Navegando por Assunto "Florestas de mangue"

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Acesso aberto (Open Access)
As comunidades tradicionais, sua importância na conservação do manguezal do município de São João da Ponta - PA
(Universidade Federal do Pará, 2016-05-31) FARIAS FILHO, Daniel Vilhena; PIMENTEL, Márcia Aparecida da Silva; http://lattes.cnpq.br/3994635795557609
In the Amazon Peoples using the mangrove ecosystem to withdraw products for their livelihood are known as extractive, and if the same comply may be called Traditional Peoples. These people have a low impact lifestyle in relation to the environment and to preserve this way of life contribute to the maintenance and balance of this ecosystem. The mangrove soil is carbon storage location and the misuse of this soil makes whether this carbon is released into the atmosphere thus contributing to the greenhouse effect. Thus the Traditional Populations contribute an environmental service in global warming mitigation process. This study attempts to make the physicochemical characterization mangrove soil of São João da Ponta, in Deolândia Communities Brasilândia, Coconut and Headquarters, relating these characteristics with the way of life and the use of mangroves by the Traditional Peoples living in if environment and Sustainable Development Index of São João da Ponta (IDSM). The methodology used for the physicochemical characterization of the area was the use of pH meter for determining pH and Eh, the refractometer to determine the salinity and Walker Black method for the determination of carbon. The survey also used questionnaire in Deolândia and Brasilândia communities, in order to determine matters concerning the social part, there was also the calculation of the Municipality of Sustainable Development Index MARTINS using the formula; CANDID 2009. It was found that the areas within the RESEX in communities Deolândia, Brasilândia and coconut tree where the forest is preserved, the physical and chemical characteristics in the soil are preserved, unlike the area where there was deforestation. The calculation of the municipality of Sustainable Development Index (IDSM) was 0.548 which according to the methodology adopted prove acceptable. The application questionnaire within each community showed concern about the presence of untreated sewage, siltation of rivers arms and a practice of burning household waste at the end of the day. The conclusion shows that despite some environmentally inappropriate practices such as burning waste and removal of nearby riparian vegetation to rivers, Traditional Peoples have a low impact way of life in relation to the use of mangroves and that the existence of Resex the municipalitycontributes for soil conservation and mangrove forest.
Acesso aberto (Open Access)
Estabelecimento e expansão dos manguezais de Laguna-SC: efeito do aquecimento global ou resultado de processos sedimentares?
(Universidade Federal do Pará, 2018-03-19) SOARES, Jaine Freitas; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
The integration of pollen, isotopes (δ13C, δ15N, C/N), sedimentary features, 14C and 210Pb dating from four sediment cores (LAG-3, LAG-4,LAG-5 e LAG-6). Sampled from a sandbar at Santo Antônio Lagoon, Laguna City, Santa Catarina, allowed the paleoenviromental reconstruction of the last 900 years BP. The dates reveal two facies associations along these cores: (A) Sandbar, represented by massive sand (facies Sm), and (B) tidal flat, represented by lenticular heterolithic bedding (Hl) and wavy heterolithic bedding (Hw). The deposits of sand bar was accumulated between >940 e ~431 cal years BP, probably under influence of a stable relative sea level (RSL) or rise of RSL during the last 1000 years. The pollen data preserved along the sandbar phase indicate a predominance of trees, shrubs herbs and some palms originating from vegetation units surrounding the lagoon. The relation δ13C (-24‰ - 15‰) and C/N (6-30) of this facies association reveals a strong contribution of organic matter from marine algae and terrestrial plants C3 and C4. During the accumulation of tidal flat deposits, occurred during the last 60 years, there was the establishment mainly of Spartina with some spaced Laguncularias shurbs. The relation δ13C (-24‰ - 16‰) and C/N (7-22) reveals an origin of sedimentary organic matter similar to the period of sandbar deposits. Based on this data and distribution gradient of Spartina and on mangrove’s trees genus along the Santa Catarina coast, is reasonable to propose that the recent colonization of Laguncularia at region of Laguna has been caused by gradual increase in minimum winter temperatures observed during last 50 years. Whether the climatic trend is the main force driving the expansion of Laguncularia trees to southern Brazil, the surface of the sandybars and tidal flats of the lagoon margin of southern Brazil, now largely occupied by Spartina, will be gradually colonized and/or replaced not only by Laguncularia, but also by Avicennia, followed during the next years, by Rhizophora.
Acesso aberto (Open Access)
A resposta dos manguezais de um estuário do sul da Bahia sob influência das mudanças do clima, flutuações do nível do mar e dinâmica dos canais durante o Holoceno
(Universidade Federal do Pará, 2017-06-09) OLIVEIRA, Nêdra Nunes; COHEN, Marcelo Cancela Lisboa; http://lattes.cnpq.br/8809787145146228
This work integrates palynology, sedimentology, geomorphology and radiocarbon dating, as well as δ13C, δ15N, and C/N from sedimentary organic matter obtained by the description of a core (5,20 m deep) sampled ~8 km from current coastline, 2m above sealevel at Jucuruçu River valley, near the city of Prado, south coast Bahia-Brazil. Based on this core and previously published works, the effects of climate and Relative Sea-level (RSL) changes on Jucuruçu’s mangroves during the Holocene were detailed. Along the studied core two phases were identified and correlated with others sediment cores. The first phase occurred in part of the middle Holocene (7200 - <6950 cal yr BP), developed on a tidal flat colonized by mangrove. It presents a transition from C3 terrestrial plants to marine organic matter upward this phase. On second phase, a fluvial plain developed followed by a mangrove shrinkage and, herbaceous and ferns expansion. At this phase, the biogeochemical data revealed an increased trend to organic matter sourced from freshwater. The integration of palaeoenvironmental data reveals an important RSL rise, which caused a marine incursion inside this river valley and allowed mangroves establishment under a strong estuarine influence, this incursion reached ~23 km upstream during the middle Holocene. The RSL fall at the middle and late Holocene caused a gradual mangrove replacement by mainly herbaceous vegetation associated to freshwater plankton predominance up river, while mangroves and marine algae migrated to the Jucuruçu river mouth. A decrease fluvial discharge during early and middle Holocene most likely favored this mangrove migration pattern and estuarine/marine organic matter spreading upstream. In contrast, probably the mangrove establishment at river mouth up present days was favored by an increase fluvial discharge at late Holocene. Noteworthy is the fact that tidal channels dynamics have controlled mangrove distribution last thousand years. Therefore, this study allowed to identify and to describe the effects of allogenic (caused by climate and RSL change) and autogenic processes (conducted, for example, by channels dynamic).