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Copyright of VAD: Veredes, Arquitectura y Divulgación is the property of Alberto Alonso Oro and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the continental Mediterranean mountains of the Iberian Peninsula is located a landscape characterized by the presence of enclosed land parcels delimited by dry stone walls or vegetation, or by both these elements. This landscape has been included, since 2018, in UNESCO's Representative List of Intangible Cultural Heritage of Humanity under the name of Art of dry stone walling, knowledge and techniques. However, today's territorial dynamics jeopardize the maintenance of this landscape heritage. This work set out to understand their origins, dynamics, and evolution from the 11th century (Middle Ages) to the present using historical documentation from different sources and diachronic cartography from aerial photographs. The fieldwork was designed to identify natural, cultural features and recent dynamics, in particular those related to urbanization changes of the last 70 years. Finally, we delved into the new dynamics of exploitation that were based on extensification and a loss of productive diversity. The results obtained lead us to consider that the loss of this agro-landscape must be prevented, with a reasonable livestock grazing criteria and a rational management of its heritage features. This requires regional, national, and European policies that recognize the enclosed landscape as a heritage ecosystem in which biodiversity and agriculture are closely linked. [ABSTRACT FROM AUTHOR]

A good understanding of historical change rates is a key requirement for effective coastal zone management and reliable predictions of shoreline evolution. Historical shoreline erosion for the coast of Guardamar del Segura (Alicante, Spain) is analyzed based on aerial photographs dating from 1930 to 2022 using the Digital Shoreline Analysis System (DSAS). This area is of special interest because the construction of a breakwater in the 1990s, which channels the mouth of the Segura River, has caused a change in coastal behavior. The prediction of future shorelines is conducted up to the year 2040 using two models based on data analysis techniques: the extrapolation of historical data (including the uncertainty of the historical measurements) and the Bruun-type model (considering the effect of sea level rises). The extrapolation of the natural erosion of the area up to 1989 is also compared with the reality, already affected by anthropic actions, in the years 2005 and 2022. The construction of the breakwater has accelerated the erosion along the coast downstream of this infrastructure by about 260%, endangering several houses that are located on the beach itself. The estimation models predict transects with erosions ranging from centimeters (±70 cm) to tens of meters (±30 m). However, both models are often overlapping, which gives a band where the shoreline may be thought to be in the future. The extrapolation of erosion up to 1989, and its subsequent comparison, shows that in most of the study areas, anthropic actions have increased erosion, reaching values of more than 35 m of shoreline loss. The effect of anthropic actions on the coast is also analyzed on the housing on the beach of Babilonia, which has lost around 17% of its built-up area in 40 years. This work demonstrates the importance of historical analysis and predictions before making any significant changes in coastal areas to develop sustainable plans for coastal area management. [ABSTRACT FROM AUTHOR]

We propose an optimized Structure-from-Motion (SfM) Multi-View Stereopsis (MVS) workflow, based on minimizing different errors and inaccuracies of historical aerial photograph series (1945, 1979, 1984, and 2008 surveys), prior to generation of elevation-calibrated historical Digital Surface Models (hDSM) at 1 m resolution. We applied LiDAR techniques on Airborne Laser Scanning (ALS) point clouds (Spanish PNOA LiDAR flights of 2014 and 2019) for comparison and validation purposes. Implementation of these products in multi-temporal analysis requires quality control due to the diversity of sources and technologies involved. To accomplish this, (i) we used the Mean Absolute Error (MAE) between GNSS-Validation Points and the elevations observed by DSM-ALS to evaluate the elevation accuracy of DSM-ALS generated with the LAScatalog processing engine; (ii) optimization of the SfM sparse clouds in the georeferencing step was evaluated by calculating the Root Mean Square Error (RMSE) between the Check Points extracted from DSM-ALS and the predicted elevations per sparse cloud; (iii) the MVS clouds were evaluated by calculating the MAE between ALS-Validation Points and the predicted elevations per MVS cloud; iv) the accuracy of the resulting historical SfM-MVS DSMs were assessed using the MAE between ALS-Validation Points and the observed elevations per historical DSM; and (v) we implemented a calibration method based on a linear correction to reduce the elevation discrepancies between historical DSMs and the DSM-ALS 2019 reference elevations. This optimized workflow can generate high-resolution (1 m pixel size) hDSMs with reasonable accuracy: MAE in z ranges from 0.41 m (2008 DSM) to 5.21 m (1945 DSM). Overall, hDSMs generated using historical images have great potential for geo-environmental processes monitoring in different ecosystems and, in some cases (i.e., sufficient image overlapping and quality), being an acceptable replacement for LiDAR data when it is not available. [ABSTRACT FROM AUTHOR]

