The Non-Native Grass-Fire Cycle: The Dynamic and Spatiotemporal Relationships Between Grass Species And Fire Regimes
Open Access
- Author:
- Munin, Barbara Leigh
- Area of Honors:
- Geography
- Degree:
- Bachelor of Arts
- Document Type:
- Thesis
- Thesis Supervisors:
- Jennifer Balch, Thesis Supervisor
Roger Michael Downs, Thesis Honors Advisor - Keywords:
- Non-native grass species
fire
grass-fire cycle
positive feedback - Abstract:
- The relationships between grass and fire are complex and dynamic. Considering that fire regimes are dependent on topography, climate, and fuel availability at the site of ignition, changes to the fuel composition and structure of a landscape have the potential to introduce novel fire behavior. Therefore, the flammability of grassy species has global consequences when considering the impact of biological invasions on fuel properties. An increase in non-native grass species invasion encourages fire, which in turn provides opportunities for further colonization of the non-native species. This positive feedback loop has significant implications for global change ecology and fire management decisions. D’Antonio and Vitousek (1992), and Brooks et al. (2004) published foundational papers on the non-native grass-fire cycle. This thesis aims to synthesize the various case studies published on the non-native grass-fire cycle since the publication of Brooks et al. (2004) in order to explore two research questions. 1) What are the mechanisms that drive the non-native grass-fire cycle? 2) How has our understanding of the global distribution of the non-native grass-fire cycle progressed since the publications of D’Antonio and Vitousek (1992) and Brooks et al. (2004)? A review of the literature on the non-native grass-fire cycle revealed that invaded plots, when compared to non-invaded plots, experience a 116% increase in fire-spread rate, a 560% increase in fire intensity, and a 208% increase in biomass. At fine scales, the interplay between biomass and fire intensity, continuity/cover and fire-spread rate, and composition and fire return interval ensure the continuation of this cycle. At broad scales, pre-existing fire regimes in the Tropical Rainforest and Tropical Savanna terrestrial biomes have been altered, and there has been a complete introduction of fire into some regions in both the Desert and Temperate Broadleaf Forest biomes.