Geomorphic Landscape Research Articles

Spatio-Temporal Geomorphic Landscape Dynamics and Possible Geological Hazards in Ghana

Spatio-Temporal Geomorphic Landscape Dynamics and Possible Geological Hazards in Ghana

해동명산도폭에 나타난 영동지역의 지형 경관에 대한 연구

해동명산도폭에 나타난 영동지역의 지형 경관에 대한 연구

Geomorphic landscape design integrated with progressive mine restoration in clay quarries of Catalonia

ABSTRACT Geomorphic-based mine restoration of clay quarries in Tortosa (Catalonia) was co-funded by the European Union’s LIFE programme. The landform design was made with GeoFluv-Natural Regrade. Their building was performed with existing machinery pool and operators. The main constraint was the impossibility of setback regrading of pre-existing-benched highwalls. Progressive geomorphic mine restoration neither reduced mineral production nor changed the operations. The approach has resulted in higher landscape functionality and integration. Monitoring showed localised erosion due to poorly planned discharge of road runoff and sporadic tunnel erosion. Sediment movement at the designed drainage network is similar to the local fluvial dynamics.

Tidal channel-mediated gradients facilitate Spartina alterniflora invasion in coastal ecosystems: implications for invasive species management

Understanding how geomorphic landscape features affect physical habitat conditions is essential for predicting if such geomorphic landscape features may act as conduits facilitating invasive species expansion in coastal ecosystems. Although the effects of various abiotic and biotic factors on plant invasion in salt marshes have been well studied, little is known about the impact of tidal channels on plant invasion. Here, we examined the effects of bottom-up determinants on the lateral expansion of Spartina alterniflora in tidal channel margins of different elevational marsh zones: the low, middle and high marsh, in the Yellow River Delta, China. Field observations and experiments showed that the microhabitats of tidal channel margins are characterized by relatively low soil salinity and high inundation, which significantly facilitated the establishment, growth, colonization and sexual reproduction of S. alterniflora. Moreover, the facilitating effect of tidal channel margins on plant landward invasion appeared more sensitive in middle and high marshes compared with the low marshes. High propagule pressure combined with suitable physical conditions of the structural microhabitats formed within tidal channels potentially promoted the rapid expansion of S. alterniflora along the tidal channel margins. Based on these results, a conceptual model was built illustrating the lateral expansion mechanisms of the invasive plant mediated by tidal channels. These results highlight the importance of tidal channel-mediated gradients in bottom-up abiotic and biotic-dispersal factors in facilitating the expansion of coastal invasive plants. For wetlands management, our results imply that geomorphic landscape features should be incorporated into ecological management and risk assessment of invasive plants.

Landform modifications within an intramontane urban landscape due to industrial activity, Wałbrzych, SW Poland

ABSTRACT The city of Wałbrzych represents a geomorphic landscape, heavily modified by nearly three centuries of industrial activity, related mainly to coal mining. The key landforms due to human impact include spoil tips of various types, extensive levelled terrains, waste ponds, and railway embankments and cuts. Ground subsidence due to mining and water pumping have affected large areas. The map shows the distribution of anthropogenic landforms due to industrial activity, mainly coal mining, over an area of 85 km2. The thematic symbol set for the main map contains 22 classes of objects which show 13 distinctive types of landform modification due to construction, excavation, levelling and complex features. The Main Map is accompanied by inset maps showing generalized geology of the area, extent and magnitude of ground subsidence, as well as relief visualization.

Geochemical characteristics of fluorine (F) in mainland China's pedosphere: On the basis of the China Geochemical Baselines project

The China Geochemical Baseline (CGB) project (2008–2013) obtained harmonious geochemical baseline data covering all of China, and provided reliable data for 76 elements including F from 3382 top and 3380 deep soil samples. This paper described the statistical and spatial distribution of fluorine (F) throughout China. F concentration ranged from 63 to 9364 μg/g in top soil and ˂ 52 to 9346 μg/g in deep soil. The median concentration of F, which is deemed to be the geochemical baseline in top and deep samples are 488 μg/g and 456 μg/g respectively. The mean concentration of F in top and deep soil samples are 506 μg/g and 482 μg/g respectively. Low F concentrations areas are linearly distributed from northeastern to southwestern China, and high F concentrations areas are distributed in northwestern, northern China and karst area. The anomalous centres of F are exactly correlated with F mineralization. This distribution pattern of F in pedosphere is influenced by minealizations, lithology background, geomorphic landscapes, drainage basins and soil types. Generally, fluorine-bearing rocks provide a reliable source of F in pedosphere, and the geochemical behavior of F determines its ability to migrate in different media.

