Francesc X. Roig-Munar

Geomorphological and ecological features of blowouts in a western Mediterranean coastal dune complex: a case study of the Es Comú de Muro beach-dune system on the island of Mallorca, Spain

Many of the coastal dune systems along western Mediterranean shores are in an advanced state of fragmentation and show distinct signs of erosion, largely because of blowout development along the dune front. The Es Comú de Muro beach-dune system on the island of Mallorca (Spain) is a good example of this. In order to better understand and quantify the current situation, 58 blowouts along a ca. 1.5-km-long dune front were investigated. In each case, a number of morphometric and ecological variables were analyzed as a basis for comparison and classification, in particular blowout dimensions and orientation, inner morphometry and topography, morphological types, the role of vegetation in defining the state of the foremost dune line, and the link between vegetation and blowout typology. In comparison with a recent preliminary investigation, the results of the present study provide a more comprehensive picture of the advanced state of fragmentation along the dune front. The blowouts are not evenly distributed, highest densities occurring along the southernmost part of the beach, lowest densities along the northern part. The blowouts were subdivided into two categories on the basis of their shape and general structure, trough blowouts being the most prevalent, followed by mixed trough-saucer shapes. Distinctly saucer-shaped blowouts could not be distinguished. In addition, the blowouts were subdivided into two morphological categories, i.e. simple and branched. It was also possible to link the morphological state of the dune front to certain ecological parameters, in particular vegetation which, in the present case, comprised herbaceous and woody plants. Cluster analyses of species associations (Bray-Curtis similarity indices) were carried out on the basis of the presence/absence of each species. It is shown that, on account of presence counts and the degree of similarity of species associations, some species play a more important role in stabilizing the mobile dune sands than others, a foremost candidate being Ammophila arenaria. It is concluded that active support for such plants should form part of any management strategy aiming to reduce and reverse coastal dune fragmentation processes.

Risk assessment of beach-dune system erosion: beach management impacts on the Balearic Islands.

ABSTRACT Roig-Munar, F.X.; Martín-Prieto, J.A.; Rodríguez-Perea, A.; Pons, G.X.; Gelabert, B., and Mir-Gual, M., 2012. Risk assessment of beach-dune system erosion: beach management impacts on the Balearic Islands. The beach–dune system is a sedimentary environment that is fragile and dynamic. Any change to it can have potential adverse effects on its stability. In recent decades, this environment has been heavily exploited for recreation with management practices that do not have enough consideration of protective and aesthetic values. As a result, erosion has increased—mainly in the foredunes—and upset the balance of the beach–dune system. The assessment of the morphoecological conservation state plays a major role in forecasting natural hazard impacts. This paper correlates the most frequented sectors with the most eroded parts in four beach–dune systems of the Balearic Islands (two in Majorca and two in Minorca) through the Digital Shoreline Analysis System. The four beaches show that the coastline retreats at locations with the highest attendance. Two situations may arise as a function of the management practices employed: (1) the beach and foredune area is eroded or (2) the beach–dune system recovers. The paper also describes appropriate beach and foredune management practices that allow recovery of a system degraded by human activity. We compare these practices with strategies adopted at beaches solely for commercial gain in the Balearic Islands. A space–time evolution, from 1956 to 2008, of 78 beaches of the Balearic Islands was carried out through multivariate analysis of a checklist of beach–dune features and management measures. The results show that beach–dune management based on geomorphological criteria improves conservation of the natural system and minimises risk of erosion. Recovery of vegetation is also encouraged. RESUMEN El sistema playa–duna constituye un medio sedimentario frágil y dinámico. Cualquier pequeño cambio puede tener efectos significativos sobre su estabilidad. En las últimas décadas, este entorno ha sido muy explotado con fines turísticos. Consecuentemente la erosión se ha incrementado, principalmente en la zona de dunas delanteras (“foredunes”), perturbando la estabilidad de todo el sistema playa–duna. La capacidad de adaptación de este entorno está relacionada con su estado de conservación. La evaluación del estado de conservación morfoecológico es importante para predecir el impacto de amenazas naturales. La primera parte del artículo muestra la correlación existente entre los sectores más frecuentados y las partes más erosivas en cuatro sistemas playa–duna de las Islas Baleares (dos en Mallorca y dos en Menorca), a través de un sistema de análisis digital del litoral. Las cuatro playas muestran una retirada de la costa donde se encuentra la urbanización, pero dependiendo de las técnicas de gestión, la erosión se concentra en la playa y en la zona de “foredunes” o bien pueden desencadenar la recuperación del sistema playa–duna. La segunda parte del artículo muestra las medidas de gestión adecuadas para la playa y la “foredune” que permitan la recuperación de todo el sistema. Comparamos estas medidas orientadas a la recuperación de los impactos antrópicos con otras medidas que se han aplicado a varias playas de las Islas Baleares, únicamente guiadas por sus fines comerciales. Por último se muestra la evolución espacio–tiempo, de 1956 a 2008, de 78 playas de las Islas Baleares a través de un análisis multivariado de una lista de las características del sistema playa–duna y de las medidas de gestión. Los resultados muestran que la gestión basada en criterios geomorfológicos mejora la conservación del sistema natural y por lo tanto, minimiza el riesgo de erosión. La recuperación de la vegetación también se ve favorecida.

