Northwest Spain Research Articles

Divergence in Thermal Physiology Could Contribute to Vertical Segregation in Intertidal Ecotypes of Littorina saxatilis.

AbstractThermal stress is a potentially important selective agent in intertidal marine habitats, but the role that thermal tolerance might play in local adaptation across shore height has been underexplored. Northwest Spain is home to two morphologically distinct ecotypes of the periwinkle Littorina saxatilis, separated by shore height and subject to substantial differences in thermal stress exposure. However, despite other biotic and abiotic drivers of ecotype segregation being well studied, their thermal tolerance has not been previously characterized. We investigated thermal tolerance across multiple life history stages by employing the thermal death time (TDT) approach to determine (i) whether the two ecotypes differ in thermal tolerance and (ii) how any differences vary with life history stage. Adults of the two ecotypes differed in their thermal tolerance in line with their shore position: the upper-shore ecotype, which experiences more extreme temperatures, exhibited greater endurance of thermal stress compared with the lower-shore ecotype. This difference was most pronounced at the highest temperatures tested. The proximate physiological basis for these differences is unknown but likely due to a multifarious interaction of traits affecting different parts of the TDT curve. Differences in tolerance between ecotypes were less pronounced in early life history stages but increased with ontogeny, suggesting partial divergence of this trait during development. Thermal tolerance could potentially play an important role in maintaining population divergence and genetic segregation between the two ecotypes, since the increased thermal sensitivity of the lower-shore ecotype may limit its dispersal onto the upper shore and so restrict gene flow.

Short communication: Effect of subclinical mastitis on reproductive performance of Holstein dairy cows in the Northwest of Spain

Aim of study: To investigate the effect of subclinical mastitis (SCM) before and after first artificial insemination (AI), characterized by a somatic cell count (SCC) higher than 200×103 cell/mL, on reproductive performance including first service conception rate (FSCR) and pregnancy loss (PL) in Holstein dairy cows. Area of study: The central area of Lugo, Galicia, Spain. Material and methods: This retrospective study was conducted on herd database of a population of 80 commercial Holstein dairy cow farms. A total number of 2053 lactations were included in this study. A binary logistic regression was carried out to analyse all data. Main results: The results of this study indicated that cows that registered a SCC lower than 200×103 cell/mL within 30 days after first AI were more likely to conceive pregnancy than cows with a higher SCC (31.2% and 25.1% FSCR, respectively; OR=1.285, 95% CI=1.000-1.653). Additionally, an increased SCC neither 30 days before nor 30 days after first AI had a negative effect on prevalence of PL in dairy cows. Research highlights: These findings revealed that SCM within 30 days after first AI negatively affected FSCR, whilst 30 days before first AI did not affect it. Therefore, it could be suggested that preventing subclinical mastitis after first AI, during a critical period of 30 days, is important to maximize the reproductive performance of dairy cows.

Evaluating the Presence and Contents of Phytochemicals in Honey Samples: Phenolic Compounds as Indicators to Identify Their Botanical Origin.

Honey is a natural product well known for its beneficial properties. It contains phytochemicals, a wide class of nutraceuticals found in plants, including compounds with highly demonstrated antimicrobial and antioxidant capacities as phenolic compounds and flavonoids. The main goal of this work is the development of a miniaturized and environmentally friendly methodology to obtain the phenolic profile of Galician honeys (Northwest Spain) from different varieties such as honeydew, chestnut, eucalyptus, heather, blackberry and multi-floral. The total phenolic content (TPC) and antioxidant activity (AA) were also evaluated. As regards sample preparation, miniaturized vortex (VE) and ultrasound assisted extraction (UAE) employing aqueous-based solvents were performed. Individual quantification of 41 target phenolic compounds was carried out by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results revealed the presence of 25 phenolic compounds in the 91 analyzed samples, reaching concentrations up to 252 µg g−1. Statistical tools such as analysis of variance (ANOVA) and principal component analysis (PCA) were employed to obtain models that allowed classifying the different honeys according to their botanical origin. Obtained results, based on TPC, AA and ∑phenolic compounds showed that significant differences appeared depending on the honey variety, being several of the identified phenol compounds being responsible of the main differentiation.

