A tale of two [equatorial] mountains: state-space modeling of tropical plant communities from fossil data
PI: Sarah Ivory (Geoscience)
The level of effort appropriate for the proposed project: 1 semester at 50% RA or summer 2026
Plan for funding tuition: existing NSF grant or I would seek support from the department or EESI
A list of specific areas of computational and/or data science expertise or skills: time series analysis, R language, statistical modeling Any other requirements or expectations: attendance at regular group meetings and weekly one-on-one meetings
A list of specific objectives for work:
• Compile paleoecological and paleoclimate data from databases
• Create new age model ensembles for estimation of age uncertainty in time series analysis
• Generate state space models to estimate parameters related to climate controls on vegetation change from sites on two African mountains
• Collaborate in the writing of a scientific paper based on the results
At least one medium to long-term goal: this is a pretty small project, but could easily be a really nice scientific publication
A short statement explaining the connection of the project to ICDS’s mission: African mountains house a biodiversity hotspot that spans isolate mountaintop environments across a continent and provide essential ecosystem services such a food, water, and medicine to people in remote areas. Recent studies suggest that these environments are at high risk from increasing temperature because of their sensitivity to warmth and isolation, thus information about their response to climate change is needed to inform management. In this project, we seek to use a community modeling approach, state-space modeling, to attribute climate drivers to ecosystem change on two equatorial African mountains in the past using fossil information. This project connects to the mission of ICDS to “address research questions of scientific and social importance” that can only be approached through “multi and interdisciplinary teams”.
A paragraph summarizing team member’s recent and/or planned engagement with ICDS: Sarah Ivory gave a short lightning talk at ICDS Day this academic year to find collaborators in applied and fundamental research in global environmental change and paleoecology in Africa. She would like to establish a more lasting collaboration with ICDS affiliates taking the form of grant proposals and jointly advised students.
Project Summary:
Motivation: African mountains house an ecologically and economically important flora that spans a discontinuous range across the Afrotropics. However, these tropical mountains in particular are disproportionately at risk to climate change due to intolerance of warm temperatures coupled with physical isolation. Further, risks to mountain ecosystems extend beyond increasing temperatures, as climate change brings other ecological disturbances such as changes in wildfire. Although fire dynamics have been well studied in lowland savannas, fires in mountains were historically considered rare due to high rainfall. However, recent fires in these environments have led to major impacts like damage to ecosystems, reduced freshwater availability, and infrastructure-damaging floods and landslides. These impacts raise questions about ecosystem vulnerability and resilience as well as downstream effects of ecosystem services to local human populations. Further complicating this issue, the broad geographic range of Afromontane ecosystems means that isolated populations may respond differently to disturbance across even moderate climatic gradients and to climatic change. Consequently, establishing spatial and temporal baselines of fire and vegetation response is essential for risk assessments and developing localized management targets.
We plan to leverage fossil pollen and paleoclimate data from across elevations on two equatorial African mountains (Rwenzori Mountains, Uganda; Mount Kenya, Kenya) to investigate vegetation responses to fire and climate across a spatial gradient over the Holocene (last 10,000 years). To attribute which factors drive ecosystem change, we will use a newly developed community modeling approach, state space modeling, to disentangle and quantify the roles of climate and fire in ecosystem change.
Workplan: This project will involve a student using time series data like fossil pollen and paleoclimate information from open-access databases to estimate parameters using a statistical model in R. Interactions between climate drivers and fire will be evaluated at both sites and compared to determine how mountains with similar vegetation today may have responded to climate change differently due to different fire histories. The junior researcher will work with a team of ecologists and paleoecologists to map these past ecosystem changes and summarize this in a paper and for local government officials.