46 results on '"Alcaraz-Hernández, Juan Diego"'
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2. Response of a pan-European fish index (EFI+) to multiple pressures in rivers across Spain
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Alcaraz-Hernández, Juan Diego, Radinger, Johannes, Luque, Yaiza, and García-Berthou, Emili
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- 2024
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3. Seasonal effects on health status and parasitological traits of an invasive minnow in Iberian waters
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Almeida, David, Alcaraz-Hernández, Juan Diego, Cruz, Alejandra, Lantero, Esther, Fletcher, David H., García-Berthou, Emili, Almeida, David, Alcaraz-Hernández, Juan Diego, Cruz, Alejandra, Lantero, Esther, Fletcher, David H., and García-Berthou, Emili
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Biological invasions are of special conservation concern in the Iberian Peninsula and other regions with high levels of endemism. Environmental variability, such as the seasonal fluctuations of Mediterranean streams, is a key factor that affects the spread of aquatic species in novel habitats. Fish parasites have a great potential to reflect such changes in the habitat features of freshwater ecosystems. The aim of this study consisted of seasonally analysing the health status and parasitological traits of non-native fish in Iberian waters. In particular, a strongly invasive population of Languedoc minnow Phoxinus septimaniae (leuciscid species native to south-east France) was assessed in Tordera Stream (north-eastern Iberian Peninsula, Mediterranean conditions). Fish were sampled in April, July, and October 2023 by electrofishing. Health status (external/internal organs) was significantly better in autumn (HAI = 28.8) than spring (HAI = 35.6). Life-cycle complexity was higher in spring (LCI = 1.98), whereas parasite abundance and Shannon diversity were significantly lower in autumn (TA = 19.6 and H’ = 2.15, respectively). In October (more ‘benign’ environmental conditions in Iberian streams), minnows could display elevated foraging activity, with fish increasing their health condition and level of parasite resistance/tolerance. Overall results showed a particular seasonal profile of health and parasite infra-communities that allow this minnow species to thrive under highly fluctuating habitat conditions. This information could help environmental managers to control non-native fish in Mediterranean streams.
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- 2024
4. Environmental filtering governs the spatial distribution of alien fishes in a large, human-impacted Mediterranean river
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Radinger, Johannes, Alcaraz-Hernández, Juan Diego, and García-Berthou, Emili
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- 2019
5. Drivers of Macroinvertebrate Communities in Mediterranean Rivers: A Mesohabitat Approach.
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Alcaraz-Hernández, Juan Diego, Sánchez-Hernández, Javier, Muñoz-Mas, Rafael, and Martínez-Capel, Francisco
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We investigated the relationship between benthic macroinvertebrate community attributes (richness, abundance, biodiversity, and climate-specific and resistance forms) and the physical characteristics of distinct mesohabitats (hydromorphological unit types) discretized into fast (e.g., riffles or rapids) and slow (e.g., pools or glides) flow types in four Mediterranean rivers of Spain. Key attributes of hydromorphological units, including length, width, depth, shade, substrate composition, embeddedness, abundance of aquatic vegetation, and density of woody debris, were considered. Through a comprehensive suite of multivariate analyses, we unraveled taxonomic and habitat distinctions among rivers and hydromorphological unit types, with a notable influence of spatial proximity (greater similarity within the same river basin). In slow hydromorphological units, aquatic vegetation, depth, and abundance of coarse substrate emerged as pivotal factors shaping macroinvertebrate assemblages, whereas in fast-flowing units, vegetation, substrate embeddedness, and density of woody debris were the most important. Contrary to the remaining community attributes, the studied resistance forms (absent, eggs, cocoons, and cells against desiccation and diapause) exhibited uniformity across rivers despite observed variations in macroinvertebrate communities, underscoring regional functional analogies in biological and ecological mechanisms within the investigated Mediterranean river basins. This study contributes valuable insights for anticipating the repercussions of ongoing climate change, particularly in regions where fast-flowing hydromorphological units are more susceptible to depletion during drought periods. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Habitat suitability modelling to assess the introductions of Aedes albopictus (Diptera: Culicidae) in the Netherlands
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Ibáñez-Justicia, Adolfo, Alcaraz-Hernández, Juan Diego, van Lammeren, Ron, Koenraadt, Constantianus J. M., Bergsma, Aldo, Delucchi, Luca, Rizzoli, Annapaola, and Takken, Willem
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- 2020
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7. Hydrological classification of non‐perennial Mediterranean rivers and streams: A new insight for their management within the water framework directive
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Alcaraz‐Hernández, Juan Diego, primary, Soler, Joaquín, additional, Mezger, Gabriel, additional, Corrochano Codorníu, Alfredo, additional, Calleja Arriero, Belén, additional, and Magdaleno, Fernando, additional
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- 2022
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8. Hydrological classification of non‐perennial Mediterranean rivers and streams: A new insight for their management within the water framework directive.
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Alcaraz‐Hernández, Juan Diego, Soler, Joaquín, Mezger, Gabriel, Corrochano Codorníu, Alfredo, Calleja Arriero, Belén, and Magdaleno, Fernando
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WATER management ,ECOLOGICAL assessment ,SELF-organizing maps ,PRINCIPAL components analysis ,CLASSIFICATION ,EPHEMERAL streams - Abstract
Classification of natural flow regimes of non‐perennial rivers and streams (NPRS) is an incipient field of research. NPRS represent approximately 70% of the total Mediterranean rivers and are expected to increase in the next decades as a result of climate change. Due to the ecological importance of NPRS and the need to improve national ecological assessment methods within the scope of the Water Framework Directive (WFD), this paper aims to classify the hydrological regime of 69 non‐regulated streams, testing several hydrological indices related to the magnitude, frequency, duration, timing, and rate of change in periods of flow cessation. Using daily flow records, a total of 315 indices were calculated and their relationships were examined with Principal Component Analysis (PCA) for different thresholds used to define zero‐flow condition (0, 1, 2, and 5 L/s). Redundancy analysis identified five indices that better describe the patterns of hydrological variability in Mediterranean NPRS: number of days per year without flow, annual percentage of months without flow, mean daily annual flow, coefficient of variation of Julian date of the annual start of zero‐flow and annual rise rate. Using these indices, a self‐organizing map (SOM) was trained in order to categorize the NPRS into three groups with similar hydrological features. The results of this study provide a statistically‐based hydrological classification of NPRS in Mediterranean environments. We expect that this classification will provide useful insights to water authorities to improve the assessments of the ecological status in this type of water bodies. [ABSTRACT FROM AUTHOR]
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- 2023
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9. Hydrological classification of non-perennial Mediterranean rivers and streams: a new insight for their management within the WFD
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Alcaraz-Hernández, Juan Diego, primary, Soler, Joaquín, additional, Mezger, Gabriel, additional, Codorníu, Alfredo Corrochano, additional, Arriero, Belén Calleja, additional, and Magdaleno, Fernando, additional
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- 2022
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10. Fúndulo - Fundulus heteroclitus (Linnaeus, 1766)
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Alcaraz-Hernández, Juan Diego, Fernández-Delgado, Carlos, and Sociedad de Amigos del Museo Nacional de Ciencias Naturales (España)
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Peces - Orden Cyprinodontiformes - Familia Fundulidae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/, A comprehensive review of the natural history of the Mummichog Fundulus heteroclitus in Spain.
