Search Results (29)

Lava rises, locally known as stony rises, are Pliocene–Holocene volcanic landforms occurring throughout the Victorian Volcanic Plain (VVP) in Victoria, Australia. Stony rises are not only important to understanding the geological history of Victoria but are culturally significant to Aboriginal Australians and have ecological importance. Currently, the mapping of stony rises is manually performed at a case study level rather than a landscape level. Remote sensing technologies such as LiDAR data, satellite imagery, and aerial imagery allow for the mapping of stony rises from an aerial perspective. This paper aims to map stony rises using remotely sensed and geophysical data at a landscape level on a younger lava flow (~42,000 years old) within the Victorian Volcanic Plain (the Warrion Hill and Red Rock Volcanic Complex) by utilizing an object based random forest machine learning approach. The results show that stony rises were successfully identified in the landscape to an accuracy of 78.9%, with 2716 potential new stony rises identified. Out of 34 predictor variables, we found the most important variables to be slope gradient, local elevation, DEM of Difference (change in height), Normalized Difference Water Index (NDWI), Clay Mineral Ratio, the concentration of radiometric elements (Potassium, Thorium, and Uranium), Total Magnetic Intensity, and Ecological Vegetation Class (EVC). The results from this study highlight the ability to detect a volcanic landform at a landscape scale using an ensemble of predictor variables that include topographic, spectral information and geophysical data. This lays the foundation towards a uniform approach for mapping stony rises throughout the VVP and similar landforms (such as tumuli) worldwide. Full article

Traditional orchards are distinctive features of cultural landscapes in Central Europe. Despite their high level of ecological importance, they are in decline, and comprehensive spatial data over broad extents, which could enable a trend analysis, are lacking. We analysed traditional orchard maps from 1952 to 1967 and a map from 2010, generated via aerial image interpretation, for the state of Hesse (ca. 21,115 km²), which has the second largest share of traditional orchards in Germany. We aimed to (1) quantify long-term orchard dynamics, (2) compare orchard characteristics in terms of topographical, ecological, and socioeconomic factors, and (3) identify key drivers of orchard loss. We found that the number and area of orchards have clearly decreased across Hesse, with varying local and regional patterns. Further, historically old orchards tended to have a larger area, higher shape complexity, and were located closer to settlements, highways, and neighbouring orchards. In contrast, newly established orchards were often found at higher elevations and on steeper slopes. Finally, the three historical orchard hotspots also experienced the most notable losses driven by different factors, namely the expansion of Artificial Surfaces, Residential Buildings, and Agricultural Land. We highlight the importance of such multitemporal spatial data for a wide range of ecological applications, and we encourage the use of novel technologies to support geospatial analyses in the future. Full article

Old-growth forests provide many ecosystem services and benefits. However, they are becoming increasingly rare and thus are an urgent priority for conservation. Accurately mapping old-growth forests is a critical step in this process. Here, we used LiDAR, an improved individual tree crown delineation algorithm for broadleaved forests, Gaussian mixture modelling, and a rule-based classification key to map the extent and location of old-growth forests across a topographically and ecologically complex landscape of 337,548 ha in southeastern Australia. We found that variation in old growth extent was largely driven by the old growth definition, which is a human construct, rather than by uncertainty in the technical aspect of the work. Current regulations define a stand as old growth if it was recruited prior to 1900 (i.e., >120 years old) and is undisturbed (i.e., <10% regrowth canopy cover and no visible disturbance traces). Only 2.7% (95% confidence intervals ranging from 1.4 to 4.9%) of the forests in the study landscape met these criteria. However, this definition is overly restrictive as it leaves many multi-aged stands with ecologically mature elements (e.g., one or more legacy trees amid regrowth) unprotected. Removing the regrowth filter, an indicator of past disturbances, increased the proportion of old-growth forests from 2.7% to 15% of the landscape. Our analyses also revealed that 60% of giant trees (>250 cm in diameter at breast height) were located within 50 m of cool temperate rainforests and cool temperate mixed forests (i.e., streamlines). We discuss the implication of our findings for the conservation and management of high-conservation-value forests in the region. Full article

