Browsing by Author "Rodríguez Martín, José Antonio"
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- Determinants of tourism destination competitiveness in the countries most visited by international tourists: Proposal of a synthetic indexPublication . Salinas Fernández, José Antonio; Azevedo, Paula Serdeira; Martín Martín, José María; Rodríguez Martín, José AntonioTourism destination competitiveness is a multidimensional concept that is widely studied in the academic literature, but multiple factors make its measurement a difficult task. In this article, we design a synthetic index to rank the 80 countries that attract the majority of international tourists by level of tourism competitiveness. In order to do this, we use all of the simple variables included in the 2017 Travel & Tourism Competitiveness Index, proposing a new methodology for the construction of this synthetic index, which it solves the problems of aggregation of variables expressed in different measures, arbitrary weighting and duplicity of information; issues that remain unresolved by the TTCI. Likewise, we analyse the most influential dimensions in tourism competitiveness. Air transport infrastructures, cultural resources and ICT readiness are the key dimensions that explain the main disparities.
- Entomopathogenic nematode food webs in an ancient, mining pollution gradient in SpainPublication . Campos-Herrera, Raquel; Rodríguez Martín, José Antonio; Escuer, Miguel; García-González, María Teresa; Duncan, Larry W.; Gutíerrez, CarmenMining activities pollute the environment with by-products that cause unpredictable impacts in surrounding areas. Cartagena-La Union mine (Southeastern-Spain) was active for >2500 years. Despite its closure in 1991, high concentrations of metals and waste residues remain in this area. A previous study using nematodes suggested that high lead content diminished soil biodiversity. However, the effects of mine pollution on specific ecosystem services remain unknown. Entomopathogenic nematodes (EPN) play a major role in the biocontrol of insect pests. Because EPNs are widespread throughout the world, we speculated that EPNs would be present in the mined areas, but at increased incidence with distance from the pollution focus. We predicted that the natural enemies of nematodes would follow a similar spatial pattern. We used qPCR techniques to measure abundance of five EPN species, five nematophagous fungi species, two bacterial ectoparasites of EPNs and one group of free-living nematodes that compete for the insect-cadaver. The study comprised 193 soil samples taken from mining sites, natural areas and agricultural fields. The highest concentrations of iron and zinc were detected in the mined area as was previously described for lead, cadmium and nickel. Molecular tools detected very low numbers of EPNs in samples found to be negative by insect-baiting, demonstrating the importance of the approach. EPNs were detected at low numbers in 13% of the localities, without relationship to heavy-metal concentrations. Only Acrobeloides-group nematodes were inversely related to the pollution gradient. Factors associated with agricultural areas explained 98.35% of the biotic variability, including EPN association with agricultural areas. Our study suggests that EPNs have adapted to polluted habitats that might support arthropod hosts. By contrast, the relationship between abundance of Acrobeloides-group and heavy-metal levels, revealed these taxa as especially well suited bio-indicators of soil mining pollution. (C) 2016 Elsevier B.V. All rights reserved.
- Vegetation drives assemblages of entomopathogenic nematodes and other soil organisms: evidence from the Algarve, PortugalPublication . Campos-Herrera, Raquel; Blanco-Pérez, Rubén; Bueno-Pallero, Francisco Ángel; Duarte, Amílcar; Nolasco, Gustavo; Sommer, Ralf J.; Rodríguez Martín, José AntonioEntomopathogenic nematodes (EPNs) are widely distributed in soils throughout the world. Their activity as biological control agents is modulated by abiotic and biotic factors (e.g. soil type, climatic fluctuation and natural enemies). We sought to identify soil properties in a Mediterranean region, which might be managed to enhance biological control agents’ services provided by EPNs. We hypothesized that responses of EPN soil food web assemblages to abiotic factors in such a Mediterranean region would be consistent with previous observations in other biomes in subtropical and temperate regions, in which pH and variables related to water content were main drivers of such association. We also expected that EPN abundance and species composition would differ between stable botanical habitats (citrus groves, palmetto areas, oaks and pines), with EPNs and associated organisms favoured in cultivated sites (citrus). In spring 2016, 50 georeferenced localities, representing four botanical habitats and two soil-ecoregions (calcareous versus non-calcareous), were surveyed. Using published and de novo real time qPCR tools, we evaluated the frequency and abundance of 10 EPN species and 13 organisms associated with EPNs: 6 nematophagous fungi (NF), 5 free-living nematodes (FLN), and 2 ectoparasitic bacteria. EPN activity was also assessed by traditional insect-baiting, allowing the evaluation of FLN-EPN mixed progeny. EPNs were detected by qPCR in 50% of localities, and strongly correlated with EPN activity. Steinernema feltiae was the dominant EPN species measured by both techniques (qPCR and insect-bait), being widespread in all Algarve, while Heterorhabditis bacteriophora was detected mainly in citrus groves. The species S. arenarium and H. indica were detected by qPCR for the fi rst time in continental Portugal. The molecular analysis of insect cadaver progeny revealed novel FLN-EPN associations with Pristionchus maupasi and P. pacificus. EPN, FLN and NF abundance differed among botanical groups, with citrus groves supporting high numbers of all trophic guilds. Oaks also favoured EPNs. Similarly, calcareous soil-ecoregion supported higher NF, FLN and EPN abundance. Two abiotic variables (pH, and clay content) explained the community variation in multivariate analysis, consistent with key abiotic variables described for other subtropical and temperate regions. The results supported the hypothesis that cultivated perennial habitats favour EPNs and soil organisms that can limit EPN activity as biological control agents.