Microbial Community Composition during a Bloom of Purple Bacteria in Intertidal Sediments in Vigo (Northwest Spain).

ABSTRACTIn summer 2019, a large, bright pink microbial mat was visible on top of macroalgal deposits in muddy sediments of an urban beach (Playa do Adro, Vigo). In order to characterize the dominant organisms in these colored mats, results from microscopic observations, photosynthetic pigments, and molecular analysis were gathered. Light microscopy examination revealed pinkish microbial aggregates with minor contributions of larger protists and cyanobacteria. High-performance liquid chromatography (HPLC) pigment analysis documented the dominance of bacteriochlorophyll a and carotenoids whose spectra were compatible with those described in photosynthetic purple bacteria. 16S rRNA gene amplicon sequencing confirmed that the vast majority of reads belonged to Proteobacteria (73.5%), and among them, nearly 88% of those reads belonged to purple sulfur bacteria (Gammaproteobacteria). A single family, Chromatiaceae, constituted the bulk of this assemblage, including the genera Thiohalocapsa (32%), Marichromatium (12.5%), Phaeochromatium (5%), and Halocromatium (2%) as main contributors. Nonetheless, a considerable number of sequences could not be assigned to a particular genus, stressing the large biological diversity in these microbial mats and the potential presence of novel taxa of purple sulfur bacteria.IMPORTANCE Urban beaches are valuable recreational areas particularly vulnerable to human disturbance. In these areas, the intertidal sediments harbor a diverse community of microorganisms, including virus, bacteria, fungi, and protozoa. In this sense, pollution events can introduce pathogenic allochthonous microbes which may constitute a human health risk. Visual and sensory observations, such as a weird color or bad smell, are usually appreciated as a warning by beachgoers and authorities, as indeed was the case at do Adro beach in 2019. The observed proliferation seems to be common in summertime, but its dimension alerted beachgoers and media. The obtained results allowed for the identification of purple sulfur bacteria as responsible for the pink-violet top layer staining the intertidal zone. These blooms have never been associated with public health risks. Beyond solving the sanitary concern, other important findings were its diversity and large proportion of novel taxa, illustrating the complexity of these ecosystems.

A Wilcoxon-Mann-Whitney spatial scan statistic for functional data

A nonparametric scan method for functional data indexed in space is introduced. The associated scan statistic is derived from the Wilcoxon-Mann-Whitney test statistic defined for infinite dimensional data. It is completely nonparametric as it does not assume any distribution concerning the functional marks. Whatever the clustering scenario, this scan test seems to be efficient to detect and locate the cluster. This method is applied to a data set for extracting features in Spanish province population growth. A significant spatial cluster of low demographic evolution rates is found, exhibiting a specific phenomenon in the North-West of Spain.

Erosive Degradation Study of Concrete Augmented by Mussel Shells for Marine Construction