During the last 3 ka, different human communities occupied the Bay of Cádiz (SW Spain), including Phoenician, Carthaginian, Roman, Medieval and Modern settlements. Traces of such historical occupations have been recognized along the bay from a geoarchaeological point of view. Some of them bear a palaeogeographical interest related to the historical location of the shoreline. At the same time, Holocene sedimentary units and geomorphological elements identified along the bay can be interpreted as evidences of its morphological evolution. The objective of the present paper is to represent all the available data about archaeological sites and geomorphology in the northern Bay of Cádiz, with the aim of combining both sources of data for elaborating a simple proposal of landscape evolution during the last 3 millennia. The base for mapping was multiple, from historical aerial photographs to satellite imagery and a digital terrain model with a maximum resolution of 0.35 m. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Investigación Geográfica is the property of Universidad de la Rioja, Servicio de Publicaciones and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jaramillo, C.; Sánchez-García, E.; Jara, M.-S.; González, M., and Palomar-Vázquez, J.M., 2020. Subpixel satellite-derived shorelines as valuable data for equilibrium shoreline evolution models. Journal of Coastal Research, 36(6), 1215–1228. Coconut Creek (Florida), ISSN 0749-0208. The analysis and prediction of shoreline variability are two of the main challenges in coastal engineering. Evaluating coastal behaviour in a target area usually requires access to long data series of high-resolution shoreline positions. Therefore, coastal engineers must have access to different data sources, such as topographic-bathymetric field campaigns, digital orthophotos, aerial photographs, video-camera monitoring systems, and satellite imagery. This last data source is the only one that has the great advantage of covering large areas of the world and including regular coverage of most coasts during all climates and seasons. However, mid-resolution satellite images have been neglected because the resolution available to the public is too coarse to provide information on most coastal morphodynamic changes. The aim of this study was to explore the applicability of mid-resolution satellite imagery with a subpixel acquisition method for the calibration and validation of equilibrium shoreline evolution models. The models' performance was assessed by means of a comparative analysis between shoreline-position data sets obtained from video-camera systems and satellite imagery at two beaches on the Mediterranean coast of Spain. Almost 4 months of shoreline measurements were considered for validation purposes of the models at Nova Icaria Beach, and more than 1.5 years of shoreline measurements were analyzed at Cala Millor Beach. The results show that the general erosion-accretion trend is adequately represented by the models compared to the shoreline measurements at a qualitative and quantitative level. [ABSTRACT FROM AUTHOR]

Geomorphological changes in recent decades in three estuaries along the Iberian coast were analysed using aerial orthophotographs. A hierarchical classification scheme, based on a literature review representing 26 estuarine eco-geomorphological features relevant to estuarine dynamics and functioning, is described. The estuaries selected were San Vicente de la Barquera (N Spain), Guadiana River (SW border between Spain and Portugal) and the Ebro River Delta mouth (NE Spain). For these systems, a 60-year time series of high-resolution maps was developed, analysing the changes in feature surfaces. The main subsystems analysed were beach, dunes, saltmarshes and the drainage network. The results of the cartographies showed general behaviour common to all transitional systems, relationships among main subsystems and processes inherent to each one. This work illustrates how beaches and dunes serve as a protective barrier for the tidal flats, acting as a sediment buffer for the entire system. The subsystems are connected by the drainage network responsible for the exchange of matter and energy between them. Furthermore, an accuracy assessment was performed in one of the study zones to identify the limitations of mapping with aerial photographs. The results explain the changes with time but also the processes and relationships between the estuarine features at a long-term scale. This work adds an important perspective towards a general understanding of their dependence on intrinsic and boundary conditions. [ABSTRACT FROM AUTHOR]

The area of Alfambra (NE Spain) is very representative of the relief evolution of the Eastern Iberian ranges. The geomorphological cartography (Main Map) includes the northern sector of the Alfambra-Teruel Neogene depression and its mountainous surroundings. The cartographic process started by using aerial photographs (1:30000 scale) and fieldwork. The structural reliefs, erosion surfaces, karst landforms, Quaternary pediments and terraces, and fluvial network are represented over a lithological background. The main cartography is complemented with two maps of lithological and geomorphological units. The obtained information enabled the main geological and geomorphological stages of the regional relief to be established. [ABSTRACT FROM AUTHOR]

The spread of economic activity in the Oviedo region in northern Spain in recent decades has deeply altered the territorial model. The traditional dichotomy between rural and urban landscapes is blurring, and many functions are being relocated in formerly rural areas. The construction of motorways, and other transport infrastructures, accompanied by the triggering action of both public and private investment, lax legal frameworks, and the amount of flat land, are the main factors that explain the process. Using historic aerial photographs and data gathered by public institutions, this article offers thematic maps to understand the phases and distribution of the spatial diffusion process. The spatial-temporal sequence of landscape changes helps us understand the processes of development in a peri-urban landscape characterised by a diffusion of functions and its role in landscape configuration. [ABSTRACT FROM AUTHOR]

A paleoglacier reconstruction during the Last Glacial Maximum (LGM) is presented for a high mountain area of La Covacha massif in Sierra de Gredos (Iberian Central System) in central Spain. The moraines that, according with the previous literature, had formed during the global LGM, were mapped through photo interpretation of digital aerial photographs and 3D images and detailed field surveys. The topography of the paleoglaciers was estimated using a simple steady-state model that assumed a perfectly plastic ice rheology, reconstructing the theoretical ice profiles and obtaining the ice thickness of the glaciers during the LGM. The reconstruction of the glaciers was carried out using automated and semi-automated physically-based models, obtaining more realistic results with semi-automated models. According to our study, the paleoglaciers in the study area covered an area of 34.79 km2 during the global LGM, with a maximum ice thickness of 366 meters in La Vega gorge, a total volume of 34.25 × 108 m3 and a mean paleoELA of 1932 meters. Most of the ice (∼82%) was in paleoglaciers facing north, and the rest was in paleoglaciers with other orientations. This emphasizes the importance of orientation in relation to glacier dynamics and ice accumulation. The results obtained in the calculation of paleoELAs during the global LGM in Gredos are average compared to the Iberian mountains of the Northwest where the values were much lower, and with respect to those of the Southwest, much higher. This demonstrates the importance of the exposure of Mediterranean mountains to the humidity sources coming from the NW during the global LGM, as is the case at present. [ABSTRACT FROM AUTHOR]

