History of Amazonian Savannas in the Last 10,000 Years

There is no arguing about the occurrence of savannas
in the middle of the Amazon forest anymore. However,
several questions still remain unresolved, such as:
How and when were they formed? Do they all share the
same origins? As an attempt to address some of these
complicated issues, we tried to investigate how
climate and human activity may have influenced areas
of disjoint savannas within Brazilian Amazonia.
Fossil pollen, charcoal, and radiocarbon records of 6
lakes were used to provide a regional
palaeoecological history of northeastern Amazonia in
the Holocene. The analyses performed on these
sediment cores allowed us to infer and date changes
in the environment, vegetation, hydrology and
sedimentation, and also to recognize human occupation
near the lakes in the last 7,000 years. Although each
individual record indicated local variation, all the
studied lakes were Holocene in age, and exhibited
rising water levels until ca. 6500 5300 years BP.
We were also able to identify the establishment of
savannas in Eastern Amazonia (Amapá), a strong signal
of human occupation in central Amazonia (Prainha),
and relatively stable savanna vegetation in the
Northernmost site (Roraima).

Autorentext
Mauro B. de Toledo, PhD: Studied Ecology at Florida Institute of Technology (FIT). Research Associate at Geology Department of Universidade Federal Fluminense, Brazil. Mark B. Bush, PhD: Professor at the Biology Department of Florida Institute of Technology (FIT).

Klappentext
There is no arguing about the occurrence of savannas in the middle of the Amazon forest anymore. However, several questions still remain unresolved, such as: How and when were they formed? Do they all share the same origins? As an attempt to address some of these complicated issues, we tried to investigate how climate and human activity may have influenced areas of disjoint savannas within Brazilian Amazonia. Fossil pollen, charcoal, and radiocarbon records of 6 lakes were used to provide a regional palaeoecological history of northeastern Amazonia in the Holocene. The analyses performed on these sediment cores allowed us to infer and date changes in the environment, vegetation, hydrology and sedimentation, and also to recognize human occupation near the lakes in the last 7,000 years. Although each individual record indicated local variation, all the studied lakes were Holocene in age, and exhibited rising water levels until ca. 6500-5300 years BP. We were also able to identify the establishment of savannas in Eastern Amazonia (Amapá), a strong signal of human occupation in central Amazonia (Prainha), and relatively stable savanna vegetation in the Northernmost site (Roraima).