This work proposes a green material for artificial reefs to be placed in Galicia (northwest Spain) taking into account the principles of circular economy and sustainability of the ecosystem. New concrete formulations for marine applications, based on cement and/or sand replacement by mussel shells, are analyzed in terms of resistance to abrasion. The interest lies in the importance of the canning industry of Galicia, which generates important quantities of shell residues with negative environmental consequences. Currently, the tests to determine the abrasion erosion resistance of concrete on hydraulic structures involve large and complex devices. According to this, an experimental test has been proposed to estimate and compare the wear resistance of these concretes and, consequently, to analyze the environmental performance of these structures. First, a numerical analysis validated with experimental data was conducted to design the test. Subsequently, experimental tests were performed using a slurry tank in which samples with conventional cement and sand were partially replaced by mussel shell. The abrasive erosion effect of concrete components was analyzed by monitoring the mass loss. It shows an asymptotic trend with respect to time that has been modeled by Generalized Additive Model (GAM) and nonlinear regression models. The results were compared to concrete containing only conventional cement and sand. Replacing sand and/or cement by different proportions of mussel shells has not significantly reduced the resistance of concrete against erosive degradation, except for the case where a high amount of sand (20 wt.%) is replaced. Its resistance against the erosive abrasion is increased, losing between 0.1072 and 0.0310 wt.% lower than common concrete. In all the remaining cases (replacements of the 5–10 wt.% of sand and cement), the effect of mussel replacement on erosive degradation is not significant. These results encourage the use of mussel shells in the composition of concrete, taking into account that we obtain the same degradation properties, even more so considering an important residue in the canning industry (and part of the seabed) that can be valorized.

Metataxonomic analysis of tissue-associated microbiota in grooved carpet-shell (Ruditapes decussatus) and Manila (Ruditapes philippinarum) clams

Culture-dependent techniques only permit the study of a low percentage of the microbiota diversity in the environment. The introduction of next generation sequencing (NGS) technologies shed light into this hidden microbial world, providing a better knowledge on the general microbiota and, specifically, on the microbial populations of clams. Tissue-associated microbiota of Ruditapes decussatus and Ruditapes philippinarum (mantle, gills, gonad and hepatopancreas) was analysed in two different locations of Galicia (northwest of Spain) during Spring (April) and Autumn (October), employing a metataxonomic approach. High bacterial diversity and richness were found in all samples where a total of 22,044 OTUs were obtained. In most samples, phylum Proteobacteria was most frequently retrieved, although other phyla as Actinobacteria, Bacteroidetes, Tenericutes, Firmicutes or Chlamydiae also appeared at high relative abundances in the samples. At genus level, great variation was found across tissues and sampling periods. A Nonmetric Multidimensional Scaling (NMDS) and a hierarchical clustering analysis allowed to further analyse the factors responsible for the differences among groups of samples in the different sites. Results showed sample ordination based on tissue origin and sampling periods, pointing out that the microbiota was influenced by these factors. Indeed, predominance of certain genera was observed, such as Endozoicomonas or Methylobacterium in gills and gonads, respectively, suggesting that selection of specific bacterial taxa is likely to occur. So far, this study provided a general picture of the tissue associated microbial population structure in R. decussatus and R. philippinarum clams, which, ultimately, allowed the identification of specific tissue-related taxa.

Linear Models for the Prediction of Animal Zone Ammonia in a Weaned Piglet Building

Measuring ammonia inside livestock buildings poses many challenges that hinder the incorporation of this variable into environmental control systems. The aim of this study was to measure various microclimate variables inside a weaned piglet building and analyse their interactions with NH3 concentrations for setpoint temperatures of 26 and 25 °C, in order to control NH3 concentrations based on other easily measurable variables. The experimental test was conducted on a conventional farm in Northwest Spain. NH3 concentrations in the animal zone were best correlated with CO2 concentrations in the animal zone (R = 0.91 and R = 0.55) and velocity of air extracted through the fan (R = 0.72 and R = 0.65) for setpoint temperatures of 26 and 25 °C, respectively. Similarly, strong correlations were found with relative humidity in the animal zone and temperature of inlet air. Because NH3 concentration in the animal zone is related to the performance of the ventilation system, strong positive correlations were found between NH3 concentration and temperature of inlet air whereas negative correlations were found between NH3 concentration and ventilation rates. Linear regression models based on CO2 concentrations in the animal zone and temperature of inlet air are recommended, because they provide a good fit for both setpoint temperatures using variables that can be readily measured.

