Dune Management Research Articles

Coastal dune management affects above and belowground biotic characteristics.

Dune vegetation mediates dune-building through trapping wind-blown sand and reduces dune erosion by attenuating wave energy via above- and belowground biomass. Despite the role of vegetation in dune functions, the amount and distribution of biomass within a dune remains poorly quantified due to a lack of ample data. Our objectives were to determine the effects of management history and elevation on (1) dune belowground biotic structure and aboveground community composition and (2) to determine best predictors of belowground biomass. We sampled belowground biomass and sedimentology across the dune profile at sites in the Outer Banks, North Carolina, USA. Dunes were classified as either unmanaged (no anthropogenic interventions) or managed (sand fencing, vegetation planting, dune construction). Living belowground biomass was higher in unmanaged dunes and decreased with depth. Non-living belowground biomass was 50% higher than living biomass and with greater abundance in unmanaged dunes. Elevation was a significant covariate of living and non-living belowground biomass, vegetative cover and species richness. Plant community composition varied less in managed dunes and differed significantly from unmanaged dunes. Vegetative cover, species richness, elevation, sedimentology and management history were predictors of belowground biomass. These results underscore the influence of management and geomorphology on dune plant communities, which may influence erosion resistance.

Review of the Quantification of Aeolian Sediment Transport in Coastal Areas

Coastal dunes, formed and shaped by aeolian sediment transport, play a crucial role in ecosystem services and act as natural flood and coastal erosion defenses. This paper delves into theoretical equations and numerical models predicting sediment transport. Numerical models like cellular automata, XBeach-DUNA, the coastal dune model, and others are analyzed for their ability to simulate dune morphology, erosion processes, and vegetation impacts accurately. Evaluated are field observation and measurement techniques, such as sand traps, impact sensors, and optical sensors, for their precision in quantifying aeolian dynamics. Further examined is the effectiveness of vegetation and fencing in dune stabilization, noting species-specific responses and the influence of fence design on sediment accumulation. These tools offer insights into optimizing aeolian sediment management for coastal protection. By conducting a systematic review and connecting theoretical, empirical, and modeling findings, this study highlights the complex challenge of measuring and managing aeolian sediment transport and proposes integrated strategies for enhancing coastal dune resilience against the backdrop of climate change and erosion. This study’s objectives to bridge gaps in current understanding are met, highlighting the need for a multidisciplinary approach to coastal dune management and conservation, especially combining wind- and wave-driven processes.

Patchy Anthropocoasts: A transdisciplinary perspective on dunes, plants, rabbits, and humans in the United Kingdom

In recent years, there has been increasing societal awareness of the crucial role that coastal dunes play in protecting against rising sea levels, mitigating climate change impacts, promoting biodiversity, and providing recreational opportunities. In some regions, dune management has been particularly focused on biodiversity and ecosystem restoration and the presence of alien species on dunes raises concerns about how these species become 'native,' 'invasive,' or 'hybrids' and whether they belong in their new ecosystems. These concerns illustrate how certain animals and plants assume different statuses according to normative categories associated with varying objectives. This article explores how perceptions of coastal dunes in the UK have transformed over time, from marginal resource frontiers to highly valued environments shaped by multispecies relations. In addition, this work explores how dunes around the UK emerge as ‘patchy anthropocoasts,’ that is, uneven landscapes designed by human purposes linked to economic activities, conservation, rabbit populations, unwanted vegetation, and the control of unpredictable sand movements. Bringing together diverse historical materials and scientific literature, this article links human and nonhuman histories with present debates on dune restoration from a transdisciplinary perspective rooted in anthropology, environmental history, and the natural sciences.

A soil mechanics model to determine the onset of wind erosion

Determining the friction threshold velocity (FTV) of wind-induced erosion is crucial to understanding and predicting the morphodynamics and management of foreshores and dunes. However, the FTV is influenced by multiple factors, including particle size, mineralogy, surface roughness, and moisture content. Although existing models account for these parameters, they suffer from limited precision, are not generalized and developed for specific sediment types, and rely on expensive and time-consuming testing procedures. Furthermore, no predictive equations for FTV currently consider the combined effects of bed inclination and moisture common to coastal dunes. This study presents a comprehensive closed-form model for predicting the FTV in the onset of wind erosion for different types of sands. The model considers various geometric and material properties, including cohesion, moisture, soil packing, slope, and grain size distribution. A soil water retention curve (SWRC) is incorporated into the formulation to establish a relationship between water content and sediment shear strength. This simple SWRC approach enables simplified calculations of the onset of wind erosion under various conditions, requiring only a few inexpensive inputs. Extensive parametric wind tunnel experiments were conducted to measure the FTV in combinations of bed slope, sand particle size, moisture, and density. The findings indicate that the combined influence of slope and moisture increases the FTV. Furthermore, compared to the FTV for dry sediments on a horizontal bed, the amplification factor exhibits a nonlinear combination of the effects of inclination and moisture. The proposed FTV predictive model demonstrates adequate agreement with published results when applied to scenarios such as dry sand on a horizontal surface, dry sand on an inclined bed, and moist sand on a horizontal surface.

