Urban ecological infrastructure: The importance of vegetation cover in the control of floods and landslides in Salvador / Bahia, Brazil

摘要

The city of Salvador has undergone a hasty population growth over the last five decades, from a mere 250,000 inhabitants in 1950 to ca. 2.9 million in 2017. This surge in population has resulted in a series of environmental issues directly connected with the reduction of the vegetation cover. Landslides and floods are among the most striking of such issues because they have put at risk, successively over the years, the lives and assets of hundreds of people, very in particular of those in less privileged circumstances. In view of this vulnerability framework and recognising the role that green areas play in the urban fabric, this work sought to determine the correlation between remnant vegetation cover and recorded occurrences of mass movements and floods. Particular consideration was given to the socioeconomic profile of the population segments most affected by these occurrences, assessed in terms of Municipal Human Development Index (M-HDI). We conclude that municipal government negligence in the control of the occupation and use of the land has been responsible for the emergence of hundreds of areas at risk, those where most mass movement and flood occurrences have taken place, which largely correspond with the neighbourhoods with the lowest rates of human development. In contrast, both the number of occurrences and their impact are smaller or non-existent in the northern part of the municipal territory, where the largest forest remnants are located, as well as in the most affluent neighbourhoods, where the ecological infrastructure has been replaced with costly public works.