Floristic study of a maërl and gravel subtidal bed in the ‘Ría de Arousa´ (Galicia, Spain)

Se presenta un catalogo de 68 especies de las algas marinas existentes en un banco de maerl y cascajo de la ria de Arousa (Galicia,Espana). Colacodictyon reticulatum y Gelidiella calcicola son novedad para la Peninsula Iberica. Otras especies de interes sBárbara, I.; Cremades, J. & Veiga, A. J. 2004. Floristic study of a maërl and gravel subtidal bed in the `Ría de Arousa' (Galicia, Spain). Bot. Complut. 28: 27-37. A catalogue of 68 species of seaweeds associated with a subtidal maërl and gravel bed in the «Arousa Ría» (Galicia, Spain) is presented. Colacodictyon reticulatum and Gelidiella calcicola are new for the Iberian Peninsula. Other interesting species are Stylonema cornu-cervi, Cruoria rosea-stage, C. cruoriaeformis, Trailliella intricata-stage, Hymenoclonium serpens-stage, Dasya punicea, Heterosiphonia japonica, Symphyocarpus strangulans and Desmarestia dudresnayi. In Dasya punicea spermatangial stichidia are described for the first time. Seasonal floristic variations in the subtidal maërl and gravel bed are described. Species adapted to this biogenic, unstable substratum with crustose or prostrate forms, like Cruoria cruoriaeformis, C. rosea-stage, Peyssonnelia dubyi, Symphyocarpus strangulans, Aglaozonia parvula-stage and Gelidiella calcicola, are abundant. The vegetation exhibits prominent seasonal variations: in winter the vegetation remains dormant (as crustose growth forms) but in summer produces erect foliose thalli. The alternation of these biological stages has heteromorphic cycles in which the crustose stages provide constant populations during the unfavourable season and the later development of the erect phase of species

Application of airborne LiDA R data in viewshed analysis

Revista oficial de la Asociación Española de Teledetección[EN] The environmental impact assessment and landscape analysis of any work or activity over the territory requires a study of the visual impact what can be done from the application of viewshed analysis. The accuracy of these results depends largely on the parameters for calculating them, accuracy and spatial resolution of initial elevation data and digital models derived. In this study viewshed analysis in 4 areas of the town of Gandia with different characteristics (urban, forest, beach, mixed) were analyzed from 4 types of geographic information: a) Digital Elevation Model (DEM) and b) Digital Surface Model (DSM) derived from LiDAR data with density of 1 point/m2; c) DTM from a photogrammetric flight with a pixel size of 5×5 m; d) Overlay cadastral cartography with the previous DTM. For the validation of the results, 120 checking points were used to calculate the overall accuracy and kappa index. The results showed a high overall accuracy for the viewsheds calculated from the DSM derived from LiDAR data being the overall accuracy and index kappa 90% and 0.80, respectively. The conclusions drawn from this study indicated that the use of this source of information showed a good performance for the generation of viewshed analysis.[ES] Los estudios de impacto ambiental o paisajismo de cualquier obra o actuación en el territorio requieren de un estudio del impacto visual de las mismas a partir de la generación de cuencas visuales. La exactitud de estos resultados depende en gran medida del tipo datos de elevaciones iniciales, de los modelos digitales que se deriven y de los parámetros del cálculo de las cuencas visuales. En este estudio se analizaron cuencas visuales generadas en cuatro zonas del municipio de Gandia con características diferenciadas (urbana, forestal, playa, mixta) a partir de cuatro tipos de información cartográfica: a) Modelo Digital del Terreno (MDT) y b) Modelo Digital de Superficie (MDS) calculados a partir de datos LiDAR con una densidad media de 1 punto/m2; c) MDT derivado de un vuelo fotogramétrico a escala 1/5000; d) Superposición cartografía catastral con elevaciones de edificios y el MDT anterior. Para la validación de las mismas se utilizaron 120 puntos de muestreo (60 visibles y 60 no visibles) con los que se calculó la fiabilidad global e índice kappa. Los resultados obtenidos muestran una fiabilidad global muy alta en las cuencas visuales calculadas a partir del MDS derivado de los datos LiDAR siendo la fiabilidad global e índice kappa del 90% y 0,80, respectivamente. La conclusión que se desprenden de este estudio indica que la utilización del MDS derivado de los datos LiDAR de baja densidad genera resultados satisfactorios en la generación de cuencas visuales para los estudios de paisajismo o impacto ambiental.Pellicer, I.; Estornell Cremades, J.; Martí, J. (2014). Aplicación de datos LiDAR aéreo para el cálculo de cuencas visuales. Revista de Teledetección. (41):9-18. doi:10.4995/raet.2014.2293SWORD9184

