Citation: Bharath H. Aithal and Ramachandra TV, 2012. Modelling the Spatial Patterns of Landscape dynamics: Review., CES Technical Report : 127, Energy & Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012. doi:http://wgbis.ces.iisc.ernet.in/biodiversity/pubs/ces_tr/TR127/index.htm
Contact Address :
  Dr. T.V. Ramachandra
Energy & Wetlands Research Group, Centre for Ecological Sciences,
New Biological Sciences Building, 3rd Floor, E-Wing, Lab: TE15,
Indian Institute of Science, Bangalore – 560 012, INDIA.
Tel : 91-80-22933099 / 22933503(Ext:107) / 23600985
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E-mail : cestvr@ces.iisc.ernet.in, energy@ces.iisc.ernet.in
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Modelling the Spatial Patterns of Landscape dynamics: Review
Bharath H. Aithal                              T.V. Ramachandra
Energy & Wetland Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore - 560012, INDIA
RAPIDLY URBANISING LANDSCAPE DYNAMICS

An urban landscape is charecterised by the parameters such as the number of residents, population density, percent of people dependent upon non-agricultural income and provision of public utilities and services. In India, an area is designated as urban if the population is more than 5000 with a population density of more than 400 persons per sq. km and at least 75 percent of the population is involved in non-agricultural occupations. India’s urban population is currently growing at about 2.3 percent per annum. An increased urban population and growth in urban areas is inadvertent with an unpremeditated population growth and migration. Urban growth, as such is a continuously evolving natural process due to population growth rates (birth and death). The number of urban agglomerations and towns in India has increased from 4369 in 2001 to 7938 in 2010. It is projected that the country’s urban population would increase to about 41.4 percent by 2030 (United Nations, 2004; Ramachandra et al., 2012). In 2010, there are 48 urban agglomerations / cities having a population of more than one million from 35 urban agglomerations in 2001, which was 25 in 1991. Of the 4000 plus urban agglomerations, about 38 percent reside in just 35 urban areas, thus indicating the magnitude of urbanisation prevailing in the country. This clearly indicates the magnitude of concentrated growth and urban primacy, which also has led to urban sprawl.

The exponential growth of cities has been noticed since the industrial revolution and as transport sector changed the mobility of the masses drastically. This phenomenon has been referred as urban sprawl, urbanization, suburbanization, urban fringe, edge cities, exurbs, etc. and all reflect the complexity of the diverse levels of dynamic process (Champion, 2001; Pacione,2001; Antrop, 2000c; Geyer and Kontuly,1993; Bryant et al., 1982; Feranec et al., 2010; Foley et al., 2005; Lo´ pez & Sierra, 2010). Rapid urbanization in the developing world is one of the crucial issues of global change in the 21st century affecting the human dimensions (Sui and Zeng, 2001).

Urbanisation is a form of metropolitan growth in response to technological, economic, social, and political forces and to the physical geography of an area. The process of urbanisation is fairly contributed by rural-urban migration leading to higher proportional population growth of urban-rural and subsequent infrastructure initiatives, resulting in the transition of villages into towns, towns into cities and cities into metros. With the extensive urbanisation followed by industrialisation, the compact and densely populated cities emerged during the last century. Over the last century, these countries saw the emergence of large metropolitan cities. Cities are continuing to spread in spite of the saturated and stagnated urbanisation, in Europe and other developed countries (Batty et al., 2003). As the cities grew in population, infrastructure facilities such as transportation were affected. The affluent also aided by individual transportation moved towards the outskirts thereby minimising costs in the central business districts, while inducing the spread of cities (Marathe, 2001). Also, at times, the civic authorities provided better public transportation facilities from the core to the outskirts and along the periphery, which encouraged people to move outskirts also inducing sprawl. In other words, be it either better transportation or the population growth, the cities expanded transforming neighbouring agricultural lands and affecting ecologically sensitive habitats. This phenomenon of urban sprawl is being witnessed, studied and documented in most cities of north-western Europe and North America even after reaching the stagnation and saturation levels of urbanisation. The problem of sprawl has been addressed through extensive studies and policy recommendations in the European Union (Gayda et al., 2005) and United States of America (TRB, 2002). Urbanisation, as such, is not seen as a threat to environment and development, but it is the unplanned urbanisation and subsequent urban growth, or the sprawl affecting land-use with loss of prime agricultural lands and also ecologically sensitive regions. Indian economy is mainly agrarian (contribution to GDP is about 28 percent) with about 70 percent of the population residing in rural areas. It is thus imperative to carry out better regional planning through proper understanding of the implications associated with the problem of unplanned urban growth or sprawl.