Identifying insect and arachnid indicator taxa for impacts and management in coastal landscapes

Insects and arachnids are abundant and diverse, respond to key human impacts and support a diversity of key ecological functions. They are therefore widely recognised as effective surrogates for ecosystem condition. Their efficacy as indicators and surrogates in coastal dunes has, however, rarely been quantified, but might be instructive in guiding management in these often highly impacted coastal ecosystems. In this study, we (1) tested the effects of spatial and habitat drivers on the abundance of key insect and arachnid groups, and (2) used these patterns to identify viable management surrogates for impacts and management actions. We surveyed insect, arachnid and plant assemblages in coastal dunes at 20 sites on the Sunshine Coast in central eastern Australia. We have identified indicators for habitat condition and indicators for impact, and taxa that could be used to measure restoration outcomes. Crucially, five indicator groups also met criteria for being umbrella species, as management actions that increase their abundance would confer benefits to most other insect and arachnid taxonomic groups. We identified seven indicator groups (five insect and two arachnid), and each were affected by multiple spatial and habitat metrics, with metrics quantifying the composition and structure of vegetation communities being the most important predictors of most indicator’s distributions. Implications for insect conservation: We highlight the importance of understanding subtleties in spatial patterns and the unique set of spatial and environmental conditions that each group requires when identifying suitable indicator taxa for use in the conservation and management of coastal dunes.

The Future of Developed Barrier Systems: 1. Pathways Toward Uninhabitability, Drowning, and Rebound

AbstractMany barrier islands and spits (collectively, “barriers”) throughout the world are highly developed. As low‐lying, sandy coastal landforms, barrier systems are naturally reshaped by processes associated with storms and sea‐level rise (SLR). The resulting landscape changes threaten development, and in response, humans employ defensive measures that physically modify barrier geometry to reduce relatively short‐term risk. These measures include the construction of large dunes, emplacement of beach nourishment, and removal of washover. Simulations conducted using a new coupled modeling framework show that, over decades to centuries, measures to protect roadways and communities alter the physical characteristics of barrier systems in ways that ultimately limit their habitability. We find that the pathway toward uninhabitability (via roadway drowning or community narrowing) and future system states (drowning or rebound) depends largely on dune management—because building dunes blocks overwash delivery to the barrier interior—and on initial conditions (barrier elevation and width). In the model, barriers can become lower and narrower with SLR to the point of drowning. The timing and occurrence of barrier drowning depends on randomness in the timing and intensity of storms and dune recovery processes. We find that under a constant rate of SLR, negative feedbacks involving storms can allow barriers that do not drown to rebound toward steady‐state geometries within decades after management practices cease.

An analysis of coastal sand dune management in Oregon (United States) from the 19th to the 21st century

The Drivers-Pressures-State-Impact-Response (DPSIR) framework was employed to understand the land use policies developed to manage coastal sand dunes and their consequences in Oregon, United States of America, during two contrasting periods: from the 19th to the late 20th century and from there to the early 21st century. A combination of historical data and scientific literature was used for this study. Dune destabilization became a socio-economic issue as Euro-Americans settled in Oregon in the 19th century. Ammophila arenaria and Ammophila breviligulata were widely used for stabilization. This led to a paradigm shift regarding dunes, at a time when their management was becoming more complex due to socio-natural factors. As non-native beachgrasses turned invasive causing the loss of biodiversity and habitats, their removal became the focus to restore the active dunes to support the natural processes of the ecosystem. However, the removal of these beachgrasses, particularly, Ammophila arenaria, results in low dune heights, increasing the risk of coastal flooding by reducing their effectiveness as a natural defense against sea-level rise and extreme storm surges. The reason for the contrasting dune management policies in Oregon since the 1930 s is that the management response to environmental impacts due to human drivers creates new drivers, pressures, and corresponding impacts, as shown in the DPSIR analysis. Thus, land use policies for managing coastal dunes in Oregon and other places must balance efforts to restore the native biodiversity while minimizing coastal flooding in a context of accelerating and continuous sea-level rise in the 21st century.