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- 2020
11. Additional file 1 of Habitat suitability modelling to assess the introductions of Aedes albopictus (Diptera: Culicidae) in the Netherlands
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Ibáñez-Justicia, Adolfo, Alcaraz-Hernández, Juan Diego, Lammeren, Ron Van, Constantianus J. M. Koenraadt, Bergsma, Aldo, Delucchi, Luca, Annapaola Rizzoli, and Takken, Willem
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Additional file 1: Figure S1. Presence records and species distribution map obtained with Aedes albopictus Maxent model. Figure S2. Relationship between nineteen European bioclimatic variables (http://www.worldclim.com) for occurrence records buffers of 200 km of radius with histogram and Kernel density (diagonal), Pearson’s correlation coefficient (r) and its significance (above the diagonal) and scatterplot and linear regression (below the diagonal). *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001. Figure S3. Cluster with nineteen European bioclimatic variables (http://www.worldclim.com) for occurrence records buffers of 200 km of radius. Figure S4. Map with eleven presence records of Aedes albopictus in the Netherlands. The sites are Almere, Assen, Emmeloord, Etten-Leur, Hardenberg, Lelystad, Moerdijk, Montfoort, Oosterhout, Oss, Weert. Map by authors. Figure S5. Maps showing maximum, median, minimum and standard deviation of habitat suitability obtained with Aedes albopictus Maxent model. Figure S6. The relative contribution of five environment variables (BIO11, BIO8, BIO7, BIO2, BIO12) to the model according to the regularized training gain of jackknife test in the Aedes albopictus Maxent model. Blue bars show the influence of each variable alone and green bars show the performance of the model when the variable is removed from the model. Figure S7. Response curves showing the relationships between the probability of presence of Aedes albopictus and five environment variables (BIO11, BIO8, BIO7, BIO2, BIO12). Figure S8. A scatter plot and the corresponding regression line and regression equation for the relationship between the dependent variable air temperature TG (°C × 0.1) and the independent variable LST (°C × 0.01). Abbreviations: r, Pearson’s correlation coefficient; R-square linear, coefficient of determination; P, P-value.
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- 2020
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12. Fúndulo - Fundulus heteroclitus (Linnaeus, 1766)
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Sociedad de Amigos del Museo Nacional de Ciencias Naturales (España), Alcaraz-Hernández, Juan Diego, Fernández-Delgado, Carlos, Sociedad de Amigos del Museo Nacional de Ciencias Naturales (España), Alcaraz-Hernández, Juan Diego, and Fernández-Delgado, Carlos
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A comprehensive review of the natural history of the Mummichog Fundulus heteroclitus in Spain.
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- 2020
13. Habitat suitability modelling to assess the introductions of Aedes albopictus (Diptera, Culicidae) in the Netherlands
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Ibañez-Justicia, Adolfo, primary, Alcaraz-Hernández, Juan Diego, additional, Lammeren, Ron van, additional, Koenraadt, Constantianus J.M., additional, Bergsma, Aldo, additional, Delucchi, Luca, additional, Rizzoli, Annapaola, additional, and Takken, Willem, additional
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- 2020
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14. Study on Invasive Alien Species – Development of risk assessments: Fundulus heteroclitus (Linnaeus, 1766)
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Alcaraz Hernández, Juan Diego and García-Berthou, Emili
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Introduced organisms -- European Union ,Espècies introduïdes -- Unió Europea ,Animals invasors-- Unió Europea - Abstract
This is a risk assessment template developed under the "Study on Invasive Alien Species – Development of risk assessments to tackle priority species and enhance prevention" Contract No 07.0202/2017/763379/ETU/ENV.D.2. It is part of the report to the Scientific Forum on Invasive Alien Species (IAS) of the European Union EU Contract No 07.0202/2017/763379/ETU/ENV.D.2
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- 2019
15. Risk assessment of Fundulus heteroclitus
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Alcaraz-Hernández, Juan Diego and García-Berthou, Emili
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- 2019
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16. Effective monitoring of freshwater fish
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Radinger, Johannes, primary, Britton, J. Robert, additional, Carlson, Stephanie M., additional, Magurran, Anne E., additional, Alcaraz‐Hernández, Juan Diego, additional, Almodóvar, Ana, additional, Benejam, Lluís, additional, Fernández‐Delgado, Carlos, additional, Nicola, Graciela G., additional, Oliva‐Paterna, Francisco J., additional, Torralva, Mar, additional, and García‐Berthou, Emili, additional
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- 2019
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17. On species distribution modelling, spatial scales and environmental flow assessment with Multi Layer Perceptron Ensembles: A case study on the redfin barbel (Barbus haasi
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Muñoz Mas, Rafael, Martinez-Capel, Francisco|||0000-0003-4991-0251, Alcaraz-Hernández, Juan Diego, and Mouton, Ans
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Artificial neural network ,Genetic algorithm ,Micro scale ,Mediterranean river ,Meso scale ,TECNOLOGIA DEL MEDIO AMBIENTE ,Iberian Peninsula - Abstract
Inconsistent performance of Species Distribution Models (SDMs), which may depend on several factors such as the initial conditions or the applied modelling technique, is one of the greatest challenges in ecological modelling. To overcome this problem, ensemble modelling combines the forecasts of several individual models. A commonly applied ensemble modelling technique is the Multi Layer Perceptron (MLP) Ensemble, which was envisaged in the 1990s. However, despite its potential for ecological modelling, it has received little attention in the development of SDMs for freshwater fish. Although this approach originally included all the developed MLPs, Genetic Algorithms (GA) now allow selection of the optimal subset of MLPs and thus substantial improvement of model performance. In this study, MLP Ensembles were used to develop SDMs for the redfin barbel (Barbus haasi; Mertens, 1925) at two different spatial scales: the micro scale and the meso scale. Finally, the potential of the MLP Ensembles for environmental flow (e flow) assessment was tested by linking model results to hydraulic simulation. MLP Ensembles with a candidate selection based on GA outperformed the optimal single MLP or the ensemble of the whole set of MLPs. The micro scale model complemented previous studies, showing high suitability of relatively deep areas with coarse substrate and corroborating the need for cover and the rheophilic nature of the redfin barbel. The meso scale model highlighted the advantages of using cross scale variables, since elevation (a macro scale variable) was selected in the optimal model. Although the meso scale model also demonstrated that redfin barbel selects deep areas, it partially contradicted the micro scale model because velocity had a clearer positive effect on habitat suitability and redfin barbel showed a preference for fine substrate in the meso scale model. Although the meso scale model suggested an overall higher habitat suitability of the test site, this did not result in a notable higher minimum environmental flow. Our results demonstrate that MLP Ensembles are a promising tool in the development of SDMs for freshwater fish species and proficient in e flow assessment. This study was funded by the Spanish Ministry of Economy and Competitiveness with the projects SCARCE (Consolider-Ingenio 2010 CSD2009-00065). We thank to Confederacion Hidrografica del Jucar (Spanish Ministry of Agriculture, Food and Environment), especially to the Office for Water Planning and Teodoro Estrela for the data provided to develop the SDMs. Finally we would like to thank TECNOMA S.A. for the development of the hydraulic model in the Mijares River and all the people who participated in the field data collection.
