Simulating Groundcover Community Assembly in a Frequently Burned Ecosystem Using a Simple Neutral Model

Area of Science:

• Ecology
• Biodiversity Science
• Ecological Modeling

Background:

• Fire is a critical ecological process influencing global biodiversity patterns.
• Frequently burned ecosystems, like southeastern US pine woodlands, exhibit high plant diversity due to surface fire regimes.
• The precise mechanisms by which fire affects groundcover community dynamics remain unclear, prompting investigation into neutral mechanisms.

Purpose of the Study:

• To investigate the role of neutral mechanisms in maintaining plant diversity in fire-driven ecosystems.
• To model groundcover species richness using demographic parameters from the unified neutral theory of biodiversity (UNTB).
• To assess the influence of dispersal limitation, mortality, and birth rates on simulated species richness.

Main Methods:

• Empirical data collection on over 7,000 individuals from 123 plant species over 4 years, including two prescribed burns in *Pinus palustris* sites.
• Development of two autonomous agent models based on UNTB assumptions, differing in spatial explicitness of local recruitment.
• Parameter sensitivity testing to evaluate the impact of empirical estimates, species frequency distributions, and community size on species richness.

Main Results:

• Dispersal limitation emerged as the most significant parameter influencing simulated species richness, followed by mortality and birth rates.
• The influence of these demographic parameters varied with the scale of species frequency distributions.
• The developed models successfully simulated fine-scale groundcover communities.

Conclusions:

• Nominal parameters derived from UNTB are effective for simulating fine-scale plant communities in frequently burned ecosystems.
• Dispersal limitation plays a crucial role in maintaining species richness in these environments.
• Further empirical research on burn severity is needed, and the modeling framework can explore neutral versus niche-based dynamics under altered fire frequencies.