Environmental consequences of exurban expansion in an agricultural area: the case of the Argentinian Pampas ecoregion

Exurban land use growth has been documented for at least thirty years in various regions around the world. Land use planners and land use/land cover change researchers have been concerned about the low-density residential developments scattered on a natural or agricultural matrix, due to their ecological and environmental impacts. In this paper, exurban sprawl in the Pampas ecoregion (Buenos Aires province, Argentina), is characterized and assessments are taken of the magnitude of two important consequences: agricultural land conversion, and excess CO₂ emission resulting from commute. The exurban developments concentrate between 50 and 70 km from Buenos Aires city, mainly at walking distances from compact towns, from 1 to 6 km of main roads, and no further than 25 km from them. Most of the exurban developments are located on the higher elevations in the study area (25 to 30 m above sea level). Even though exurban land use covers a very small proportion of land, the results show a tendency for conversion of land in the highest soil productivity capacity classes. While the best agricultural lands accounted for 29% of the land in the study area, it accounted for 54% of the exurban development. Preference of exurban land use conversion for good quality agricultural soils is observed even in those counties with a scarcity of good soils. However, there are great differences among counties in the relative proportion of land converted to exurban land use in each soil productivity capacity class. At the county level, from 0 to 100% of the highest production capacity lands have been converted to exurban uses, regardless of the proportion of land in each soil productivity capacity class for individual counties. Excess CO₂ equivalents emission was calculated for both the actual and the potencial number of households in the exurban developments. According to the automobile marque, range and fuel type, the actual emission ranges from 81,065 to 190,446 tons/year, and the potential from 296,643 to 696,908 tons/year. The excess emission per household is higher than that produced by domestic energy consumption within the Buenos Aires city during the same time period. The amount of CO₂ emitted in a year by personal vehicle transportation, in the study area, is equivalent to that captured by 16,000 ha of temperate forests or 27,600 ha of temperate grasslands during the same time period.