Research

Invasive grass fire cycles threaten ecosystem stability in western US deserts. Using experimental burn and rodent exlcusion treatments I have shown the impacts of fire, climate, rodent herbivory in these systems.

Relevant publications

1. Pienaar, R. et al. Long-Term Rodent Community Responses to Fire and Climate Across Western US Deserts. In review at Journal of Animal Ecology

2. Pienaar, R., Bishop, T. B. B. & St Clair, S. B. Rodent competition and fire alter patterns of mound and disk formation of western harvester ants. Oecologia https://doi.org/10.1007/s00442-024-05617-9 (2024) 

3. Pienaar, R., Bishop, T. B. B., Schill, S. R. & St. Clair, S. B. Detecting spatiotemporal changes in harvester ant disks in response to fire and rodent competition using small unoccupied aerial systems imagery. Landsc Ecol 40, 72 https://link.springer.com/article/10.1007/s10980-025-02078-0 (2025).

Wildfires burn increasingly large areas with burn perimiters that provide access to burned and unburned resources. Studying how ungulates use these insights can inform how they choose between maximizing forage and cover

Relevant publications

1. Pienaar, R. et al. Ungulate use of burned edges across forest types. In review at Forest Ecology and Management

2. Kerr, S. B., Rhodes, A. C., Hulet, A., Pienaar, R. & St. Clair, S. B. Long-term monitoring of aspen forest regeneration and ungulate use shows successful recruitment amid landscape-scale forest restoration. Forest Ecology and Management 602, 123373 https://doi.org/10.1016/j.foreco.2025.123373 (2026).

Oak trees are ecologically important for the resources they provide to a huge variety of animals. Oak forests in Wisconsin are threatened by oak wilt disease. We can reduce the impact of this pathogen by predicting where it might occur and have the greatest impact to prioritize monitoring efforts