The coexistence model (Di Paola et al., 2012) is a simple quantitative dynamic model able to explain the observed co-occurrence of sclerophyllous evergreen oak species with deciduous ones of the Mediterranean forests.

The model is formulated as a set of differential equations describing the competitive dynamic between two groups of species having different physiological responses to water stress. The work is based on a minimalistic approach in which the soil water content may act both as a limiting resource and as a chronic stress. Evapotranspiration processes, a simple hydrological balance, and a rudimentary form of competition for space are also included.

In spite of its simplicity, the model is able to explain the observed coexistence in forests of Tyrrhenian central Italy.

References:

• Di Paola, A., Valentini, R., & Paparella, F. (2012). Climate change threatens coexistence within communities of Mediterranean forested wetlands. PloS one, 7(10), e44727
• Di Paola A., Paquette A., Trabucco A., Mereu S., Valentini R., Paparella F.
  Coexistence trend contingent to Mediterranean oaks with different leaf habits
  2017, Ecology and Evolution, DOI: 10.1002/ece3.2840