Land Cover Situation Research Articles

Changes in the water retention of mountainous landscapes since the 1820s in the Austrian Alps

Interactions of humans with the environment are strongly related to land use and land cover changes (LULCCs). In the last decades, these changes have led to a degradation of ecosystem services, including water regulation and flood control. In the Alpine areas of Austria, land cover changes have increased flood risk since the middle of the 19th century. In this paper, we assess the influence of these long-term land use changes on the landscape’s ability to retain water using the qualitative Water Retention Index (WRI). The changes are thereby evaluated on the basis of the historical (1826–1859) and present (2016) land cover situation, which is to our knowledge the first high-resolution and regional application of the WRI. The results show that the water retention potential mimics the mountainous characteristic and features. Except for areas strongly dominated by settlement areas, the highest retention potentials are found in valley floors and the lowest values are depicted along the main Alpine complex. In low-lying areas, the retention decreased by over 10%. It was found that this decrease can be mostly attributed to settlement expansion. Above 1,250 m, land use transformations led to slightly increasing water retention values owing to the transformation of wasteland or glaciers to stagnant waters and to the expansion of forest and grassland in high elevations. This examination allows for a holistic and spatially distributed LULCC impact assessment on the landscape’s water regulation capacities and offers valuable high-resolution information for future land use planning and sustainable land development.

Localising and quantifying night-time cooling effects from sub-catchments in a mid-European low mountain area

We propose a novel method to analyse and quantify cooling effects provided to a settlement by source areas of nocturnal cold-air drainage. In an interdisciplinary approach, these source areas were defined as hydrological sub-catchments of a complex catchment area in a low mountain range. The cold-air drainage model KLAM_21 was used to exclude the energetic influence of the sub-catchments from the model area by surrounding them with artificial barriers. The outputs of these runs were then compared to a reference run without exclusion to derive the cooling effect of each source area. The results were evaluated at sample points along the main valley and for residential areas of a medium sized city and two smaller settlements. We find that in the complex terrain of the study area, also comparatively remote source areas can have a noticeable cooling effect on the residential neighbourhoods of the target settlements from the middle of the night. The strongest effect however, could be attributed to the sub-catchments in direct vicinity of the target areas. The results at the sample points along the main valley showed that the cooling effect decreased with increasing distance to the sub-catchments and usually gets stronger during the night. The variation in strength of cooling effect between different sub-catchments is likely due to their individual properties such as remoteness, size, terrain, land-cover situation and cold-air exchange with other sub-catchments through overflow effects.

Outbreak of Moroccan Locust in Sardinia (Italy): A Remote Sensing Perspective

The Moroccan locust has been considered one of the most dangerous agricultural pests in the Mediterranean region. The economic importance of its outbreaks diminished during the second half of the 20th century due to a high degree of agricultural industrialization and other human-caused transformations of its habitat. Nevertheless, in Sardinia (Italy) from 2019 on, a growing invasion of this locust species is ongoing, being the worst in over three decades. Locust swarms destroyed crops and pasture lands of approximately 60,000 ha in 2022. Drought, in combination with increasing uncultivated land, contributed to forming the perfect conditions for a Moroccan locust population upsurge. The specific aim of this paper is the quantification of land cover land use (LCLU) influence with regard to the recent locust outbreak in Sardinia using remote sensing data. In particular, the role of untilled, fallow, or abandoned land in the locust population upsurge is the focus of this case study. To address this objective, LCLU was derived from Sentinel-2A/B Multispectral Instrument (MSI) data between 2017 and 2021 using time-series composites and a random forest (RF) classification model. Coordinates of infested locations, altitude, and locust development stages were collected during field observation campaigns between March and July 2022 and used in this study to assess actual and previous land cover situation of these locations. Findings show that 43% of detected locust locations were found on untilled, fallow, or uncultivated land and another 23% within a radius of 100 m to such areas. Furthermore, oviposition and breeding sites are mostly found in sparse vegetation (97%). This study demonstrates that up-to-date remote sensing data and target-oriented analyses can provide valuable information to contribute to early warning systems and decision support and thus to minimize the risk concerning this agricultural pest. This is of particular interest for all agricultural pests that are strictly related to changing human activities within transformed habitats.