Urban sprawl is an unplanned outgrowth of urban areas along the periphery of cities, along highways, and along the road connecting a city. Towns and cities are expanding in certain pockets with changes in land use along highways and in immediate vicinity of the cities due to ad hoc approaches in planning and decision-making. This uncontrolled and un-coordinated, dispersed development outside the compact urban and rural centres (along highways and in rural countryside) has the environmental impacts such as loss of agricultural land, open space, and ecologically sensitive habitats in and around the urban areas. These regions lack basic amenities due to lack of prior information and predictions of such growth during planning, policy and decision-making. Sprawl results in engulfing of surrounding / neighbouring villages into peri-urban areas, peri-urban areas to towns and towns into cities. However, in such a phenomenon of development, to have basic infrastructure, regional planning requires an understanding of the process and dynamics. Nevertheless, in a majority of the cases there are inadequacies to ascertain the nature of uncontrolled growth. This necessitates prior planning, coordinated decision-making and visualisation of the consequences of urbanization to ensure the sustainability of the resources.

Urban growth patterns resulting in sprawl are ‘unsustainable’, with the current consumption surging ahead of regions’ carrying capacity and leading to depletion of natural resources for future generations. The need for managing urban sprawl also arises out of the global concerns of achieving sustainable urbanisation. Sustainable urbanisation is a dynamic, multi-dimensional process covering environmental as well as social, economic and political-institutional sustainability (UN-Habitat, 2002). Understanding the sprawl processes, its dynamics and modelling provide an insight of future growth trends, which is useful for effective resource utilisation and infrastructure planning. The efficiency of urban settlements largely depends on how well they are planned; how well they are developed economically and how efficiently they are managed.

In industrialised developed countries the growth of urban population is comparatively modest as population growth rates are low and over 80 percent of their population already live in urban areas. Conversely, developing countries with higher growth rates are in the middle of a transition. The exceptional growth of many urban agglomerations in many developing countries is the result of a threefold structural change process: the transition away from agricultural employment, high overall population growth, and increasing urbanisation rates (Grubler, 1994). Developing countries are faced with the problem of increasing urban poverty levels, higher population growth rates and rising numbers of slums or squatters resulting out of sprawl. This is in contrast to developed countries, where the problem of sprawl has to be addressed in terms of transport, energy, land use, and environment. It is in this context that the study on urban sprawl gains importance.

Rapid urbanization from landscape perspective has given rise to significant changes in the ecosystem structure, impacting its functions. Dramatic urban expansion and resultant land use changes have induced serious environmental issues threatening sustainable development (Yeh and Li, 1999; Ji et al., 2001; Weng, 2001; Li and Yeh, 2004; Chen et al., 2005; Xiao et al., 2006; Liu et al., 2007). Cities form extended circular networks affecting large areas with a multitude of different functions (Cheshire, 1995) describes this complexity. Management of the countryside along with functional urban areas is complex and interdisciplinary (Brandt et al., 2001).

Urban landscapes are charecterised by building, city blocks with the scattering of parks and uncommon landscape (Stearns and Montag, 1974, Dorney and McLellan, 1984). These are relatively unorganized homogeneous ensemble transforming the landscape into organized structure which cycles energy and information within itself (Wilson et al., 1973; Dorney and McLellan, 1984). Urban areas interact with the neighbouring landscape structures in the form flows of commuters, pollution, obtaining food grain, vegetables, etc. This creates stretch of dwelling localities between the metropolis and the rural landscapes and often these areas are devoid of basic amenities like treated water supply, electricity, sanitation, health, etc., these localities are often referred as urban sprawl.

The adverse effects of the process of unplanned urbanisation are amplification of the mosaic character of landscape, simplification of composition of the spatial landscape complexes with severe fragmentation of habitats (Solon, 1990). Landscape transformations under the influence of urbanization are multi-directional and differentiated in time and space. Li et al. (2003) pointed out that the dynamic process of urban expansion depends very much on topography, land use of the influenced area, as well as on demography and economy in a city.

Humans influence landscape heterogeneity in three ways: (i) landscape is modified to feed human stock, (ii) modification of landscape structure (example.: extraction of mineral deposits), and (iii) the aggregation process from rural to semi urban to urban. Therefore for the better utilization of landscape and its features, regional planning need to account all classes of the landscape ranging from urban area to rural area, which is possible only when the data is available for all classes and on a temporal scale.