Beaches of Ibiza and Formentera (Balearic Islands): a classification based on their environmental features, tourism use and management

ABSTRACT Roig-Munar, F.X., Mir-Gual, M., Rodríguez-Perea, A., Pons, G.X., Martín-Prieto, J.A., Gelabert, B. and Blázquez, M., 2013. Beaches of Ibiza and Formentera (Balearic Islands): a classification based on their environmental features, tourism use and management, In order to define their character a total of 100 beaches of Ibiza (76) and Formentera (24) are analyzed on the basis of 35 variables of beach use, state and management. We take as a reference a primary classification where three types of beaches have been considered; urban beaches (A), semi-natural beaches with urban features (B), and natural beaches (C). Departing from this scenario, and taking into account the identified variables, statistical analysis (Cluster and PCA analysis) have been done in the sense of identifying the current state of each beach and the differences among them. Currently many of the beaches of Ibiza are urban beaches (A). Furthermore the results suggest a potential trend that some of natural beaches (B-C) can become to A type in the next future. Understanding this classification, and also the recent history of the management applied in the study units, allow predicting trend scenarios. In this sense, management changes should be proposed in order to improve their current situation, and drive them toward a better conservation status.

Coastal Management in the Balearic Islands

Coastal dunes represent important natural systems for balancing the beach while providing different functions such as protection against erosion and important ecological niches.

Environmental Analysis and Classification of Coastal Sandy Systems of the Dominican Republic

The Dominican Republic is the most visited insular tourist destination in the Caribbean, being its beaches its main attractiveness. This tourism generates 37% of the total revenues of the country, concentrated in coastal regions. As a result of this pressure, the coastal ecosystems are threatened by the increasing tourist development. Parameters such as site and dune morphology, beach condition, surface character of the seaward 200 m of the dune, pressure of use and recent protection measures make good regional comparison of beach-dune systems. A checklist was developed to calculate Vulnerability Index (VI) and Management Measures (MM) in 99 beach-dune systems of Dominican Republic allowing to identify and prioritize the different pressures. This method of study, associated with Geographical Information Systems (GIS), give more visibility to beach-dunes conditions, and by this facilitate the necessary decisions in the context of a sustainable management of coastal areas. The results indicate that the risk of beach erosion and degradation is directly related to the pressure of use of the coastal area.

Tsunamis boulders on the rocky shores of Minorca (Balearic Islands)

Large boulders have been found on marine cliffs of 24 study areas of Minorca, Balearic Archipelago. These large imbricated boulders, of up to 229 tonnes, are located on platforms that conform the rocky coastline of Minorca, several tenths of meters from the edge of the cliff, up to 15 m above the sea level, and kilometres away from any inland escarpment. They are mostly located on the southeast coast of the island, and numerical models have identified this coastline as a high tsunami impact zone. The age of the boulders in most of the studied localities show a good correlation with historical 15 tsunamis. Age of the boulders, direction of imbrication and estimation of run-up necessary for their placement, indicate dislodging and transport by North Africa tsunami waves that hit the coastline of Minorca.

Description of erosion processes in Spratt Bight (San Andrés Island, Colombia) using Sequential End Point Rates (EPR)

ABSTRACT Martín-Prieto J.A., Roig-Munar, F.X., Pons G.X., Rodríguez-Perea A., Alvarado, M. and Mir-Gual M. 2013. Description of erosion processes in Spratt Bight (San Andrés Island, Colombia) using Sequential End Point Rates (EPR). San Andrés is a coral island located in the Colombian Caribbean, 700 km northwest of the main land. Twelve kilometers in length and three kilometers in width, it is one of the most populated islands with 2.612 inhabitants per square kilometer. Its economy is based on tourism. Despite being protected from storms and hurricanes by a chain of reefs that stretches across the north and east of the island, beaches suffer significant erosion. Spratt Bight is the biggest and the most important beach of the island. Temporal evolution of Spratt Bight was analyzed and the End Point Rate for several periods (from the year 1984 to 2010) has been calculated. Although beach nourishment between 1984 and 1990, erosive processes are dominant all over the beach. Erosion rates reach up to 35 m with an average of −1.3 m/year, in its central part. The other erosive sector is placed in the half north of the beach, with a maximum of 20 m and an average of −0.7 m/year. Detected erosion can be attributed to the construction of two perpendicular structures to the shoreline and a promenade located on top of the upper beach. The rigidity of these facilities does not allow the natural evolution of the beach, disconnecting the beach from the dunes and causing significant losses of sand by wind action.