Records of climate changes and anthropogenic actions over dune fields in historical times

2020 ◽  
Author(s):  
Mihaela Tudor ◽  
Ana Ramos-Pereira ◽  
Joana Gaspar de Freitas
Keyword(s):  
Climatic Variability ◽  
Coastal Dunes ◽  
Coastal Dune ◽  
Environmental Data ◽  
Dune System ◽  
Climatic Fluctuations ◽  
Dune Systems ◽  
Sand Drift ◽  
Aeolian Activity ◽  
Historical Times

<p>Coastal dunes are very complex systems and very sensitive to climatic variability and human actions. In Portugal, coastal dune fields have undergone major changes over historical times. The aim of the paper is focused on the coastal dune systems evolution over the last five centuries, natural and man induced (namely by deforestation and afforestation) and their transformation under the present global changes (sea level rise and coastal storms). The analysis of historical records and environmental data using a set of proxies recorded over the last 1,000 yrs, show intense aeolian activity and sand drift episodes during Little Age Period, causing serious problems for human settlements and agriculture. Coastal society have responded to the wind-blown sands fixing the dunes through afforestation. The process is well documented in the historical sources and many management measures, including abundant legislation, projects and reports were carried out by Portuguese authorities to avoid sand incursion inland.  According to the main report of the General Forest Administration, in the final of 18th century, was estimated an area of about 72 000 ha of free aeolian sands in need of afforestation. Thus, along Portuguese coastline, the dunes experienced a period of stability during the 20th century, due to planting of grasses and pine forest. This paper examines the pathways of the transgressive dune fields of the Central Western Portuguese coast, over various stages of coastal evolution. Mapping the morphological features between Mondego river mouth and Nazaré, using a combination of satellite images, aerial photographs and Lidar data we identified distinct phases of aeolian activity and landforms modification that were associated to climatic fluctuations. This coastal dune system is composed by a succession of different aeolian phases, including a littoral foredune, which lies inland with a complexity of morphologies with transverse and crescentic ridges, and also parabolic dunes. The results show that the dunes building and sand migration inland appears to be linked to the conditions of predominantly negative winter North Atlantic Oscillation index (NAOi), driven by climatic variability during Holocene/Antrhopocene. The consistency of intense sand drift episodes with abrupt cold events during Little Age Period, drastically reduced the area occupied by vegetation, causing changes in aeolian sedimentary processes. Thus, it seems that coastal dunes evolution over the past centuries have been controlled by the two-way interactions between natural conditions and human activities, shaping the Portuguese coastline. Placing historical evidence in a geographical perspective, we hope to fill the gaps in coastal zone dynamics, providing new insights of the human-landscape relationships to predict the future response of the coastal dune systems to human pressure and climate change.<br>Key-words: coastal dunes evolution, geomorphological features, sand drift, anthropogenic impacts, climatic fluctuation, Western Portugal.</p>

No evidence for interspecific interactions between plants in the first stage of succession on coastal dunes in subarctic Quebec, Canada

1997 ◽  
Vol 75 (6) ◽  
pp. 902-915 ◽  
Author(s):  
Gilles Houle
Keyword(s):  
Plant Biomass ◽  
Interspecific Interactions ◽  
Regional Climate ◽  
Salt Spray ◽  
Coastal Dunes ◽  
Growing Season ◽  
Coastal Dune ◽  
Dune System ◽  
Abiotic Conditions ◽  
Herbaceous Perennials

