Landscape change in Aizawl city: A geospatial approach to assess landscape indices and human-induced transformation

The change in an area’s natural surroundings is called landscape change. This change may be gradual or accelerated depending on the factors that influence the change. Natural elements such as native animals and birds seldom bring about any modification to the environment. However, human-induced change is devastating and severely transforms the environment. Such environmental transformation can be evaluated with the land use/ land cover assessment through satellite imagery and calculation of landscape indices. This paper attempts to ascertain the direction and the nature of the human-induced change in the city of Aizawl. To this end, the city has been divided into four zones to enable inter-zone comparisons. A northeast and southwest direction of human landscape transformation has been ascertained with the help of GIS and remote sensing techniques and landscape indices in Aizawl city.

Landuse/landcover change process in a tropi¬cal semi-arid zone: case of two rural com¬munes (Chadakori and Saé-Saboua) in Maradi region, Republic of Niger

The study aimed to analyze the process of Landuse/Landcover change of two rural communes (Saé
Saboua and Chadakori) of Maradi region (Republic of Niger) over the past 28 years (1986 – 2014),
through landscape structure analysis by diachronic cartographic approach and landscape indices. Mixed
classification of temporal series of Landsat images led to identifying six Landuse/Landcover (LULC)
classes, namely ”cultivated land under shrubs and trees”, ”cultivated land under trees”, “continuous
cropland”, ”fallow/pasture land”, ”forest reserve”, and ”settlement”. The composition and structure of
the studied landscapes have greatly changed from 1986 to 2014. The class ”cultivated land under trees”
was the landscape matrix in 1986 with 38.65% of landscape total area but in 2001 and 2014 the class
”continuous cropland” became the landscape matrix. The changes also affected the ”forest reserve”
which was transformed to smallholder agricultural land from 1986 to 2014. The area occupied by
classes ”cultivated land under trees” changed from 38.65% in 1986 to 8.78% in 2014; and from 1986
to 2014, the area occupied by ”fallow/pasture land” has decreased of about 16%. The decrease in these
classes was in favor of ¨continuous crop land¨, ¨settlement¨ and “cultivated land under shrubs and trees”
which respectively gained 38%, 0.3% and 8.15% of their areas in 1986. The results of this study reflect
the problem of access to land and even land saturation in semi-arid region, a consequence of strong
population growth. They also contribute to a better rethinking of agricultural practices in order to initiate
adaptation and resilience strategies for the population facing food insecurity and poverty.

The effect of aridification on dry and wet habitats of Illancs microregion, SW Great Hungarian Plain, Hungary

By the beginning of the 21st century, investigations aiming landscape history and landscape changes became especially important in the environmental research. The decreasing number of natural areas called the attention of the world to the rapid changes in the landscape caused by human activities and climate change. Certain places are facing with increased problems caused by the sensitiveness of landscapes. In Hungary, in the Danube–Tisza Interfluve a continuous groundwater-table sinking process was observed, as a result of anthropogenic effects of the last century and the consequences of climate change. On the highest part of this mesoregion (e. g. Illancs microregion), the decrease of the groundwater-level has reached 7 metres compared with the 1970s which affected significantly the nature and the local inhabitants as well. This study aimed to investigate the effect of this aridification process on dry and wet habitats of Illancs microregion. It reveals the ongoing processes in the landscape, referring to the previously affecting factors. In case of dry habitats, fragmentation and invasive species play important role as threatening factors. Wet habitats are significantly decreasing, shift of the vegetation zones can be observed. The stands are degraded, their steppification is dominant and can be observed only in the deepest parts of the depressions.

Landscape shape index, as a potencial indicator of urban development in Hungary

The study of settlement shape, morphology and structure is a classic topic of urban geography. Since the 1960s multiple shape indices have been developed. Urban patterns were then compared with geometric forms or, alternatively their temporal changes were tracked and analysed. In the current study we adapted the landscape shape index (LSI) to analyse the historical shape development of eight Hungarian cities. The LSI is capable to demonstrate the functional and mutual relationship between the developed area and their immediate physical and natural environment. Over the past 230 years the land area of the studied cities has increased manifold for several reasons: on average, an areal increase of 10.4 to 24.5 was observed for the eight settlements, while their perimeter increased by 8.8 to 30.3 times. Simultaneously with their size growth, the studied cities are characterized by an increasingly fragmented and dissected ground plans. Consequently, due to the longer border between the developed areas and the adjacent natural zones, urban areas have become increasingly sensitive to environmental effects over the past century, while mutual ecological and environmental interactions has also considerably increased between the adjoining zones. In general, cities of hilly and low-mountain areas had the highest LSIs, whereas cities located on relatively flat grounds had comparatively low LSIs. We also investigated the rank correlation of the historical change of LSI of the studied settlements. Cities of high positive correlations (> 0.9) were classified into two major categories. Miskolc, Pécs, Szeged and Kecskemét belonged to the group of higher LSIs, whereas Székesfehérvár and Nyíregyháza fell into the class of medium LSIs and the third category included Debrecen and Győr, cities of low (< 0.9) LSIs. Based on the temporal trends of the LSIs, our results provide applicable information for decision makers in order to monitor, manage and track their investments, city management policies and infrastructural development strategies.

