BOZEMAN, Mont. -- New research indicates that the speed of early forest clearance following human colonisation of the South Island of New Zealand was much faster and more intense than previously thought.
Charcoal recovered from lake-bed sediment cores show that just a few large fires within 200 years of initial colonization destroyed much of the South Island's lowland forest. Grasslands and shrubland replaced the burnt forest and smaller fires prevented forests from returning.
The findings - by an international team led by Dave McWethy and Cathy Whitlock from Montana State University- have just been published in the prestigious journal Proceedings of the National Academy of Sciences in the United States and will be explored further under new grants from the National Science Foundation Geography and Spatial Science (GSS) and Partnerships in International Research and Education (PIRE) programs (www.wildfirepire.org).
Previous studies by co-authors Matt McGlone and Janet Wilmshurst at Landcare Research in New Zealand showed that closed forests covered 85-90% of New Zealand prior to the arrival of Polynesians (Māori ) 700-800 years ago, but by the time Europeans settled in the mid 19th century, grass and shrubs had replaced over 40% of the South Island's forests. Despite this information, questions over the timing, rapidity, and cause of the extensive forest clearance have remained.
The international team of scientists reconstructed the environmental history of 16 small lakes in the South Island, New Zealand. They used pollen records to reconstruct past vegetation, charcoal fragments to document fires, and algae and midge remains to quantify changes in lake chemistry and soil erosion.
The cores showed several high-severity fire events occurred within two centuries of known Māori arrival in the 13th Century.
"The impacts of burning were more pronounced
|Contact: Melynda Harrison|
Montana State University