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- 2017
18. Microhabitat competition between Iberian fish species and the endangered Júcar nase (Parachondrostoma arrigonis
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Muñoz Mas, Rafael, Soares Costa, Rui Manuel, Alcaraz-Hernández, Juan Diego, and Martinez-Capel, Francisco|||0000-0003-4991-0251
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Invasive species ,Habitat duration curve ,Generalized Additive Mixed Model ,Mediterranean river ,TECNOLOGIA DEL MEDIO AMBIENTE ,Physical habitat simulation - Abstract
[EN] Competition with invasive species is recognized as having a major impact on biodiversity conservation. The upper part of the Cabriel River (Eastern Iberian Peninsula) harbours the most important population of the Júcar nase (Parachondrostoma arrigonis; Steindachner, 1866), a fish species in imminent danger of extinction. Currently, this species cohabits with several non-native species, such as the Iberian nase (Pseudochondrostoma polylepis; Steindachner, 1864) and the bermejuela (Achondrostoma arcasii; Steindachner, 1866). The potential habitat competition with these species was studied by analysing the spatial and temporal overlapping of suitable microhabitats. Generalized Additive Mixed Models (GAMMs) were developed to model microhabitat selection and these GAMMs were used to assess the habitat suitability (i.e. probability of presence) under several flows simulated with River2D. The Júcar nase will compete, spatially and temporally, for the few suitable microhabitats with bermejuela and, to a lesser extent, with small Iberian nase; conversely, large Iberian nase was of minor concern, due to increased differences in habitat preferences. This study represents an important assessment of potential competition and, therefore, these results might assist to better define future management practices in the upper part of the Cabriel River. This study was funded by the Spanish Ministry of Economy and Competitiveness through the SCARCE project (Consolider Ingenio 2010 CSD2009 00065); the Universitat Politècnica de València, through the project UPPTE/2012/294 [PAID 06 12]; it was also partially funded by the IMPADAPT project (CGL2013-48424-C2-1-R) with Spanish MINECO (Ministerio de Economía y Competitividad) and FEDER funds. The authors would like to thank the help of the Conselleria de Territori i Vivenda (Generalitat Valenciana) and the Confederación Hidrográfica del Júcar (Spanish government), which provided environmental data to Alfredo Ollero, and the two anonymous reviewers who first suggested the submission of the paper to a regular journal. Finally, we would like to thank TECNOMA S.A. for the development of the hydraulic model.
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- 2017
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19. Environmental and spatial correlates of hydrologic alteration in a large Mediterranean river catchment
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Radinger, Johannes, primary, Alcaraz-Hernández, Juan Diego, additional, and García-Berthou, Emili, additional
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- 2018
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20. Relationship of fish indices with sampling effort and land use change in a large Mediterranean river
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Almeida, David, primary, Alcaraz-Hernández, Juan Diego, additional, Merciai, Roberto, additional, Benejam, Lluís, additional, and García-Berthou, Emili, additional
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- 2017
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21. Microhabitat competition between Iberian fish species and the endangered Júcar nase (Parachondrostoma arrigonis; Steindachner, 1866)
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Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, European Regional Development Fund, Universitat Politècnica de València, Ministerio de Economía y Competitividad, Muñoz Mas, Rafael, Soares Costa, Rui Manuel, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, European Regional Development Fund, Universitat Politècnica de València, Ministerio de Economía y Competitividad, Muñoz Mas, Rafael, Soares Costa, Rui Manuel, Alcaraz-Hernández, Juan Diego, and Martinez-Capel, Francisco
- Abstract
"This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Ecohydraulics on 24-01-2017, available online: https://www.tandfonline.com/doi/full/10.1080/24705357.2016.1276417", [EN] Competition with invasive species is recognized as having a major impact on biodiversity conservation. The upper part of the Cabriel River (Eastern Iberian Peninsula) harbours the most important population of the Júcar nase (Parachondrostoma arrigonis; Steindachner, 1866), a fish species in imminent danger of extinction. Currently, this species cohabits with several non-native species, such as the Iberian nase (Pseudochondrostoma polylepis; Steindachner, 1864) and the bermejuela (Achondrostoma arcasii; Steindachner, 1866). The potential habitat competition with these species was studied by analysing the spatial and temporal overlapping of suitable microhabitats. Generalized Additive Mixed Models (GAMMs) were developed to model microhabitat selection and these GAMMs were used to assess the habitat suitability (i.e. probability of presence) under several flows simulated with River2D. The Júcar nase will compete, spatially and temporally, for the few suitable microhabitats with bermejuela and, to a lesser extent, with small Iberian nase; conversely, large Iberian nase was of minor concern, due to increased differences in habitat preferences. This study represents an important assessment of potential competition and, therefore, these results might assist to better define future management practices in the upper part of the Cabriel River.
- Published
- 2017
22. On species distribution modelling, spatial scales and environmental flow assessment with Multi Layer Perceptron Ensembles: A case study on the redfin barbel (Barbus haasi; Mertens, 1925)
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Escuela Politécnica Superior de Gandia - Escola Politècnica Superior de Gandia, Ministerio de Ciencia e Innovación, Muñoz Mas, Rafael, Martinez-Capel, Francisco, Alcaraz-Hernández, Juan Diego, Mouton, Ans, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Escuela Politécnica Superior de Gandia - Escola Politècnica Superior de Gandia, Ministerio de Ciencia e Innovación, Muñoz Mas, Rafael, Martinez-Capel, Francisco, Alcaraz-Hernández, Juan Diego, and Mouton, Ans
- Abstract
Inconsistent performance of Species Distribution Models (SDMs), which may depend on several factors such as the initial conditions or the applied modelling technique, is one of the greatest challenges in ecological modelling. To overcome this problem, ensemble modelling combines the forecasts of several individual models. A commonly applied ensemble modelling technique is the Multi Layer Perceptron (MLP) Ensemble, which was envisaged in the 1990s. However, despite its potential for ecological modelling, it has received little attention in the development of SDMs for freshwater fish. Although this approach originally included all the developed MLPs, Genetic Algorithms (GA) now allow selection of the optimal subset of MLPs and thus substantial improvement of model performance. In this study, MLP Ensembles were used to develop SDMs for the redfin barbel (Barbus haasi; Mertens, 1925) at two different spatial scales: the micro scale and the meso scale. Finally, the potential of the MLP Ensembles for environmental flow (e flow) assessment was tested by linking model results to hydraulic simulation. MLP Ensembles with a candidate selection based on GA outperformed the optimal single MLP or the ensemble of the whole set of MLPs. The micro scale model complemented previous studies, showing high suitability of relatively deep areas with coarse substrate and corroborating the need for cover and the rheophilic nature of the redfin barbel. The meso scale model highlighted the advantages of using cross scale variables, since elevation (a macro scale variable) was selected in the optimal model. Although the meso scale model also demonstrated that redfin barbel selects deep areas, it partially contradicted the micro scale model because velocity had a clearer positive effect on habitat suitability and redfin barbel showed a preference for fine substrate in the meso scale model. Although the meso scale model suggested an overall higher habitat suitability of the test site, this did n
- Published
- 2017
23. Heterogeneidad del mesohabitat en cuatro ríos mediterráneos de la cuenca del río Jucar (Este de España)
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Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Peredo Parada, Matías Manuel, and Hernández Mascarell, Aina Berta
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Mesohábitat ,Ríos mediterráneos ,Jucar Basin ,Mediterranean environment ,Velocity ,Unitats hidromorfològiques ,Unidades hidromorfológicas ,Península Ibérica ,Aquatic Science ,Similarity ,Mediterranean streams ,Mesohabitat ,Fluvial geomorphology ,Similaritat ,Hydromorphological units ,TECNOLOGIA DEL MEDIO AMBIENTE ,Water Science and Technology ,Habitat conservation ,Ecology ,Habitat type ,Habitat classification ,Península Ibèrica ,Spatiotemporal analysis ,Spain ,Clasificación de hábitats ,Rius mediterranis ,Stream ,Classificació d'hàbitats ,Similaridad ,Heterogeneity ,Mesohàbitat ,Iberian Peninsula - Abstract
