and lay the foundation for interpreting geochemical stalagmite records. Here we report the monitoring of cave air, bedrock chemistry, and drip water δ13CDIC, δ18O, and δD, as well as 16 trace elements, covering a full annual cycle spanning the 16 months between November 2019 and March 2021 in La Vallina cave in the northwestern Iberian Peninsula. While decreased rainfall and increased evapotranspiration in the summer months lead to a strong reduction in drip rates, there is little seasonal variation in δ18O and δD in a given drip, likely reflecting the discrete moderately mixed to well-mixed karst water reservoirs. Small differences in δ18O and δD between drip sites are attributed to variable evaporation intensity and/or transit times. The carbon isotope signature of the dissolved inorganic carbon of drip water (δ13CDIC) is likely driven by seasonal changes in the temperature controlling biological processes (vegetation and microbial soil activity), resulting in minimum δ13CDIC in summer and autumn months. Increased bedrock dissolution due to higher soil pCO2 in summer and autumn results in increased trace element concentrations of congruently dissolved elements. Cave air measurements (pCO2, δ13Cair, and temperature) indicate the seasonal ventilation (winter) and stagnation (summer) of cave air. The opposite effects of reduced cave air pCO2, seasonally variable biological activity, and increased drip rate limit the extent of the seasonal variation in degassing and prior calcite precipitation (PCP) supported by trace elements (Sr/Ca index). Estimated stalagmite growth rates using monitoring data suggest biannual phases of potential calcite precipitation in summer and winter and growth cessation during spring and autumn, depending on cave and drip water conditions and the location within the cave, which has important implications for the proxy interpretation of stalagmite records.