Urban land expansion is one of the most direct representation forms of land use/land cover change, and refers specifically to change in land use pattern and urban space distribution resulting from land, social and economic pressure (Alphan et al., 2009; Gilliesa et al., 2003).

The best approach to understand the process of urbanization and its consequences can be easily understood by quantifying landscape pattern, either based on the analysis of indices (e.g., polygon shape index, Comberet et al., 2003) or a set of landscape metrics. The most classical is the urban–rural gradient analysis (Luck and Wu, 2002), extended by incorporation of temporal trends analysis (Weng,2 007), and multiplication of transects (Kong and Nakagoshi, 2006; Yu and Ng, 2007). The other approach based on grid analysis for the entire landscape, fills in the information gaps that arise by only presenting a cross-section of the study area (Hahs and McDonnell, 2006). An assumption is made that the landscape structure is shaped by different processes, occurring simultaneously at the same area, or separately in different parts of the region.

Urbanisation and sprawl were initially investigated in relation to population growth and the spatial extent of urban areas. Subsequently, studies dealt the problem of sprawl in relation to transportation, demography, economics, energy, land use, vehicular emissions, climate and safety. The problem of sprawl needs to be addressed considering all disciplines with an integrative approach (TRB, 1998 and 2002; Gayda et al., 2003 and 2005). The problem has been acknowledged for nearly six decades and ascribe sprawl as low-density development beyond the edge of service and employment (Sierra Club, 1998; Batty et al., 1999; Batty et al., 2002; Torrens and Alberti, 2000; and TRB, 2002). Urban sprawl has been accompanied with three interrelated problems of spatial dynamics: densification of central or core cities which usually mark the historical origins of growth; the emergence of edge cities which compete with and complement the functions of the core; and the rapid suburbanisation of the periphery of cities - core and edge - which represent the spatially most extensive indicator of such growth. This uncoordinated and unplanned incremental urban growth along the fringes of the metropolitan areas invading prime agricultural and resource land is unsustainable as such areas are over reliant on the automobile for access to resource and community facilities.

The study of urban sprawl and its implications have been addressed (TRB 1998, 2002; Sierra Club, 1998), considering the sprawl as the spread-out development that consumes significant amount of natural and man-made resources, including land and public works infrastructure of various types. Ascribing the resource impacts of sprawl in terms of costs, these impacts have been classified as land conversion, water and sewer infrastructure, local road infrastructure, local public-service cost and real estate development costs. The personal costs of sprawl have been mainly attributed to travel distance and costs. Sprawl also adds to overall travel costs due to the increasing use of automobile to access work and residence locations which are widely spaced. Sprawl raises the costs of operating urban infrastructure and hence leads to economic inefficiency (Ciscel, 2001) evident from the quantification of three components: the jobs, business and housing, commuting, and government infrastructure capital costs. Increase in population, rise in incomes and falling commuting costs have also fuelled the spatial growth (Brueckner, 2001). Studies have addressed issues of urbanization, urban growth, urban sprawl in relation to transportation, energy, land use, climate, etc. (Jothimani, 1997; Lata et al., 2001; Subidhi and Maithani, 2001; Sudhira et al., 2003 & 2004a, Ramachandra and Sudhira, 2011, Ramachandra et al., 2012), and modeling urban sprawl in India (Subudhi and Maithani, 2001; Sudhira et al., 2004b, Ramachandra et al., 2012). In India, as per constitutional provisions, urban local bodies are mandated for administering, managing and preparing master / development plans. Mostly these plans are static maps with limited forecasting capabilities. Nevertheless there is a need for modeling the dynamics planning process to prevent ad-hoc decisions. Further, with planning authorities restricting to mostly land uses, there is hardly any coordinated effort to involve or integrate transport, electricity, water and sanitation, etc. in the planning process. This results in organisations involved or catering to different services (transport, health, water, energy, etc.) work in isolation to address basic amenities. Lack of coordination among many agencies has led to unsustainable use of land and other resources and also uncoordinated urban growth. Much of this growth is normally attributed to migration of people from other places.

Rural-urban migration takes place mainly due to uncertain employment in agrarian based rural areas. It is found that lack of good governance and administration in the local bodies has resulted in unplanned and uncoordinated urban outgrowth. Urban governance and administration needs to keep track of various processes, activities, services and functions of the urban local body. In this context, regional models based on the information systems involving simulation for evolving location specific strategy and policy options are desirable.


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