[EN] The hydromorphological units or mesohabitats of the headwaters of four Mediterranean streams were studied by classifying them according to their length, width, average and maximum depth, percentage of substrate and water volume. These characteristics of the streams were assessed over four consecutive years (2003-2006). The main objective of the study was to analyse the spatial and temporal pattern of the physical attributes of the mesohabitats. Classification strength and dendrograms were examined for each stream, mesohabitat type, and combination of stream and mesohabitat type and for stream mesohabitat type and year, whereas Nonmetric Multidimensional Scaling ordination (NMDS) was used to analyse classification patterns. The Villahermosa and Ebr ón streams were more homogeneous than the Palancia and Vallanca streams, whereas riffles and glides were more homogeneous than pools and rapids. The NMDS indicated that the slow water-velocity (pools, glides) and fast (riffles, rapids) mesohabitats tended to group together. Temporally, the Ebr ón stream pools were homogeneous and very stable over the four years, whereas the Vallanca and Villahermosa pools showed a certain degree of variability. The Palancia pools were the most variable and heterogeneous during the study period. These results underscored the importance of separating different types of deep, slow-velocity habitats in mesohabitat inventories and the importance of evaluating habitat classifications in eco-hydromorphological and hydrobiological studies, especially in Mediterranean streams and rivers., [ES] Las unidades hidromorfologicas o mesoh ´ abitats de cuatro r ´ ´ıos mediterraneos de cabecera fueron estudiadas en funci ´ on de su ´ longitud, anchura, profundidad media y maxima, porcentaje de sustrato y volumen de cada mesoh ´ abitat durante cuatro a ´ nos ˜ consecutivos (2003-2006). El objetivo principal fue analizar la variacion espacio-temporal de los diferentes mesoh ´ abitat ´ segun sus atributos f ´ ´ısicos. La fortaleza de la clasificacion y su dendrograma se examin ´ o seg ´ un cada r ´ ´ıo, cada tipo de mesohabitat, una combinaci ´ on de cada r ´ ´ıo y tipos de mesohabitats y seg ´ un cada r ´ ´ıo y tipos de mesohabitats de los cuatro a ´ nos ˜ de muestreo. El Escalado Multidimensional No Metrico (NMDS) se us ´ o para analizar los patrones de las clasificaciones. El ´ NMDS indico que tanto los mesoh ´ abitats lentos (pozas y tablas) como los mesoh ´ abitats r ´ apidos (corrientes y r ´ apidos) tienden ´ a agruparse juntos. Desde la una perspectiva temporal, las pozas del r´ıo Ebron fueron homog ´ eneas y muy estables durante ´ los cuatro anos de muestreo, mientras que las pozas de los r ˜ ´ıos Vallanca y Villahermosa mostraron un cierto grado de variabilidad y las del r´ıo Palancia fueron las mas variables y heterog ´ eneas durante el periodo de estudio. Los resultados ´ destacan la importancia de diferenciar distintos tipos de habitats lentos en los inventarios de mesoh ´ abitat, y la importancia ´ de evaluar las clasificaciones de los mesohabitats en estudios de eco-hidromorfolog ´ ´ıa e hidrobiolog´ıa, especialmente los desarrollados en r´ıos mediterraneos., The collection of the data for this study was partially funded by the Conselleria de Medio Ambiente, Agua, Urbanismo y Vivienda, of the Generalitat Valenciana, Spain. Partial funding was furnished by the Institut d’Investigacio per a la Gestio Integrada de Zones Costaneres of the Universitat Politecnica de València. We thank Pau Lucio, Rafael Casas, Pascual Puerto, Javier Izquierdo, Consuelo Perez and Rosa de la Salud for their participation in the field work. We also thank Juan Theureau and Francisco J. Martínez García (Generalitat Valenciana), and Roberto Coll for their help during the development of the study.
- Published
- 2011
24. Microhabitat competition between Iberian fish species and the endangered Júcar nase (Parachondrostoma arrigonis; Steindachner, 1866)
- Author
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Muñoz-Mas, Rafael, primary, Costa, Rui Manuel Soares, additional, Alcaraz-Hernández, Juan Diego, additional, and Martínez-Capel, Francisco, additional
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- 2017
- Full Text
- View/download PDF
25. On species distribution modelling, spatial scales and environmental flow assessment with Multi–Layer Perceptron Ensembles: A case study on the redfin barbel (Barbus haasi; Mertens, 1925)
- Author
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Muñoz-Mas, Rafael, primary, Martínez-Capel, Francisco, additional, Alcaraz-Hernández, Juan Diego, additional, and Mouton, Ans M., additional
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- 2017
- Full Text
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26. Risk of invasion predicted with support vector machines: A case study on northern pike ( Esox Lucius , L.) and bleak ( Alburnus alburnus , L.)
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Muñoz-Mas, Rafael, primary, Vezza, Paolo, additional, Alcaraz-Hernández, Juan Diego, additional, and Martínez-Capel, Francisco, additional
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- 2016
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27. Risk of invasion predicted with support vector machines: A case study on northern pike (Esox Lucius, L.) and bleak (Alburnus alburnus, L.)
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València. Escuela Politécnica Superior de Gandia - Escola Politècnica Superior de Gandia, Ministerio de Economía y Competitividad, Confederación Hidrográfica del Júcar, Muñoz Mas, Rafael, Vezza, Paolo, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València. Escuela Politécnica Superior de Gandia - Escola Politècnica Superior de Gandia, Ministerio de Economía y Competitividad, Confederación Hidrográfica del Júcar, Muñoz Mas, Rafael, Vezza, Paolo, Alcaraz-Hernández, Juan Diego, and Martinez-Capel, Francisco
- Abstract
The impacts of invasive species are recognised as a major threat to global freshwater biodiversity. The risk of invasion (probability of presence) of two avowed invasive species, the northern pike (Esox Lucius, L.) and bleak (Alburnus alburnus, L.), was evaluated in the upper part of the Cabriel River (eastern Iberian Peninsula). Habitat suitability models for these invasive species were developed with Support Vector Machines (SVMs), which were trained with data collected downstream the Contreras dam (the last barrier impeding the invasion of the upper river segment). Although SVMs gained visibility in habitat suitability modelling, they cannot be considered widespread in ecology. Thus, with this technique, there is certain controversy about the necessity of performing variable selection procedures. In this study, the parameters tuning and the variable selection for the SVMs was simultaneously performed with a genetic algorithm and, contradicting previous studies in freshwater ecology, the variable selection proved necessary to achieve almost perfect accuracy. Further, the development of partial dependence plots allowed unveiling the relationship between the selected input variables and the probability of presence. Results revealed the preference of northern pike for large and wide mesohabitats with vegetated shores and abundant prey whereas bleak preferred deep and slightly fast flow mesohabitats with fine substrate. Both species proved able to colonize the upper part of the Cabriel River but the habitat suitability for bleak indicated a slightly higher risk of invasion. Altogether may threaten the endemic species that actually inhabit that stretch, especially the Jucar nase (Parachondrostoma arrigonis; Steindachner), which is one of the most critically endangered Iberian freshwater fish species. (C) 2016 Elsevier B.V. All rights reserved.
- Published
- 2016
28. Generalized additive models to predict adult and young brown trout (Salmo trutta Linnaeus, 1758) densities in Mediterranean rivers
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Ciencia e Innovación, Universitat Politècnica de València, Confederación Hidrográfica del Júcar, Generalitat Valenciana, Alcaraz-Hernández, Juan Diego, Muñoz Mas, Rafael, Martinez-Capel, Francisco, Garófano-Gómez, Virginia, Vezza, Paolo, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Ciencia e Innovación, Universitat Politècnica de València, Confederación Hidrográfica del Júcar, Generalitat Valenciana, Alcaraz-Hernández, Juan Diego, Muñoz Mas, Rafael, Martinez-Capel, Francisco, Garófano-Gómez, Virginia, and Vezza, Paolo
- Abstract
Habitat suitability models (HSM) are concerned with the abundance or distribution of species as a consequence of interactions with the physical environment. Generalized Additive Models (GAMs) were used to model brown trout (Salmo trutta L.) density as a function of environmental variables at the scale of river reach and hydromorphological units (HMU) in the Jucar River Basin (Eastern Spain). After 4years of observations (2003-2006) the data representing trout density were split into two categories, young (<2years) and adult (2years), for modelling independently. The environmental descriptors at reach-scale described the geographical position, hydrological conditions, proportions and diversity of habitats. At the scale of HMUs (pool, glide, riffle or rapid), habitat descriptors representing dimensions, substrate, cover and velocity were used. The best and parsimonious GAM for each category was selected after a comprehensive trial of all possible combinations of input variables. The models explained 61% (adult) and 75% (young) of the variability of the data (R(2)adj). The results demonstrated the relevance of mean width, mean depth, cover index, mean velocity and slope for adult brown trout. Young trout densities were mainly related to maximum depths, cover index, mean velocity, elevation, average distance between rapids and number of slow water HMUs. This article shows the relevance of considering geographical and habitat-related requirements at different scales to describe the patterns of trout density. Furthermore, the importance of considering non-linear relationships with habitat variables was demonstrated. The results are useful for environmental managers to design effective and science-based restoration measures, and result in a more efficient management of brown trout populations.