A characteristic periglacial landform: Automated recognition and delineation of cryoplanation terraces in eastern Beringia

AbstractAutomated recognition and delineation of specific landforms and their constituent elements ranks among the most active areas of contemporary geomorphological research. This study contributes to that literature by applying semi‐ and fully automated recognition procedures to upland periglacial geomorphic landscapes. The Cryoplanation Terrace semi‐Automated Recognition (CTAR) algorithm utilizes basic terrain parameters to identify locations of cryoplanation terraces (CTs) from the high‐resolution ArcticDEM. Using a multistep process, candidate areas are identified based on morphometric characteristics. CTAR uses terrain derivatives to search ridges, hills, and mountains for flat areas bounded by abrupt breaks in slope. Because CTs are found exclusively in upland periglacial environments, some locations require that low‐lying areas be filtered out. To assess accuracy, CTAR was tested at five local study sites distributed across eastern Beringia, each containing multiple CTs delimited manually in a previous study. CTAR performed well, with an overall accuracy of 90%. A strong linear relationship exists between the size of CTAR‐delimited terraces and those identified in a previous study through air‐photo interpretation. In addition to identifying nearly all of the CTs in the five study areas, a fully automated version of the algorithm (GEE‐CTAR), implemented in Google Earth Engine, identified nearly 8,000 previously unmapped potential CTs in the Seward Peninsula region of western Alaska. The ability to identify CTs from digital elevation models provides a useful tool for recognizing and delineating upland periglacial topography. Objective recognition of large erosional landform elements created by periglacial processes is a critical step in developing the field of periglacial geomorphometry.

Geomorphological Evolution and Palaeoenvironmental Change in the Western Alashan Plateau, China

Although neotectonic activity is considered to be the main factor of theterrain evolution of the Qinghai Tibet Plateau and its surrounding high-altitude areas, further geomorphological analysis and literature analysis areneeded for the understanding of the geomorphic evolution and the Quaternary environment change of the western area of the Alxa Plateau nearthe northern Tibet Plateau. The purpose of this study is to investigate thedistribution of site-specific geomorphic units of the landforms developedin the vast topography of Ejina Basin (Western Alxa), in order to identifythe geostructural and climatic causes of the geomorphic landscape and itsimpact on the change of paleoenvironment. At present, the climate andhydrological conditions in Ejina are relatively monotonous and stable. Inaddition to tectonic dynamic factors, the most widely distributed landform in the basin is climate landform. There are both geomorphologicaland sedimentological anomalies of Aeolian landforms occurred in thewhole basin, indicating that the underlying surface effect (retention effect) of river (Ejina River) and its related uneven ground and weak winderosion (deflation) process in the nearby area may be the important factors controlling the formation of Ejina dunes, rather than the arid climate.It is believed that the extensive interaction between the aeolian and fluvialprocesses is the main mechanism of the regional geomorphic difference inEjina Basin. According to the comparability of regional geomorphologyand sedimentology, the period of the formation of relic geomorphologyin the edge of Ejina Basin can be reasonably attributed to the local glacialmaximum of the last glacial. The geomorphic transformation from quasiplain and desert valley to desert plain, the appearance of widely movingsand dunes and the presence of large ancient lake geomorphology allindicate that the drought index of Ejina Basin is increasing on the scaleof geomorphic formation. Paleogeomorphological and chronological evidences show that the climatic and hydrological conditions of the basin inthe last glacial period and the early Holocene are much better than thoseat present. For example, the average annual precipitation in the area before 39-23ka BP is between 60-350 mm (about 36 mm today), but thereare large waves in the Holocene. The coexistence of various climates andlandforms in Ejina Basin and the resulting geomorphic diversity shouldbe the composite result of various geomorphic processes and surface processes besides glaciation. The low aridity (relative humidity) in the EjinaRegion in the late Pleistocene may be the result of the enhancement of thewesterly rain belt and the weakening of the Asian Winter Monsoon in thearid region of Central Asia.