A new integrated methodology for characterizing and assessing suitable areas for viticulture: A case study in Northwest Spain

In 2018, Spain was the third largest producer and the leading exporter of wine in the world. Viticulture is an important economic activity in the Castilla y León region, and is an element capable of halting the flight from the countryside and favouring demographic settlement in rural areas. A new integrated methodology for characterizing and delimitating areas suitable for vineyard cultivation is proposed here. The approach combines traditional climate indices with others used in bioclimatology and with soil variables, and applies various statistical analyses to select the predictors that best characterize the vineyards. These predictors are then integrated in species distribution models and a geographic information system. The methodology was tested in the Denomination of Origin León (hereafter DO León) in northwest Spain. Ten single models using the maximum entropy modelling algorithm were run for each of the six wine-grape varieties. Single-model projections built as a consensus of the ten models into an ensemble-forecasting approach were later used to generate maps of suitable areas for each variety.The results confirm the delimitation of the DO León as a Denomination of Origin. The bioclimatic variables Compensated Thermicity Index and Continentality Index and the soil variables pH, Clay Content, Soil Retention Capacity and Soil Saturation Humidity are defining for all the varieties studied. Garnacha and Mencía were the most different varieties in relation to their bioclimatic and soil requirements. Suitability maps revealed that the DO could be extended into neighbouring areas up to 30 km around it.The proposed methodology is a useful tool for agronomic and oenological management; it allows a more effective selection of sites for new vineyards, improves vineyard management, and can even be used to protect territories with a historical and cultural heritage of grape cultivation, thus favouring demographic settlement in rural areas and avoiding depopulation.

Influence of overliming vineyard acid soils on the macro-nutritional status of grapevines

Aim of study: The main aim of this study was to evaluate the effect of overliming with dolomitic lime on the topsoil and grapevine macro-nutritional levels (both petiole and grape tissues), as well as on berry weight and must quality properties in grapevines growing on an acid soil. Area of study: The study was carried out in the viticultural region of El Bierzo (Spain), one of the main wine protected designation of origin in the northwest of Spain. Material and methods: The effects of overliming were studied in soil parameters, petiole and grape tissues, as well as in must quality during three years (2014-2016). Data analysis was performed using factorial ANOVA (both parametric and non-parametric tests have been used). Main results: The results found on the soil levels of magnesium and phosphorus were mirrored by those shown in petiole and grape tissues. Data suggest that insufficient Mg supply in vineyard acid soils could lead to a lower P vascular movement in vines. Additionally, our findings suggest that a great decrease of K levels in vine tissues as a consequence of overliming, could lead to changes in harvest quality. Research highlights: Overliming with dolomitic limestone in large quantities decreased soil exchangeable K, as well as improved supply of exchangeable Mg and available P. Additionally Mg and P levels in both petiole and grape tissues were significantly affected by overliming.

Organ dysfunction as determined by the SOFA score is associated with prognosis in patients with acute traumatic spinal cord injury above T6.

This is a retrospective, observational study. To evaluate organ dysfunction in patients with an acute traumatic spinal cord injury (ATSCI) above T6 using the Sequential Organ Failure Assessment (SOFA) score to determine its association with mortality. The study was performed at the intensive care unit (ICU) of a tertiary hospital in the northwest of Spain. The study included 241 patients with an ATSCI above T6 who had been admitted to the ICU between 1998 and 2017. A descriptive analysis of all variables collected was performed to compare the survivors with the non-survivors. In addition, a logistic regression model was used in the multivariate analysis to identify variables that were independently associated with mortality. The results revealed significant differences between the survivors and non-survivors in terms of their age, Charlson Comorbidity Index, Glasgow Coma Scale score on admission, APACHE II score, SOFA score on day 0 and day 4, and delta SOFA 4-0 (ΔSOFA 4-0). The results of this multivariate analysis identified the following variables as independent predictors of intra-ICU mortality: age (OR = 1.05; 95% CI: 1. 01-1.08), SOFA score on day 0 (OR = 1.42; 95% CI: 1.13-1.78), ΔSOFA 4-0 (OR = 1.53; 95% CI: 1.25-1.87), and fluid balance on day 4 (OR = 1.16; 95% CI: 1.00-1.35). The SOFA score is useful for evaluating organ dysfunction in patients with an ATSCI above T6. After adjusting the analysis for conventional variables, organ dysfunction on admission, changes in organ function between day 4 and day 0 (ΔSOFA 4-0), and fluid balance on day 4 were seen to be independently associated with mortality in our study.

