Collaborative Research: Assessing the ecoclimate sensitivity of North American biome-scale ecotones to environmental changes since the last ice age

About This Grant

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 datasets drawn from the Neotoma Paleoecology Database and new compilations of carbon isotopic data. Land cover will be reconstructed using the REVEALS model and interpolated using a Bayesian hierarchical model with spatial dependence. Past temperature and rainfall patterns will be reconstructed using paleoclimate data assimilation (PDA), an ensemble of Earth system models, and over 600 proxy records from LiPDverse. A novel addition of statistical downscaling into the PDA workflow will enable high-resolution reconstructions and the modeling of local ecotone movements as a function of changes in temperature and rainfall. A hands-on, specimen-rich demonstration will be built for K-5 students and the general public that teaches about past ecosystem change and will be deployed via in-person science fairs, meetings of opportunity, and on-line educational portals. The project also will build new high-school to college-level curricular materials that draw upon these high-quality datasets and data visualizations, engaging students in scaffolded analysis and interpretation of data about ecosystem change at local to global scales. Curricular materials will be shared via the Teach the Earth website, which reaches >5 million visitors annually. This project also will engage with Tribal and agency land management professionals, train early-career researchers, and openly share these next-generation reconstructions of past environments and ecosystems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.