Predicting suitable breeding areas for different locust species – A multi-scale approach accounting for environmental conditions and current land cover situation

In this study, we present a fused multi-scale approach to model habitat suitability index (HSI) maps for three different locust species. The presented methodology was applied for the Italian locust (Calliptamus italicus, CIT) in Pavlodar oblast, Northern Kazakhstan, for the Moroccan locust (Dociostaurus maroccanus, DMA) in Turkistan oblast, South Kazakhstan and for the desert locust (Schistocerca gregaria) in Awash river basin, Ethiopia, Djibouti, Somalia. The main novelty is based on implementing results from ecological niche modelling (ENM) with time-series analyses of high spatial resolution remote sensing data (Sentinel-2) and further auxiliary datasets in a fused HSI model. Within the ENM important climatic variables (e.g. temperature, rainfall) and edaphic variables (e.g. sand and moisture contents) are included at a coarse spatial resolution. The analyses of Sentinel-2 time-series data enables mapping locust breeding habitats based on recent remotely sensed land observation at high spatial resolution and mirror the actual vegetation state, land use, land cover and in this way identify areas with favorable conditions for egg survival and breeding. The fused HSI results for year 2019 were validated based on ground field observation and reach area under curve (AUC) performance of 0.747% for CIT, 0.850% for DMA and 0.801% for desert locust. The innovation of this study is a multi-scale approach which accounts not only for climatic and environmental conditions but also for current vegetation and land management situation. This kind of up-to-date spatial detailed information on breeding suitability could enable area prioritization for risk assessment, monitoring and early intervention of locust pests.

Exploring Plantation Development and Land Cover Changes in the Meme-Mungo Corridor of Cameroon

There is an apparent nexus between the development of plantations and changes in landcover. The Meme-Mungo Corridor is an example par excellence of a tropical plantation corridor in Cameroon which has witnessed significant expansion in tropical plantations of cocoa, banana, rubber and oil palm, among others. This paper analyzes the connection between land cover changes and plantation development over a 42-year period (1960 and 2012). A total of 100 households were sampled using the systematic sampling technique. Furthermore, multispectral data, obtained from the Global Land Cover Facility (GLCF, 2005) were used in the classification of the study area. These images were processed using Geographic Information System (GIS) and Remote Sensing (RS) software and further compiled into a GIS database using ESRI ArcGIS software. The results showed that between 1960 and 2012, a more than 50% increase in the surface area of plantation crops was registered, leadingto a corresponding change in the land cover situation. Based on this, the study probed into the implications of further plantation development on land cover; further land cover changes could be attributed to the extension of plantations. This paperrecommends among others, the need for intensive agriculture to be encouraged so as to ensure an increase in agricultural output against the backdrop of a decline in agricultural space. Furthermore, augmenting agro-product value chains will stem the loss of agro-produce due to perishability. This will contribute to regulate extensive plantation development in the area.

Assessing the Impact of Secondary City Development on Sanitation Services: The Case of Muhanga District 2013-2017

This research was conducted on the assessment of the impact of Muhanga city development on sanitation services, the primary data regarding sanitation was collected using questionnaire survey, interviews and observation. To evaluate land use land cover situation from the year 2013 up to 2017 remote sensing techniques was used. The results from collected data showed that 65% of generated solid waste is composed by organic waste, while waste collection coverage from household level is low with a percentage of 9%. The analysis of land use land cover situation showed that during the five years, settlement area increased by 8.67%, the amount of waste generation is increasing with population growth, and it varied from 1,555m 3 in 2014 to 3,045m 3 in 2017. The analysis of variance (ANOVA) results shows that the amount of solid waste generated is significantly difference between the year 2014 and the year 2017. Regarding liquid waste management there are drainage systems constructed, although the survey made showed that 39.2% of households sampled highlighted that storm water is still a problem in their residential area. The obtained results evidenced that solid waste collection at household level by a private company is a new practice in the city, and the collection coverage is still low compared to city resident, consequently there is still informal dumpsite in open area across the city. The private sector needs to be more committed in sanitation services provision, and the public sector needs to be involved in sanitation infrastructures development by focusing on composting facilities as a big percentage of generated waste is biodegradable. The public sector has a direct influence on the private sector and the community, the community and the private sector need to become familiar with working together for the purpose of improving sanitation with the aim to protect the environment.