Considering how difficult it is for a pin in the ocean to be found, painstaking searches among historical documents and eyewitness accounts often end up with more unknowns and questions. We developed a three-tier geo-spatial tech-based approach to discover and unfold the lost WWII heritage features in the countryside of Hong Kong that can be applied in other contexts. It started with an analysis of historical texts, old maps, aerial photos, and military plans in the historical geographic information system (HGIS) Project ‘The Battle of Hong Kong 1941: a Spatial History Project’ by Hong Kong Baptist University to define regions/points of interest. Then, 3D point clouds extracted from the government’s airborne LiDAR were migrated to form a digital terrain model (DTM) for geo-registration in GIS. All point clouds were geo-referenced in HK1980 Grid via accurate positioning using the global navigation satellite system—real-time kinematics (GNSS-RTK). A red relief image map (RRIM) was then used to image the tunnels, trenches, and pillboxes in great detail by calculating the topographical openness. The last tier of the tech work was field work involving ground validation of the findings from the previous two tiers and on-site imaging using terrestrial LiDAR. The ground 3D LiDAR model of the heritage feature was then built and integrated into the DTM. The three-tier tech-based approach developed in this paper is standardised and adopted to streamline the workflow of historical and archaeological studies not only in Hong Kong but also elsewhere. Full article

Land use and land cover (LULC) strongly influence soil erosion/sediment yield, and predicting changes in soil erosion is an important management strategy. Tracing the Earth’s past also helps us better understand the future evolution of the landscape, but research using modern mapping capabilities is hampered by the scarcity of historical landscape information. To fill the data gap and provide an example of how historical maps might be used in land-use change research, we combined an old paper map based on the IT Military Topographical Institute (ITM), aerial photos, and orthophotos to derive land-use history and landscape dynamics at fine scales for a segment of the Roman route “Via Herculia” located in the north-western sector of the Basilicata Region, Italy. Three LULC scenarios were then analysed to represent land use in 1870, 1974, and 2013. Starting from such scenarios, we applied a soil erosion model (Unit Stream Power Eosion and Deposition—USPED) to understand how land-use change over time has modified the areas subject to erosion and deposition. The results show an increase in erosion (from 17% to 20% of the total area) and sediment deposition (from 15% to 19%) over the period 1870–1974. In contrast, over the period of 1974–2013, the results show a decrease in gross erosion (from 20% to 14% of the total area) and sediment deposition (from 19% to 13%). Full article

Morocco’s meteorological observation network is quite old, but the spatial coverage is insufficient to conduct studies over large areas, especially in mountainous regions, such as the Fez-Meknes region, where spatio-temporal variability in precipitation depends on altitude and exposure. The lack of station data is the main reason that led us to look for alternative solutions. TerraClimate (TC) reanalysis data were used to remedy this situation. However, reanalysis data are usually affected by a bias in the raw values. Bias correction methods generally involve a procedure in which a “transfer function” between the simulated and corrected variable is derived from the cumulative distribution functions (CDFs) of these variables. We explore the possibilities of using TC precipitation data for the Fez-Meknes administrative region (Morocco). This examination is of great interest for the region whose mountain peaks constitute the most important reservoir of water in the country, where TC data can overcome the difficulty of estimating precipitation in mountainous regions where the spatio-temporal variability is very high. Thus, we carried out the validation of TC data on stations belonging to plain and mountain topographic units and having different bioclimatic and topographic characteristics. Overall, the results demonstrate that the TC data capture the altitudinal gradient of precipitation and the average rainfall pattern, with a maximum in November and a minimum in July, which is a characteristic of the Mediterranean climate. However, we identified quasi-systematic biases, negative in mountainous regions and positive in lowland stations. In addition, summer precipitation is overestimated in mountain regions. It is considered that this bias comes from the imperfect representation of the physical processes of rainfall formation by the models. To reduce this bias, we applied the quantile mapping (QM) method. After correction using five QM variants, a significant improvement was observed for all stations and most months, except for May. Validation statistics for the five bias correction variants do not indicate the superiority of any particular method in terms of robustness. Indeed, results indicate that most QM methods lead to a significant improvement in TC data after monthly bias corrections. Full article