A historic geographic approach to the anthropic disturbance in the Bükk region

This paper introduce a historical geographical study on the process of land cover transformation in the Bükk Region, which can be regarded as a two-faced area concerning its anthropogenic disturbance. Based on historic mapping that began as early as the late 18th century, a database was produced, and the data was interpreted in the context of economic and social processes that took place in the area. Results could be presented in maps using the so-called Anthropogenic Disturbance Index (ADI). These maps demonstrate the peculiar land use pattern in the Bükk Region, namely co-habitation of the significantly transformed margins and the natural or quasi-natural central part. Between them, there are linear areas of intermediate disturbance. These areas, however, due to the foundation and activity of the Bükk National Park and modification of their economic value after the change of the political system, have not increased during the last several decades; rather a re-naturalization of the landscape is aimed.

The developement of red mud flood environmental information system and the methodology for the spatial analysis of the degraded area

The red mud disaster occurred on 4th October 2010 in Hungary has raised the necessity of rapid intervention and drew attention to the long-term monitoring of such threat. Both the condition assessment and the change monitoring indispensably required the prompt and detailed spatial survey of the impact area. It was conducted by several research groups - independently - with different recent surveying methods. The high spatial resolution multispectral aerial photogrammetry is the spatially detailed (high resolution) and accurate type of remote sensing. The hyperspectral remote sensing provides more information about material quality of pollutants, with less spatial details and lower spatial accuracy, while LIDAR ensures the three-dimensional shape and terrain models. The article focuses on the high spatial resolution, multispectral electrooptical method and the evaluation methodology of the deriving high spatial resolution ortho image map, presenting the derived environmental information database

Analysis of landscape geographic impacts of potential climate change in Hungary

Change of climate can be a remarkable turning point in the 21st century history of mankind. An important task of landscape geographic research is forecasting environmental, nature protection, land use demands and helping mitigation of disadvantageous processes from the aspect of society. ALADIN and REMO numeric climate models predict strong warming and lack of summer precipitation for the area of Hungary for the period between 2021 and 2100. There is a predicted growth in frequency of extreme weather events (heat waves, droughts hailstorms). Changes have been forecasted using data presented in table 1. For analyses of complex landscape geographic impacts of climate change the area of Hungary have been divided into 18 mesoregions with 5.000-10.000 km2 area each (figure 1). The main aspect of choosing the regions was that they should have homogeneous physical, geographic and land use endowments and, for this reason, they should react to climate change the same way. Relationships between landscape forming factors and meteorological elements examined by us have been taken into consideration. Results of analyses of impacts of the meteorological factors on the changes of relief through the mass movements are presented in this paper. Changes of landscape sensibility of mesoregions to mass movements have been presented in the last chapter for the periods between 2021-2050 and 2071-2100 according to numeric climate models.

Specific features of NDVI, NDWI and MNDWI as reflected in land cover categories

The remote sensing techniques provide a great possibility to analyze the environmental processes in
local or global scale. Landsat images with their 30 m resolution are suitable among others for land
cover mapping and change monitoring. In this study three spectral indices (NDVI, NDWI, MNDWI) were
investigated from the aspect of land cover types: water body (W); plough land (PL); forest (F); vineyard
(V); grassland (GL) and built-up areas (BU) using Landsat-7 ETM+ data. The range, the dissimilarities
and the correlation of spectral indices were examined. In BU – GL – F categories similar NDVI values
were calculated, but the other land cover types differed significantly. The water related indices (NDWI,
MNDWI) were more effective (especially the MNDWI) to enhance water features, but the values of other
categories ranged from narrower interval. Weak correlation were found among the indices due to the
differences caused by the water land cover class. Statistically, most land cover types differed from each
other, but in several cases similarities can be found when delineating vegetation with various water
content. MNDWI was found as the most effective in highlighting water bodies.