Effects of urban growth on coastal and continental wetlands in the semiarid environment of Tierra del Fuego, Argentina

Abstract

Coastal and continental wetlands in semi-arid environments near urban areas denote a valuable socioenvironmental heritage. These areas are exposed to stresses generated by urban expansion, especially if that expansion is rapid. This paper focuses on the physical changes in wetlands caused by such urban expansion and on the factors that increase this problem. The study case is focused on the city of Río Grande. This coastal city is on the steppe of Tierra del Fuego, Argentina, and its expansion started in 1972 following industrial promotion policies. Wetland identification, classification, and mapping from the multispectral analysis of satellite images is used to consider three periods related to changes in national policies for industrial development. The space-temporal analysis indicates a strong link between applied policies and the dynamic of urban growth and natural land occupation. Urban expansion involved the loss of one-third of the wetland and this includes fragmented units. Urban settlements on wetlands demand large amounts of gravel and soil to raise the land level and this represents a significant environmental externality to consider. Finally, informal settlements and a lack of planning are factors than increase wetland loss.