OUR COMMON SOILS: West Lausanne Urbanization as Anthropedogenesis, A Section through the Spaces and Times of Urban Soils

Motivated by ever-increasing soil degradation and artificialization due to past and present urban growth dynamics, the current trend of spatial planning policies at the European and Swiss levels is promoting increased soil protection, by avoiding new developments on agricultural and natural land, and by reorienting development towards existing urban areas that must be densified and restructured. This objective, which is formulated as "inward urbanization", not only puts pressure on the soils situated within urban areas, which are cast as priority development targets, but also gives a strategic role to this significant component of anthropogenic ecosystems, the multifunctionality of which must be considered as a crucial driver facing cities forthcoming social-ecological transition. However, urban soils are insufficiently studied as a long-term record of environmental history and heavy anthropization. In this context, the originality of this research is to consider urbanization not only as consuming and degrading, but also as transforming and producing soils, and to provide a methodology for the study of anthropedogenesis as a coevolution process of urban forms and soil functionalities, in both retrospective (history) and prospective (project) perspectives. Thus spatial development and urbanization do not only appear as a threat to soil capital but also as a key lever on which it is possible to act in order to valorize this resource. Based on a case study in fast-growing West Lausanne mixed-use district (Switzerland), this PhD thesis investigates the extreme qualitative variability of urban soils by presenting a conceptual model, a set of cartographic layers and profile descriptions. These research operations highlight soil evolution processes as a value which co-variates with Swiss Plateau city-territory urbanization. The various layers and map series of an Atlas of Urban Soils underscore the applicability of different types of information for documenting the combined influence of native geomorphology, anthrosediments and land cover changes, through various spatial and quantitative analyses. Complemented by empirical Urban Soils Portraits, such a consolidated concept map defines a template on which to apply the state factor and process-response approaches. Instead of using a simple spatial transect or time gradient, contrasting urban soil development pathways and their resilience are explained, mapped and quantified in the form of a complex spatiotemporal anthroposequence, and as a coherent bundle of historical trajectories and systematic patterns. Such a narrative integrates various facets of land use, integrating one-off construction techniques and recurring maintenance practices, planning tools, and morphologies, into a specific 'project for the ground' which brought forth the mixed-use mesh of the Swiss Plateau city-territory. Ultimately, in light of the ongoing planning policies, the dynamic vision conveyed by these intertwined soil-urbanization coevolution trajectories outlines opportunities and strategies for the regeneration of the resource deposit made up of both West Lausanne urban fabric and its soils. Such opportunities and strategies, which aim at a sustainable implementation of the inward urbanization principle, rest on the understanding of both the city-territory and its urban soils as palimpsests forming a dynamic system.

Mapping Urbanization as an Anthropedogenetic Process: A Section through the Times of Urban Soils

Antoine Vialle

Current trends of spatial planning policies give a strategic role to soils, the multifunctionality of which must be considered as a crucial driver facing cities’ forthcoming social-ecological transition. However, soils within urban areas are insufficiently studied as a long-term record of environmental history and heavy anthropization. This article investigates the extreme qualitative variability of urban soils by presenting a conceptual model and cartographic workflow highlighting soil evolution processes as a value which co-variates with urbanization. Based on a case study in West Lausanne (Switzerland), the layers and map series of an atlas underscore the applicability of different types of information and spatial analysis for documenting the influence of anthrosediments and land cover changes. Combined with empirical profile descriptions, such a consolidated concept map defines a template, in the form of a complex spatio-temporal figure, on which to apply the state factor approach. Instead of using a simple spatial transect or gradient, the increasing anthropic dominance over original landscape conditions is explained using a section through time. An urban anthroposequence consequently retraces contrasting soil development pathways as a coherent bundle of historical trajectories. Such a narrative integrates various facets of land use, including one-off construction techniques and recurring maintenance practices, planning tools, and morphologies, into a specific ‘project for the ground’ which brought forth the mixed mesh of the Swiss Plateau ‘cityterritory.’ Ultimately, the dynamic vision conveyed by these intertwined soil–urbanization coevolution trajectories outlines opportunities for the regeneration of the resource deposit made up of both West Lausanne’s urban fabric and its soils as a palimpsest.