The geomorphic landscape of the Barva volcano, Costa Rica

ABSTRACT Volcanoes have a beneficial role in human development; however, this balance could turn to hazardous processes or even environmental disturbances. Costa Rica is a volcanic country. The people of Costa Rica live upon these landscapes and take advantage of the benefits afforded, such as water recharge, the fertile soils for agriculture purposes, and world-renowned ecological tourism. The Barva volcano is a complex andesitic shield located in the Central Volcanic Range of Costa Rica. Its southern slopes bound the Greater Metropolitan Area (GAM) that contains 65% of the country’s population. We performed a geomorphic landscape analysis which delineated seven landforms that consider the climatic, edaphic, hydrologic, and land use characteristics that describe the largest volcanic massif in Central America. This work is a basic input for environmental, disaster risk, and land use planning for tropical volcanic landscapes under urban and rural pressures. This methodology could facilitate the natural resources management in developing countries where baseline information is scarce.

Multi-resolution soil-landscape characterisation in KwaZulu Natal: Using geomorphons to classify local soilscapes for improved digital geomorphological modelling

Continual advances in quantitative modelling of surface processes, combined with new spatio-temporal and geo-computational algorithms, have revolutionised the auto-classification and mapping of landform components through the automated analysis of high-quality digital elevation models (DEMs). Digital geomorphic mapping (DGM) approaches that can simplify and translate the inclusion of “human knowledge” to automatic terrain classification across a broader spectrum of terrain morphological units as well as a range of spatial scales, therefore, offer great potential for improved topographic and landscape analysis. One such approach is the mapping of landform elements using the concept of the Geomorphon (geomorphological phonotypes). The output of the geomorphon approach is the stratification of the landscape into ten unique but recognisable landform elements: peak, ridge, shoulder, spur, and slope, hollow, foot slope, valley, depression and flat. Equally appealing is the way the model self-adapts to local topography using a line-of-sight principle enabling better matching of landform elements to computational spatial scale. The purpose of this paper is to observe the effects that different pixel resolution (grain size) and digital elevation model source (DEM) would have on the replication of observed geomorphic spatial patterns and representation of terrain selected parameters within the landscape. This paper provides a comprehensive exploratory assessment of digital terrain representation and relief classification using an automated geomorphometric mapping approach, by evaluating three different digital surface models (SUDEM, SRTM, ASTER GDEM2) and different spatial resolution (30 m & 90 m) for an 11,200 ha catchment in KwaZulu-Natal, South Africa. To test the self-adapting ability of the geomorphon approach under regional conditions, we use 4750 gridded terrain samples to quantitatively analyse how the choice of terrain model and scale influence the extraction, generalisation and representation of digitally-derived terrain attributes such as slope, elevation and terrain unit feature extent. We further show how the variation in resulting terrain unit representation is limited by spatial resolution discontinuities of selected elementary soil association distribution, soil texture and soil depth. We also introduce the results of a Similarity Index used to gauge the degree of recall and precision between the different geomorphic landscape features. Finally, the findings of the regional geomorphon-soil relationships are presented in a readily interpretable and qualitative manner, providing a “quasi-landscape signature” for potential localised geomorphons. The application of the study findings may be beneficial to practitioners looking to align or refine modelled terrain classification approaches with expert perception and formalised heuristic approaches.

Combined unsteady denudation and climatic gradient factors constrain carbonate landscape evolution: New insights from in situ cosmogenic 36Cl

Abstract In situ cosmogenic nuclides are widely employed to quantify topographic and geomorphic landscape evolution. However, few studies are devoted to investigating possibly unsteady denudation. In this work the denudation rates of five surface bedrock and one depth profile are measured using in situ cosmogenic 36Cl in different climate zones in China; cosmogenic 36Cl is a powerful proxy for the surface denudation processes of carbonate landscapes in different climatic gradients since carbonates are more sensitive to climate change than silicates. Compiling previous worldwide surface denudation studies in different gradients, we find that: (I) denudation rate increases systematically with mean annual precipitation (MAP) in arid climatic zones (MAP lower than ~700 mm yr−1) and is dominated by long-term climatic gradients; (II) humid climatic zone (MAP greater than ~700 mm yr−1) denudation rates are about constrained to 34.1 ± 11.7 mm kyr−1 by carbonate dissolution kinetics; and (III) denudation rate is also influenced by short-term physical erosion or abrupt erosive events. Accordingly, the reconstructed evolutionary history of the Guizhou depth profile results from either a relatively high denudation rate (55.5–4.4 +5.6 mm kyr−1) and long duration exposure (274–147 +120 ka), or an alternative a low denudation rate (0.8–0.8 +13.3 mm kyr−1) and a recent abrupt erosive event (13.0–1.6 +1.9 ka). These two possible solutions suggest that assumed long-term averaged denudation rate can conceal episodic erosion events. Given tectonic quiescence we propose that climate change might mainly control an erosive event during the last glacial termination (~14 ka), which also implies that caution should be taken when determining the denudation rate of a landscape where climate change and/or tectonic activity plays an important role.