Classification of UAV-based photogrammetric point clouds of riverine species using machine learning algorithms: a case study in the Palancia river, Spain

[EN] The management of riverine areas is fundamental due to their great environmental importance. The fast changes that occur in these areas due to river mechanics and human pressure makes it necessary to obtain data with high temporal and spatial resolution. This study proposes a workflow to map riverine species using Unmanned Aerial Vehicle (UAV) imagery. Based on RGB point clouds, our work derived simple geometric and spectral metrics to classify an area of the public hydraulic domain of the river Palancia (Spain) in five different classes: Tamarix gallica L. (French tamarisk), Pinus halepensis Miller (Aleppo pine), Arundo donax L. (giant reed), other riverine species and ground. A total of six Machine Learning (ML) methods were evaluated: Decision Trees, Extra Trees, Multilayer Perceptron, K-Nearest Neighbors, Random Forest and Ridge. The method chosen to carry out the classification was Random Forest, which obtained a mean score cross-validation close to 0.8. Subsequently, an object-based reclassification was done to improve this result, obtaining an overall accuracy of 83.6%, and individually a producer¿s accuracy of 73.8% for giant reed, 87.7% for Aleppo pine, 82.8% for French tamarisk, 93.5% for ground and 80.1% for other riverine species. Results were promising, proving the feasibility of using this cost-effective method for periodic monitoring of riverine species. In addition, the proposed workflow is easily transferable to other tasks beyond riverine species classification (e.g., green areas detection, land cover classification) opening new opportunities in the use of UAVs equipped with consumer cameras for environmental applications.Carbonell-Rivera, JP.; Estornell Cremades, J.; Ruiz Fernández, LÁ.; Torralba, J.; Crespo-Peremarch, P. (2020). Classification of UAV-based photogrammetric point clouds of riverine species using machine learning algorithms: a case study in the Palancia river, Spain. ISPRS. 659-666. https://doi.org/10.5194/isprs-archives-XLIII-B2-2020-659-2020S65966

Multi-criteria characterization and mapping of coastal cliff environments: A case study in NW Spain

This paper presents a novel approach to characterize cliff exposure to marine action that combines wave power and biology. This multidisciplinary approach is illustrated through a case study on a coastal stretch in NW Spain – the Catedrales Natural Monument. The engineering perspective is based on quantifying the wave power acting on the cliff. To this end, a statistical characterization of the wave climate in deep water is carried out, and relevant sea states are propagated numerically from deep water to the cliff. Four levels of cliff exposure, from sheltered to exposed, are defined based on wave power and mapped onto the study area. As for the biological perspective, ecological factors, bioindicated variables and biological indicators characterized through field observations are considered and, on this basis, also four levels of cliff exposure are established and mapped. In general, there is good agreement between the exposure patterns obtained through the engineering and biological perspectives; however, there are some differences in certain areas. The upshot is that the engineering and biological points of view should be regarded as complementary. The multi-criteria characterization performed in this paper may be used as a management tool to establish different degrees of exposure to marine action on cliff coasts elsewhere

Biodiversidad Marina del golfo Ártabro (A Coruña): 50 aniversario del Centro Oceanográfi co de A Coruña.