Assessment of soil physical properties' statuses under different land covers within a landscape dominated by exotic industrial tree plantations in south-central Chile

Land use and land cover changes (LULCC) within a highly anthropized Mediterranean landscape dominated by industrial tree plantation leads to degradation of soil physical properties. This process has been more intense in the coastal range of south-central Chile due to its soils, which are highly susceptible to erosion, combined with a long history of intensive land use changes during the last century, transitioning from native forest (NF) to agriculture and the more recent establishment of Pinus radiata and Eucalyptus spp. exotic tree plantations. In this context, the aim of this study was to assess the statuses of soil physical properties over different land cover situations. Historical land cover maps were determined via supervised classifications using the maximum likelihood classifier applied to satellite imagery. Five land use and land cover categories (LULC) were defined according to main land cover transitions associated with active and abandoned forestry operations that have been reported in the region: NF, pine plantation (P), eucalyptus plantation (Eu), early successional (E-S), and secondary successional (S-S). Successional stages were generated using change detection statistics considering changes between 2001 and 2014 maps. Soil samples were collected at three depths in 39 plots that describe the five LULC. High clay contents were found in all the LULC except Eu and P. These sites have shown more signs of degradation, with lower organic matter (SOM) and macropores and higher shear strength (ShS). Soil organic matter was consistent with litter contribution and quality, establishing lower bulk density (Db) for NF and S-S and higher values for Eu and E-S. ShS and dispersion rate (DR) exhibit a correlation with SOM with lower ShS and higher DR when SOM increased. Relevant differences were identified for structural stability index (SSI) between LULC depending on soil physical quality, besides a positive correlation with SOM. Those results show the need to generate appropriate conditions of vegetation cover in order to recover soils subjected to current forestry management of industrial plantations.

Classification of Rainfall Warnings Based on the TOPSIS Method

Extreme weather, by definition, is any unexpected, unusual, unpredictable, severe or unseasonal weather condition. A rainfall event that is considered normal in one region may be considered a torrent in a dry region and may cause flash flooding. Therefore, appropriate weather warnings need to be issued with respect to areas with different climates. Additionally, these alerts should be easy to understand—by clear classification—in order to apply reinforcements. Early warning levels not only depend on the intensity and duration of rainfall events, but also on the initial water stress conditions, land cover situations and degree of urbanization. This research has focused on defining different warning levels in northwest Iran using long-term precipitation data from 87 weather stations well distributed across the study area. Here, in order to determine alert levels, TOPSIS (The Order of Preference by Similarity to Ideal Solution), as one of the most common methods in multi-criteria decision making, has been used. Results show that five main levels of alerts can be derived, leading to the provision of spatial maps. Further, it can be deduced that these levels are highly associated to the location of a region at different times: months/seasons. It has been observed that the issuance of a warning for precipitation should correspond with the location and time. At one location during different seasons, different alert levels would be raised corresponding to the rainfall. It was also concluded that using of fixed alert levels and extending them to larger areas without considering the seasons could be grossly misleading.

VHR GeoEye-1 imagery reveals an ancient water landscape at the Longcheng site, northern Chaohu Lake Basin (China)

ABSTRACTThis study mainly focuses on revealing an ancient water landscape at the Longcheng site in the northern Chaohu Lake Basin using very high-resolution (VHR) GeoEye-1 imagery. First, prior to classification, the GeoEye-1 image was processed following atmospheric and geometric correction. The supervised classification was carried out in order to show the land-cover situation in the Longcheng area. The overall classification accuracy was 89.98%, with a kappa coefficient of 0.87. The moat system around the city walls was discovered by using rule-based object-oriented segmentation of the postclassified image, and the other walls of ancient Longcheng were manually identified from the pansharpened VHR GeoEye-1 image. Finally, a map of the ancient water landscape containing the ancient city, wall and moat at the Longcheng site was produced. This paper demonstrates that VHR remote sensing has the ability to uncover an ancient water landscape and provide new insights for archaeological and paleoenvironmental studies.

