Heterogeneous Agricultural Areas Research Articles

Evaluation of the MODIS Albedo product over a heterogeneous agricultural area

In this article, the Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF)/Albedo product (MCD43) is evaluated over a heterogeneous agricultural area in the framework of the Earth Observation: Optical Data Calibration and Information Extraction (EODIX) project campaign, which was developed in Barrax (Spain) in June 2011. In this method, two models, the RossThick-LiSparse-Reciprocal (RTLSR) (which corresponds to the MODIS BRDF algorithm) and the RossThick-Maignan-LiSparse-Reciprocal (RTLSR-HS), were tested over airborne data by processing high-resolution images acquired with the Airborne Hyperspectral Scanner (AHS) sensor. During the campaign, airborne images were retrieved with different view zenith angles along the principal and orthogonal planes. Comparing the results of applying the models to the airborne data with ground measurements, we obtained a root mean square error (RMSE) of 0.018 with both RTLSR and RTLSR-HS models. The evaluation of the MODIS BRDF/Albedo product (MCD43) was performed by comparing satellite images with AHS estimations. The results reported an RMSE of 0.04 with both models. Additionally, taking advantage of a homogeneous barley pixel, we compared in situ albedo data to satellite albedo data. In this case, the MODIS albedo estimation was (0.210 ± 0.003), while the in situ measurement was (0.204 ± 0.003). This result shows good agreement in regard to a homogeneous pixel.

Remote sensing and GIS-based integrated analysis of land cover change in Duzce plain and its surroundings (north western Turkey)

The aim of this study is to research natural land cover change caused by the permanent effects of human activities in Duzce plain and its surroundings, and to determine the current status of the land cover. For this purpose, two Landsat TM images were used in the study for the years 1987 and 2010. These images are analysed by using data image processing techniques in ERDAS Imagine©10.0 and ArcGIS©10.0 software. Land cover change nomenclature is classified according to the Coordination of Information on the Environment Level 2 Classification (1--urban fabric, 2--industrial, commercial and transport units, 3--heterogeneous agricultural areas, 4--forests, and 5--inland wetlands). Furthermore, the image analysis results are confirmed by the field research. According to the results, a decrease of 33.5 % was recorded in forest areas from 24,840.7 to 16,529.0 ha; an increase of 11.2 % was recorded in heterogeneous agricultural areas from 47,702.7 to 53,051.7 ha. Natural vegetation, which is the large part of land cover in the research area, has been changing rapidly because of rapid urbanisation and agricultural activities. As a result, it is concluded that significant changes have occurred on the natural land cover between the years 1987 and 2010 in the Duzce plain and its surroundings.

Understanding land cover change in a Special Protection Area in Central Spain through the enhanced land cover transition matrix and a related new approach

This work analyses land cover changes occurring between 1990 and 2000 within a Natural Protected Area, southwest of Madrid (Spain). We develop a new methodology that considers the net change in different land cover categories in each municipality of the study area. Our methodology, which uses Factorial Correspondence Analysis, allows identification of the most important changes at the municipality level and groups the municipalities where land use dynamics are similar. This method is a powerful tool for synthesis and can potentially be applied to non-spatial geographical data sources (e.g. agrarian census statistics). Our results show that the land cover around SW Madrid is highly dynamic. The shrub vegetation, arable land, heterogeneous agricultural and human-created area categories show the highest total change. The dynamics of the changes detected are dominated by decreases in the area of different types of crops and increases in forest areas. These changes may have indirect effects on the conservation of natural resources and wildlife if not managed appropriately.

Change detection of land cover and land use using remote sensing and GIS: a case study in Kemer, Turkey

Suitable climate conditions as well as rare natural and cultural resources in the Mediterranean region of Turkey have made it a centre of attraction for two conflicting interests: agricultural production and tourism activity. In recent years, the natural appeal of the area and economic interests have dominated tourism over agriculture, forestry and wildlife and led to significant urban sprawl. The objective of this study was to investigate the dimensions of the land cover/use conversion of a quiet, small village (Kemer) into an internationally popular touristic destination. In the scope of this study, land cover and land use changes were analysed over approximately 30 years using Landsat Multispectral Scanner (MSS) data (1975), and Landsat Thematic Mapper (TM) data (1987, 1995 and 2003) by image classification techniques. In the land use hierarchy, the Coordination of Information on the Environment (CORINE) methodology was used as a base. Data organization and collection stages were achieved in a geographical information system (GIS) environment. Finally, the results indicate that, from 1975 to 2003, permanent crops decreased by 75% and most of these areas were structured. Throughout the same years a 55% decrease was determined to arise in heterogeneous agricultural areas. From 1975 to 2003, there had been no serious change in forests. The main reason for this is the accommodation of the Olympos‐Bey Mountains national park in the region.