- Published
- 2016
29. Can multilayer perceptron ensembles model the ecological niche of freshwater fish species?
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Ciencia e Innovación, Universitat Politècnica de València, Muñoz Mas, Rafael, Martinez-Capel, Francisco, Alcaraz-Hernández, Juan Diego, Mouton, A. M., Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Ciencia e Innovación, Universitat Politècnica de València, Muñoz Mas, Rafael, Martinez-Capel, Francisco, Alcaraz-Hernández, Juan Diego, and Mouton, A. M.
- Abstract
The potential of Multilayer Perceptron (MLP) Ensembles to explore the ecology of freshwater fish specieswas tested by applying the technique to redfin barbel (Barbus haasi Mertens, 1925), an endemic and mon-tane species that inhabits the North-East quadrant of the Iberian Peninsula. Two different MLP Ensembleswere developed. The physical habitat model considered only abiotic variables, whereas the biotic modelalso included the density of the accompanying fish species and several invertebrate predictors. The results showed that MLP Ensembles may outperform single MLPs. Moreover, active selection of MLP candidatesto create an optimal subset of MLPs can further improve model performance. The physical habitat modelconfirmed the redfin barbel preference for middle-to-upper river segments whereas the importance ofdepth confirms that redfin barbel prefers pool-type habitats. Although the biotic model showed higheruncertainty, it suggested that redfin barbel, European eel and the considered cyprinid species have similarhabitat requirements. Due to its high predictive performance and its ability to deal with model uncertainty, the MLP Ensemble is a promising tool for ecological modelling or habitat suitability prediction in environmental flow assessment.
- Published
- 2015
30. Estudio de las comunidades de los macroinvertebrados acuáticos de los ríos Ebrón y Vallanca (Valencia)
- Author
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Martínez Capel, Francisco, Alcaraz Hernández, Juan Diego, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integrada de Zonas Costeras - Institut d'Investigació per a la Gestió Integrada de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València. Escuela Politécnica Superior de Gandia - Escola Politècnica Superior de Gandia, Arenas Sáez, Mercedes, Martínez Capel, Francisco, Alcaraz Hernández, Juan Diego, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integrada de Zonas Costeras - Institut d'Investigació per a la Gestió Integrada de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València. Escuela Politécnica Superior de Gandia - Escola Politècnica Superior de Gandia, and Arenas Sáez, Mercedes
- Abstract
En el presente proyecto nos centraremos en calcular qué factores pueden afectar a la abundancia y diversidad de los macroinvertebrados. para ello se han analizado una serie de muestras recogidas en los años 2004 y 2005, siempre en el mes de agosto, y procurando obtener muestras en los mismos puntos en ambos años. La finalidad del análisis ha sido ver que familias habitan en los puntos de muestreo, qué cantidad de ejemplares hay de cada familia por superficie y cual es su biomasa. Una vez finalizado el análisis, se calculó el índice de calidad del agua según la diversidad de especies existente. Con los datos obtenidos, se estudió cómo varían estos valores frente a condiciones hidráulicas en los tramos de estudio. De esta forma se ha intentado ver la influencia de la velocidad de la corriente y la profundidad sobre la densidad y biomasa de macroinvertebados.
- Published
- 2015
31. Length weight relationships of two endemic fish species in the Júcar River Basin, Iberian Peninsula
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Ciencia e Innovación, Generalitat Valenciana, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Olaya Marín, Esther Julia, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Ciencia e Innovación, Generalitat Valenciana, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, and Olaya Marín, Esther Julia
- Abstract
This study provides length-weight relationship (LWRs) information for two fish species (family Cyprinidae) in two headwater streams of the Júcar River Basin (Eastern Iberian Peninsula). Both species are endemic to the Iberian Peninsula and have no previous LWR estimates.
- Published
- 2015
32. Can multilayer perceptron ensembles model the ecological niche of freshwater fish species?
- Author
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Muñoz-Mas, Rafael, Martínez Capel, Francisco, Alcaraz Hernández, Juan Diego, Mouton, A.M., Muñoz-Mas, Rafael, Martínez Capel, Francisco, Alcaraz Hernández, Juan Diego, and Mouton, A.M.
- Abstract
The potential of Multilayer Perceptron (MLP) Ensembles to explore the ecology of freshwater fish species was tested by applying the technique to redfin barbel (Barbus haasi Mertens, 1925), an endemic and montane species that inhabits the North-East quadrant of the Iberian Peninsula. Two different MLP Ensembles were developed. The physical habitat model considered only abiotic variables, whereas the biotic model also included the density of the accompanying fish species and several invertebrate predictors. The results showed that MLP Ensembles may outperform single MLPs. Moreover, active selection of MLP candidates to create an optimal subset of MLPs can further improve model performance. The physical habitat model confirmed the redfin barbel preference for middle-to-upper river segments whereas the importance of depth confirms that redfin barbel prefers pool-type habitats. Although the biotic model showed higher uncertainty, it suggested that redfin barbel, European eel and the considered cyprinid species have similar habitat requirements. Due to its high predictive performance and its ability to deal with model uncertainty, the MLP Ensemble is a promising tool for ecological modelling or habitat suitability prediction in environmental flow assessment.
- Published
- 2015
33. Habitat suitability modelling at mesohabitat scale and effects of dam operation on the endangered Júcar nase, Parachondrostoma arrigonis (River Cabriel, Spain)
- Author
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Soares Costa, Rui Manuel, Martinez-Capel, Francisco, Muñoz Mas, Rafael, Alcaraz-Hernández, Juan Diego, and Garófano-Gómez, Virginia
- Subjects
Habitat conservation ,River management ,Dam ,Mediterranean rivers ,Modeling ,Cyprinid ,Dam effects ,Ecological impact ,GAM ,Endangered species ,Jucar River ,Júcar nase ,Mesohabitat ,Spain ,Environmental flow regimen ,Hydromorphological units ,Habitat suitability model ,TECNOLOGIA DEL MEDIO AMBIENTE ,Habitat quality - Abstract
Habitat degradation has reduced the complexity of the Mediterranean streams in Spain and contributed to decreasing the historical range of the endangered Júcar nase, Parachondrostoma arrigonis. This species is endemic to the Júcar River Basin (Spain), and most of its populations live in the Cabriel River, which is divided into two segments by the large Contreras Dam. The main objective of this study was to develop a multivariate habitat suitability model (HSM) for this species that can be used to evaluate environmental flows and water management scenarios for the Cabriel River. We first assessed the fish densities (from 2006 to 2008) and compared the habitat characteristics and variability among eight study sites based on the physical characteristics of hydromorphological units (HMUs) or mesohabitats. The abundance of the Júcar nase then was related to the HMU type, and generalized additive models of fish abundance were developed for the sites for both small and large fish. Both models showed acceptable or good performance (adjusted R 2 of 69.4 for small fish and 72.4 for large fish), and fish abundance was used as an indicator of potential habitat quality ['potential nase habitat' (PNH)] for the Júcar nase. The final step was to apply the HSM to evaluate environmentally friendly flow regimens. Hydraulic simulations were used to estimate the PNH under two flow regimen scenarios and in the actual flow regimen for the regulated study site located below the large dam. This article supports the need for new management actions in the Cabriel River, such as implementation of an environmental flow regimen, and illustrates a procedure for the practical application of habitat selection models at the mesohabitat scale., This study was partially funded by the Spanish Government (Ministerio de Medio Ambiente y Rural y Marino, Confederacion Hidrografica del Jucar) and partly by the Spanish Ministry of Education and Science (POTECOL, CGL2007-66412). We especially thank Matias Peredo and Aina Hernandez for the co-operation in the field work and suggestions on data analysis; we also thank Rafa Casas, Marta Bargay, Pau Lucio, Merce Arenas and the students that cooperated in the field work. Thanks to Colin Custard for the academic review of English. We also acknowledge the comments and suggestions of the reviewers on this paper.