Rock glaciers of the Beartooth and northern Absaroka ranges, Montana, USA

AbstractSix hundred sixty‐one rock glaciers in the northern Absaroka and Beartooth Ranges of south‐central Montana were digitized and evaluated using geographic information systems technology and an array of topographic and environmental parameters. Beartooth rock glaciers are larger, occur at higher elevations, receive more precipitation, and are subject to lower temperatures than northern Absaroka rock glaciers. Elevation is strongly correlated with rock glacier activity. Comparative analysis of these adjacent mountain ranges indicates that Beartooth geomorphic landscapes are shifting from predominantly glacial to periglacial regimes, and that the northern Absarokas have largely completed this transition. Because glaciers are declining in response to climate warming, rock glaciers could soon become the most important source of ice in the region.

Lake sedimentation as an agent of postglacial transformation of interfluves and fluvial landscapes of the Borisoglebsk Upland, Central European Russia

Abstract. Borisoglebsk Upland is considered an example of a secondary upland plain in the marginal zone of the last Middle Pleistocene glaciation. Moraine hills and kames were reworked by glaciofluvial processes and incised by small fluvial forms later. Its postglacial surface drift cover is regularly defined as an undivided complex of mantle loams of dominantly subaerial origin with characteristic cryogenic features and remnants of paleosols. However, some previous studies suggest that lake sedimentation played an important role in the postglacial history of the Borisoglebsk Upland. This paper presents results of a detailed investigation of postglacial sedimentary cover of the eastern part of the Borisoglebsk Upland aimed to reconstruct the co-evolution of surface deposits, soil cover and geomorphic landscapes since degradation of the last Middle Pleistocene glaciation about 150 ka (MIS-6). The study is essentially based on a comprehensive lithological, pedological and geocryological description of postglacial deposits in cores (hand or machine-driven) and open sections, systematic sampling for grain size analysis and selective sampling for 14C absolute dating and monoliths structural examination. The results indicate that most of the surface drifts in this feature consists of stratified lacustrine deposits. Their Late Pleistocene age is stratigraphically confined by the underlying paleosols and incorporated peats of the Mikulino interglacial age (MIS-5) and several organic-rich layers within the lake sequence 14C dated to the Middle Valdai interstadial (MIS-3). Overlying mantle loams and colluvial deposits with cryogenic features and low organic matter content those facially substitute lacustrine sediments were attributed to the Late Valdai stadial (MIS-2). After the Mid-Holocene stabilization, relatively thin colluvial cover identified by the increased amount of organic matter also deposited. We conclude that lacustrine sedimentation is the primary Late Pleistocene agent that transformed the initial glacial topography and most characteristic type of lithodynamics of the eastern Borisoglebsk Upland.

Assessing the performance of decision tree and neural network models in mapping soil properties

To build any spatial soil database, a set of environmental data including digital elevation model (DEM) and satellite images beside geomorphic landscape description are essentials. Such a database, integrates field observations and laboratory analyses data with the results obtained from qualitative and quantitative models. So far, various techniques have been developed for soil data processing. The performance of Artificial Neural Network (ANN) and Decision Tree (DT) models was compared to map out some soil attributes in Alborz Province, Iran. Terrain attributes derived from a DEM along with Landsat 8 ETM+, geomorphology map, and the routine laboratory analyses of the studied area were used as input data. The relationships between soil properties (including sand, silt, clay, electrical conductivity, organic carbon, and carbonates) and the environmental variables were assessed using the Pearson Correlation Coefficient and Principle Components Analysis. Slope, elevation, geomforms, carbonate index, stream network, wetness index, and the band’s number 2, 3, 4, and 5 were the most significantly correlated variables. ANN and DT did not show the same accuracy in predicting all parameters. The DT model showed higher performances in estimating sand (R2=0.73), silt (R2=0.70), clay (R2=0.72), organic carbon (R2=0.71), and carbonates (R2=0.70). While the ANN model only showed higher performance in predicting soil electrical conductivity (R2=0.95). The results showed that determination the best model to use, is dependent upon the relation between the considered soil properties with the environmental variables. However, the DT model showed more reasonable results than the ANN model in this study. The results showed that before using a certain model to predict variability of all soil parameters, it would be better to evaluate the efficiency of all possible models for choosing the best fitted model for each property. In other words, most of the developed models are site-specific and may not be applicable to use for predicting other soil properties or other area.

