Urban ecosystem functions. The process of material accumulation: technomass
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Urban expansion is a fundamental ecosystem function of cities. All cities expand, and some as Latin American cities, at very fast speeds that can reach 40 m2/minute.
This expansion can be understood in two main ways: as an ecosystem behavior, where cities like any other ecosystem, are accumulating matter. In fact it is this accumulated matter, as physical structure which allows energy and information to flow. The second form to understand expansion, that derives from the first, is metabolic: the process of material accumulation is in both cases, natural and artificial ecosystems (urban), a metabolic process, where accumulated matter comes from out of the system.
This process of material accumulation has received very littl attention in urban studies. In this paper I proposed a new indicator to measure this material accumulation process: technomass. As in natural ecosystems is biomass, technomass is the general sum of accumulated matter in different spatial compartments. From here it is possible to set ecosystem’s and metabolic behavior of urban systems, which allows to understand in a better way how they work and how they will evolve. Finally, biomass and technomass are in constant competition for the same space. This is the expression of the metabolic process of land cover change.
Urban Sprawl and Fragmentation in Latin America and Europe
Cities develop according to demographic and economic changes. In Latin America, fast growing metropolitan areas are subject to very diverse and complex urban sprawl and fragmentation scenarios. Land policy is confronted with an economically prosperous class demanding modern infrastructure and land development on the one hand side. On the other hand, a large number of underprivileged put pressure on the land-use with their demand for cheap housing, which develops rather uncontrolled.
Hence, the main development patterns and their implications remain mostly unknown. Urban sprawl is a land consumption process which impacts both, human and natural environment, stressing surrounding ecosystems. In the context of Latin America, urban sprawl must be seen under the specific regional and geographical characteristics. The spatial configuration of sprawling patterns is an important regional planning aspect insufficiently considered by Latin American land policy.
Urban sprawl and fragmentation are key factors of the urban policy in the XXI century.