Looking for a sustainable potato crop. Field assessment of early blight management

Potato crops are susceptible to numerous field diseases causing significant losses in the quality and tuber yield. Control measures have a negative impact in soil and water resources affecting also farmers’ health and food security. Hence, a more sustainable agriculture management is a need to preserve ecosystems. Therefore, the objective of this study was to evaluate the response of nine potato cultivars (Fleur Bleue, Frisia, Fontane, Louisa, Agria, Daifla, Red Pontiac, Kennebec and Desiree) against early blight using a Decision Support Systems (DSS) in a potato-producing area from Northwest Spain. The experimental design was established using control plots and sprayed plots with fungicide according to a disease risk model adapted to the geographical region (DSS plots). Disease rating and severity were evaluated in field from the appearance of the first symptoms to final of senescence and the area under disease progress curve (AUDPC and r-AUDPC) was calculated. Aerobiological monitoring of main Alternaria species responsible potato early blight (Alternaria solani and Alternaria alternata) and the most vulnerable phenological stages were also considered. The susceptibility of the potato cultivars was analyzed based on the weather, severity of the disease and tuber yields. Specifically, temperature and leaf wetness were the meteorological variables that most influenced on the concentration of Alternaria. Conidia accounted for the previous week was the variable that most influenced in development of symptoms measured by AUDPC in natural conditions. Yields in the cultivars of DSS plots were higher than in control plots. Therefore, alternative pest management strategies, and specifically, Decision Support Systems for pest assessment are crucial for sustainable potato production. In this sense, the integration of particular information on disease resistance of commercial cultivars, phenological development of plant, or fungal particles surrounding the crop atmosphere could support these systems for better adjustment without compromising tuber yield and environment.

Factors Affecting e-Government Adoption by Dairy Farmers: A Case Study in the North-West of Spain

With the objective of assessing the farmers’ situation regarding the use of the ICT and their relations with the electronic government, a case study consisting in the realization of 34 face-to-face surveys was conducted between February and March 2020 in dairy farms in the region of Galicia (Spain). The sample was selected according to one of the most important online journals in the farming sector at a national level. From the census, we chose those farms considered most representative taking into account the main criteria: the level of PAC (Common Agrarian Politics) subsidies and milk production (litres/cow and year). The results show that the majority of the farmers used the internet, but on many an occasion, they were discontented in relation to the poor connection quality in their farms. In regard to the use of the electronic government for procedures related to their farms, many of them were able to perform them through the government website; however, there were procedures which the users defined as “complex” and which had to be outsourced to authorised entities. The results also show that the farmers do want to employ the e-government, mainly because of the time and cost saving; however, the current web pages do not meet the users’ expectations. Finally, this situation, applied to a region placed among the 10 most productive regions of milk, is comparable to what happens in other regions.

Evaluation of simple sequence repeats (SSR) and single nucleotide polymorphism (SNP)-based methods in olive varieties from the Northwest of Spain and potential for miniaturization

Miniaturization of DNA-based techniques can bring interesting advantages for food analysis, such as portability of complex analytical procedures. In the olive oil industry, miniaturization can be particularly interesting for authenticity and traceability applications, through in situ control of raw materials before production and/or the final products. However, variety identification is challenging, and implementation on miniaturized settings must be carefully evaluated, starting from the selected analytical approach. In this work, SSR- and SNP-based genotyping strategies were investigated for the identification and differentiation of two olive varieties from the Northwest of Spain. For the selected SNPs two genotyping methods were tested: real-time allele-specific PCR and high resolution melting analysis. These methods were compared and evaluated regarding their potential for integration in a microfluidic device. Both SNP-based methods proved to be successful for identification of the selected varieties, however real-time allele-specific PCR was the one that achieved the best results when analyzing mixtures, allowing the identification of both monovarietal samples and mixtures of the varieties tested with up to 25%.