Spatial and Temporal Dynamics of the Vegetation of Comoé-Léraba Reserve and its Surrounding Lands (Burkina Faso, West Africa)

Abstract In Burkina Faso, vegetation dynamic has been more influenced by human activities. Actually, the interest is focus on protected areas, which are more green areas and the last habitat for biodiversity. Conservation and restoration require a thorough understanding of the dynamic of each protected area and its surrounding zones. This study aim to analyze Comoé-léraba protected area vegetation spatial and temporal changed. For this study, we use satellite images taking account a period of twenty years (1990-2000-2009). Then the diachronic analysis considers globally and separately the land cover situation inside the protected zone and outside in the surrounding zone. As results, the diachronic study of Comoé-Léraba vegetation revealed significant changes. Some plant communities have remained intact; others were restored inside the protected area and against others suffered a severe deterioration. The vegetation degradation occurs, around and close to the protected area. During the twenty years 14.28 % of the natural vegetation has been loss, versus expanding fields and settlements. Beyond the obtained maps, an important data based is available. These results are important scientific stools which can support policy, conservationists and researchers for improving strategies of conservation in Comoé-Léraba zone.

Space and time dynamics of urban water demand in Portland, Oregon and Phoenix, Arizona

Critical to effective urban climate adaptation is a clearer understanding of the sensitivities of resource demand to changing climatic conditions and land cover situations. We used Bayesian Maximum Entropy (BME) stochastic procedures to estimate temperature and precipitation at the very small scale of urban Census Block Groups (CBGs) in Phoenix, Arizona and Portland, Oregon, and then compared average household water use patterns by climate conditions and land cover characteristics between and within the two cities. Summer household water use was positively related to maximum temperatures and dense vegetation cover in terms of grass cover and trees and shrubs; it was negatively related to precipitation amounts in both cities. Water use was more sensitive to maximum temperature, precipitation levels, and vegetation cover in Phoenix than in Portland. There was substantial intra-city variation with greater sensitivity in urban water use associated with higher densities of trees and shrubs in both cities, but in Phoenix, the highest sensitivities to maximum temperatures occurred in CBGs with the most grass cover while in Portland, high sensitivity was associated with CBGs with the least grass cover. Many of the latter are in highly built-up downtown areas of Portland where artificial irrigation is required to maintain landscapes during the hot summer season. Take-home messages are: (1) BME space/time statistics provide efficient estimates of missing precipitation and temperature data to create continuous high resolution meteorological data that improve water demand analysis and (2) use of landscaping for urban climate adaptation will have differing impacts on water use, depending on local climate conditions, urban layout, and the type of vegetation cover.

Exploring the Potential of Object Based Image Analysis for Mapping Urban Land Cover

The paper investigates the performance and potential of object based image analysis technique (OBIA) for land cover information extraction from high resolution satellite datasets. Efficiency of the technique has been assessed in different urban land cover situations using merged CARTOSAT-1 and IRS-P6 LISS-IV image subsets of Dehradun, India. Multi-scale iterative Nearest Neighbour classification has been applied. Classification results have been quantitatively evaluated. Results reveal that OBIA is a fast, simple, flexible and efficient semi automated tool to deal with high spatial and spectral heterogeneity inherent in high resolution urban datasets. Integration of shape and texture characteristics with traditional spectral signatures, and use of multiple object levels in the classification process yielded classified map units having high correspondence with real world geographical entities. High accuracies were achieved for spectrally and spatially distinct classes like built up structures and tree covered land. Performance of the technique is impaired in case of classes having overlapping spectral characteristics. The parameters for segmentation and class descriptions developed for one area were successfully transferred to the other with minor adaptations. Utility of the technique is further enhanced by flexibility of visualisation of maps at different levels of classification hierarchy and immediate integration of the classified product in GIS environment with direct realization of vector maps for spatial analysis.

