Eduard Ariza

Measuring geomorphological vulnerability on beaches using a set of indicators (GVI): A tool for management

A system of indicators has been developed to evaluate beach geomorphological vulnerability (GVI) through: intrinsic susceptibility, the agents that model them, and their ability to remain stable over time. The method is applied to 34 beaches on the island of Gran Canaria (Spain) that experience different levels and conditions of human occupation, marine incidence, landforms and sediments, and spatial evolution that have been recorded since 1960. In contrast with other studies, the analysis of these dimensions (and their relationships) allows a diagnosis of the geomorphology of the beaches with an integrated approach. The results illustrate the numerous causes that generate geomorphological vulnerability, such as wave intensity, the presence of dikes or breakwaters, coastline variations, the absence of foredunes and embryonic dunes, the width of the intertidal zone, or the absence of beachrocks or lavic stones outcropping onto the shore. These variables combine and operate differently in five defined groups of beaches with different management needs. The most vulnerable ones were those with strong marine incidence, which require maintenance of their landforms in order to guarantee their stability. The opposite situation is found in beaches with little impact from anthropic and marine components. These beaches are less vulnerable since they have moderate susceptibility and high resilience. Their management requirements consist of soft measures since they have a strong geomorphological robustness. In this context, the proposed indicator system is a potentially relevant contribution to the management of beaches, especially for those that are under threat.

Assessing the geomorphological vulnerability of arid beach-dune systems

In this study, an arid dune vulnerability index (ADVI) is developed using a system of indicators to evaluate the geomorphological vulnerability of beach-dune systems of arid regions. The indicators are comprised of three analytical dimensions (susceptibility, exposure and resilience) and their corresponding sub-indices and variables and were assessed for eleven sites located in four aeolian sedimentary systems of the Canary archipelago (Spain). The selected sites have varying geomorphological characteristics, vegetation types, marine and wind conditions and human pressure degrees, and have seen different trends in their geomorphological evolution since 1960. The eleven sites were separated into three groups according to their different conservation status and different management needs, and the results of the ADVI dimensions and variables were compared and analyzed for these three groups. In general, the results obtained in the analyzed sites reveal that susceptibility and exposure dimensions are related to low-moderate values, while resilience was high. Only one site presented a state of critical vulnerability, due to the loss of its capacity to maintain its geomorphological function in recent decades. Given the lack of knowledge about geomorphological vulnerability processes in foredunes of arid regions, ADVI is the first approximation to geomorphological diagnostic in these environments and can be useful for managers.

User’s Perception of Beach Characteristics and Management in Summer and Autumn Seasons: The Case of Gran Canaria Island (Spain)

The beaches located in warm regions (with mild and stable climate) are spaces with a potentially continuous arrival of visitors throughout the year. That is a main difference with respect to temperate zones, where the increased demand for activities on the beaches and their surroundings are concentrated in the summer season. In warm regions, like the Canary Islands (Spain), there are differences in the annual flow of visitors in relation to the intensity of their arrival and their origin (local, national and international). In this environment, with insular character and limited resources, the management of beaches as a natural and economic resource, is especially important, as well as meeting the needs of users who visit them. Therefore, the knowledge of the user’s profile and public perception is an essential tool for establishing management measures.