The future geomorphic landscape in Ireland

There are multifaceted challenges in conducting geomorphology research in third level institutions in Ireland in an academic era rife with pressures to publish and expectations to conduct relevant research with high societal impact. This special issue includes a series of innovative papers that address that challenge, focused specifically on the vulnerability of Irish landscape systems to climate change and human activity. A series of recommendations are presented that promote the visibility of geomorphology research and teaching and identify opportunities where geomorphologists can contribute to national plans on broad landscape planning and building climate resilience. These include: (i) using climate change as a vehicle to foster new cross disciplinary research programmes and to bridge the physical-human divide in the discipline of geography; (ii) monetising ecosystems goods and services as a means to obtain proportional capital investment to conserve and protect our neglected and underappreciated geomorphic features and landscapes; and (iii) advocating for appropriately resourced research funding to support essential field-based research in the wider geomorphological field across universities.

The future geomorphic landscape in Ireland

There are multifaceted challenges in conducting geomorphology research in third level institutions in Ireland in an academic era rife with pressures to publish and expectations to conduct relevant research with high societal impact. This special issue includes a series of innovative papers that address that challenge, focused specifically on the vulnerability of Irish landscape systems to climate change and human activity. A series of recommendations are presented that promote the visibility of geomorphology research and teaching and identify opportunities where geomorphologists can contribute to national plans on broad landscape planning and building climate resilience. These include: (i) using climate change as a vehicle to foster new cross disciplinary research programmes and to bridge the physical-human divide in the discipline of geography; (ii) monetising ecosystems goods and services as a means to obtain proportional capital investment to conserve and protect our neglected and underappreciated geomorphic features and landscapes; and (iii) advocating for appropriately resourced research funding to support essential field-based research in the wider geomorphological field across universities.

Monitoring landscape changes and spatial urban expansion using multi-source remote sensing imagery in Al-Aziziyah Valley, Makkah, KSA

The CORONA satellite imagery acquired in 1967 enabled retrieving the initial geomorphic landscape of Al-Aziziyah valley which comprises mountain ridges, extended mountain ridges, isolated hills, and alluvial plains. The CORONA image implied a minimal landuse features in Al-Aziziyah valley. On the other hand, the QuickBird image acquired in 2005 demonstrated extensive urban expansion on the expense of the initial morphologic features. The various urban features have occupied ∼62% of Al-Aziziyah valley. The residential areas and road networks are the major landuse features occupying ∼39% of the entire study area. The governmental, hotels, educational, and the commercial features along with the public service locations represented ∼21% of the study area. The QuickBird image acquired in 2005 enabled mapping the bare lands located among the various landuse features along with the mountainous areas that are under preparation for future urban expansions. Both the bare lands and the planned mountainous areas represented ∼18% of the study area. All urban expansions have occurred either over, through, or instead the various initial morphologic features resulting in reshaping the physiographic characteristics of the landscape of the study area.

Spatial distributions and the identification of ore-related anomalies of Cu across the boundary area of China and Mongolia