Down the rabbit-hole: satellite-based analysis of spatiotemporal patterns in wild European rabbit burrows for better coastal dune management

Down the rabbit-hole: satellite-based analysis of spatiotemporal patterns in wild European rabbit burrows for better coastal dune management

Managing Coastal Sand Drift in the Anthropocene: A Case Study of the Manawatū-Whanganui Dune Field, New Zealand, 1800s-2020s

Abstract In the Anthropocene, dunes act as a natural defence from sea-level rise and storm surges while providing 'ecosystem' services. This article uses scientific and historical data to examine the Manawatū-Whanganui dune field in New Zealand from the nineteenth to the twenty-first century. Dunes that were destabilised due to European settlements and their activities were drifting inland causing social, economic and political problems. Attempts to prevent dune mobility occurred at the time in many parts of the world. Thus, knowledge was shared between countries through experts and migrants. The consequences of the implemented solutions and new environmental conditions mean that dunes are still a major issue in the region. A comparative analysis of historical and present-day dune management practices provides a better understanding of long-term dune drift. In conclusion, interdisciplinary analyses of long-term relations between dunes and society must be taken into account for their holistic management.

Dune ecosystems along the central Caribbean coast of Colombia: Evolution, human influences, and conservation challenges

The need for effective coastal dune management holds prominence due to its crucial role in preserving these unique and diverse ecosystems. Dunes have become a focal point in coastal management which reflects their extensive use of coastal areas. This study presents the first assessment of 19 dune systems along an 83 km reach on the Central Caribbean coast of Colombia. These dune systems are classified into four groups: i) Nebkha, ii) Foredunes, iii) Foredune and Blowout, and iv) Foredune, Blowout, and Transgressive dunes; each with unique characteristics and distribution patterns. Vegetation analysis identified 37 species, dominated by herbaceous forms. Four species were found to be new records for the Atlántico Department. Recent analysis of the evolution of these dune systems (1954–2022) revealed both accretion and erosion processes, with a dominant erosion trend in the more recent years. Anthropogenic interventions were minimal in most dune systems, but some exhibited varying levels of human-made structures. Litter was assessed across four grades (A-D), with no dune systems reaching Grade A, and most dunes exhibiting elevated to high-extreme levels of litter (Grades C and D). Coastal dunes are threatened by urbanization, sand mining, litter, invasive species, and beach driving, and lack of clear landward back-dune areas for migration due to sea-level rise and climate change. The results provide valuable information for coastal managers and planners to make informed decisions and conserve these unique ecosystems.

Contemporary research in coastal dunes and aeolian processes

AbstractCoastal dunes are found along the sandy coasts of oceans, seas, and large lakes all around the world. They are dynamic landforms that evolve along complex morphological and biological continua in response to a range on controls linked to climate, sea level, sediment movement, vegetation cover, and land use. By collating research across the full spectrum of processes shaping different types and sizes of dunes and smaller aeolian bedforms, special issues can aid researchers to identify new research directions and methods emerging from the discipline. This editorial summarizes the 25 contributions to the special issue Coastal dunes: links between aeolian processes and landform dynamics. We grouped the contributions into four broad themes: (1) long‐term dune evolution, (2) short‐term aeolian transport, (3) research methods, and (4) coastal dune management. Contributions to the special issue demonstrate that research interest in coastal dunes, and particularly the impacts of human interventions on dunes, continues to grow. It also shows how aeolian research on coastal dunes covers a range of temporal and spatial scales, from ripple dynamics and instantaneous airflow‐transport processes to dune field evolution with rising sea levels and large‐scale dune stage shifts. We highlight potential avenues for future research including vegetation roughness characteristics and their effect on wind flow and sediment transport, the challenges of upscaling short‐ and small‐scale results to larger and longer spatiotemporal scales, and the study of both natural and managed dune landscapes.

Management of coastal dunes affected by shrub encroachment: are rabbits an ally or an enemy of restoration?