- Published
- 2012
34. Relaciones entre densidades y biomasas de Salmo trutta fario y mediciones del mesohábitat en tramos trucheros de la Comunidad Valenciana
- Author
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Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Peredo Parada, Matías Manuel, and Hernández Mascarell, Aina Berta
- Subjects
Mesohábitat ,Ecology ,Unitats hidromorfològiques ,Biomasa ,Unidades hidro-morfológicas ,Density ,Biomassa ,Aquatic Science ,Mesohabitat ,Salmo trutta ,Biomass ,Hydro-morphological units ,Densitat ,Densidad ,Mesohàbitat ,TECNOLOGIA DEL MEDIO AMBIENTE ,Water Science and Technology - Abstract
[EN] In the year 2003, populations of Salmo trutta fario were studied in the Valencian rivers. Habitat conditions were also studied along the successive hydro-morphological units in 300 m long reaches, along with geographic and water-quality variables. With the objective of relating density and biomass with the habitat, all the independent variables were used in a stepwise multiple regression analysis (for common trout density and relative biomass). Through a step-wise analysis, the most significant variables were chosen for each of the two multivariate models, showing all a low correlation coefficient, but with good significance (p < 0.10). The most relevant variables in both models were stream width (negative correlation) and percentage of cobbles (64-256 mm) in each mesohabitat. The water surface area, and mean and maximum depth did not appear in the final model, but their correlation with stream width was demonstrated. All these variables were included within the mesohabitat characteristics, having being discarded the rest that were not significant at the scale of the study., [ES] En el año 2003 se estudiaron las poblaciones autóctonas de Salmo trutta fario en los ríos valencianos. Por otro lado se midieron las condiciones del hábitat según las sucesivas unidades hidro-morfológicas en tramos de 300 m de longitud, junto con variables geográficas y de calidad del agua. Con el objeto de relacionar densidades y biomasas con el hábitat, todas las variables independientes fueron introducidas en modelos de regresión múltiple (para la densidad y la biomasa relativa de trucha común). Mediante análisis paso a paso eliminatorio quedaron seleccionadas las más significativas para cada uno de los dos modelos multivariantes, obteniéndose en todos un bajo coeficiente de correlación pero con una significación adecuada ( p < 0.10). Las variables establecidas en los dos modelos fueron la anchura del cauce (con signo negativo) y el porcentaje de cantos rodados (64-256 mm) en cada mesohábitat. La superficie, así como la profundidad media y máxima no aparecieron en el modelo final, pero se demostró su correlación con la anchura del cauce. Todas estas variables estaban englobadas dentro del grupo de características del mesohábitat, habiéndose descartado las demás que no fueron significativas a la escala del estudio.
- Published
- 2007
35. Modelling native fish richness to evaluate the effects of hydromorphological changes and river restoration (Júcar River Basin, Spain)
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Olaya Marín, Esther Julia, Martinez-Capel, Francisco, Soares Costa, Rui Manuel, Alcaraz-Hernández, Juan Diego, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Olaya Marín, Esther Julia, Martinez-Capel, Francisco, Soares Costa, Rui Manuel, and Alcaraz-Hernández, Juan Diego
- Abstract
The richness of native fish is considered to be an indicator of aquatic ecosystem health, and improving richness is a key goal in the management of river ecosystems. An artificial neural network (ANN) model based on field data from 90 sample sites distributed throughout the Júcar River Basin District was developed to predict the native fish species richness (NFSR). The Levenberg-Marquardt learning algorithm was used for model training. When constructing the model, we tried different numbers of neurons (hidden layers), compared different transfer functions, and tried different k values (from 3 to 10) in the k-fold cross-validation method. This process and the final selection of key variables with relevant ecological meaning support the reliability and robustness of the final ANN model. The partial derivatives method was applied to determine the relative importance of input environmental variables. The final ANN model combined variables describing riparian quality, water quality, and physical habitat and helped identify the primary drivers of the NFSR patterns in Mediterranean rivers. In the second part of the study, the model was used to evaluate the effectiveness of two restoration actions in the Júcar River: the removal of two abandoned weirs and the progressive increase in the proportion of riffles. The model indicated that the combination of these actions produced a rise in NFSR, which ultimately reached the maximum values observed in the reference site of that river ecotype (sensu the European Water Framework Directive). The results demonstrate the importance of longitudinal connectivity and riffle proportion for improving NFSR and the power of ANNs to help decisions in the management and ecological restoration of Mediterranean rivers. Furthermore, this model at the basin scale is the first step for further research on the effects of water scarcity and global change on Mediterranean fish communities.
- Published
- 2012
36. Habitat suitability modelling at mesohabitat scale and effects of dam operation on the endangered Júcar nase, Parachondrostoma arrigonis (River Cabriel, Spain)
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Educación y Ciencia, Confederación Hidrográfica del Júcar; Ministerio de Medio Ambiente y Medio Rural y Marino, Soares Costa, Rui Manuel, Martinez-Capel, Francisco, Muñoz Mas, Rafael, Alcaraz-Hernández, Juan Diego, Garófano-Gómez, Virginia, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ministerio de Educación y Ciencia, Confederación Hidrográfica del Júcar; Ministerio de Medio Ambiente y Medio Rural y Marino, Soares Costa, Rui Manuel, Martinez-Capel, Francisco, Muñoz Mas, Rafael, Alcaraz-Hernández, Juan Diego, and Garófano-Gómez, Virginia
- Abstract
Habitat degradation has reduced the complexity of the Mediterranean streams in Spain and contributed to decreasing the historical range of the endangered Júcar nase, Parachondrostoma arrigonis. This species is endemic to the Júcar River Basin (Spain), and most of its populations live in the Cabriel River, which is divided into two segments by the large Contreras Dam. The main objective of this study was to develop a multivariate habitat suitability model (HSM) for this species that can be used to evaluate environmental flows and water management scenarios for the Cabriel River. We first assessed the fish densities (from 2006 to 2008) and compared the habitat characteristics and variability among eight study sites based on the physical characteristics of hydromorphological units (HMUs) or mesohabitats. The abundance of the Júcar nase then was related to the HMU type, and generalized additive models of fish abundance were developed for the sites for both small and large fish. Both models showed acceptable or good performance (adjusted R 2 of 69.4 for small fish and 72.4 for large fish), and fish abundance was used as an indicator of potential habitat quality ['potential nase habitat' (PNH)] for the Júcar nase. The final step was to apply the HSM to evaluate environmentally friendly flow regimens. Hydraulic simulations were used to estimate the PNH under two flow regimen scenarios and in the actual flow regimen for the regulated study site located below the large dam. This article supports the need for new management actions in the Cabriel River, such as implementation of an environmental flow regimen, and illustrates a procedure for the practical application of habitat selection models at the mesohabitat scale.