2020

Métropolisation, habitat précaire et relogement forcé: entre phénomènes d'exclusion et tactiques populaires d'intégration

Sébastien Wust

This work was carried out within the interdisciplinary scientific program named "Sustainable Development, Metropolisation and Pollution of Natural Resources in Ho Chi Minh-City, Vietnam". This program, launched in 1994, is financed by the Swiss National Science Foundation (Priority Program Environment, Module 7 "Environment and development"). The main goal of this thesis is to grasp the social, economic and spatial dimensions at stake of involuntary resettlement of precarious settlements. in the context of developing countries' metropolisation. One of the approach selected fits within a thorough study of southern metropolis evolution dynamics, more precisely that of disadvantaged neighbourhoods. Moreover, we decided to develop a specific approach of involuntary resettlement, which is constructed using mainly two dialectical and interdependent concepts: exclusion and integration. In this way, this work differs from the most frequently used theoretical models, which are based on impoverishment or stress dimensions. In third world metropolis, government forces have an increasing tendency to turn to involuntary resettlement in order to implement or promote urban planning. Every year, approximately 6 million people are forced to move into an urban environment. This concerns mainly the most underprivileged sections of the population corning from precarious settlements. In recent times, this phenomenon has grown to such a point that some international institutions have even talked about the century of involuntary resettlement. The theoretical framework of this thesis refers to three different fields of knowledge, which nevertheless are linked to one another. The first field concerns developing countries metropolisation. Closely associated with the globalisation and polarisation of international trade, this process leads not only to the rise of exclusion but also to the dualisation of economic, social and political spheres and the fragmentation of urban spaces. The second theoretical field of study is based on questions raised by precarious settlements in southern metropolis. We analyse the way vulnerable populations living in disadvantaged neighbourhoods develop urban integration tactics in order to counter metropolitan exclusion forces and to alleviate precariousness. Finally, the third field is part of involuntary resettlement problematic. While it shares a close link to public policy evaluation, this problematic analyses the institutional values, norms, and practices underlying relocation policies of the people living in disadvantaged neighbourhoods. Our goal is also to develop a better understanding of the consequences associated to this kind of urban program and the way they might contribute to strengthening living conditions as well as residential situation precariousness for those who have been forced to move, leading them to develop defence mechanisms in order to guaranty their integration in the metropolis. In this analysis, we will focus on Ho Chi Minh-City and on the relocation program concerning the populations living in Nhieu Loc-Thi Nghe canal's precarious settlements. In the empirical part of this work, we will analyse and measure the consequences of this policy on their living conditions as well as on their behaviour. We will try to analyse to what extent those consequences tend to increase exclusion of underprivileged populations, limit their integration capacity, and enhances their residential mobility towards new precarious settlements that fit more to the aspirations, and above all, to the means of the underprivileged. Given the complexity of the topic covered in this work, we opted for an interdisciplinary approach. It appeals to different fields of social sciences: sociology, economics, geography, political sciences, but also architecture and urban planning. Moreover, we chose a quantitative as well as a qualitative method. Based on a multidimensional analysis of Nhieu Loc-Thi Nghe canal's population living in precarious settlements, we will be able to grasp the discriminating dimension of involuntary resettlement policy set up by metropolitan authorities as well as its severe impact on the population at a residential, social and economical level. Restrictive economic criteria or in some cases insufficient compensations offered by public authorities are such that a number of persons are excluded from the program. But on top of that, part of the families relocated in modern and salubrious apartments suffer from exclusion. As regards housing, the new apartments are characterised by their limited residential functions. This is mainly due to constraints linked to high rise housing, which acts as an economic and social barrier. In terms of social organisation, involuntary resettlement leads to a family nuclearisation process, and traditional sociability tends to turn to a more individualistic way of life, a phenomenon which results in a partial deconstruction of solidarity and protection networks. Finally, at the domestic economy level, resettled populations have to deal with an increase in service charges as well as working conditions deterioration which involve decreasing incomes. Although this modern way of life appeals to resettled families, most of them are brought to develop new integration tactics in order to limit involuntary resettlement exclusion effects. These tactics are to a large extent conservative inasmuch as they tend to reproduce ways of life and space habits characteristic of the former residential areas. To a large extent, they are characterised by palliative measures of space utilisation, professional insertion, income improvement and domestic means reallocation. Despite their willingness, families have a hard time fighting against resettlement exclusion forces. Residential mobility as well as subsidised apartments resale then become the way for some families to minimise precarious living conditions. Nevertheless, the benefits they gain from these illegal practices are often insufficient for them to buy or build an accommodation close to the center of the metropolis. The only possibility left to the reseller is then to rent a dwelling unit in a disadvantaged neighbourhoods or to move on the outskirts. While residential mobility leads to the creation of new precarious settlements in Ho Chi Minh-City, some families living conditions as well as residential situation keep on deteriorating, a decline which might bring some of them to experience a kind of urban nomadism. While the results of our study confirm the hypothesis stated at the beginning of this work, they also point out how hard it is to fulfill the housing aspirations of the most underprivileged considering the precariousness of their living conditions. The inadequacy of precarious settlements relocation policy is even worse when based on a modernist and standardised approach of the housing problem which favours typological and technical dimensions of residential space to the detriment of social, economic and ecological dimensions. What is at stake in involuntary resettlement concerns mainly the multidimensional mechanisms of exclusion and integration of which depends the subsistence of the most underprivileged in Ho Chi Minh-City. Urban authorities need to make political adjustments if they want resettlement impacts to fit the goals of sustainable development. In order to achieve this objective, popular participation and exchange between involved actors is the first condition they need to fulfill for the implementation of any policy in order to fight against exclusion and promote the integration of the most underprivileged as well as for any policy which aims to take into account the capacity of urban ecosystems.