In coastal dunes, shrub encroachment disrupts natural disturbance, and reduces habitat heterogeneity and species composition. In this paper, we implemented a pilot scale trial aimed at restoring coastal dunes affected by the encroachment by the shrub Retama monosperma (hereinafter Retama) as well as strengthening the populations of Thymus carnosus (regionally cataloged as ‘Critically Endangered’). A total 3 ha of Retama shrub was clearcut in two sites with different Retama cover (54 and 72%). The effect of rabbits on vegetation recovery was assessed by placing exclosures both in treated and untreated plots in Spring, 2015. Plant composition, species richness and diversity were evaluated two years after treatments (with and without Retama clearing, and with and without rabbit exclusion). Retama clearing alone did not allow the recovery of plant composition typical of gray dunes two-years after treatments, but resulted in a biodiversity loss within the Retama understorey when rabbits were present. However, Retama clearing resulted in a significant vigor improvement of T. carnosus in the site with the highest density of Retama. Rabbit exclusion significantly increased species richness and Shannon-Wiener diversity index, and allowed the recovery of plant composition typical of gray dunes. The results suggest that shrub encroachment caused by Retama has a long-lasting negative impact on dune vegetation and that periodic clearing should be combined with rabbit exclusion at least during early restoration stages of dune vegetation. To recover the population of T. carnosus, Retama should be prevented from reaching high cover and periodic clearing without rabbit exclusion is suggested.

Observations and modeling of shear stress reduction and sediment flux within sparse dune grass canopies on managed coastal dunes

AbstractWind flow over coastal foredunes adapts to vegetation, resulting in spatial gradients in bed shear stresses that contribute to the formation of localized bedforms. Understanding, and having the capability to numerically predict, the distribution of sediment deposited within sparsely vegetated dune complexes is critical for quantifying the ecological, protective, and economic benefits of dune management activities. Data from wind tunnel experiments have indicated that there is a spatial lag from the canopy leading edge to a downwind location where sediment deposition first occurs. The length scale of this deposition lag is further quantified here using new field measurements of aeolian sediment transport across sparsely vegetated managed dune systems in Oregon, USA. We develop a deposition lag length scale parameter using both lab and this new field data and then incorporate this parameter into the process‐based aeolian sediment transport model, Aeolis, which also includes a new far‐field shear stress coupler. Results from numerical simulations suggest that the spatial deposition lag effect is significant for model skill in sparsely vegetated dunes. We observe with field and laboratory observations that, as canopy density increases, the length of the deposition lag decreases. As such, within the model framework the implementation of the deposition lag length does not affect the results of models of coastal dune geomorphological evolution within higher density canopies. Dune canopy density can vary due to natural (e.g., storm overwash, burial, die‐off) or anthropogenic (e.g., managed plantings, dune grading) processes.

해안보호 관점에서 본 국내 해안사구 복원의 잠재적 쟁점과 고려사항

The government’s coastal dune management policy has been in place for over two decades. However, preservation-focused measures have not been as effective as anticipated. Restoration should now take precedence over preservation in light of rising sea levels and more frequent storms. This study addresses potential challenges and aspects that Korean coastal authorities should consider while implementing efforts to restore coastal dunes. Two significant issues investigated are handling ambiguities in stakeholder dialogue and overcoming the hard engineering-centric practices for coastal protection. Restoration initiatives may drift away by unnecessary misunderstanding and conflicts without identifying and covering various viewpoints and demands of different groups. During interactions between stakeholders, disagreements from different perspectives and preferences, known as ambiguity, should be carefully managed. It is also essential to get through the inertia of hard engineering-based solutions to coastal erosion issues since they impede stakeholders from adopting more natural solutions for restoring beaches and coastal dunes. We suggest a diagnostic quadrant for coastal dune restoration based on two variables, the need for disaster mitigation and accommodation space, to aid decision-making and communication.

Alongshore Variable Accretional and Erosional Coastal Foredune Dynamics at Event to Interannual Timescales

AbstractNatural and constructed dunes are increasingly being utilized to buffer flooding impacts from storms and rising sea levels along sandy coastlines. However, a lack of data at the appropriate spatial and temporal resolution often precludes isolating the total magnitude, specific timing, and alongshore variability of volumetric coastal dune changes resulting from both wave and wind‐driven processes. Here mobile terrestrial lidar data from 46 collections along a 6.5 km stretch of sandy beach and dunes in Duck, NC, USA are used to assess the magnitude and drivers of alongshore variable dune responses between 2012 and 2020. Despite numerous major storm events which impacted the dunes over this time period, the dunes grew volumetrically both in nourished and un‐nourished sections of the study site. Growth of the dunes was seasonally and spatially variable with the largest total growth recorded in the Fall, coinciding with a period of frequent windy storms but also the highest total water levels, and along the regions with the lowest gradient βbeach. The vertical accretion patterns of these wind‐blown sediments are shown to vary depending on the dune management style, specifically, if dunes were not managed, sand fenced, or artificially constructed. Dune erosion also occurred episodically within the study period, with the steepest sloped beach sections likely to be the most impacted during individual storm events.