Hace más de 50 años comenzó su andadura el Centro Oceanográfico de A Coruña. Ocurrió en un vetusto local del puerto, y se denominó por aquel entonces como Laboratorio del Noroeste. Durante este medio siglo este centro ha trabajado básicamente en las áreas de la biología pesquera, la acuicultura marina y la oceanografía multidisciplinar, si bien los equipos de investigación han ido evolucionando a lo largo de este tiempo, abriendo o cerrando líneas de trabajo según las circunstancias. A pesar de haber trabajado en todos los océanos del mundo, incluidos el ártico y el antártico, una parte importante de las investigaciones del oceanográfico coruñés siempre han estado centradas en su entorno cercano: el golfo Ártabro. Desde los años ochenta, este centro coruñés monitorea el ambiente pelágico y bentónico de la ría de A Coruña y su plataforma adyacente. Esto supone una valiosísima serie histórica de datos oceanográficos, cuya utilidad quedó de sobra demostrada durante las catástrofes de los petroleros Aegean Sea y Prestige. La idea de crear este libro surgió justo antes del 50 Aniversario del Centro Oceanográfico de A Coruña (1968-2018). Nace con la intención de recopilar y resumir el conocimiento científico en torno a la biodiversidad marina en el ámbito de trabajo más cercano al centro coruñés. Es intención de este libro el servir como publicación de referencia a todo tipo de estudio sobre la biodiversidad y la oceanografía biológica del golfo Ártabro. Para ello nos servimos de la información obtenida directamente del oceanográfico herculino tanto de sus series históricas, como de otros estudios realizados en la zona. Además, la colaboración en materia de pesca de los centros oceanográficos de A Coruña, Vigo, Santander y Gijón permitió aportar a este volumen el capítulo dedicado a las especies desembarcadas por la flota artesanal en la lonja coruñesa. Por otra parte, los especialistas en bentos duro del Centro de Gijón fueron los encargados de elaborar la parte dedicada a este tipo de fauna. Por último, reseñar la inestimable contribución del Grupo de Investigación BioCost de la Universidade da Coruña, auténticos referentes en el conocimiento de la botánica marina de la zona en cuestión.Versión del edito

Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives

Atlas de las praderas marinas de España

Knowledge of the distribution and extent of seagrass habitats is currently the basis of management and conservation policies of the coastal zones in most European countries. This basic information is being requested through European directives for the establishment of monitoring programmes and the implementation of specific actions to preserve the marine environment. In addition, this information is crucial for the quantification of the ecological importance usually attributed to seagrass habitats due to, for instance, their involvement in biogeochemical cycles, marine biodiversity and quality of coastal waters or global carbon budgets. The seagrass atlas of Spain represents a huge collective effort performed by 84 authors across 30 Spanish institutions largely involved in the scientific research, management and conservation of seagrass habitats during the last three decades. They have contributed to the availability of the most precise and realistic seagrass maps for each region of the Spanish coast which have been integrated in a GIS to obtain the distribution and area of each seagrass species. Most of this information has independently originated at a regional level by regional governments, universities and public research organisations, which explain the elevated heterogeneity in criteria, scales, methods and objectives of the available information. On this basis, seagrass habitats in Spain occupy a total surface of 1,541,63 km2, 89% of which is concentrated in the Mediterranean regions; the rest is present in sheltered estuarine areas of the Atlantic peninsular regions and in the open coastal waters of the Canary Islands, which represents 50% of the Atlantic meadows. Of this surface, 71.5% corresponds to Posidonia oceanica, 19.5% to Cymodocea nodosa, 3.1% to Zostera noltii (=Nanozostera noltii), 0.3% to Zostera marina and 1.2% to Halophila decipiens. Species distribution maps are presented (including Ruppia spp.), together with maps of the main impacts and pressures that has affected or threatened their conservation status, as well as the management tools established for their protection and conservation. Despite this considerable effort, and the fact that Spain has mapped wide shelf areas, the information available is still incomplete and with weak precision in many regions, which will require an investment of major effort in the near future to complete the whole picture and respond to demands of EU directives.Versión del edito