38 research outputs found
A research tool for integrated palaeo- and actuoecological studies: the Amsterdam information management system (AIMS)
Palynological data on the history of tropical savannas in northern South America
A number of pollen diagrams from the Llanos Orientales of Colombia and the Rupununi Savannas of Guyana show that the actual open savannas were preceded by a closed savanna woodland or dry forest with Byrsonima as principal pollen producer. Human influence during the last 3000 years was apparently an important factor in the extension of open savannas. Nevertheless, open savannas occurred also earlier in the Holocene. Even in approximately Late-Glacial time, open savanna sometimes extended temporarily at the expense of the dry forest or woodland. It seems that climatic and atmospheric influences (periods of very dry climate, lightning) were the cause of these extensions. The pollen diagrams suggest anyhow a very unstable equilibrium between the woody Byrsonima association and the herbaceous open savanna. In the North Rupununi Savannas dry forest dominated in most of what probably corresponds to Late-Glacial time.
Open savanna was common or dominating there during a shorter interval of the above-mentioned „Late-Glacial” and during most of the Holocene
Dataset: Age determination results from site Padul
Minimum DEPTH, sediment/rock: 0.000 m * Maximum DEPTH, sediment/rock: 14.120
Comparisons of changes in vegetation in northeast Greece with records of climate variability on orbital and suborbital frequencies over the last 450 000 years.
Comparisons of changes in vegetation in northeast Greece with records of climate variability on orbital and suborbital frequencies over the last 450 000 years.
Dataset: Age determination results from site Voorthuizen
Minimum DEPTH, sediment/rock: 0.000 m * Maximum DEPTH, sediment/rock: 10.300