The 1:1, 000, 000 geochemical mapping across the boundary area of China and Mongolia has acquired high-quality basic geochemical data, yielding more than 9000 stream sediment samples and over 400 rock samples. Each stream sediment and rock sample site was assigned to the regional tectonic unit, geological background and geomorphic landscape maps, respectively, resulting in spatial data for three categorical variables. The contents and spatial distributions of Cu in stream sediment and rock samples across the boundary area of China and Mongolia were studied. The stream sediment geochemical data set was centered logratio transformed (clr) to avoid the closure effect. Random forest regression (RFR) was applied to predict Cu geochemical background for each sample with tectonic unit, geological background, and geomorphic landscape as characteristic variables, then the residuals were used to map geochemical anomalies. The study shows that Cu contents in stream sediments and rocks are high in the west and low in the east of the study area, and the median Cu varies with different tectonic units, geological backgrounds, and geomorphic landscapes. The background values of Cu are strongly spatial heterogeneous. The distributions of predicted Cu background values by random forest regression algorithm are similar to the distribution characteristics of Cu in stream sediments and rocks. The influence of tectonic units on the spatial variations of Cu geochemical background was greatest, followed by geological background, the influence of geomorphic landscape was smallest. The geochemical anomalies drawn by the residuals produced in random forest regression are in good agreement with the known deposits, indicating that the predicted geochemical background of Cu is reasonable and accurate, and has certain theoretical and practical significance.

Spatial patterns of vegetation and climate in the North China Plain during the Last Glacial Maximum and Holocene climatic optimum

Reconstructing the spatial patterns of regional climate and vegetation during specific intervals in the past is important for assessing the possible responses of the ecological environment under future global warming scenarios. In this study, we reconstructed the history of regional vegetation and climate based on six radiocarbon-dated pollen records from the North China Plain. Combining the results with existing pollen records, we reconstruct the paleoenvironment of the North China Plain during the Last Glacial Maximum (LGM) and the Holocene Climatic Optimum (HCO). The results show that changes in the regional vegetation since the LGM were primarily determined by climatic conditions, the geomorphic landscape and by human activity. During the LGM, the climate was cold and dry; mixed broadleaf-coniferous forest and deciduous-evergreen broadleaf forest developed in the southern mountains, and cold-resistant coniferous forest and mixed broadleaf-coniferous forest were present in the northern mountains. The forest cover was relatively low, with mesophytic and hygrophilous meadow occupying the southern part of the plain, and temperate grassland and desert steppe were distributed in the north; Chenopodiaceae-dominated halophytes grew on the exposed continental shelf of the Bohai Sea and Yellow Sea. During the HCO, the climate was warm and wet; deciduous broadleaf forest and deciduous-evergreen broadleaf forest, with subtropical species, developed in the southern mountains, and deciduous broadleaf forest with thermophilic species was present in northern mountains. Although the degree of forest cover was greater than during the LGM, the vegetation of the plain area was still dominated by herbs, while halophytes had migrated inland due to sea level rise. In addition, the expansion of human activities, especially the intensification of cultivation, had a significant influence on the natural vegetation. Our results provide data and a scientific basis for paleoclimate modelling and regional carbon cycle assessment in north China, with implications for predicting changes in the ecological environment under future global warming scenarios.

Dating the Cooloola coastal dunes of South-Eastern Queensland, Australia

The Cooloola sand dunes are part of a series of aeolian parabolic dunes that stretch along the east coast of Australia. They form a chronosequence showing increasing weathering, soil formation and water erosion across six geomorphically recognized soil landscapes. These landscapes were recognized from air photographs and further refined on the basis of some 150 auger holes across the dunes. Data about the structure and floristics of the vegetation were collected at the same time. There is a significant body of literature about the Cooloola dunes but there are two areas that have not been satisfactorily considered. First the previous dating which gave inconsistent results has been superseded by single grain OSL dates and second Cooloola has not been considered in a regional context. Here we report the results of single grain optically stimulated luminescence (OSL) analyses for 31 samples for 21 sites across the geomorphic landscapes. The sites were selected near the apex of each dune as this represents the last depositional date and the least disturbed by sand movement.We recognized 10 units across the dunes on the basis of the dates available. The dune ages ranged from recent to 725 ka. The largest dunes at some 320 m high were dated at around 140 ka and these dunes carry the maximum vegetation biomass of this dunefield. Beyond this vegetation maximum the dunes had lost their parabolic shape due to prolonged weathering and erosion and the vegetation is greatly reduced in height and biomass. The depth to the soil B horizon gradually deepens with age to form giant podzols in the older dunes. The depth to the B horizon was remarkably consistent within the geomorphic landscapes across the length and breadth of the dunes.These studies place the Cooloola dunes in a unique position as the chronosequence is intact. The possible processes that lead to the formation of the dunes and the regional implications are discussed. Secondly, it shows the buildup and decline of the dune ecosystems and acts as a model for all ecosystems. Forest succession models which place less emphasis on soil development miss this important process.