Fire Responses Shape Plant Communities in a Minimal Model for Fire Ecosystems across the World

Abstract

Across plant communities worldwide, fire regimes reflect a combination of climatic factors and plant characteristics. To shed new light on the complex relationships between plant characteristics and fire regimes, we developed a new conceptual, mechanistic model that includes plant competition, stochastic fires, and fire-vegetation feedback. Considering a single standing plant functional type, we observed that highly flammable and slowly colonizing plants can persist only when they have a strong fire response, while fast colonizing and less flammable plants can display a larger range of fire responses. At the community level, the fire response of the strongest competitor determines the existence of alternative ecological states, i.e. different plant communities, under the same environmental conditions. Specifically, when the strongest competitor had a very strong fire response, such as in Mediterranean forests, only one ecological state could be achieved. Conversely, when the strongest competitor was poorly fire-adapted, alternative ecological states emerged, for example between tropical humid savannas and forests, or between different types of boreal forests. These findings underline the importance of including the plant fire response when modeling fire ecosystems, e.g. to predict the vegetation response to invasive species or to climate change.MM contributed to the software development, coding simulation, model parameterization, analysis of results, visualization, writing the original draft, reviewing, and editing. RDS derived the nondimensional formulation of the model, and contributed to the analysis of results, writing the original draft, reviewing, and editing. LS contributed to conceiving the original idea of this work, writing the original draft, the reviewing and editing. AP provided useful feedback during result analysis, and contributed to supervision, reviewing, and editing. MB conceived the original idea of this work, and contributed to software development, model parameterization, analysis of results, supervision, visualization, writing the original draft, reviewing, and editing.

Reassessing the alternative ecosystem states proposition in the African savanna‐forest domain

“…A variety of non‐spatial theoretical models that make reasonable ecological assumptions have demonstrated that savanna and forest can be AES (e.g. van Langevelde et al ., 2003; Scheiter & Higgins, 2007; Accatino et al ., 2010; Baudena et al ., 2010; Staver et al ., 2011a; Staver & Levin, 2012; Goel et al ., 2020; Djeumen et al ., 2021; Magnani et al ., 2023). Such models demonstrate that for a single set of parameters that the ecosystem states forest or savanna can emerge as stable states and which emerges depends on the initial conditions (Fig.…”