Plant post-fire response shapes the occurrence of plant communities worldwide

Marta Magnani, Università degli studi di Torino and INFN, Turin, Italy, Marta Magnani and Mara Baudena, Centre of Complex System Studies and Copernicus Institute of Sustainable Development, Utrecht University, Utrecht, Netherlands, Rubén Díaz-Sierra, Universidad Nacional de Educación a Distancia, Madrid, Spain, Luke Sweeney, Department of Geography and Environmental Science, University of Reading, Reading, United Kingdom, Antonello Provenzale, Institute of Geoscience and Earth Resources, National Research Council of Italy, Turin, Italy, Mara Baudena, Institute of Atmospheric Science and Climate, National Research Council of Italy, Turin, Italy

Background/Question/Methods
Fire regimes reflect a combination of climatic factors and varied plant characteristics across fire-prone communities worldwide. In the attempt to shed new light on the complex relationships between plant community types and plant characteristics in fire-prone ecosystems, we developed a new conceptual, mechanistic model that represents plant competition, includes stochastic fires, a fire-vegetation feedback, and plant fire-responses.
Results/Conclusions
We observed a universal flammability vs fire-response relationship for single standing plant functional types. The possible occurrence of alternative ecological states was related to differences in the fire-response of the dominant plant and in the competition between plant functional types. Different plant communities under the same climatic conditions can occur when the most competitive plant types do not have a strong resistance to fires. This mechanism led to alternative ecological states for example in some tropical humid savannas and forests, or in boreal forests. Conversely, when the dominant plant type had a very strong fire-response, such as in Mediterranean forests, only one ecological state could be achieved. These findings underline the importance of including plant fire-responses when modelling fire ecosystems under climate-change scenarios. Furthermore, they can help improving understanding of changes in future fire regimes, possibly assisting fire management efforts.