Foredune responses to the impact of aggregate extraction in an arid aeolian sedimentary system

Abstract

Coastal dunes have long suffered the effects of human interventions that have altered the landscape and operation of these ecosystems. Aggregate extractions have been shown to modify the biogeomorphological processes in aeolian sedimentary systems. The impacts associated to aggregate extraction include the reduction of available sediment and changes to the topography and vegetation patterns, thereby altering the sedimentary dynamics and limiting the recovery capacity of the dunefield. The aim of this article is to analyse the environmental effects produced by historical aggregate extraction in the foredune area of an arid aeolian sedimentary system (El Médano, Tenerife, Spain) through a study of the airflow dynamics and spatial distribution of vegetation, sediment and topographic changes. The methodology was designed with two temporal scales: (i) a long‐term approach which compares historical sources and current ones; (ii) a short‐term approach through experimental data collection to characterize the present functioning. For the latter, a field study was carried out in June 2021, collecting wind speed and direction data at a height of 0.50 m, sediment data (sand sheet thickness, grain size and sorting), and vegetation data (cover and species richness) at 40 sample points. The main results show that when the anthropic stress ceased the foredune did not follow a natural environmental pattern, and that the way it functions at the present time is determined by the changes induced by the aggregate extraction. Changes include alterations to the topography, the creation of a lagoon, and the generation of an aeolian deflation area and flow acceleration zones with the associated sand transport. This research contributes to an understanding of the environmental consequences of aggregate extractions on the foredunes of arid aeolian sedimentary systems and can enable the relevant authorities to make better‐informed decisions that help the management of these ecosystems.

Contemporary research in coastal dunes and aeolian processes

“…Satellite images and aerial photos are still the standard for estimating land cover (Fisher et al, 2023; Garzon et al, 2022; Hesp et al, 2022; Konlechner & Hilton, 2022; Robin et al, 2022). Similarly, the research community is using LiDAR (Fisher et al, 2023; Garzon et al, 2022; Robin et al, 2022; Sanromualdo‐Collado et al, 2022; Zhang, Sherman, et al, 2022) and differential global navigation satellite systems (GNSS) (He et al, 2022; Nguyen et al, 2022; Zhang, Qui, et al, 2022) to measure topography. It is interesting to note that Uncrewed Aerial Systems (UAS) are now emerging as a feasible survey technique within the coastal dune community.…”

“…The increasing need for dune research on developed coasts was made explicit by Nordstrom (2004) in Beaches and dunes of developed coasts, and themes such as the restoration of coastal dunes have been the focus of dedicated textbooks, for example, Restoration of coastal dunes (Martínez et al, 2013). Examples of human interventions in coastal dunes in this special issue include the removal of invasive vegetation Hilgendorf et al, 2022;Konlechner & Hilton, 2022), engineered foredune notches (Nguyen et al, 2022), and intensely managed or constructed foredunes (Dickey et al, 2023;He et al, 2022;Sanromualdo-Collado et al, 2022;Walker et al, 2023).…”

“…As coastal dunes are increasingly being targeted as feasible 'Nature- The research within this special issues also reflects the increasingly sophisticated and holistic approach being taken to understanding coastal dune dynamics. For example, a range of research measured or modelled abiotic and biotic factors that impact aeolian systems including waves (Garzon et al, 2022;He et al, 2022;Ruessink et al, 2022), surface moisture (Ruessink et al, 2022), and vegetation Dickey et al, 2023;Konlechner & Hilton, 2022Kooijman et al, 2022Li et al, 2022;Sanromualdo-Collado et al, 2022). The data sources were dominated by field experiments and remote sensing, with only five of the 25 articles using data derived from experimental laboratory work or numerical models.…”

“…At Padre Island (Texas, USA), a decrease in sediment influx together with a rise in sea level has driven a shift towards dune stabilization over the last 50 years (Fisher et al, 2023). At El Médano (Tenerife, Spain), mining and sand extraction in the 1960s led to a marked decrease in dune volumes (Sanromualdo-Collado et al, 2022) and long-term changes to dune evolution. Despite attempts to restore the foredune following the cessation of mining activities in the 1970s, the reduction of overall sediment budgets limited the capacity of the dune field to grow again, with permanent landscape changes still measurable today.…”

“…The increasing need for dune research on developed coasts was made explicit by Nordstrom (2004) in Beaches and dunes of developed coasts , and themes such as the restoration of coastal dunes have been the focus of dedicated textbooks, for example, Restoration of coastal dunes (Martínez et al, 2013). Examples of human interventions in coastal dunes in this special issue include the removal of invasive vegetation (Bauer et al, 2022; Hilgendorf et al, 2022; Konlechner & Hilton, 2022), engineered foredune notches (Nguyen et al, 2022), and intensely managed or constructed foredunes (Dickey et al, 2023; He et al, 2022; Sanromualdo‐Collado et al, 2022; Walker et al, 2023). Many manuscripts within the special issue that investigated the coastal dynamics of naturally forming dunes also explicitly situated the research in the context of contemporary sea‐level rise and climate change (Arce Chamorro et al, 2022; Fisher et al, 2023; Garzon et al, 2022; Hesp et al, 2022; Robin et al, 2022) or hazard mitigation (He et al, 2022).…”