EPFL2001

Land use changes and transnational migration

Silvia Hostettler

The present study focuses on the economic, political/institutional, technological, cultural, demographic and environmental drivers of land use change. It aims to understand the factors influencing land use decisions at the household level, in particular the influence of migration. The study is guided by the hypothesis that international migration is driving land use change through the investment of remittances, funds sent back by migrants to their families in the country of origin. This research is based on a political ecology approach and the conceptual framework relies on three theoretical concepts. First, the concepts of proximate causes and driving forces were used to identify the factors behind changing land use. In addition, the concept of remittance landscapes, a concept developed in the framework of this study, which is defined as an emerging type of landscape driven by the investment of remittances, was used to evaluate the impact of remittances on land use in the study area. Fieldwork was conducted in the municipality of Autlán in the state of Jalisco in Mexico over a total period of 8 months between 2002 and 2004. Land use changes between 1990 and 2000 were quantified based on satellite image analysis. Underlying driving forces of these changes were examined based on land use change data collected by survey as well as data available from municipal, state and federal agencies. Land use changes observed in the study area between 1990 and 2000 include a slight increase of agricultural land (2%), of urban land cover (0.5%) and of pine-oak forest (0.7%). Over the same period, pasture increased by 18% while dry forest decreased by 10%. Rapid and extensive land use change is occurring on rainfed agricultural land, as maize cultivation is converted to the cultivation of agave azul used for the production of tequila. The first plantations of agave azul were established in 1996 and by 2002, agave azul was planted on 33% of all rainfed agricultural land of the municipality. 84% of owners of rainfed land included in the survey had changed land use from maize to agave during this time period. The dynamics of several proximate causes are driving this change: 1) Market prices for maize decreased by 46% between 1994 and 2004 while the costs for agricultural inputs continually increased so that the cultivation of rainfed maize was no longer economically profitable; 2) The variability of rainfall combined with a lack of irrigation water limits the choice of economically viable alternatives to agave azul; 3) In the large majority of cases, landowners rent out their land to tequila companies in reverse leasing arrangements for seven-year periods (the duration of one growing cycle of agave azul). During this time they do not have to work on their own fields and are free to find off-farm employment or to migrate to the US and; 4) Landowners continue to receive agricultural subsidies even though the land is rented out, as agave azul is one of the eligible crops. Overall, the main driving forces identified in the study area are economic (market prices), environmental (variability of rainfall, soil quality, topography), political/institutional (agricultural subsidies, land tenure) and demographic (labor availability). Technology and culture appear to be less important. Results of the present study confirm the hypothesis that global factors, especially international trade agreements such as NAFTA (North American Free Trade Agreement) increasingly influence land use change. However, they are not sufficient to function as a sole driver of land use change. Environmental factors are a critical determinant of whether a certain land use change will occur or not. The decisive aspect behind the observed land use changes are the multiple interactions between specific factors at different levels and not the predominance of one particular driving force functioning at a particular level. International migration is a significant livelihood strategy in the study area, especially for lower-income communities. On average, 50% of all households have or had at least one family member in the US as a migrant between 1980 and 2004, and remittances represent 45% of total household income. In general, the bulk of remittances income is used for subsistence needs and to repay debts. Nevertheless, on average, 30% of migrant households invest remittances in land, livestock, agricultural production and in house construction. All these investments lead to land use changes. The impact of remittances on land use changes is variable, and depends on the socio-economic, political and environmental context of the community and the individual situation of the migrant household. In low-income communities, remittances might be used to repair existing housing, while in higher-income communities, remittances are used to construct a new house, converting agricultural to urban land. With regard to changes in labor availability due to out-migration, the results are ambiguous. Migration can drive land use change by encouraging a shift to low-labor land use systems, but these land use changes that require less labor can also drive migration. The concept of remittance landscape developed by the researcher has proved useful for analysing the impact of remittances on land use changes. A combination of area-based and actor-based evaluation criteria are effective in order to describe quantitative as well as qualitative landscape transformations driven by the investment of remittances. Landscapes where the investment of remittances leads to a change of land use from subsistence to cash crop cultivation should be included as a potential type of remittance landscape, even though the basic type of the landscape (agricultural) remains unchanged. Accordingly, at least six different types of transformations into remittance landscapes are possible: a) forest to pasture, b) forest to agriculture, c) forest to urban, d) agriculture to pasture, e) agriculture to urban and f) change of agricultural system. In conclusion, the study area on which this research focused is not considered to contain any remittance landscapes because remittances are only partially driving the extensive land use changes occuring in the region.