Search

Forest fragmentation caused by human activities has many implications for natural landscapes, such as habitat reduction and the loss of biodiversity. This study investigated the temporal fragmentation process of forest remnants in a strongly agro-industrialised region in southern Brazil over 25 years. The studied watershed area hosts two important typologies of the Atlantic Forest biome as well as Quaternary remnants of the Brazilian Savanna biome, which are considered hotspots of biodiversity and reflect the intense process of forest fragmentation caused by Brazilian urban and agro-industrial development. Thus, studies encompassing multitemporal scales are paramount to understanding changes in forest patterns and are fundamental for trend predictions of landscape dynamics. To perform the calculation of the mean normalised difference vegetation index, Landsat satellite images from 1991 to 2016 were processed using SPRING® software. Subsequently, FRAGSTATS® software was used to calculate landscape metrics. A reduction in the number of forest fragments since 1991 was observed, with a maximum amount of 5 243 fragments in 1993 that declined to 4 015 fragments in 2016. Although the number of fragments in the watershed decreased, the mean area increased by 72.9% and the mean of the shape index increased from 1.3 in 1991 to 1.5 in 2016. In addition, there was a 64.7% increase in the edge density and a reduction of 35.6 m in the isolation between the nearest neighbours. The degree of isolation of the fragments underwent a process of expansion and reduction when compared to 1991, presenting results that support the hypothesis that the Atlantic Forest is in a process of stabilisation and forest restoration.Keywords: Atlantic Forests, conservation, ecotone zone, GIS, spatial analysis

The elaboration of environmental sustainability indexes (ESI) aims to describe the complexity between social, environmental and ecological health. These indexes play a crucial role by helping stakeholders during the decision-making process and by identifying possible sites that require practical sustainable actions. In this study, we aim to elaborate an ESI for hydrographic basins. We use three factors to build the index: land use; vulnerability to soil degradation and topographic land attributes; and human development. The human development factor includes the dimensions of education, sanitation, longevity and income. These three factors are recommended by the Organization for Economic Cooperation and Development and reflect the pressure–state–impact assessment model. To verify the effectiveness of the proposed ESI, we applied it in a hydrographic basin located in southern Brazil. The sustainability level variation in the basin was classified into five groups: very low (0%), low (17%), intermediate (72%), high (11%) and very high (0%). The predominance of the intermediate sustainability level was found to mainly owe to the extent of agricultural land and the high degree of susceptibility to soil erosion in areas with low environmental conservation. In areas with native vegetation, environmental sustainability was found to be higher than in areas with other land use types. The resulting ESI will help facilitate future studies in environmental, economic or social dimensions in any hydrographic basin.

Forest fragmentation may negatively impact fauna and flora. An important tool for the development and implementation of research on these effects is the use of a geographic information system (GIS). This paper aims to perform an integrated analysis of the landscape fragments that compose the Alonzo River watershed, Paraná State, by using remote sensing tools and landscape ecology metrics. The analyzed landscape metrics were Patton’s index, total area of the patches, edge length, edge density, forest fragment density, and the core area of the patches. The results showed 888 forest patches with area values ranging from 0.15 ha to 2509.82 ha, and it represents 12.5% of the total forest land cover of the studied basin; this means that 85.3% of the forest patches are less than 50 ha and that 75% of those fragments have a Patton’s index value of less than 3.9. The fragments that compose the studied area may be subject to edge effects and biodiversity loss as long as they present reduced areas and small core areas. Thus, the use of GIS and landscape ecology metrics is a quick and efficient way to evaluate the effect of fragmentation over large areas.

International audience