Coastal dunes are very dynamic systems, particularly where the coast is rising as a result of isostatic rebound. In those environments, succession proceeds from plants highly tolerant to sand accumulation, salt spray, and low nutrient availability to less disturbance-tolerant and stress-tolerant, more nutrient-demanding, and supposedly more competitive species. In the subarctic, the regional climate exacerbates the stresses imposed by local abiotic conditions on the dunes. I hypothesized that facilitation would be particularly significant on the foredune of subarctic coastal dune systems because of intense stresses (local and regional) and frequent disturbance in the form of sand deposition. Belowground and aboveground plant biomass was sampled at three different periods during the 1990 growing season along transects perpendicular to the shoreline on a coastal dune system in subarctic Quebec (Canada). The three herbaceous perennials found on the foredune (Honckenya peploides, Elymus mollis, and Lathyrus japonicus) were segregated in time during the growing season and in space along the topographical gradient. The biomass of Honckenya, the first species encountered as one progresses from the upper part of the beach towards the foredune ridge, was not correlated to substrate physicochemistry. However, the biomass of Elymus and that of Lathyrus, the next two species to appear along the flank of the foredune, were related to pH, Mg, Na, and Cl (negatively), and to P and Ca (positively). These results suggest variable linkages between substrate physicochemistry and plant species along the foredune, possibly in relation to species-specific tolerance for abiotic conditions and requirements for substrate resources or to microscale influence of the plants themselves on substrate physicochemistry. Removal experiments carried out over 2 years revealed only one significant unidirectional interaction between these three species along the topographical gradient, and little plant control over abiotic variables (e.g., soil temperature, wind velocity, and photosynthetically active radiation). Early primary succession on subarctic coastal dunes (and elsewhere) appears to be under the control of strong limiting abiotic conditions. As plants slowly gain more control over the physical environment, interspecific interactions (positive and negative) may become more significant. Key words: Elymus mollis, facilitation, Honckenya peploides, inhibition, Lathyrus japonicus, removal experiment, succession, tolerance.

Patterns of grazing on coastal dune systems by insular populations of two species of macropod

1994 ◽  
Vol 21 (1) ◽  
pp. 107 ◽  
Author(s):  
DSL Ramsey ◽  
RM Engeman
Keyword(s):  
Coastal Dune ◽  
Forest Vegetation ◽  
Relative Area ◽  
Dune System ◽  
Negatively Associated ◽  
Dune Systems ◽  
Open Forest ◽  
Wallabia Bicolor ◽  
Coastal Dune System ◽  
Insular Populations

A study of grazing patterns on a coastal dune system on South Stradbroke Island, Queensland, by two species of wallaby was undertaken. Utilisation of sand spinifex (Spinifex sericeus) by agile wallabies (Macropus agilis) and swamp wallabies (Wallabia bicolor) was highly variable between different sites on the dune system. Although wallaby activity on secondary dune strata was significantly higher than on the primary dune, this was not reflected statistically in spinifex grazing levels. However, spinifex stolons on the toe of the primary dune were heavily grazed. Grazing levels on dune systems on the island were negatively associated with the width of the frontal dune and the relative area of open forest vegetation adjacent to the dune system.

Seasonal sand transport through a trough blowout at Pinery Provincial Park, Ontario

1997 ◽  
Vol 34 (11) ◽  
pp. 1460-1466 ◽  
Author(s):  
M. -L. Byrne
Keyword(s):  
Late Summer ◽  
Coastal Dune ◽  
Sand Transport ◽  
Dune System ◽  
Seasonal Differences ◽  
Transport Pathways ◽  
Dune Systems ◽  
Erosion Pins ◽  
Major Loss ◽  
Provincial Park

Trough blowouts represent transport pathways for sediment through coastal dune systems. This paper documents seasonal differences in sand transport through a trough blowout. Measurements were made by trapping sand in Rosen-style traps installed at the mouth and crest of the parabolic dune and with erosion pins in the throat. Erosion-pin data indicated that the surface of the dune was generally accreting in late summer and eroding in winter, suggesting that the major loss of sediment from the dune was occurring in winter. The traps were emptied every 2–4 weeks and showed that, in general, more sand left the dune system than entered it. The amount of sand transported past the traps at the mouth of the dune varied seasonally, with smaller amounts during the summer months than in winter. The upper traps showed greater variability, but had more sediment transported in all months when compared with the lower traps. Amounts of sand transported during winter were greater than in summer.

