Consulta: subjectFacets:"Pollen record"
Registros recuperados: 2
Data/hora: 10/06/2024 11:58:33

A Holocene pollen record of savanna establishment in coastal Amapá
Provedor de dados: 42
Autores: Toledo,Mauro B. de; Bush,Mark B.
The main goal of this study was to investigate how climate and human activities may have influenced ecotonal areas of disjoint savannas within Brazilian Amazonia. The fossil pollen and charcoal records of Lake Márcio (Amapá) were used to provide a Holocene palaeoecological history of this region. Detrended correspondence analysis (DCA) was used to enhance the patterns of sample distribution along the sediment core. A marked vegetation change from closed forests with swamp elements to open flooded savanna at c. 5000 yrs BP was evident from the pollen record. Charcoal analysis revealed a pattern of increased accumulation of particles coincident with the establishment of savannas, suggesting higher fire frequency and human impacts near the lake. A 550-year...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Pollen record; Palaeofires; Amazonia; Savannas; Climate change; Palaeoecology.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000200013

Vegetation and hydrology changes in Eastern Amazonia inferred from a pollen record
Provedor de dados: 42
Autores: Toledo,Mauro B. de; Bush,Mark B.
Pollen, charcoal, and C14 analyses were performed on a sediment core obtained from Lake Tapera (Amapá) to provide the palaeoenvironmental history of this part of Amazonia. A multivariate analysis technique, Detrended Correspondence Analysis, was applied to the pollen data to improve visualization of sample distribution and similarity. A sedimentary hiatus lasting 5,500 years was identified in the Lake Tapera. Because the timing of the hiatus overlapped with the highest Holocene sea-level, which would have increased the local water table preventing the lake from drying out, it is clear that sea-level was not important in maintaining the lake level. Lake Tapera probably depended on riverine flood waters, and the sedimentary gap was caused by reduced Amazon...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Vegetation change; Hydrology change; Amazonia; Pollen record; Climate change.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652008000100014