Dune Systems’ Characterization and Evolution in the Andalusia Mediterranean Coast (Spain)

Abstract

This paper deals with the characterization and evolution of dune systems along the Mediterranean coast of Andalusia, in the South of Spain, a first step to assess their relevant value in coastal flood protection and in the determination of sound management strategies to protect such valuable ecological systems. Different dune types were mapped as well as dune toe position and fragmentation, which favors dune sensitivity to storms’ impacts, and human occupation and evolution from 1977 to 2001 and from 2001 to 2016. Within a GIS (Geographic Information System) project, 53 dune systems were mapped that summed a total length of ca. 106 km in 1977, differentiating three dune environments: (i) Embryo and mobile dunes (Type I), (ii) grass-fixed dunes (Type II) and (iii) stabilized dunes (Type III). A general decrease in dunes’ surfaces was recorded in the 1977–2001 period (−7.5 × 106 m2), especially in Málaga and Almería provinces, and linked to dunes’ fragmentation and the increase of anthropic occupation (+2.3 × 106 m2). During the 2001–2016 period, smaller changes in the level of fragmentation and in dunes’ surfaces were observed. An increase of dunes’ surfaces was only observed on stable or accreting beaches, both in natural and anthropic areas (usually updrift of ports).

Coastal Sensitivity/Vulnerability Characterization and Adaptation Strategies: A Review

“…Rangel-Buitrago and Anfuso [18] categorized dune height and spatial density of washovers by means of absolute values according to the classes proposed by García-Mora et al [98] and Gracia et al [99]. In a recent study, Molina et al [114] proposed a Fragmentation Index to express in an objective and reliable way the level of dune toe fragmentation along the Mediterranean coast of Andalusia, Spain.…”

Shoreline Evolution and Environmental Changes at the NW Area of the Gulf of Gela (Sicily, Italy)

“…The dune fragmentation index (F) was proposed for the first time by Molina et al [5]. It was used to assess how the dune systems have been impacted over time.…”

“…Each shorefront dune system was divided into 100 m sectors, and the F index was calculated for each. The F index can be grouped into three classes that were computed by us-ing the Natural Breaks Function [5]. The annual level of dune fragmentation was computed as the average value for all sectors for each available photogrammetric flight.…”

“…Shorelines are dynamic in nature, and coastal behaviour is the result of natural and anthropic processes occurring and interacting on a variety of time and spatial scales [1][2][3] The coastal sediment budget can be altered both by such physical processes, including waves, currents, tides, storm surges, seasonal fluctuations, aeolian transport and relative changes in sea level and by human actuations, such as the construction of inland infrastructure (e.g., dams) and coastal structures (e.g., protection structures and ports/harbours) [4]. However, decreased sediment river load and altered longshore drift appear to be pivotal factors in sediment coastal changes, and therefore manmade actuations can be the main causes of coastal erosion [5,6].…”

“…Most of the world's major cities are in coastal regions, and 40% of all people on the planet live within 100 km of a coastal zone [5]. Coastal settlements are often planned with insufficient attention to natural hazards such as coastal erosion and flooding, and often…”