No Brasil, uma das principais causas da perda de biodiversidade é a modificação dos habitats devido à conversão da paisagem natural para a agrícola. Dessa forma, o presente estudo teve como objetivo analisar a dinâmica temporal do uso e cobertura da terra da Área de Proteção Ambiental Estadual do Rio Pandeiros (APA Pandeiros) em um intervalo de 20 anos (1995 e 2015), para compreender as mudanças que ocorreram na paisagem da APA desde a sua criação, no ano de 1995. Foram utilizadas técnicas de Sistemas de Informação Geográfica (SIG) no mapeamento do uso e cobertura da terra e para a caracterização ambiental. Tal análise permitiu a identificação de uma redução na vegetação nativa ao longo do tempo decorrente da expansão de algumas atividades agrícolas, como pastagem. Essa perda de vegetação nativa, juntamente com o avanço das atividades agrícolas, expõe esta Unidade de Conservação de Uso Sustentável a susceptíveis impactos ambientais e a perda significativa de biodiversidade.

AVALIAÇÃO DA VULNERABILIDADE AMBIENTAL DE SÃO CARLOS – SP

The expansion of agricultural frontiers in the Amazon region poses a significant threat to forest conservation and biodiversity persistence. This study focuses on Pará state, Brazil, aiming to identify and characterize the predominant production systems by combining remote sensing data and landscape structure metrics. A rule-based classification tree algorithm is applied to classify hexagonal cells based on land cover, deforestation patterns, and distance from dairy facilities. The results reveal three dominant production systems: Natural Region, Non-Intensive Beef, and Initial Front, with livestock production being prominent. The analysis indicates that there is a correlation between the productive area and deforestation, emphasizing the role of agriculture as a driver of forest loss. Moreover, road networks significantly influence production system spatial distribution, highlighting the importance of infrastructure in land use dynamics. The Shannon diversity index reveals that areas with production systems exhibit greater diversity in land use and land cover classes, reflecting a wider range of modifications. In contrast, natural vegetation areas show lower Shannon values, suggesting that these areas are more intact and are less affected by human activities. These findings underscore the urgent need for sustainable development policies that will mitigate threats to forest resilience and biodiversity in Pará state.

Secondary vegetation (SV) is the vegetation regenerating after deforestation or degradation of primary vegetation. Its identification and qualification are relevant to public policies for conservation and sustainable land management. This study analyzed the structural attributes of SV in the Amazon biome and their associations with land-tenure categories, considering the mapping evolution from 2008 to 2022. SV were analyzed regarding the age of each patch; landscape ecology metrics: area, core area, fractal dimension index, and Euclidean nearest-neighbor distance; the nearest-neighbor vegetation type; and the land-tenure categories. A principal component analysis synthesized the qualification of the vegetation. The SV landscape is predominantly in early-to-intermediate stages, with a mean age and half-life of approximately 7 years. Most polygons were small and had no core area, suggesting edge-dominated SV. Primary vegetation was the dominant neighboring class, and this prevalence of near-zero distances indicates a high degree of connectivity between these vegetation areas. Nearly half of the SV is associated with the land-tenure class, area without land registration, reflecting the fragility of forest conservation in contexts of weak or undefined land regulation. Four SV clusters were identified: Initial regeneration, Isolated small fragments, Consolidated regeneration, and Largest patch. This information is the basis for public policies such as the Brazilian National Vegetation Recovery Plan to identify priority areas for conservation and/or restoration.