Coastal dunes - A nature based coastal protection element exposed to exacerbated anthropogenic stress

2021 ◽  
Author(s):  
Björn Mehrtens ◽  
Viktoria Kosmalla ◽  
Oliver Lojek ◽  
David Schürenkamp ◽  
Nils Goseberg
Keyword(s):  
Vertical Wall ◽  
Coastal Dunes ◽  
High Energy ◽  
Coastal Dune ◽  
Water Levels ◽  
Flood Protection ◽  
Coastal Protection ◽  
Dune System ◽  
Sand Surface ◽  
Joint Research Project

<p>Natural coastal dunes covered by vegetation are an essential component on many sandy coastlines worldwide and often provide the only physical protection against flooding by dissipating wave energy and enhancing erosion resilience. However, sea level rise, changing and widely intensifying coastal wave climates and storm surges constitute severe exacerbated stresses, calling into question the perseverance of such unique coastal ecosystems as dunes and their protective functions taken for granted.</p><p>Here we investigate the extensive coastal dune system of St. Peter-Ording, a major tourist draw of the German North Sea within a marine high energy zone. Lining the coast along 15 km, extending up to 1.5 km in cross-shore direction it covers an area of 18 sqkm characterized by overgrown dunes separating the tidal foreshore from the topographically flat hinterland. Featuring a dedicated, Germany wide unique, coastal protection function sets it apart from other national coastal dune systems - potentially creating a role model for mitigating coastal squeeze related driving factors, further adding to its awe-inspiring landscape character.</p><p>Consequently, the joint-research project ''Sandküste St. Peter Ording'' examines whether the local flood protection dune “Maleens Knoll”, a 16.6 m high natural coastal dune stretching a roughly 1.2 km long gap in the sea-dike defense, will continue to offer adequate protection in the future. Current hypothesis is, that due to the overgrowth with non-endemic and invasive vegetation species, the natural dynamic and self-adaptation of the system is impaired and will not withstand projected changes in coastal drivers. Therefore, the long-term goal is to develop a variety of nature-friendly flood protection measures to reinforce the dune and reduce its probability of failure during an extreme storm surge.</p><p>Possible options comprise the installation of hybrid systems, combining the existing dune core with one of the following structures: 1) a vertical wall to gain more stability during erosion of the sand cover, 2) rock filling to increase wave dissipation and reduce wave reflection and erosion and 3) geotextiles to provide a temporary and more environmentally protection against runup. The built-in materials will be covered with sand, to mimic the original landform and yield its previous degree of freedom regarding topographic adaptation. Another approach is to strengthen the resistance of the sand surface against aeolian and fluvial erosion. Through a microbiological process based on calcium carbonate precipitation (MICP), the strength can be increased in a particularly environmentally friendly way that saves raw materials. Furthermore, adapted or additional planting with a site-typical vegetation can promote sand accumulation at the surface and thereby stabilize the dune.</p><p>Large-scale physical model experiments will be performed in a wave flume to investigate the protection potential of the dune. First, the natural dune condition will be recreated and tested under a combination of water levels and wave conditions to investigate current and future load cases. Based on the findings, a second series of experiments will be conducted to determine which engineering methods are most appropriate to reinforce the dune and ensure its coastal protection character and retain its naturalness at the same time.</p>

scholarly journals Nature-Based Solution along High-Energy Eroding Sandy Coasts: Preliminary Tests on the Reinstatement of Natural Dynamics in Reprofiled Coastal Dunes

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2518 ◽  
Author(s):  
Bruno Castelle ◽  
Quentin Laporte-Fauret ◽  
Vincent Marieu ◽  
Richard Michalet ◽  
David Rosebery ◽  
...  
Keyword(s):  
Large Scale ◽  
Coastal Dunes ◽  
High Energy ◽  
Coastal Dune ◽  
Coastal Hazards ◽  
Dune System ◽  
Bare Sand ◽  
Stage Of Development ◽  
Scale Experiment ◽  
Natural Dynamics