Study of Forest Productivity in the Occurrence of Forest Fires in Galicia (Spain)

The occurrence and intensity of forest fires is a phenomenon in which factors of various kinds converge, including climatic, physiographic, socioeconomic and territorial, among others. While the scientific literature has been stating that the causes of fires are related social conflict, other factors must also be considered for a more thorough analysis. In Galicia (northwest Spain), human-caused fires account for up to 95% of the total annual fires, highlighting the importance of examining in detail social and/or economic factors that may influence the occurrence or absence of this type of phenomenon. This paper discusses the influence and weight of forest productivity and the potential economic value of wooded areas on the incidence of forest fires in private mountains of collective ownership (montes vecinales en mano común). Our results indicate that the presence of productive wooded areas of the region determines a lower incidence, both in terms of the number of forest fires and the area affected. It was found that in areas where there was a loss in productivity, the fire rate increased by almost 36%. It is also observed that in MVMCs with productivity gain, the incidence of fires in shrubland areas was 46.26% higher than in wooded areas, while in MVMCs with productivity loss, the occurrence of fires in shrubland areas was 18.95% higher than that observed in wooded areas.

Botrytis cinerea Airborne Conidia and Their Germination Ability Assessed by Immunological Methods in a NW Spain Vineyard

Grey mould is a fungal disease responsible for important crop losses in most winemaking regions worldwide. In the present study, we developed immunological techniques for the detection and quantification of Botrytis cinerea conidia germinative material to obtain additional information about epidemic’s development on the vineyard. The study was carried out in a northwest Spain vineyard during the grapevine flowering in 2017 and 2018. An aerobiological study was developed for the identification and quantification of Botrytis cinerea conidia. For the immunological analysis, we developed a specific protein extraction protocol and a standard curve to analyze the cyclone-trap samples by an indirect PTA-ELISA. The airborne B. cinerea protein concentrations showed a similar variation pattern than the airborne conidia concentrations in the atmosphere of the vineyard. We recorded a total of 5673 B. cinerea spores in 2017, and 7562 spores in 2018. Regarding the airborne protein concentrations, we detected 9.692 ng/m3 in 2017 and 7.715 ng/m3 in 2018. Based on the statistical influence of the considered variables, we developed a predictive model able to explain 40% of protein data variability. The resulting methodology based on the combination of immunological techniques and aerobiological monitoring leads to a more reasoned treatment schedule consistent with real phytosanitary vineyard conditions and a more effective responsiveness against the increasing variability associated to climate change on the crop-pathogen system.

Forecasting Variations in Profitability and Silviculture under Climate Change of Radiata Pine Plantations through Differentiable Optimization

Climate change might entail significant alterations in future forest productivity, profitability and management. In this work, we estimated the financial profitability (Soil Expectation Value, SEV) of a set of radiata pine plantations in the northwest of Spain under climate change. We optimized silvicultural interventions using a differentiable approach and projected future productivity using a machine learning model basing on the climatic predictions of 11 Global Climate Models (GCMs) and two Representative Concentration Pathways (RCPs). The forecasted mean SEV for future climate was lower than current SEV (∼22% lower for RCP 4.5 and ∼29% for RCP 6.0, with interest rate = 3%). The dispersion of the future SEV distribution was very high, alternatively forecasting increases and decreases in profitability under climate change depending on the chosen GCM. Silvicultural optimization considering future productivity projections effectively mitigated the potential economic losses due to climate change; however, its ability to perform this mitigation was strongly dependent on interest rates. We conclude that the financial profitability of radiata pine plantations in this region might be significantly reduced under climate change, though further research is necessary for clearing the uncertainties regarding the high dispersion of profitability projections.