Cereal and olive cultivation are thought to have played a major role in triggering soil erosion since humans have settled in the south of Spain and in increasing gully activity since the relatively recent intensification of olive cultivation. To test these hypotheses, we dated the sediments and reconstructed the soil erosion history of two gullied catchments, in Baena and Montefrío, both located in the South of Spain but with well differentiated land management histories. To date the sediments, we established a multi-proxy chronostratigraphy based on radiocarbon dating, optical stimulated luminescence and archaeology. In addition, we used the reconstructed land management history of the two catchments and aerial photographs. The reconstructed soil histories of the two catchments suggest a close link between agricultural land management practices and soil erosion in the last seven millennia. Notably, results indicate that soil erosion activity started earlier in Montefrío, corresponding to the first human settlements seven millennia ago. However, in the last two millennia erosion and gully activity in Baena have rapidly overtaken that of the Montefrío due to a more intense economic and agricultural activity of the former. In the last decades, erosion and gully activity in both catchments have been very high due to the intensification of the olive cultivation. [ABSTRACT FROM AUTHOR]

Forecasting coastal dynamics and sea cliff retreat under different sea level rise scenarios requires a good understanding of the conditioning factors and their relative contribution to cliff stability. The so-called Jurassic Cantabrian Coast extends along 76 km of the coastline of the Asturias region (N Spain) and is well-known worldwide due to its paleontological heritage, in particular the presence of dinosaur remains and footprints. The abundance of stratigraphic, paleontological and tectonic studies contrasts with the scarcity of studies focused on the stability of this rocky coastline where cliffs predominate, sometimes exceeding 120 m in height. In fact, evidence of current and recent instability processes can be observed along the entire coastline. In this regard, continuous monitoring is crucial to understand ongoing instabilities in rocky coastlines, as in these settings some instabilities might initiate as slow movements that induce subtle topographic changes whose detection from either satellite or aerial imagery is problematic due to the spatial and temporal resolutions. This contribution presents a 4D evolution model of a key site, the Tazones Lighthouse landslide, located on the Cantabrian Coast of Asturias (N Spain), which affects subvertical rocky cliffs sculpted in the Jurassic bedrock made of alternating sandstone and marl. A high resolution multiapproach methodology was developed in order to understand its structure and kinematic characteristics, including: i) interpretation of aerial photographs and unmanned aerial photogrammetric surveys (UAV); ii) 22 monthly monitoring campaigns by total station; iii) 5 manual boreholes; iv) geomechanical characterization of the cliff bedrock; v) geomorphological evidence mapping; vi) analysis of landscape deformations obtained from UAV; and vii) precipitation, soil moisture and significant wave height (H s) data analysis. The results show that the slope evolves by means of a complex-type mass movement, which combines translational and sliding mechanisms, and occupies tens of thousands of square meters. DTM and fieldwork analysis indicate that mass movement is mainly controlled by bedrock discontinuities (S0, 360/15-17; J1, 262/85; J2 166/75). The most important accelerations of slope movement correlate very well with rainfall, soil moisture and waves. Thus, the largest displacements occurring in January and October–November 2019, coincide with 2 periods of storms (maximum 24-h rainfall of 64.5 mm and 82.1 mm and maximum H s of 6.54 and 9.09, respectively) and soil moisture values above 90%. Half of the markers moved more than 1 m and one of them exceeded 15 m. The 4D model obtained after the interpretation of the Tazones Lighthouse slope whole dataset, allows an understanding of how the surrounding cliffs have evolved in the past, fundamental to predicting their future behaviour. [Display omitted] • The Tazones Lighthouse landslide has accelerated its activity since February 2018. • A series of 22 monthly monitoring campaigns reveal total displacements exceeding 15 m. • Jurassic sedimentary bedrock lithology and structure condition the slope evolution. • Monthly monitoring establishes a close relationship between rainfall and displacement. • Recent sea storm episodes are apparently related to landslide motion acceleration. [ABSTRACT FROM AUTHOR]

Biomass models are key to the correct quantification of aboveground biomass and carbon stocks. Most of the current available sets of biomass models were developed for adult trees although very few have been employed to accurately estimate biomass during the first years of reforestations, despite the increasing number of reforestations over recent years. In this study, species-specific and generalized models for aboveground biomass of single trees have been developed for the main 14 species used in reforestations in Spain. A comparison with the existing biomass models at individual tree level for larger trees of these species was also conducted to confirm the hypothesis that specific models are required for the first years of the reforestation. A new set of biomass models was fitted simultaneously per species, based on three different independent variables – root-collar-diameter, total height and crown projection area- and their combinations. The fitted models provide more accurate and unbiased predictions of aboveground biomass in the first years after reforestation when compared with previously existing models for adult trees. The generalized models can be applied to reforestations when the main species is unknown or for mixed plantations where species are not individualized. The set of models provided can be used in a wide variety of surveys and monitoring conditions depending on the available data, from classical field inventories to more novel approaches such as airborne LiDAR data or aerial photographs. • Species-specific tree biomass models were fitted for those most used in reforestations in Spain. • Generalized models also presented can be used when the species identity are unknown. • Differences with estimations from adult tree biomass models were stated at this stage. • Field data, LIDAR or remote sensing data can be used with these models. • Models developed are key to estimate carbon stocks from afforestation/reforestations. [ABSTRACT FROM AUTHOR]

