Late Quaternary vegetation and coastal environmental changes at Ilha do Cardoso mangrove, southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A 190 cm mangrove sediment core from the Ilha do Cardoso State Park, State of Sao Paulo, southeastern Brazil was analyzed for pollen, diatoms as well as carbon and nitrogen isotopes. The goal was to determine the dynamics of the coastal terrestrial/aquatic ecosystems, vegetation history and climate change in this region of the Brazilian Atlantic rainforest, during the Late Pleistocene and Holocene. The values for total organic carbon-TOC (from similar to 3 up to 40%), C/N ratios (from similar to 10 up to 130), and delta N-15 (similar to 0 to >8) are associated with well preserved aquatic and terrestrial organic matter and possibly influenced by nitrogen cycling (e.g., denitriflcation) that caused N-15 enrichment between >40,000 cal yr B.P. and similar to 23,000 cal yr B.P. Depleted delta C-13 values (similar to -28.0 parts per thousand) are also observed and indicate the predominance of C-3 plants. During this time interval, the pollen analysis reveals the presence of the genera Ilex. Alchomea, Weinmannia, Myrsine, Symplocos, Drimys and Podocarpus on a site currently occupied by mangrove vegetation. These data suggest that in the past prevailed a colder and more humid climate than today, with a low relative sea-level. From similar to 23,000 cal yr B.P. to similar to 2200 cal yr B.P. a sedimentary hiatus likely occurred, related to an erosive event associated to the post glacial sea-level rise. Since at least similar to 2200 cal yr B.P., sediments are marked by relatively low C/N ratios (from 2 to 27), exhibit more enriched delta C-13 (from similar to-26.0 parts per thousand to -24.0 parts per thousand) and delta N-15 (up to similar to 7) values and are characterized by the presence of marine diatoms. This indicates the return of the marine coastal line to its current position, and consequently the development of mangrove. (C) 2012 Elsevier B.V. All rights reserved.3635768Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [04/00978-1, 04/15531-2

An assessment of urban vulnerability in the Amazon Delta and Estuary: a multi-criterion index of flood exposure, socio-economic conditions and infrastructure

The Amazon Delta and Estuary (ADE) is a region of continental and global ecological importance. Controversy, many of the basic infrastructure and services essential for quality of life and sustainable development of this delta are absent. Using a conceptual model to define socio-economic vulnerability in the urban ADE, a thorough assessment of indicators including sanitation services, housing conditions, household income, population, flood risk and unplanned settlements was conducted in 41 cities at the census sector scale (n = 2938). A multi criterion index was applied to classify urban vulnerability from three dimensions: flood exposure, socio-economic sensitivity and infrastructure. This is the first study to examine urban vulnerability within and between urban areas of the ADE. Results indicated that most of the urban sectors of the ADE are exposed to potential risks due to a combination of flood hazards, poverty and basic structural deficiencies such as insufficient drinking water or inadequate waste water collection, with several sectors being afflicted by similar problems. The assessment of vulnerability indicates that 60-90 % of the urban population live in conditions of moderate to high degree of vulnerability. The ADE cities presented a pattern where vulnerability increases from city center to their newly developed urban areas. Inadequate planning coupled with rapid urbanization has contributed to the development of unplanned settlements in almost half of the urban sectors of the ADE. Combined, these factors contribute to widespread socio-economic vulnerability along the urban spaces of the ADE, increasing exposure to health risks and more frequent seasonal and stochastic events such as storm surges and high flooding levels