Alpine treeline ecosystems are generally expected to advance with increasing temperatures and after land-use abandonment. Multiple interacting factors modify this trend. Understanding the long-term processes underlying treeline advance is essential to predict future changes in structure and function of mountain ecosystems. In a valley in the Central Swiss Alps, we re-assessed a 40-year-old survey of all treeline trees (>0.5 m height) and disentangled climate, topographical, biotic, and disturbance (land use and avalanche risk) factors that have led to treeline advance with a combination of ground-based mapping, decision tree, and dendroecological analyses. Between the first ground survey in 1972/73 and the resurvey in 2012, treeline advanced on average by 10 meters per decade with a maximum local advance of 42 meters per decade. Larch consistently advanced more on south-facing slopes, while pine advance was greater on north-facing slopes. Newly established spruce mostly represented infilling below the previous treeline. The forefront of treeline advance above 2330 m a.s.l. occurred mainly on favorable microsites without competing dwarf shrub vegetation. At slightly lower elevations, treeline advanced mainly on sites that were used for agriculture at the beginning of the 20th century. This study indicates that although treeline advances under the effect of climate warming, a combination of additional ecological factors controls this advance at regional and local scales. Full article

The island of Cyprus is famous for its rich deposits of volcanic mineralisation that yielded large quantities of copper, gold, and silver. The abandonment of the waste material in several dump sites during exploitation severely impacted the environment. A significant environmental issue is the acid mine drainage from the hydration of large barren piles that cover these old open pit mines. However, abandoned piles are still enriched in precious metals and perhaps even rare earth metals. These dump sites may form a new possible “deposit”, which may attract companies’ economic interest. Removing the stockpiles can be cost-effective, since the secondary extraction process is profitable, in addition to the benefits from the restoration of the natural environment. The case study considered here pertains to the North Mine of Mathiatis, where unmanned aerial vehicle (UAV) images were used to create not only a 3D topographic map but also to locate these dump sites and finally to create a 3D model of one of these waste stockpiles. The methodology proposed here to locate dump sites by using point cloud data (x, y, z, RGB) and high-resolution images provided by UAVs will assist in the secondary mining of old open-pit mines by defining the bottom and top stockpile surfaces. The reconstructed 3D waste piles can also be used to calculate the volume they occupy and other parameters, such as the gradient of slopes, that are essential for estimating the cost of possible restoration. The proposed methodology was applied to the stockpile STK1 with the most available drillhole data, and its volume was estimated at 56,000 m³, approximately. Full article

The interest to assess the relationship between forest gap characteristics and topography features has been growing in the last decades. However, such an approach has not been studied in undisturbed mixed sessile oak–beech old-growth forests. Therefore, the present study carried out in one of the best-preserved sessile oak–beech old-growth forests in Europe, aims to assess the influence of topographic features (slope, altitude and aspect) on (i) some characteristics of canopies and expanded gaps (surface, diameter and perimeter) and (ii) the proportion of beech and sessile oak as bordering trees, gap fillers and gap makers. Through a complete gap survey on an area of 32 ha, 321 gaps were identified and mapped. The largest gaps and also the highest gap frequency (140) was found in the slope class (15.1–20°), while the gap frequency increased with altitude, with 99 gaps being recorded at 601–650 m a.s.l. The size and perimeter of the canopy and expanded gaps, as well as the number of gap makers, were negatively related to the slope and altitude. The expanded gap to canopy gap size ratio decreased with the slope and was positively related to the altitude, while a significant negative decrease in gap filler density with altitude was encountered. The sessile oak participation ratio as bordering trees forming the gap increased not only with the altitude but also with the slope. The topography plays an important role in the formation of gaps as well as in the characteristics of the future stand. This study provides valuable insights into the relationship between canopy gap characteristics and topography, which is useful information for forest owners that pursue the design of forest management toward nature-based solutions. Full article

