Assessing Naturalness Changes Resulting from a Historical Land Use in Brazil South Region: An Analysis of the 1986-2016 Period

Abstract

The effects of land use and cover changes and the application of the Urbanity Index were analyzed to identify critical or non-critical naturalness scenery in the Northern Region of Rio Grande do Sul (Brazil), over a period of 30 years. Between 1986 and 2016, the main significant land use change was the reduction of the agricultural anthropic and the increase of the natural vegetation land use areas. About 90%-80% of the total study areas were characterized by anthropic pattern features, with a predominantly agricultural matrix. The conversion of agricultural anthropic into natural areas resulted in increased naturalness landscape and a gain in the stock of natural capital. The increase in the natural vegetation area, mainly to the north and east of the region, set in a steep relief, became remarkable after 1990. The Urbanity Index values evidenced a highest naturalness condition (natural vegetation areas) to the northern and eastern, while a smaller naturalness condition (agricultural and non-agricultural areas) to the southern and western and central of the Northern Region of Rio Grande do Sul. These changes are related to a non-impaired (northern and eastern) and a impaired scenery (southern, western and central portion) of the ecological sustainability of the Northern Region of Rio Grande do Sul, after a 30-year period (1986-2016). These results pointed out that land use transitions resulted in a consolidated farming scenario in which agricultural intensification coincided with the reduction of farming area and increased naturalness as a reverse trend to the agricultural frontier dynamics.

Biodisponibilidade de metais em riachos e a acumulação por insetos aquáticos

“…Embora os metais pesados possam estar presentes devido a processos naturais (e.g. intemperismo das rochas) (MAGALHÃES et al, 2015), na região de estudo cerca de 90% dos usos do solo são destinados a cultivos de culturas agrícolas, principalmente a cultura da soja (ROVANI et al, 2019). Os riachos localizados em regiões com intensa atividade antrópica se tornam vulneráveis à contaminação de metais, expondo assim a biodiversidade aquática presente nesses ambientes.…”

Alpha and beta diversities of Trichoptera (Insecta) assemblages in natural and rural subtropical streams

“…Agricultural practices require a large amount of land, which may result in the removal of riparian vegetation (Rovani et al, 2019). Removal of vegetation causes numerous physical and chemical changes in freshwater environments, causing variations in biological communities (Hepp et al, 2010).…”

“…The region under study has a subtropical climate, with average annual temperatures of 18 °C and annual mean rainfall of 1,500 mm (Alvares et al, 2013). About 20% of the region is covered by arboreal vegetation, the rest being occupied by rural and urban activities (Rovani et al, 2019). The vegetation is part of the Atlantic Forest biome, comprising a vegetative structure characterized by the presence of Araucaria angustifolia (Oliveira-Filho et al, 2015).…”

Nestedness of stream insects in Subtropical region: importance of inter-annual temporal scale

“…The vegetation consists of a mixture of Subtropical Forest, mostly composed of species with tropical-subtropical distribution and Araucaria forest with predominance of Araucaria angustifolia (Oliveira-Filho et al, 2015). The region has its area occupied by human activities, in particular by intensive agricultural practice (~ 80% of the total area; Rovani et al, 2019). We selected 10 small-order streams (<3 rd order) with an approximate width of 2 m, depth of about 0.3 m and substrate composed mainly of stones and leaves (Restello et al, 2014).…”