These factors will allow them to better understand why they became extinct and what environmental conditions existed at the time of their survival. Research has raised questions concerning the possibility of accurately cataloging anthropogenically uninfluenced diatom assemblages in high-Arctic freshwater systems. The sediments correlate to the mid-1800s and are a potential indicator of environmental change due to human activity, especially global warming. Two core samples were examined from Laguna Tamarindito in Guatemala to make inferences concerning the local environmental impact of Mayans in the past 10,000 years. Sediments, pollen, and gastropod populations within the core suggest that Holocene climate change resulted in local vegetation change consistant with regional trends.
Human impact is documented as well including major deforestation and increased soil erosion.
Macrofossil remains of thermophilous trees were discovered at higher elevations than their present day limits in the Scandes Mountains. The presence of these trees at higher elevations suggests that the regional climate may have been more continental and more diverse then that it is today. Due to inaccuracies in past pollen analyses, the author suggests that macrofossil records need to be analyzed also to provide accurate interpretations of plant communities. Aimee Buelow Lavoie, C. and Payette, S. 1996. The long-term stability of the boreal forest limit in subarctic Quebec.