Cenários de naturalidade e sustentabilidade ecológica da Região Norte do Rio Grande do Sul, Brasil

Abstract

The effects of land use changes on the landscape naturalness to identify a critical or favorable scenery for ecological sustainability in the northern Region of Rio Grande do Sul (Brazil), based on the quantification of land use and land cover types and the application of the Urbanity Index, over a period of 30 years (1986 to 2016), were analyzed. Between 1986 and 2016, the main significant land use change was the area reduction of the anthropic-agricultural land use and the increase of the natural vegetation area. About 80 - 90% of the total study, area remains unchanged relative to land use types, with the continuity of a predominantly agricultural matrix. The conversion of agricultural anthropic into natural areas resulted in increased naturalness landscape and natural capital stock gain. The increase of natural vegetation, mainly in areas located to the northern and eastern of the region, set in more steep relief, became remarkable after 1990, and was accompanied by an increase in the number of fragments, and the gain of proximity and connectivity between fragments of native vegetation. The Urbanity Index values evidenced a highest naturalness condition to the northern and eastern (native vegetation areas), while a smaller naturalness condition to the southern and western and central (agricultural and non-agricultural areas) of the northern Region of Rio Grande do Sul. These changes showed a favorable (northern and eastern) and committed scenery (southern, western and central portion) of the ecological sustainability of the northern Region of Rio Grande do Sul, over a period of 30 years (1986 - 2016). This study showed that land use transitions reflected a farming consolidated scenery, where anthropic-agricultural intensification coincides with the reduction of arable land area, and the increase of naturalness as a reverse trend to the dynamics of the agricultural frontier.