Linking Geoheritage and Traditional Architecture for Mitigating Depopulation in Rural Areas: the Palaeozoic Villages Route (Courel Mountains UNESCO Global Geopark, Spain)

The use of stone in traditional architecture represents one of the most relevant links between geological and cultural heritage. As a topic of general interest and easily understandable to all public, this link is a guiding thread for touristic routes mitigating the depopulation trend that affects large inland rural areas, including many areas in UNESCO Global Geoparks (UGGp). In the northwest of Spain, the Courel Mountains UGGp created the Palaeozoic Villages Route for touristic purposes in 2018, highlighting the relevance of local stones in traditional architecture as a key feature for sustainable development. For the design and creation of this route, seven villages were selected along six criteria: (1) the representativeness of the building stone with the bedrock of the UGGp, (2) the preserved traditional architecture, (3) their link with geoheritage, (4) the scenic beauty of their surroundings, (5) the potential combination with other touristic activities, and (6) the presence of local services. The Palaeozoic Villages Route exhibits four rock types/sections/structures spanning four Palaeozoic periods, as well as different uses for walling and roofing depending on the rock feature. Since 2018, the route experienced an increased revenue of 19% in the touristic sector to the traditional villages, while visitors used up to 61% of the local services of the UGGp for one or more days. In addition, the route reinforces the awareness of depopulation and abandonment of rural villages, fostering the purchase and/or restoration of dwellings as second regular residences in tranquil and scenic environments. In the short to medium term, these actions are expected to reverse or, at least, minimise the loss of population in the UGGp.

Monumental Sweet Chestnuts (Castanea sativa Mill.) in Galicia’s Cultural Landscape (NW Spain)

ABSTRACT Soutos – single-species groves of sweet chestnut (Castanea sativa Mill.) trees – are a highly characteristic component of the Galician cultural landscape in northwest Spain, and a clear expression of the interactions between nature and culture that define landscapes. The trees in the soutos have for centuries been subject to cultural practices aimed at increasing the production of fruit, timber, or both at the same time. Other products from the soutos not long ago considered secondary, for example ecosystem services, fungal production or beekeeping, are nowadays becoming steadily more valued by people. Individual trees, many of them catalogued as of outstanding value in the Inventario de Árboles Sobresalientes de Galicia, are often of unusual size and age thanks to the long tradition of pollarding, and they are often important landmarks and cultural icons. This paper based partly on research carried out for the Galician Catalogue of Heritage Trees, and focussing on 180 outstanding specimens of sweet chestnut (Castanea sativa Mill.), summarises the significance and use of the Galician soutos, and the traditional management that has created them. It also identifies the processes which over the past several decades have encouraged a decline in the numbers and preservation of the groves, and proposes good management practice for the future which could help to preserve these distinctive landscape.

Mine Water for the Generation and Storage of Renewable Energy: A Hybrid Hydro–Wind System

Mine water is normally considered as waste that has to be managed. However, new applications are increasingly being sought for the water that floods mining voids, especially in relation to its use as an energy resource. The worldwide energy market, within the current transition framework, is searching for creative approaches to produce and store clean energy. In particular, underground pumped hydroelectric energy storage systems (UPHS) constitute efficient and flexible alternatives to deal with intermittent renewable energy sources. In this work, a UPHS is designed using the mine water and the voids of a closed coal mine in Asturias (North-west Spain) as a lower reservoir. Moreover, this system is combined with a wind energy generation facility and the efficiency of the hybrid system is evaluated. With an investment cost of EUR 193 M, a 40 MW UPHES joined to a 60 MW wind farm would generate benefits of about EUR 54 M in 40 years. The reduction in CO2 emissions (29,000 equivalent tons per year) and the social benefits in a traditional mining area are other intangible advantages of this system.