Land cover change and environmental quality assessment using GIS techniques - a case study in Brazilian Southeastern region for the period 1988 - 2003

A close relation exists between the land cover situation and the environmental conditions of local wildlife species. This paper aimed to analyze the alterations of the land cover in two periods (1988 / 1995 and 1995 / 2003) regarding changes or persistence of the each land cover class and habitat assessment (establishment of categories of habitat quality) for a place in Brazilian Southeastern region. The study was carried out using digital land cover maps of the study area. Using a routine of GIS software, data were analyzed and the thematic maps generated. The data indicates that the region presented a dynamic land cover change, where almost a half of the study area presented changing in the land cover during the studied period. Major portion of the study area (~80%) was considered unsuitable for wildlife species establishment. It is urgent the necessity for a territorial reorganization in some regions aiming the construction of a biodiversity corridor to avoid a total isolation of the patches classified as primary habitat. The recovery of riparian forests along the rivers could accomplish it.

Water balance and vegetation change in the Sahel: A case study at the watershed scale with an eco-hydrological model

The Sahel, a semiarid area set in a fragile context, has been undergoing dramatic climate and land-use changes since the middle of the 20th century. The effects of these changes on the water cycle are analyzed using a coupled eco-hydrological model at the scale of a small representative catchment. Three land cover situations, corresponding to the 1950, 1975, and 1992 states, are simulated with two contrasted rain seasons, to produce the respective and combined effects of these two factors on the catchment water balance. The latter is largely dominated by rain-season evapotranspiration, representing some 60–65% of annual rainfall for the wet year in the three land use situations, but over 85% for the dry year. In absolute terms, evapotranspiration appears more sensitive to land-use changes than to the climate, but with variations that remain below 10%. These evapotranspiration figures are corroborated by field observations. Relative runoff sensitivity is much higher, nearly in the same 1.5:1 ratio as the annual rainfall for the climate effect, and with an increase by a factor of about 2.6 for the land-use effect. Confronting long-term runoff and water table dynamics evidences a direct linkage between these two processes.

Soil moisture mapping over the Chinese Loess Plateau using ENVISAT/ASAR data

In this paper, we used the available algorithm for soil moisture estimation over LOPEX05 (the Loess Plateau land surface process Experiment (2005)) area. The available algorithm used ENVISAT/ASAR AP mode VV polarization observational data at a low incidence angle and ground measured soil moistures. The ground measurements were performed in the summer of the 2005 during the LOPEX05 field campaign. The validated results indicate that an average difference between the soil moistures estimated from the microwave remote sensing and ground measurements is less than 0.02cm3/cm3, with a RMS error of 2.0%, and a maximum less than 0.04cm3/cm3. The algorithm was applied to the surface soil moisture mapping later. The results show that this algorithm is suitable for monitoring soil moisture information of the agricultural fields over the Chinese Loess Plateau, when ground land cover situation and the resolution of imagery data are taken into account. However, we also find that there are large differences over the steep slope region, the edge of mesa. The results are not acceptable for surface soil moisture estimation in these regions. Thus, the surface soil moisture retrieval in the steep slope region of the Loess Plateau need to be further investigated in the future.

Modeling the Contribution of the Brussels Heat Island to a Long Temperature Time Series

Abstract A mesoscale meteorological model containing a detailed land surface model is used to assess the contribution of urban heating to the temperature record of the national recording station of Belgium in Uccle, near Brussels. The Advanced Regional Prediction System (ARPS) was applied over a domain of 60 km × 60 km with a horizontal resolution of 1 km. Four meteorological episodes were selected, and, for each of these, the model was integrated using two different land cover situations. The first consisted of a detailed reconstruction of the early nineteenth-century setting of Brussels and its wide surroundings, while the second corresponded to the present-day land cover. Since the nineteenth century, when the recording station of Uccle was established, a major land cover change from an agricultural area to a built surface has taken place. The temperature difference between the simulations at the site of Uccle was assumed to represent the urban effect on the site since the beginning of recording. The urban heat island (UHI) of Brussels was found to have a significant impact on the temperature record in Uccle. The urban–rural temperature difference was found to build up during the evening, gradually decreasing during the night and becoming zero during the day. By analyzing the surface energy balance it was revealed that the UHI is mainly caused by a greater storage of energy in the urban fabric during the day and a release of this heat in the evening. The UHI had a significant average impact on the Uccle temperature record during two of the four selected weather situations. The effect amounted to 0.77°C in a cloudy weather situation with westerly winds and to 1.13°C in a clear and calm weather situation.