1. In Mediterranean mountainous areas, forests have expanded in recent decades because traditional management practices have been abandoned or reduced. However, understanding the ecological mechanisms behind landscape change is a complex undertaking because the influence of land use may be reinforced or constrained by abiotic factors such as climate. In this work, we evaluated their combined effects on recent forest expansion across climatic, topographic and management gradients. 2. We used orthorectified aerial photographs from the second half of the twentieth century (1956, 1974, 1983, 1990 and 2004) to monitor changes in forest distribution in a set of 20 head-water basins in the Cantabrian Mountains of north-west Spain, at the Eurosiberian-Mediterranean limit. In particular, we evaluated the role of land-use history (comparing natural vs. anthropic basins) and microclimate (comparing shaded vs. sunny aspects) of forest gain/loss rates and spatial distribution shifts. Finally, we applied Species Distribution Modelling techniques (MaxEnt and BIOMOD) in the stated scenarios of land-use history and microclimate, to assess habitat suitability for forest expansion on the basis of topography, soil properties and mesoclimatic variables. 3. Forest cover increased from 10.72% in 1956 to 27.67% in 2004 in the area. The rate of expansion was significantly higher in natural basins and, particularly, on shaded slopes. In all cases, the mean elevation of new forest patches increased during the study period, which was particularly evident on natural sunny slopes. The performance of the models and the magnitude of the effects varied across land-use histories and microclimatic conditions. Soil properties and temperature and precipitation in late spring and early summer were the main drivers of forest expansion in modelling exercises, although expansion rates and upward altitudinal shifts were primarily controlled by landuse history and the biogeographic origin of the forests. 4. Synthesis. The combination of monitoring and modelling techniques used in this work contributed to the understanding of forest expansion in cultural systems, indicating that ecological succession is not a homogeneous process, but varies spatially due to human and abiotic constraints since historical times. [ABSTRACT FROM AUTHOR]

In Mediterranean countries, a change in traditional uses of land has caused an increase in both the number of fires and the land area affected by fires. This situation creates a need to improve the efficiency and effectiveness of wildfire extinguishing devices. This improvement should be based on knowledge of the fire behaviour of various fires affecting similar areas. To study these fires, we considered a methodology to obtain isochrones at different stages of a wildfire through temporal georeferencing of aerial fire photographs. This methodology was applied to two large wildfires (1098 and 4609 ha) that occurred in 2009 in the south of Spain. A total of 463 and 611 photographs were considered to respectively obtain seven and nine isochrones. These isochrones are representative of the development of the fires. In periods of greater intensity, this study exhibits a rate of propagation much higher than expected, reaching 7.8 ha min-1 of burned surface and 160.0 m min-1 of perimeter growth in one example, whereas if we considered only the final perimeter of the fire, the speed of burned perimeter generation would be 28.2 m min-1 and of burned surface, 2.4 ha min-1. [ABSTRACT FROM AUTHOR]

Abstract: An analysis of morphological changes during the last six decades is presented for a 16.5-km reach of the Rambla de Cervera, a Mediterranean ephemeral stream located in eastern Spain. Channel changes were analysed through a range of techniques, specifically the analysis of aerial photographs with geographical information systems (GIS) and comparison of topographic surveys. The gravel channel underwent a general decline over the study period, losing width (68.5%) and surface area (45.7%) caused by the development of established islands frequently attached to the floodplain. These morphological changes exhibit an interesting temporal variability, with a maximum decrease of the gravel channel in the period 1946–1956 and another narrowing stage between 1977 and 1991. Two periods (1956–1977 and 1991–2006) also had mixed performance. In addition, incision processes occurred along the entire study reach at an average depth of 3.5m. Natural and human-induced factors producing contradictory effects are considered responsible for changes in the Rambla de Cervera. [Copyright &y& Elsevier]

Abstract: Coastal changes on sandy shorelines are continuous and occur at diverse spatial and temporal scales. Gaining knowledge on beach change processes increases our capability to manage risks, especially shoreline erosion, affecting the increasing population living in coastal areas. Processes and factors involved in medium- and short-term beach changes depend on the morphological and dynamic characteristics of the coast. In this work, the decadal behaviour of 58 sandy beaches along the 150km long South-Atlantic coast of Spain, between the Guadalquivir river mouth and the Strait of Gibraltar, is analysed in order to investigate the relationships between shoreline change patterns and the diverse morphological and dynamic factors controlling beach evolution in the area. For this purpose, georectified aerial photographs spanning the period 1956–2008 were compared in a GIS environment to calculate rates of shoreline change. Short-term evolution of beach profiles was also analysed in selected areas of interest. Results show that the study area exhibits a great variety of shoreline evolution trends, with erosion prevailing in the northern and central sectors and stability or even accretion in the southern sector. In general, sediment availability is the main factor determining coastal erodibility in the area, largely conditioned by the reduction in fluvial sediment supply caused by river basin regulation. Nearshore bathymetry also has a great significance, as it controls wave refraction-diffraction patterns and wave energy concentration on certain zones. Human interventions on the coast also represent a major influence on beach erodibility in the study area. Severe detrimental effects are caused at certain points by shore-normal engineering structures blocking longshore drift. Additionally extensive urban development in backbeach environments has a significant influence on the sediment budget at certain areas. On the basis of these results, a morphological and evolutionary classification of sandy beaches is proposed taking into account the way beach morphology influences erosion/accretion processes. Rectilinear beaches and enclosed beaches typically show dynamic equilibrium or even accretion trends, whereas reef-supported beaches tend to be dominated by erosion. Headland-bay beaches show complex evolution patterns greatly influenced by local conditions, such as specific shoaling processes or local winds. This classification is useful not only in forecasting general shoreline behaviour in the near future, but also in selecting the most appropriate type of intervention when managing retreating coasts. [Copyright &y& Elsevier]