The construction of reservoirs has a major impact on the floodplain landscape, and their existence also affects land use in the hinterland. The aim of this article is to evaluate the influence of artificial lakes on changes in landscape use and transport networks; in this context, an assessment is provided of the significance of this anthropogenic activity as one of the drivers of landscape change. Old topographic maps and archival aerial photographs are used to analyze changes in the use of landscape and road networks, and these materials are complemented with the latest geographic data in digital form. Utilizing geographic information systems, we assessed the landscape changes and processes in the hinterland of those Czech Republic reservoirs that have an area of 100 ha or more. The results of the research show that landscape change processes are more intensive in the hinterland of the lakes than in the surrounding landscape. The predominant utility function of a reservoir emerged as a key factor in landscape use changes and ongoing processes. A different landscape use scenario can be observed in drinking water reservoirs, especially regarding the leisure and irrigation functions that dominate elsewhere. After the completion of reservoirs, the road and railway networks had an impact on, above all, the connection of the nearest villages in the hinterland of the lakes. The information that we found can be employed in projecting future changes in land use and road networks at newly planned dams. Full article

An analysis of 17 Romanian cities’ Urban General Plans showed that urban planning documents do not satisfactorily rely on groundwater information. The associated hydrogeological supporting studies include only general recommendations. However, they should include specifications to improve water-balance and detail the need to implement monitoring systems to monitor groundwater levels. The studies do not recommend special construction measures to be implemented for future infrastructure elements and do not include maps delimiting the particular geotechnical and hydrogeological characteristics. A study conducted on an urban river corridor using satellite remote sensing and a methodology characterizing the chosen zone clearly shows a major concordance between the groundwater level and vertical displacements. In addition, the presence of urban anthropogenic strata associated with the groundwater level fluctuations showed amplified vertical displacements of the ground when compared to the areas where the natural deposits exist. The methodology combines subsidence occurrence, land-cover changes, hydrogeological, geological, and hydrological characteristics, climatic aspects, the location, the extension of old quarries, and the last 100 years of topographical changes. These observations emphasize the need for accurate studies to properly discriminate between phenomena and processes generating subsidence, which must be used systematically to support the general urban plans of cities as the documentation of future developments. Full article

Water-powered facilities (WPFs) have traditionally been a pillar of the economy and social development. Therefore, the state took an interest in having these objects recorded and mapped in relevant maps and registers. This article focuses on identifying and localizing WPFs in the Moravice River basin in the so-called Sudetenland, Czechia, between the years 1763 and 2021. Specifically, the evolution and (dis)continuity of the WPFs are assessed through an analysis of cartographic and archival sources, reflecting the wider socioeconomic and demographic context as explanatory variables. The cartographic sources included old military topographic maps of Austria-Hungary and Czechoslovakia from four periods (the mid-18th century, mid-19th century, end of the 19th century, and mid-20th century) on the one hand and two state water-powered facility registers from 1930 and 1953 on the other. The archival sources included funds from regional and state archives. The results show that the count of WPFs peaked during the 19th century, after which there occurred a steep decline caused by societal and economic changes, namely, the expulsion of the local German population, nationalization in the postwar period, and economic and organizational transformations in the socialist era. Special attention is paid to hydropower plants, whose evolution reflects the outlined economic processes. Full article

