Geology, climate links make Guiana Shield region particularly sensitive to change
June 14, 2008
David Hammond, an environmental consultant, told a gathering of scientists from the Association for Tropical Biology and Conservation that the Guiana Shield's ancient — and therefore nutrient-deficient — soils make it biologically "frail" relative to parts of the Amazon basin. Archaeological evidence suggests that the region has always been sparsely inhabited relative to the wider Amazon.
Hammond also highlighted the susceptibility of the Guiana Shield to ENSO events. The region shows one of the strongest responses to to El Niño in the world. Charcoal signatures and forestry records show an environment "plagued by ENSO-driven flood and fire."
From humanity's standpoint, these characteristics put the region at risk of tipping toward a bleak future, said Hammond.
White sands forest in Suriname. White sands forests grow on soils that are particularly nutrient-deficient.
The Guiana Shield is part of the world's largest contiguous block of tropical forest. The region — made up of parts of Venezuela, Guyana, Suriname, and French Guiana — presently has the highest percent of forest cover and lowest rate of deforestation on the planet.
However, development pressures in the shield are increasing due to rising prices for metals, minerals, and timber. The geology of the region means the Guiana Shield is particularly well-endowed with gold, bauxite, and diamonds.
Amazon rainforest fires date back thousands of years March 14, 2007
Fires are nothing new to the Amazon reports a study published in the journal Biotropica. Analyzing soils in the interior of Guyana, South America, a team of scientists led by David S. Hammond of NWFS Consulting, has found evidence of forest fires dating back thousands of years. While the origin of these fires is unclear, the authors propose intriguing scenarios involving pre-Colombian human populations and ancient el Niño events which could have so dried rainforest areas that they became more prone to forest fires.