Assessing land-use and -cover changes in relation to geographic factors and urban planning in the metropolitan area of Concepción (Chile). Implications for biodiversity conservation

The conservation of biodiversity in Latin American metropolitan areas is threatened by the intense land-use and -cover change. Assessing the overall biodiversity changes in entire regions faces with the traditional lack of consistent biodiversity data. This work aims at contributing to this assessment through a set of major pressures to biodiversity defined from land-use and -cover changes, and evaluating their extent, distribution and correlations with geographical variables. The study was performed in the framework of the Metropolitan Urban Plan of Concepción (MUPC, Chile). Land-use and -cover maps were obtained through image classification for the years 2000 and 2010, before and after the MUPC approval, and combined in a land-use and -cover change (LUCC) map. A set of pressures to biodiversity (natural and artificial forestation, deforestation, agricultural abandonment and expansion, and urbanization) was obtained from reclassifying the LUCC map. The correlations of these pressures with a set of geographical variables were assessed using canonical ordination methods. Finally, a preliminary forecast analysis of the effects of the MUPC was performed by combining the land-use and -cover map of 2010 with the urban-extension areas of the plan.Results showed that, in only 10 years, 57% of the Concepción Metropolitan Area (CMA) was affected by land-use and -cover changes, and 48% was affected by the pressures to biodiversity. Artificial forestation and deforestation were the dominant pressures, followed by agricultural abandonment and urbanization. The geographical distribution of pressures during the 2000–2010 period also contributed to affect the conservation of biodiversity and the sustainable management of the CMA. Indeed, natural forestation occurred close to urbanization, thus threatening the ecological integrity of native forests, while artificial forestation, deforestation and agricultural abandonment took place in steeply areas thus increasing landslide risk. Despite urbanization was not the most relevant pressure in the short studied period, urban development planned in the MUPC would determine an overall increase of 60% in the built-up area of the CMA, mostly affecting brushwood and forest plantations but also native forest and wetlands. Implications of these results for the strategic environmental assessment (SEA) and the sustainable management of Latin American metropolis are finally discussed.