Land Cover, Landscape Structure, and West Nile Virus Circulation in Southern France

The transmission of West Nile virus (WNV) is strongly influenced by environmental factors. In France, two endemic areas for WNV have been identified: Camargue and Var. The objective of our study was to test whether landscape characteristics could be associated with the risk of endemic circulation of WNV in these two ecologically different areas. Equine serological data collected during outbreaks in Var (2003) and Camargue (2004) were used. Both areas were marked out in cells of 5 km(2), and data were aggregated for each cell. Sixteen cells, classified as "high" level viral circulation, and 28 cells, classified as "low" level viral circulation were used for the analysis. The Corine Land Cover database (European Environment Agency) was used to evaluate, for each geographic cell, the area covered by 12 land cover classes, as well as the value of 5 landscape metrics (patch richness and density, edge density, the Shannon's diversity index, and interspersion and juxtaposition index (IJI). Multivariate linear generalized regression showed that IJI as well as the surface covered by heterogeneous agricultural areas were significantly higher in high level WNV circulation cells than in low level ones (p = 0.01 and 0.05 respectively). Both variables are indicators of a complex spatial biotope configuration that may favor the co-existence of competent vectors and reservoir hosts: the structure of the landscape thus appeared as a key element in WNV circulation. An internal validation was performed and the model was used to compute a risk map for the French Mediterranean coast. Cells with a probability > 0.8 of having a high level of viral circulation were found near Aix-en-Provence, Beziers, and Perpignan, areas where no serological study has yet been conducted. Equine cases reported in 2006 were all located in the neighborhood of cells having a > 0.8 probability for high WNV circulation status.

Evidence of selective burning in Sardinia (Italy): which land-cover classes do wildfires prefer?

The objective of this paper is to identify land-cover types where fire incidence is higher (preferred) or lower (avoided) than expected from a random null model. Fire selectivity may be characterized by the number of fires expected in a given land-cover class and by the mean surface area each fire will burn. These two components of fire pattern are usually independent of each other. For instance, fire number is usually connected with socioeconomic causes whereas fire size is largely controlled by fuel continuity. Therefore, on the basis of available fire history data for Sardinia (Italy) for the period 2000–2004 we analyzed fire selectivity of given land-cover classes keeping both variables separate from each other. The results obtained from analysis of 13,377 fires show that for most land-cover classes fire behaves selectively, with marked preference (or avoidance) in terms of both fire number and fire size. Fire number is higher than expected by chance alone in urban and agricultural areas. In contrast, in forests, grasslands, and shrublands, fire number is lower than expected. In grasslands and shrublands mean fire size is significantly larger than expected from a random null model whereas in urban areas, permanent crops, and heterogeneous agricultural areas there is significant resistance to fire spread. Finally, as concerns mean fire size, in our study area forests and arable land burn in proportion to their availability without any significant tendency toward fire preference or avoidance. The results obtained in this study contribute to fire risk assessment on the landscape scale, indicating that risk of wildfire is closely related to land cover.

Inventory of major landscape changes in the Czech Republic, Hungary, Romania and Slovak Republic 1970s – 1990s

One of the most important achievements in 1998–1999 of Phare Topic Link on Land Cover has been the development and practical application of a methodological approach to landscape change identification and analysis in the territories of four Phare countries (the Czech Republic, Hungary, Romania, and the Slovak Republic). The changes were identified on a national level from Landsat TM and MSS satellite images by application of the CORINE Land Cover databases for two time horizons (the late 1970s and early 1990s) at the second hierarchic level. Based on identified causality, the landscape changes were grouped into 7 types: intensification of agriculture, extensification of agriculture, urbanisation-industrialisation, enlargement (exhaustion) of natural resources, afforestation, deforestation and other anthropogenic causes. The results of the groupings are presented in the form of contingency tables and maps showing the spatial distribution of the changes. From the point of view of total extent, forest landscape changed the most in the Czech Republic. This change represents a reduction of forest by 167,702 ha and an enlargement of transitional woodland-scrub by about 26,339 ha. In Hungary the most pronounced changes were decrease of forests by 66,622 ha and decrease of arable land, orchards and vineyards by 21,529 ha. The most remarkable changes identified in Romania were decrease of arable land, forests and wetlands by 366,817 ha, 285,887 ha, and 59,967 ha, respectively, as well as enlargement of areas of complex cultivation pattern by almost 347,220 ha. The most pronounced changes in Slovakia were represented by diminution of forest by 94,935 ha and that of heterogeneous agricultural areas by 18,451 ha; enlargement of transitional woodland-scrub areas and urbanised area were about 13,107 ha and 14,990 ha, respectively.