SPATIO-TEMPORAL DYNAMICS OF BIOMES IN THE NORTHWESTERN UNITED STATES (9000 YBP TO THE PRESENT)

The goal of this study was to quantitatively analyze and map the vegetation composition of forest, grassland, and steppe ecosystems in the northwestern United States in the present and through the last 9,000 years. The modern analysis used canonical correspondence analysis (CCA) on pollen percentages from recent sediment cores reflecting modern vegetation assemblages and climates to evaluate the amount of influence of selected environmental variables on present species distributions. The fossil analysis used non-metric multi-dimensional scaling (NMDS) on a merged database containing relative pollen percentages from the last 9000 years. A predefined list of environmental parameters and floristically and ecologically important pollen percentages were used to measure the dissimilarity between modern and fossil pollen regimes over the region at specific time periods. The numeric values obtained from both statistical analyses were interpolated and mapped via Geographic Information Systems (GIS) to display major vegetation types throughout the northwestern United States through time, allowing visual assessment of changing environmental gradients.

Name thesis:degree_name

Master of Science (MS)

Grantor dc:publisher

University of Montana

Year

2009

Author dc:creator

• Stump, Christopher Caleb

• CCA
• climate change
• environmental gradients
• GIS
• gradient analysis
• landscape trajectories
• NMDS
• ordination statistics
• Paleobiogeography
• pollen analysis
• statistics
• trajectory analysis
• vegetation change

Repository record dc:identifier

https://scholarworks.umt.edu/etd/907

OAI identifier oai:identifier

oai:scholarworks.umt.edu:etd-1926