- Published
- 2012
37. Estado de las poblaciones de trucha en los ríos de la Comunidad Valenciana y caracterización de sus hábitats
- Author
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Martínez Capel, Francisco, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Alcaraz Hernández, Juan Diego, Martínez Capel, Francisco, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, and Alcaraz Hernández, Juan Diego
- Abstract
Los estudios acerca de la ecología de los peces tienen como una de sus principales bases la evaluación de las poblaciones, encaminados a definir el conjunto de los individuos de una misma especie que vive en un espacio común. Por lo tanto, el análisis del hábitat es clave para la estructura de las poblaciones. Desde el punto de vista de la teoría jerárquica ecológica, los patrones biológicos que gobiernan a las poblaciones de peces de los ríos son controlados y ajustados por los patrones físicos del hábitat. Así pues, una descripción exacta de los ríos es un primer paso en la descripción de los requerimientos ecológicos de los organismos durante su vida así como en los procesos que influyen en su abundancia y distribución. En este sentido, esta tesis aporta un mayor conocimiento de las poblaciones de trucha común (Salmo trutta) y de sus hábitats en ríos mediterráneos. El estudio se llevó a cabo en cuatro ríos de la Comunidad Valenciana (España) donde hoy en día la especie habita de forma natural; Ebrón y Vallanca (en la provincia de Valencia), Villahermosa y Palancia (en la provincia de Castellón). Los muestreos se realizaron entre los meses de Junio y Agosto entre los años 2003 y 2006. El primer año se establecieron dos estaciones de muestreo en cada río. En los restantes años se amplió a cuatro estaciones de muestreo en cada río. Se destaca el hecho de que en los dos últimos años de estudio (2005 y 2006) hubo una fuerte sequía que hizo que los tramos más altos de los ríos Vallanca y Villahermosa se secaran, perdiéndose tres de las dieciséis estaciones establecidas. En total se muestrearon 50 tramos en los cuatro años de muestreo. Para la caracterización del hábitat se adaptó el protocolo de muestreo "Basinwide Visual Estimation Technique - BVET". Esta técnica consiste en estratificar visualmente el cauce según sus diferentes biotopos (unidades hidromorfológicas o mesohábitats), registrándose en ellos las distintas características hidromorfológicas.
- Published
- 2012
38. Mesohabitat heterogeneity in four mediterranean streams of the Jucar river basin (Eastern Spain)
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València, Generalitat Valenciana, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Peredo Parada, Matías Manuel, Hernández Mascarell, Aina Berta, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Universitat Politècnica de València, Generalitat Valenciana, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Peredo Parada, Matías Manuel, and Hernández Mascarell, Aina Berta
- Abstract
[EN] The hydromorphological units or mesohabitats of the headwaters of four Mediterranean streams were studied by classifying them according to their length, width, average and maximum depth, percentage of substrate and water volume. These characteristics of the streams were assessed over four consecutive years (2003-2006). The main objective of the study was to analyse the spatial and temporal pattern of the physical attributes of the mesohabitats. Classification strength and dendrograms were examined for each stream, mesohabitat type, and combination of stream and mesohabitat type and for stream mesohabitat type and year, whereas Nonmetric Multidimensional Scaling ordination (NMDS) was used to analyse classification patterns. The Villahermosa and Ebr ón streams were more homogeneous than the Palancia and Vallanca streams, whereas riffles and glides were more homogeneous than pools and rapids. The NMDS indicated that the slow water-velocity (pools, glides) and fast (riffles, rapids) mesohabitats tended to group together. Temporally, the Ebr ón stream pools were homogeneous and very stable over the four years, whereas the Vallanca and Villahermosa pools showed a certain degree of variability. The Palancia pools were the most variable and heterogeneous during the study period. These results underscored the importance of separating different types of deep, slow-velocity habitats in mesohabitat inventories and the importance of evaluating habitat classifications in eco-hydromorphological and hydrobiological studies, especially in Mediterranean streams and rivers., [ES] Las unidades hidromorfologicas o mesoh ´ abitats de cuatro r ´ ´ıos mediterraneos de cabecera fueron estudiadas en funci ´ on de su ´ longitud, anchura, profundidad media y maxima, porcentaje de sustrato y volumen de cada mesoh ´ abitat durante cuatro a ´ nos ˜ consecutivos (2003-2006). El objetivo principal fue analizar la variacion espacio-temporal de los diferentes mesoh ´ abitat ´ segun sus atributos f ´ ´ısicos. La fortaleza de la clasificacion y su dendrograma se examin ´ o seg ´ un cada r ´ ´ıo, cada tipo de mesohabitat, una combinaci ´ on de cada r ´ ´ıo y tipos de mesohabitats y seg ´ un cada r ´ ´ıo y tipos de mesohabitats de los cuatro a ´ nos ˜ de muestreo. El Escalado Multidimensional No Metrico (NMDS) se us ´ o para analizar los patrones de las clasificaciones. El ´ NMDS indico que tanto los mesoh ´ abitats lentos (pozas y tablas) como los mesoh ´ abitats r ´ apidos (corrientes y r ´ apidos) tienden ´ a agruparse juntos. Desde la una perspectiva temporal, las pozas del r´ıo Ebron fueron homog ´ eneas y muy estables durante ´ los cuatro anos de muestreo, mientras que las pozas de los r ˜ ´ıos Vallanca y Villahermosa mostraron un cierto grado de variabilidad y las del r´ıo Palancia fueron las mas variables y heterog ´ eneas durante el periodo de estudio. Los resultados ´ destacan la importancia de diferenciar distintos tipos de habitats lentos en los inventarios de mesoh ´ abitat, y la importancia ´ de evaluar las clasificaciones de los mesohabitats en estudios de eco-hidromorfolog ´ ´ıa e hidrobiolog´ıa, especialmente los desarrollados en r´ıos mediterraneos.
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- 2011
39. Data-driven fuzzy habitat suitability models for brown trout in Spanish Mediterranean rivers
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ghent University, Generalitat Valenciana, Mouton, A.M., Alcaraz-Hernández, Juan Diego, De Baets, B., Goethals, , P.L.M, Martinez-Capel, Francisco, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Ghent University, Generalitat Valenciana, Mouton, A.M., Alcaraz-Hernández, Juan Diego, De Baets, B., Goethals, , P.L.M, and Martinez-Capel, Francisco
- Abstract
[EN] In recent years, fuzzy models have been acknowledged as a suitable approach for species distribution modelling due to their transparency and their ability to incorporate the ecological gradient theory. Specifically, the overlapping class boundaries of a fuzzy model are similar to the transitions between different environmental conditions. However, the need for ecological expert knowledge is an important constraint when applying fuzzy species distribution models. Moreover, the consistency of the ecological preferences of some fish species across different rivers has been widely contested. Recent research has shown that data-driven fuzzy models may solve this `knowledge acquisition bottleneck¿ and this paper is a further contribution. The aim was to analyse the brown trout (Salmo trutta fario L.) habitat preferences based on a data-driven fuzzy modelling technique and to compare the resulting fuzzy models with a commonly applied modelling technique, Random Forests. A heuristic nearest ascent hill-climbing algorithm for fuzzy rule optimisation and Random Forests were applied to analyse the ecological preferences of brown trout in 93 mesohabitats. No significant differences in model performance were observed between the optimal fuzzy model and the Random Forests model and both approaches selected river width, the cover index and flow velocity as the most important variables describing brown trout habitat suitability. Further, the fuzzy model combined ecological relevance with reasonable interpretability, whereas the transparency of the Random Forests model was limited. This paper shows that fuzzy models may be a valid approach for species distribution modelling and that their performance is comparable to that of state-of-the-art modelling techniques like Random Forests. Fuzzy models could therefore be a valuable decision support tool for river managers and enhance communication between stakeholders.