Abstract: Aerial photographs, historical cartographies, and field inspection are useful tools in urban planning design on mantled karst because they permit a wide time interval to be analyzed. In the case of Zaragoza city, several works have confirmed the interest of these approaches in configuring the urban planning code and therefore represent a promising technique. Nevertheless, some caveats should be taken into account when using this kind of information. A detailed analysis is presented comparing (in a case study from the surroundings of Zaragoza) geomorphological, historical analysis, and field inspection with geophysical data. Field inspection in a noncultivated area permits the constraint of the presence of karst indicators below the geomorphological resolution of aerial photographs and shows results consistent with geophysical surveys. The studied case shows an inner zone coinciding with the sinkhole mapped from aerial photographs that correlates with changes in the position of the substratum and changes in thickness of alluvial sediments. The integrated analysis permits us to define an external subsidence ring around the geomorphological sinkhole whose surface is twice the size of the inner zone. This outer ring is indicated by geometrical changes in GPR profiles, increases of thickness of the conductive shallower unit toward the collapse, and small collapses on marginal cracks. These results support the higher extension of karst hazards linked to sinkholes with respect to their geomorphological expression and the needed detailed analysis to constrain the real sinkhole size or the use of security radii surrounding this surficial evidence when geomorphological data is used for the hazard analyses or the urban planning at karstic zones. [Copyright &y& Elsevier]

Abstract: Dunes in temperate latitudes have experienced a significant stabilization in recent times, essentially as a consequence of the expansion of dense vegetation cover. Yet, the causes for this gradual stabilization as well as the causes promoting antecedent aeolian mobilization remain poorly understood. The Traba coastal dune field, located in NW Spain, was examined to explore the causes inducing aeolian activity and subsequent stabilization since 1940. Morphological changes were identified through the combination of aerial photographs and geophysical techniques. Local wind field regimes were simulated using a regional climate model to obtain the variability of the most relevant modes of atmospheric circulation in the North Atlantic and European regions; North Atlantic Oscillation (NAO), Eastern Atlantic (EA) and Scandinavian (SCAND). This allows us to identify the impact of these circulation modes over dune dynamics. Results document an episode of aeolian activity during the 1950s followed by a gradual stabilization and fixation of the dune coincident with a decrease on storm and wind intensity. Yet, aeolian sand movement remained active in small areas (blowouts), occurring mainly during the summer. NE winds associated with a negative phase of the EA explain the movement of sand within the dune field under favorable conditions of sand supply. On the other hand, sand supply to the dune field from the beach was promoted by NW winds coincident with the summer negative phase of NAO. During winter, the negative NAO favored frequent SW winds associated with the passage of intense storms, which in turn explain sand remobilization from the beach making sediment available for the NW winds to blow inland. With this work, it is proven that to understand past and future aeolian activity requires critical consideration of the variability and impact of the two principal modes of atmospheric circulation in the North Atlantic (NAO and EA). The SCAND mode explaining a lower percentage of the local wind field variability was also included to achieve higher significance levels of explained variance. [Copyright &y& Elsevier]

Ancient quarries are intriguing archaeological sites, but their detailed recording is complex. This paper presents a cost-effective approach to mapping of the Roman quarry site of Pitaranha (Portugal-Spain). First, aerial photographs were acquired using a radio-controlled digital reflex camera attached to a Helikite, which allowed the acquisition of the necessary low-altitude aerial footage in the very unstable wind conditions above the quarry. Using computer vision algorithms, the resulting set of photographs was semi-automatically transformed into a Digital Surface Model (DSM) and a corresponding orthophotograph. Besides focusing on the acquisition and processing method, this paper evaluates the accuracy of the generated products. The orthophotograph proved to be satisfactorily accurate for 1:200 hard-copy mapping. [ABSTRACT FROM AUTHOR]

The article presents a study which examines to what degree the accuracy of gully measurements using photogrammetric techniques depends on the morphology of the gully. It notes that field measurements obtained from gullies in Navarre, Spain having diverse morphology and dimension were used as reference data for investigating the errors linked with a corresponding photogrammetry-derived dataset. It discusses the implications for the analysis on larger arroyos with conventional aerial photography.

Aims The combined effects of changes in climate and land use on tree mortality and growth patterns have rarely been addressed. Relict tree species from the Mediterranean Basin serve as appropriate models to investigate these effects, since they grow in climatically stressed areas which have undergone intense cover changes. The aim is to use climate, aerial photographs, stand structure and radial-growth data to explain the mortality and historical patterns of growth of Abies pinsapo in the area where this relict species was first protected. Location Sierra de las Nieves, West Baetic Range, southern Spain. Methods We assessed variations of tree cover in A. pinsapo forests through image analyses of aerial photographs spanning the last 50 years. We sampled 31 stands to assess current altitudinal patterns of forest structure and mortality. We evaluated the relationships between radial growth and regional climate using linear models in three sites at different elevations. Results Regional warming and a decrease in precipitation were detected. Forest tree cover increased at all elevations from 1957 until 1991, but it afterwards decreased below 1100 m. Currently, the likelihood of tree mortality increases downwards and is associated with dense, closed stands with a low living basal area. In contrast to previous droughts, a sharp synchronized reduction in tree growth, not fully accounted for in linear climate–growth models, occurred at low elevations in 1994–95, but not upwards. It was preceded by a weakening of the negative association between low-elevation growth and water deficit since the late 1970s. Conclusions The intense densification of A. pinsapo forests following strict protection measures in the late 1950s enhanced the vulnerability of climate-sensitive A. pinsapo forests to recent drier conditions. Such abrupt land-use changes help to explain recent patterns of mortality and growth decline in low-elevation A. pinsapo forests. [ABSTRACT FROM AUTHOR]