This paper describes a large-scale experiment designed to examine if reinstating natural processes in the coastal dune systems of Southwest France can be a relevant nature-based adaptation in chronically eroding sectors and a nature-based solution against coastal hazards, by maintaining the coastal dune ecological corridor. An experiment started in late 2017 on a 4-km-long stretch of coast at Truc Vert, where experimental notches were excavated and intensively monitored in the incipient and established foredunes. Preliminary results indicate that most of the excavated notches did not develop into blowout. Only the larger elongated notches subsequently excavated in the established foredune in 2018 showed evidence of development, acting as an effective conduit for aeolian landward transport into the dunes. All notches were found to have a statistically significant impact on vegetation dynamics downwind, even those that did not develop. The area of bare sand landward and within the elongated notches notably increased implying a loss of vegetation cover during this first stage of development. Observations of a nearby coastal dune system that has been in free evolution over the last 40 years also indicate that, although the dune migrated inland by more than 100 m, it is now mostly made of bare sand. Further work is required to explore if and how dunes maintained as dynamic systems can become an efficient nature-based solution along this eroding coastline.

scholarly journals A 7000-year record of coastal evolution, Vejers, SW Jutland, Denmark

2006 ◽  
Vol 53 ◽  
pp. 1-22 ◽  
Author(s):  
Lars B. Clemmensen ◽  
Karsten Pedersen ◽  
Andrew Murray ◽  
Jan Heinemeier
Keyword(s):  
Large Scale ◽  
Coastal Dunes ◽  
Aeolian Sand ◽  
Coastal System ◽  
Dune Field ◽  
The Holocene ◽  
The North ◽  
Sedimentary Evolution ◽  
Sand Drift ◽  
Aeolian Activity

The Holocene coastal lowland at Vejers in western Jutland has formed during the last 7000 years. The lowland is composed of a large, NNE-SSW trending spit system associated with minor and only locally developed strandplain or beach ridge systems. The main spit and back-barrier system is bounded to the north and east (inland) by old moraine landscapes (Varde Bakkeø). Most of the coastal system and also large parts of the adjacent moraine landscape is covered by aeolian sand. In this study one of the minor strandplain systems is investigated. This system is developed at the south-western margin of the old moraine landscape at Grovsø, a lake near Vejers. The Holocene sedimentary evolution of this latter system is evaluated on the basis of data from two closely situated cores and Ground-Penetrating Radar (GPR) mapping. Both cores consist of a lowermost unit with marine sediment, a middle unit with lake-aeolian sand and an uppermost unit with aeolian sandplain deposits. Peat layers and peat-rich paleosols are common. These peat-rich horizons are dated by the Accelerator Mass Spectrometry (AMS) radiocarbon technique, while the intervening sand layers are dated by Optically Stimulated Luminescence (OSL). Combined evidence from the sedimentological and chronological studies of the cores and the GPR survey, indicate that the area was first transgressed at about 5100 BC. During the subsequent period (5100–2700 BC) relative sea level rose about 5 meters, the strandplain prograded, and small coastal dunes formed. During this progradational event a large strandplain lake formed behind the frontal dune ridge and this lake was filled primarily by aeolian sand. Aeolian sand drift may have been most intense around 3000 BC. This first period of large-scale aeolian activity ended some time before 2300 BC with formation of a peat-rich paleosol. Aeolian activity, however, was soon re-established and resulted in the formation of a large sandplain with small dunes. Aeolian sand movement and accumulation, however, was punctuated by periods of landscape stabilisation and peat-rich paleosol formation. Changes from landscape stabilisation to dune field activity took place at about 2300 BC, 1450 BC, 800 BC, and 650 BC. Aeolian accumulation at the study site terminated at about AD 0, but other evidence indicates renewed aeolian activity in the dune field after AD 300 and between AD 1100 and 1900. The chronology of some of these aeolian activity phases are synchronous with cooling events in the North Atlantic region suggesting that climatic change strongly influenced dune field dynamics.