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- 2010
40. Relaciones entre densidades y biomasas de Salmo trutta fario y mediciones del mesohabitat en tramos trucheros de la Comunidad Valenciana
- Author
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Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Peredo Parada, Matías Manuel, Hernández Mascarell, Aina Berta, Universitat Politècnica de València. Instituto de Investigación para la Gestión Integral de Zonas Costeras - Institut d'Investigació per a la Gestió Integral de Zones Costaneres, Universitat Politècnica de València. Departamento de Ingeniería Hidráulica y Medio Ambiente - Departament d'Enginyeria Hidràulica i Medi Ambient, Alcaraz-Hernández, Juan Diego, Martinez-Capel, Francisco, Peredo Parada, Matías Manuel, and Hernández Mascarell, Aina Berta
- Abstract
[EN] In the year 2003, populations of Salmo trutta fario were studied in the Valencian rivers. Habitat conditions were also studied along the successive hydro-morphological units in 300 m long reaches, along with geographic and water-quality variables. With the objective of relating density and biomass with the habitat, all the independent variables were used in a stepwise multiple regression analysis (for common trout density and relative biomass). Through a step-wise analysis, the most significant variables were chosen for each of the two multivariate models, showing all a low correlation coefficient, but with good significance (p < 0.10). The most relevant variables in both models were stream width (negative correlation) and percentage of cobbles (64-256 mm) in each mesohabitat. The water surface area, and mean and maximum depth did not appear in the final model, but their correlation with stream width was demonstrated. All these variables were included within the mesohabitat characteristics, having being discarded the rest that were not significant at the scale of the study., [ES] En el año 2003 se estudiaron las poblaciones autóctonas de Salmo trutta fario en los ríos valencianos. Por otro lado se midieron las condiciones del hábitat según las sucesivas unidades hidro-morfológicas en tramos de 300 m de longitud, junto con variables geográficas y de calidad del agua. Con el objeto de relacionar densidades y biomasas con el hábitat, todas las variables independientes fueron introducidas en modelos de regresión múltiple (para la densidad y la biomasa relativa de trucha común). Mediante análisis paso a paso eliminatorio quedaron seleccionadas las más significativas para cada uno de los dos modelos multivariantes, obteniéndose en todos un bajo coeficiente de correlación pero con una significación adecuada ( p < 0.10). Las variables establecidas en los dos modelos fueron la anchura del cauce (con signo negativo) y el porcentaje de cantos rodados (64-256 mm) en cada mesohábitat. La superficie, así como la profundidad media y máxima no aparecieron en el modelo final, pero se demostró su correlación con la anchura del cauce. Todas estas variables estaban englobadas dentro del grupo de características del mesohábitat, habiéndose descartado las demás que no fueron significativas a la escala del estudio.
- Published
- 2007
41. Modelling native fish richness to evaluate the effects of hydromorphological changes and river restoration (Júcar River Basin, Spain)
- Author
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Olaya-Marín, Esther Julia, primary, Martínez-Capel, Francisco, additional, Soares Costa, Rui Manuel, additional, and Alcaraz-Hernández, Juan Diego, additional
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- 2012
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42. Mesohabitat heterogeneity in four mediterranean streams of the Jucar river basin (Eastern Spain)
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Alcaraz-Hernández, Juan Diego, primary, Martínez-Capel, Francisco, additional, Peredo Parada, Matías, additional, and Hernández-Mascarell, Aina B., additional
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- 2011
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43. Estado de las poblaciones de trucha en los ríos de la Comunidad Valenciana y caracterización de sus hábitats
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ALCARAZ HERNÁNDEZ, JUAN DIEGO, primary
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44. Relaciones entre densidades y biomasas de Salmo trutta fario y mediciones del mesohábitat en tramos trucheros de la Comunidad Valenciana
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Alcaraz-Hernández, Juan Diego, primary, Martínez-Capel, Francisco, additional, Peredo, Matías, additional, and Hernández-Mascarell, Aina Berta, additional
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- 2007
- Full Text
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45. Effective monitoring of freshwater fish
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Radinger, Johannes, Britton, J Robert, Carlson, Stephanie M, Magurran, Anne E, Alcaraz-Hernández, Juan Diego, Almodóvar, Ana, Benejam, Lluís, Fernández-Delgado, Carlos, Nicola, Graciela G, Oliva-Paterna, Francisco J, Torralva, Mar, and García-Berthou, Emili
- Subjects
Environmental Management ,Rivers ,13. Climate action ,Environmental Assessment ,Biodiversity Targets ,Ecological Monitoring ,14. Life underwater ,15. Life on land ,6. Clean water ,Sampling Design - Abstract
This is the pre-peer reviewed version (preprint) of thearticle: "Effective monitoring of freshwater fish". Freshwater ecosystems constitute only a small fraction of the planet's water resources, yet support much of its diversity, with freshwater fish accounting for more species than birds, mammals, amphibians, or reptiles. Freshwaters are, however, particularly vulnerable to anthropogenic impacts, including habitat loss, climate and land use change, nutrient enrichment, and biological invasions. This environmental degradation, combined with unprecedented rates of biodiversity change, highlights the importance of robust and replicable programmes to monitor freshwater fish assemblages. Such monitoring programmes can have diverse aims, including confirming the presence of a single species (e.g. early detection of alien species), tracking changes in the abundance of threatened species, or documenting long-term temporal changes in entire communities. Irrespective of its motivation, monitoring programmes are only fit for purpose if they have clearly articulated aims and collect data that can meet those aims. This review, therefore, highlights the importance of identifying the key aims in monitoring programmes, and outlines the different methods of sampling freshwater fish that can be used to meet these aims. We emphasise that investigators must address issues around sampling design, statistical power, species’ detectability, taxonomy, and ethics in their monitoring programmes. Additionally, programmes must ensure that high-quality monitoring data are properly curated and deposited in repositories that will endure. Through fostering improved practice in freshwater fish monitoring, this review will help programmes improve understanding processes that shape the Earth's freshwater ecosystems, and help protect these systems in face of rapid environmental change.
46. Seasonal Effects on Health Status and Parasitological Traits of an Invasive Minnow in Iberian Waters.
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Almeida D, Alcaraz-Hernández JD, Cruz A, Lantero E, Fletcher DH, and García-Berthou E
- Abstract
Biological invasions are of special conservation concern in the Iberian Peninsula and other regions with high levels of endemism. Environmental variability, such as the seasonal fluctuations of Mediterranean streams, is a key factor that affects the spread of aquatic species in novel habitats. Fish parasites have a great potential to reflect such changes in the habitat features of freshwater ecosystems. The aim of this study consisted of seasonally analysing the health status and parasitological traits of non-native fish in Iberian waters. In particular, a strongly invasive population of Languedoc minnow Phoxinus septimaniae (leuciscid species native to south-east France) was assessed in Tordera Stream (north-eastern Iberian Peninsula, Mediterranean conditions). Fish were sampled in April, July, and October 2023 by electrofishing. Health status (external/internal organs) was significantly better in autumn (HAI = 28.8) than spring (HAI = 35.6). Life-cycle complexity was higher in spring (LCI = 1.98), whereas parasite abundance and Shannon diversity were significantly lower in autumn (TA = 19.6 and H' = 2.15, respectively). In October (more 'benign' environmental conditions in Iberian streams), minnows could display elevated foraging activity, with fish increasing their health condition and level of parasite resistance/tolerance. Overall results showed a particular seasonal profile of health and parasite infra-communities that allow this minnow species to thrive under highly fluctuating habitat conditions. This information could help environmental managers to control non-native fish in Mediterranean streams.
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- 2024
- Full Text
- View/download PDF
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