Vertical stereographic aerial photographs obtained as photographic plates or, more recently, as digital images represent a primary source of data for desk studies on all engineering projects. New methods of data acquisition from both airborne and spacecraft-based scanners provide unparalleled opportunities to obtain high-resolution data. However, interpretation of the images remains as much an art as a science and is critically dependent on the skill and experience of the interpreter. Relevant experience can be obtained only by the practice of ground-truthing an interpretation that the interpreter has carried out. Although it has rarely been quantified there are important lessons for all engineering projects on the divergence between the interpreted image and the actual ground situation. Some of these are exemplified in a case study undertaken by the authors using large-scale aerial photographs for a landslide hazard investigation in Spain. Based on this investigation it can be assumed that up to 50% of landslide features of engineering geological significance might not have been identified by the aerial photograph interpretation. The alternative is to use the images to divide the landscape into terrain units that allow the landslide potential to be evaluated. It can be demonstrated that this approach is more effective than trying to create a landslide inventory based on aerial photographs alone. Given the potential expansion in the use of large-scale image analysis associated with the recent improvement in data acquisition systems this has implications for the use of images and the training of interpreters. [ABSTRACT FROM AUTHOR]

Coastal landslides cause great economic damage to human installations along the Mediterranean shoreline. In the Alboran Sea, this phenomenon is very common and causes many problems for residential resorts and road infrastructures in coastal areas. In the last two decades, such slope instability processes were the subject of many studies, which employed multidisciplinary approaches to understand their underlying mechanisms and surficial kinematics in Southern Spain and elsewhere in the Mediterranean. However, advanced and new investigation methods and techniques used in these studies have never been performed in Northern Morocco despite the geomorphological, geological and climatic resemblance between the two regions. In this paper we analyze the mechanisms and processes controlling the Tamegaret slow-moving deep-seated landslide (Northern Morocco) in order to bridge this knowledge gap and to understand landslide slope dynamics on their regional context. To do so, Electrical resistivity Tomography, field investigations and multi-temporal Synthetic Aperture Radar Interferometry (InSAR) were performed to characterize slope instability processes at the study area. The interpretation of Historic aerial photographs and UAV surveys was also conducted to study the major redistribution of mass caused by recent road widening work at the landslide headscarp. Results show that the Tamegaret landslide owes its existence to deep creep processes controlled by a rock flow type gravitational deformation. Extensional tectonic structures and marine erosion processes that eliminate landslide deposits from the foot area constitute the most relevant control factors of this dynamic. InSAR results show that this deep-seated landslide is currently (2017–2019) characterized by very slow displacement rates (2–3 cm/year maximum). Yet, the substantial deformation observed both in the field and on aerial/satellite photographs suggests that the acceleration occurred during the road-widening work which caused major changes to the natural topography in the period (2009–2012). This deformation phase was manifested by local shoreline advancement at the landslide foot area. Such results show that studying historic shoreline variations can be an effective low-cost time-saving tool allowing the reconstruction of active landslide kinematics in coastal areas. On a regional scale, findings of this study highlight the resemblance between the coasts of Southern Spain and Northern Morocco in terms of (i) the geomorphological processes controlling the coastal slope dynamics at the region; (ii) the displacement rates measured in Tamegaret compared to other unstable slopes in the Northern shore of the Alboran Sea and (iii) the bad-engineering on old dormant landslides which compromises their stability. Therefore, we suggest limiting construction work on coastal hillslopes of Northern Morocco in order to prevent bad construction practices from causing economic losses in the Southern shoreline of the Alboran Sea as well. • Along the southern shoreline of the Alboran Sea, slope instability processes on coastal slopes are poorly studied. • Hence, a multidisciplinary approach is used in this work to study the Tamegaret coastal landslide. • Field surveys and ERT profiles show that the landslide is guided by a system of geological fractures. • The PSinSAR results for the period (24/09/2017 to 15/05/2019) demonstrate the very slow activity of the landslide, which was accelerated during road construction. • This period also corresponds to shoreline advancement at the landslide toe area as was proven by the historic shoreline variations map. • The same displacement rates, geomorphological processes and bad engineering on coastal landslides are observed in both shores of the Alboran Sea. [ABSTRACT FROM AUTHOR]

• The three Parks exhibited similar processes of afforestation between 1956 and 2016. • Gains in forest result from densification and aggregation of small forest patches. • Afforestation is related to reduction of livestock during summer in subalpine areas. • We report a common pattern of morphological & functional landscape homogenization. Mountain regions in Western Europe have gone through a massive rural–urban migration and the collapse of their traditional socioeconomic system. As a result, forest has occupied many old pastures and croplands. In protected areas – such as National Parks – changes in the landscape can affect biodiversity and other services, including the values that motivated their declaration. Any policy decision in these areas requires quantifying the extent and impact of land-cover changes and their consequences on landscape structure and functioning. In this study we analyze the patterns of change in forest cover during six decades in three mountain National Parks in Spain. Our aim is to quantify those patterns, their effects on the landscape, and discuss the potential consequences for the main natural values and services. We assessed changes in forest cover through reclassification of aerial ortophotographs taken in 1956–57 (past images) and 2016–17 (recent images). The three Parks show a relatively low change in total forest area (+5–10%), and a much larger increase in dense forest (+20–30%), with an important effect of land-use legacies, and similar patterns of landscape homogenization. There were fewer but larger forest patches in 2016 than in 1956, and most of the gain in dense forest occurred in core areas (+20%), while transition areas such as edges, bridges or loops decreased between 30 and 55%. Given their potential consequences on biodiversity and other services, these patterns of land-cover change and landscape configuration should be explicitly considered when designing the sustainable management of abandoned landscapes in protected areas. [ABSTRACT FROM AUTHOR]