Extending the DPSIR framework to analyse Driver-Pressure-State-Impact-Response of sand dune management in Manawatu-Whanganui (New Zealand) since the 19th century

Coastal sand dunes are multifunctional landscapes with rich biodiversity. In New Zealand, with the establishment of European settlement around 1840, dunes in the Manawatu-Whanganui region were affected due to the removal of their vegetation cover by human activities and animal grazing. As a result, sand drifted further inland affecting villages, infrastructure and agricultural areas. The main response was to introduce marram grass (Ammophila arenaria) used in Europe to stabilize dunes. This solution caused significant environmental impacts as marram grass turned invasive and native habitats of fauna and flora significantly decreased.This paper focused on the long-term analysis of aspects related to sand dune management in the region during two-time frames: 1) from the 19th to the late 20th century and 2) from then on to the early 21st century, using the innovative spiral DPSIR (Driver-Pressure-State-Impact-Response) framework. Data for this study comes from historical records, scientific literature and present management reports.The integrated spiral framework allows for establishing the connections between historical and future management initiatives for mitigating and adapting to environmental impacts due to socio-economic drivers and their pressures. The study reinforces the paradigm shift from dune stabilization before the late 20th century to the restoration of stabilized dunes to make them active for enhancing native biodiversity should be again assessed in the context of sea-level rise during this century. Coastal managers should adopt an optimized solution between these two extreme solutions adopted from the 19th century to the present, by considering long-term and interdisciplinary analysis to better understand the systems’ evolution and the full consequences of human actions.

Management of coastal dunes on the Catalan and on the Valencian shorelines (Spain)

Coastal areas constitute one of the most difficult domains to manage, due to the several human activities and natural processes concentrated in it. The case of the coastal dunes is special, since they are so fragile and any intervention on them can cause alterations in the landforms and dynamics. This work assesses the level and role of management and the morphological status of coastal dunes on the Catalan and Valencian shorelines. To that end, ten beach-dune systems from Catalan and Valencian shorelines have been studied to guess how management actions determine the morphological status of them. A set of variables, comprising management actions and morphological status, have been selected and analyzed through a Hierarchical Clustering on Principal Components (HCPC). Results show that the beach-dune systems can be gathered in 2 main groups: those where sustainable management measures were not applied and present an advanced erosive state, and the ones where sustainable management measures were applied and present a good state of conservation. The good state of conservation is related to restoring dunes applying nature-based solutions, whereas degraded morphologies appear when artificial management actions have been carried out.

Extending the Dpsir Framework to Analyse Driver-Pressure-State-Impact-Response of Sand Dune Management in Manawatu-Whanganui (New Zealand) as a Time-Series

Extending the Dpsir Framework to Analyse Driver-Pressure-State-Impact-Response of Sand Dune Management in Manawatu-Whanganui (New Zealand) as a Time-Series

What is Area to physical and environmental geography?

What is <i>Area</i> to physical and environmental geography?

Evolution and management of Atlantic Canadian coastal dunes over the next century

ABSTRACT Dune systems in Atlantic Canada are relatively small given a relatively low sediment supply. The dunes are built primarily of reworked sediments as relative sea level (RSL) has risen. The foredune (at least) is reworked several times a decade by extreme weather events and many are transgressing on a decadal scale as a result of normal geomorphic processes. The key drivers shaping the dunes are, however, changing over time with climate change.The rate of RSL rise is accelerating, which will almost certainly mean an acceleration of dune transgression rates. As well, there is some evidence that storms are becoming more frequent and sea ice is diminishing, meaning more frequent reactivation. Predicting how dunes will respond to changes in the key controlling variables on an annual or decadal scale is challenging. Examination of how the dunes evolve on a decadal to century scale, however, suggests that the dunes in Atlantic Canada should continue to exist. Thus, we advocate using a dune management approach that focuses on minimizing human impacts and allowing natural processes to continue unimpeded. The highest priority for managing our coastal dunes should be to provide them with sufficient accommodation space into which they can transgress naturally.