scholarly journals Monitoring the Dynamics of Formby Sand Dunes Using Airborne LiDAR DTMs

2021 ◽  
Vol 13 (22) ◽  
pp. 4665
Author(s):  
Ahmed Mutasim Abdalla Mahmoud ◽  
Ekbal Hussain ◽  
Alessandro Novellino ◽  
Panos Psimoulis ◽  
Stuart Marsh
Keyword(s):  
Sand Dunes ◽  
Digital Terrain Model ◽  
Coastal Dunes ◽  
Airborne Lidar ◽  
Dune System ◽  
Erosion Risk ◽  
Dune Systems ◽  
Sand Erosion ◽  
The Uk ◽  
The Impact

Coastal dunes play an important role in coastal erosion risk management, where they act as a dynamic natural sea defence line. Formby coast is part of the Sefton coast in the Northwest of England and is one of the largest and most rapidly evolving sand dune systems in the UK. Such dune systems require continuous comprehensive monitoring activity to understand their dynamics. In this research, we investigate the use of airborne LiDAR digital terrain model DTMs for monitoring the dynamics of the sand dunes at Formby between 1999 and 2020. We found that the rate of elevation change for the beach and the dune areas ranges from −0.78 to 0.02 m/year and −0.92 to 0.73 m/year, respectively. The beach and the frontal dunes have had significant sand erosion, while the inner dunes gained sand during the measurement period. Vegetated areas remained unchanged due to the impact of vegetation in stabilizing the movement of the dunes. Formby beach had a volume loss of about 907,000 m3 in the last 21 years, while the dunes had a volume increase of about 1,049,000 m3 over the same period. The total volume of the entire dune system, consisting of both the beach and dune areas, remained unchanged, which indicates that the growth of the inland dunes is fed by sand from the beach. All the volumetric changes occurred due to sand redistribution within the system, with erosion along the beach, and deposition and erosion in the dune areas.

scholarly journals Demographic effects of interacting species: exploring stable coexistence under increased climatic variability in a semiarid shrub community

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana I. García-Cervigón ◽  
Pedro F. Quintana-Ascencio ◽  
Adrián Escudero ◽  
Merari E. Ferrer-Cervantes ◽  
Ana M. Sánchez ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Species Coexistence ◽  
Climatic Factors ◽  
Demographic Data ◽  
Climatic Variability ◽  
Biotic Interactions ◽  
Vital Rates ◽  
Climatic Fluctuations ◽  
Demographic Models ◽  
Shrub Community

AbstractPopulation persistence is strongly determined by climatic variability. Changes in the patterns of climatic events linked to global warming may alter population dynamics, but their effects may be strongly modulated by biotic interactions. Plant populations interact with each other in such a way that responses to climate of a single population may impact the dynamics of the whole community. In this study, we assess how climate variability affects persistence and coexistence of two dominant plant species in a semiarid shrub community on gypsum soils. We use 9 years of demographic data to parameterize demographic models and to simulate population dynamics under different climatic and ecological scenarios. We observe that populations of both coexisting species may respond to common climatic fluctuations both similarly and in idiosyncratic ways, depending on the yearly combination of climatic factors. Biotic interactions (both within and among species) modulate some of their vital rates, but their effects on population dynamics highly depend on climatic fluctuations. Our results indicate that increased levels of climatic variability may alter interspecific relationships. These alterations might potentially affect species coexistence, disrupting competitive hierarchies and ultimately leading to abrupt changes in community composition.

scholarly journals The spatiotemporal distribution of historical malaria cases in Sweden: a climatic perspective