The 1:50,000 geomorphological map of the Pyrenean Alta Ribagorza is presented here. The Spanish Alta Ribargoza is located in the northern sector of the provinces of Huesca and Lérida, and includes the highest summit of the Pyrenean mountains (Pico de Aneto, 3404 m a.s.l.). The mapped sector measures approximate 700 km². The basic source of information for the completion of the map was derived from the photointerpretation of two series of aerial photos (the 1981 "Pirineos Sur" flight, scale 1:30,000, black and white; and the 2006 PNOA flight, scale 1:5,000, colour), and field work. The map-legend includes 44 elements classified into six main sections, covering lithology and structure, processes and landforms of glacial, periglacial, nival, hillslope, karstic and fluvial origin, and conventional symbols. The variety of the identified processes and landforms demonstrates the geomorphological richness of this mid-latitude, high-mountain area, and the map constitutes a useful tool for land management. [ABSTRACT FROM AUTHOR]

Abstract: The present paper is a combined study on the medium and short-term evolution of the littoral between Chipiona and Rota (SW Spain). The analysis of coastal evolution over a period of 24 years (i.e. medium-term), was carried out using six, well temporally spaced, photogrammetric flights. Cliff top and dune toe were used as shoreline indicators to solve problems related to the use of watermark in tidal environments. Short-term littoral variations were monitored monthly by means of an electronic theodolite over a period of 2 years. The width variations of the dry beach were surveyed by always using a constant, average value for the mean sea level position derived from the numerous surveys carried out. The obtained data was representative of both seasonal and annual variations. Over medium-term, most of the littoral recorded erosion, while accretion has been recorded over recent years in the southern part. Coastal erosion was related to the impact of several storms and dune accretion was linked to the action of eastern winds. Over the short-term time frame, about the same percentage of coastal erosion and accretion was recorded. Most of the important accretion trends were observed at the central and southern parts of the littoral, the largest amount of erosion being recorded in the southern end of the littoral, in a nourished beach. All the studied beaches (except Punta Candor dunes) showed more short-term changes than medium-term ones, because of different factors, essentially the great seasonal variability of the studied beaches. The partial discrepancy between the medium and the short-term trends was related to the applied methodology, which demonstrates the problem of comparing different coastal features (dunes and cliffs on one hand, and beaches on the other) and to the implications of 2–3 years of lasting fair weather conditions that favoured beach and dune accretion, within an historical retreat tendency related to storm actions. [Copyright &y& Elsevier]

Abstract: This paper analyses the role of climatic aridity on the spatial differences of vegetation activity and its inter-annual variability in a semi-arid region of the North East of the Iberian Peninsula. The vegetation activity was quantified by means of a monthly Normalized Difference Vegetation Index (NDVI) database from NOAA–AVHRR satellite images (1987–2000) at 1km2 of spatial resolution. Coefficients of variation (CoV) from temporal NDVI series were also calculated. The greater temporal variability of NDVI was recorded in areas with low vegetation cover (steppe and dry farming lands), whereas the lowest temporal variability of NDVI was recorded in the irrigated lands and forests located in the most humid areas. There is a strong and negative relationship between the CoV and the NDVI distribution, but we recorded important differences among land uses. Using maps of annual precipitation and temperature obtained by means of a regression-based method, we studied the influence of aridity on spatial patterns of NDVI and CoV values. The results show the high influence of aridity on the spatial distribution of vegetation activity in the Middle Ebro Valley. Aridity causes a general decrease of NDVI and an increase of CoV. Nevertheless, non-linear relationships between aridity and NDVI and CoV were recorded for the whole of the study area and for the different land uses. The relationships between aridity and vegetation patterns in the semi-arid region studied are discussed in depth. [Copyright &y& Elsevier]

Coastal erosion is anissuewhich affects beaches all over the world and that signifies enormous economic and environmental losses. Classed as a slow phenomenon, the evolution of the coastline requires long-term analysis. In this study, old cartography and aerial photographs from various dates have been used to study the evolution of the coastline. The information has been processed with free software (QGIS) and for the calculation of sediment transport the Coastal Modeling System (SMC) software. The results show the accretion/erosion phenomena that occurred after the construction of the port in San Pedro del Pinatarin 1954 and which changed the coastal dynamics of a highly protected area. In some sectors, the beach has been reduced almost in its entirety, with retreat rates of up to −2.05 m per year and a total area loss of 66,419.81 m2 in Las Salinas beach and 76,891.13 m2 on Barraca Quemada beach. [ABSTRACT FROM AUTHOR]

• By flood scenarios for urban-rural transition zones are feeble in Extremadura, Spain, particularly on regulations. • Public-access information provides modelling flood scenarios, considering irregular housing in areas without territorial planning. • A multivariate and integrated system can strengthening territorial policies on irregular settlements in areas of rural predominance. The natural risks of flooding inherent to Mediterranean climates is a well-known fact, but one difficult to gauge and rarely accurately in terms of space, quantity and degree. Fortunately, in Spain the national Cartographic System for Flood Areas (SNCZI) partially compensates for the deficit, calculating the probability of these natural phenomena. The present paper describes the number, location and characteristics of the homes exposed to flooding in Extremadura. The methodology used in the study reveals in great detail the clandestine homes built on land not apt for urban development (via scans and visual detection techniques using the available series of ortho-rectified aerial photographs), particularly those at flood risk (determined by SNCZI cartography). This reveals deficiencies in risk management and land use. Also, the information leads to the conclusion that current action from the Administration is ineffective in preventing any risk of flooding, and that the risk is known, but ignored. [ABSTRACT FROM AUTHOR]

