The end of the last ice age and its transformation of North American ecosystems provides a natural experiment for studying how far species and ecosystems can move as environments change and a naturally engaging way to teach students about the history of their local landscapes. This project will employ state-of-the-art open databases of fossils and Earth system models to map past biome distributions in North America and measure how far these biomes moved as ice sheets melted, temperatures rose, and rainfall patterns shifted. The project focuses on four major ecotones: Arctic treeline, the northern transition from temperate to cold-hardy trees, the eastern Great Plains, and the Great Plains transition between cool-season and warm-season grasses. These ecotones moved by hundreds to thousands of miles in the past; this project will more precisely estimate these movements and quantify the amount of movement per degree Celsius warming or mm rainfall change. This information is directly relevant to land managers and policymakers seeking to help species adapt to current changes and to mitigate risks associated with ecosystem transformations. The project will harness the rich datasets and visualizations produced by this project to develop a variety of data-powered and place-based educational materials for multiple student audiences and shared through multiple in-person and online venues. Land cover reconstructions for the last 21,000 years will be based on fossil pollen data