Effect of the aggregation level of surface runoff fields and sewer network for a SWMM simulation

The partitioning level of a catchment in storm water runoff modelling becomes an issue if the calculated results from the different number of subcatchments show the same performance. This study aims to identify the proper processing level of spatial resolution for the SWMM model application in an urban area. Using GIS overlaying technique, the division of subcatchments as a hydrologic similarity unit (HSU) is achieved with a comprehensive consideration of surface slope conditions, flow directions of storm sewers, and current land cover situation. Three surface-sewer alternatives are made on the basis of three different levels of surface divisions as well as the number of sewer connections and used as runoff simulation fields for the application of SWMM. As the result, it is found that the effect of a spatial resolution on the surface runoff results is not significant. On the other hand, the accumulated pollution load from a unit subcatchment, which is built by aggregation of several unit subcatchments consisting of various land cover conditions, is reduced through the deterioration of surface spatial resolution. Although overall runoff pattern and accumulated runoff are slightly affected by spatial resolution, the simulated runoff from sewer outlet shows slight difference at the peak appearance time.

Mapping Equus kiang (Tibetan Wild Ass) Habitat in Surkhang, Upper Mustang, Nepal

Abstract The present paper describes land cover classification and habitat mapping for the Tibetan wild ass (Equus kiang), also commonly known as kiang, in the Surkhang VDC, Upper Mustang, Nepal. Remote sensing techniques were applied for this classification, employing an ASTER satellite image from October 2002. The whole region was classified into 6 land cover types, relevant to the application of habitat mapping for the kiang. The classes are: grassland, shrubland, bare land, water bodies, snow cover, and agriculture and settlement. The area of each land cover type was tabulated to give a general picture of the land cover situation. Habitat information was collected mostly from the literature and partially from a field visit. GIS tools for spatial analysis were used to identify the suitability of the habitat in the region. The whole region was classified into 3 different suitability levels, ie primary, secondary, and non-suitable, based on use and potential use by the species in the particular area. The...

Preliminary evaluation of eCognition object-based software for cut block delineation and feature extraction

Pixel-based classifications have difficulty adequately or conveniently exploiting expert knowledge or contextual information. Object-based image-processing techniques overcome these difficulties by first segmenting the image into meaningful multipixel objects of various sizes, based on both spectral and spatial characteristics of groups of pixels. The segments (objects) are assigned classes using fuzzy logic and a hierarchical decision key. To date, the main drawback has been the lack of effective software. This paper evaluates a simple object-based approach to classifying forest cut blocks near Revelstoke, British Columbia, in a Landsat enhanced thematic mapper plus (ETM+) image using recently released eCognition software. Three subsets of the image test the software. Two subsets are chosen to evaluate it in different land-cover situations, and the third subset is used to test the effectiveness of replicating a rule system developed elsewhere in the image. Rules for class assignment include traditional spectral signatures, polygon shape parameters, and context with other classes. Use of multiple image object levels (sizes) greatly assists in image classification. Cut block scars, areas of mature, young, and sparse forest, water, and urban features are classified with significantly higher accuracy than using a traditional pixel-based method. The software allows expert knowledge to be documented and retained for use elsewhere or for later modification.

Assessing the land cover situation in Surkhang, Upper Mustang, Nepal, using an ASTER image

This paper describes the remote sensing technique used to prepare a land cover map of Surkhang, Upper Mustang Nepal. The latest ASTER image (October 2002) and an ASTER DEM were used for the land cover classification. The study was carried out in Surkhang Village Development Committee (area 799 km2) of Upper Mustang region. The study area falls within the Annapurna Conservation Area. Field surveys for training data, ground truthing and spectral signature collection were carried out during May-June 2002. Various image classification algorithms were tested, and the one that yielded the best result was used for image classification. The land cover situations with their aerial extents were identified and topographic analysis was carried out to study the variations of different land covers types in the region. Various species of grasses covered about 36 %; shrubs covered about 32%; bare land, which includes area from completely bare to less than 10% vegetation, constituted about 20% of the land resources of the study area. Grassland was found abundant in east- to south-facing slopes, while shrub species were abundant in flat regions and west- to north-facing slopes. 
 
 Key words: ASTER image, DEM, land cover mapping, Mustang, Nepal, GIS, remote sensing
 
 Himalayan Journal of Sciences 1(2): 93-98, 2003