Abandoned fields form an integral part of the landscape of Mediterranean mountains. For centuries, very steep slopes with poor soils were cultivated to feed the local population. From the mid-20th century, agriculture on many slopes has been abandoned and secondary succession is taking place with environmental, socio-economic and landscape implications. This paper investigates the role of physical (climate variability and topography) and human (age of abandonment and field type - flat, sloping, terraced) factors in the process of secondary succession in abandoned fields in a representative Mediterranean mountain area. Aerial photographs from 1956 and 1978 were used to map the space-time process of land abandonment, and field types. Data on vegetation cover in abandoned fields was obtained in the SIOSE, the information system on land use in Spain (2006). The map was incorporated into a GIS and statistical analysis was done with R software (R, version 3.2.3). The results show that altitude and climate variability are the principal factors explaining the distribution of areas of forest and shrub. The slope and solar radiation are less important. Human management, although apparently a lesser determinant, has a strong influence. Management before abandonment conditions the spatial distribution of the seed bank and the extent of soil degradation. Management following abandonment (afforestation of conifers, shrub clearings and livestock grazing) decides where pine forest and pastures are located. The results of our case study suggest, that unlike most of cases in the literature, the age of abandonment is not the main factor explaining the natural succession processes. The knowledge about how natural and anthropogenic factors affect secondary succession should be considered a tool for land management in mountain areas. • We study the factors explaining the process of plant colonisation in abandoned fields. • Mapping of old cultivated, abandoned areas and land covers were carried out. • Altitude and climate are the main factors explaining land cover distribution. • Human management (age of abandonment and field types) has a strong influence. • Management after abandonment decides where pines and pastures are located. [ABSTRACT FROM AUTHOR]

Sedimentary coastal areas change rapidly and are economically and environmentally important. This research focuses on determining the extent to which natural dynamics and human activity have contributed to visible changes on Rodas, Cíes Islands in southwestern Galicia (NW Spain). The number of visitors to the islands has increased in recent years, and the port infrastructure has therefore been expanded. Previously, this zone experimented with important sand extraction phases. These changes have influenced the ecosystem directly by modifying the sedimentary behavior and indirectly by promoting even greater numbers of visitors to the area. Aerial images and orthophotographs of the study zone were examined to identify changes that have taken place over the last sixty-one years (1956–2017). Changes in the position of the shoreline, defined as the boundary of the dune vegetation, were mapped at different times between 1956 and 2017. Changes in the shoreline were quantified using GIS (Geographic Information System) technology and Digital Shoreline Analysis System (DSAS) software. The findings revealed that the system regressed by more than 30 m between 1956 and 1981, in part as a result of sand extraction. We also identified different erosion/accretion phases that occurred before the reformation of the Rodas dock in 2010. The system is currently undergoing important changes, especially in the northern area, with a regression of 14.14 m in the last seven years. In this context, LiDAR analysis from 2010 and 2015 using Geomorphic Change Detection (GCD) tools allowed variations in the dune system to be verified. The elevation in the study zone increased in 83% of the area, mainly in the frontal dune and close to the winter inlet (north sector). However, the variations were very small. [ABSTRACT FROM AUTHOR]

A set of dimensionless morphological ratios are commonly used as a basis for studies of stream stability and natural channel restoration. Often, such ratios have been obtained from morphometric measurements made in the field and developed into a template for a given geomorphic reference site. In this study, high resolution aerial photographs from 2018 and ground-based surveys were used to map the spatial variability of dimensionless ratios (DR) in an ephemeral channel. In particular, three reaches of 0.5-1 km long were chosen along upper Mula stream, in South-east Spain. Different ratios (width/depth, entrenchment, bank height ratio, root depth/bank height, among other) were estimated from measured channel dimensions, such as bankfull width, maximum and mean bankfull depth, flood prone width, bankfull depth in pools, riffles and runs. Field indicators (the back of point bars, significant breaks in slope, changes in vegetation, the highest scour line or the top of the bank) and a DEM developed from UAV and GNSS data were used to obtain the bankfull stage along each reach. All the data then was transferred to HEC-RAS to obtain the channel profile and cross-sections (separated from each other every 1-5 m). We used a GIS to integrate the high resolution DEM, field measurements and hydraulic geometry data, to calculate the dimensionless ratios and to map the channel reaches. Finally, a statistical analysis of spatial data was performed with R in order to model the morphological relationships for the DR as a function of bed slope and planform parameters. [ABSTRACT FROM AUTHOR]

Costas, S. and Alejo, I., 2007. Local and Global Influences on the Evolution of a Transgressive Sand Barrier: Cies Barrier, Northwest Spain. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 1121 – 1125. Gold Coast, Australia, ISSN 0749.0208 The decadal evolution and the factors that control the variability of a recent welded barrier located in the northwest of Spain have been investigated. Analysis of the morphological changes and the evolution of the shoreline were carried out using georectified aerial photographs spanning from 1949 to 2003. The barrier shows a complex temporal and spatial behavior. Erosive and constructive, or accretionary stages, alternate over time giving rise to a cyclical evolution. Shoreline behavior differed according to geomorphic setting. In regards to the spatial behavior, the shoreline presented different response patterns depending on the presence of dunes, cliffs or an inlet. The evolution of the sand barrier was related to the effect and variability of global (sea level and climate change) and local factors (storm regime or sediment input). Despite some cyclic behavior between 1949 and 2003, the net shoreline position moved landward approximately 24 m. This was associated with inlet relocation and lagoon infilling. Despite the episodic behavior of the shoreline from 1949 to 2003, the barrier receded around 24 m causing important morphological changes such as the adjacent lagoon infilling or inlet relocation. The evolution of the sand barrier seems to result from the combined effect of different factors such as sediment scarcity, wave exposure, climate oscillation or mean sea level rise. These factors interact so that their combined effect is greater than the sum of their individual effects. [ABSTRACT FROM AUTHOR]