The impact of irrigation reservoirs requires investigation through hydrological analysis to identify the flood control functions of these reservoirs. However, there is insufficient information concerning important geographical, morphological, and topographic characteristics, such as the reservoir cross-section. Therefore, this study aimed to identify the morphological and topographic characteristics of reservoirs using geographical information instead of measurement data. Ten reservoirs, including the Ga-Gog reservoir located in Miryang City, South Korea, were selected. The topographic information of the reservoirs was obtained using topographic maps and GIS techniques. Based on this information, the volume (V)-area (A)-depth (H) relationship and the hypsometric curve (HC) according to the relative area (a/A) and relative height (h/H) were created. A comparison of the reservoir volume, estimated using topographic information, with the measured volume revealed an error rate between 0.23% and 14.27%. In addition, two collapsed reservoirs located near Miryang City were investigated by creating V-A-H relationships and HCs using topographic information. The morphological characteristics of the reservoirs were identified by analyzing the (1) morphology index, (2) full water storage area-levee height relationship, and (3) full water storage area relationship. The analysis results showed that the collapsed reservoirs had high water depth and a large area relative to other reservoirs. Similar types of reservoirs were grouped by conducting a cluster analysis using basic properties such as the basin area, storage, and levee height. The cluster analysis results, based on HC analysis, grouped the reservoirs into three shapes: convex upward (youthful stage), relatively flat (mature stage), and convex downward (old stage). The HCs of the collapsed reservoirs exhibited a convex downward shape, indicating that they were subjected to considerable erosion due to aging. Moreover, this considerable erosion caused a large quantity of sediment to accumulate in the reservoirs, resulting in an insufficient allowable storage capacity of the reservoir because the flood control capacity was reduced, which may have led to their collapse during heavy rainfalls. Therefore, the identification of potential causes of reservoir collapse through the morphological characteristics and HCs of reservoirs are expected to support the operation and management of reservoirs to reduce flood damage. Full article

Urban flooding is a complex natural hazard, driven by the interaction between several parameters related to urban development in a context of climate change, which makes it highly variable in space and time and challenging to predict. In this study, we apply a multivariate analysis method (PCA) and four machine learning algorithms to investigate and map the variability and vulnerability of urban floods in the city of Tangier, northern Morocco. Thirteen parameters that could potentially affect urban flooding were selected and divided into two categories: geo-environmental parameters and socio-economic parameters. PCA processing allowed identifying and classifying six principal components (PCs), totaling 73% of the initial information. The scores of the parameters on the PCs and the spatial distribution of the PCs allow to highlight the interconnection between the topographic properties and urban characteristics (population density and building density) as the main source of variability of flooding, followed by the relationship between the drainage (drainage density and distance to channels) and urban properties. All four machine learning algorithms show excellent performance in predicting urban flood vulnerability (ROC curve > 0.9). The Classifications and Regression Tree and Support Vector Machine models show the best prediction performance (ACC = 91.6%). Urban flood vulnerability maps highlight, on the one hand, low lands with a high drainage density and recent buildings, and on the other, higher, steep-sloping areas with old buildings and a high population density, as areas of high to very-high vulnerability. Full article

River ferries were historically important in crossing medium- and large-sized watercourses, with rivers often a barrier to trade routes and journeys. Using old medium-scale Austrian military topographic maps from 1763–1768, 1836–1852, and 1876–1880, Prussian maps from 1825 and 1877, and Czechoslovakian maps from 1953–1955, we systematically localized the ferries within what is now the Czech Republic over a monitoring period between the mid-18th century and the present. We also analyzed the map keys of relevant surveys to examine ways of depicting the ferries in the maps. In this context, a database of river ferries in the Czech Republic was prepared in GIS, containing all localities where river crossing ferries were shown on the topographic maps. A total of 514 historical ferry sites were identified on the military mapping survey maps, with an additional 28 recognized from auxiliary sources that did not appear in the military topographic maps. The sample information obtained from the maps was also verified by using independent sources. Full article