| Description |
During the 21st century global change and deforestation have increased fires in the Amazon. Protection of rainforests and sustainable land-use practices in the Neotropics are critical for preserving biodiversity and buffering for climate. To make informed policy decisions it is necessary to understand how natural and anthropogenic disturbance shaped modern Neotropical ecosystems. Long-term paleoecological records can aid in understanding the susceptibility and resiliency of Amazonia ecosystems to modern disturbance. The purpose of this research is to reconstruct fire, vegetation, and soil geochemistry histories from Neotropical ecosystems to advance the understanding of long-term ecological variability on subcentennial to multimillennial temporal scales and local-to-regional spatial scales. Three primary research aims are addressed: (1) provide subcentennial resolution of ecological change and natural disturbances at control sites in savanna and rainforests ecosystems, (2) evaluate the climate-fire relationship on local-to-regional scales, and (3) synthesize existing pollen data from the Amazon basin to identify potential ecosystem thresholds in the past. Results from this study indicate edaphic/climatic controls drove cerrdo savanna fire and vegetation histories for the past 15,000 years, fire activity exhibited similar patterns on local and regional scale, and regional scale vegetation change was associated with periods of increased climatic variability since the last Glacial period, the last 21,000 years. The combined pressures of climate and human activities over the past 1,500 years have resulted in the highest levels of regional vegetation change. Increased ecosystem variability, a result of both human and natural drivers, in recent times suggests greater ecological instability and lowered buffering capacity of tropical ecosystem. These data can inform adaptive management policy to preserve diversity across a range of ecosystems in the Neotropical South America. |