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Tzu Tung Chen ◽  
Fredrik Charpentier Ljungqvist ◽  
Helene Castenbrandt ◽  
Franziska Hildebrandt ◽  
Mathias Mølbak Ingholt ◽  
...  
Keyword(s):  
Severe Malaria ◽  
Hot Spots ◽  
Climatic Variability ◽  
Warm Season ◽  
Temporal Variations ◽  
Malaria Vectors ◽  
Military Hospital ◽  
Climate Variables ◽  
Superposed Epoch Analysis ◽  
Historical Times

Abstract Background Understanding of the impacts of climatic variability on human health remains poor despite a possibly increasing burden of vector-borne diseases under global warming. Numerous socioeconomic variables make such studies challenging during the modern period while studies of climate–disease relationships in historical times are constrained by a lack of long datasets. Previous studies have identified the occurrence of malaria vectors, and their dependence on climate variables, during historical times in northern Europe. Yet, malaria in Sweden in relation to climate variables is understudied and relationships have never been rigorously statistically established. This study seeks to examine the relationship between malaria and climate fluctuations, and to characterise the spatio-temporal variations at parish level during severe malaria years in Sweden 1749–1859. Methods Symptom-based annual malaria case/death data were obtained from nationwide parish records and military hospital records in Stockholm. Pearson (rp) and Spearman’s rank (rs) correlation analyses were conducted to evaluate inter-annual relationship between malaria data and long meteorological series. The climate response to larger malaria events was further explored by Superposed Epoch Analysis, and through Geographic Information Systems analysis to map spatial variations of malaria deaths. Results The number of malaria deaths showed the most significant positive relationship with warm-season temperature of the preceding year. The strongest correlation was found between malaria deaths and the mean temperature of the preceding June–August (rs = 0.57, p < 0.01) during the 1756–1820 period. Only non-linear patterns can be found in response to precipitation variations. Most malaria hot-spots, during severe malaria years, concentrated in areas around big inland lakes and southern-most Sweden. Conclusions Unusually warm and/or dry summers appear to have contributed to malaria epidemics due to both indoor winter transmission and the evidenced long incubation and relapse time of P. vivax, but the results also highlight the difficulties in modelling climate–malaria associations. The inter-annual spatial variation of malaria hot-spots further shows that malaria outbreaks were more pronounced in the southern-most region of Sweden in the first half of the nineteenth century compared to the second half of the eighteenth century.

Coastal Observations: Rapid development and colonization of a UK sand dune system

Shore & Beach ◽  
2021 ◽  
pp. 17-21
Author(s):  
A.T. Williams
Keyword(s):  
Sand Dune ◽  
Rapid Development ◽  
Sea Buckthorn ◽  
Ammophila Arenaria ◽  
Couch Grass ◽  
Dune System ◽  
Dune Systems ◽  
Frontal Part ◽  
Agrostis Tenuis ◽  
South Wales

Between the years 1200 and 1600, vast quantities of sand were brought inshore from offshore bars as a result of centuries of ferocious storms, to form a series of dune systems along the South Wales coastline. Today, as a result of many housing, leisure, and industrial developments only a few remnants exist. On one such remnant at Porthcawl, Wales, UK, became a caravan site in the 1930s, which was abandoned in 1993 for political reasons. Within 27 years a minimum of 120,000 m3 of sand was transported from the adjacent beach and formed dunes >4 m in height along a 400- m frontal edge that extended some 130 m inland, approximately a third of the site. Typical vegetation found along the frontal part of the system are Ammophila arenaria (marram), Agropyron junceiforme (sand couch grass) and Euphorbia maritimum (spurge). To the rear of the system, vegetation included Agrostis tenuis and stolonifera, (bent and creeping bent grass), Cirsium avense (creeping thistle), and Caluna vulgaris (heather). A 4-m-high and c. 3000m2 area of a vigorous stand of Hippophae rhamnoides (sea buckthorn) has also formed. The rapidity of dune formation and vegetation colonization is staggering.

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