Microhabitat locality allows multi-species coexistence in terrestrial plant communities

Abstract

Most terrestrial plant communities exhibit relatively high species diversity and many competitive species are ubiquitous. Many theoretical studies have been carried out to investigate the coexistence of a few competitive species and in most cases they suggest competitive exclusion. Theoretical studies have revealed that coexistence of even three or four species can be extremely difficult. It has been suggested that the coexistence of many species has been achieved by the fine differences in suitable microhabitats for each species, attributing to niche-separation. So far there is no explicit demonstration of such a coexistence in mathematical and simulation studies. Here we built a simple lattice Lotka-Volterra model of competition by incorporating the minute differences of suitable microhabitats for many species. By applying the site variations in species-specific settlement rates of a seedling, we achieved the coexistence of more than 10 species. This result indicates that competition between many species is avoided by the spatial variations in species-specific microhabitats. Our results demonstrate that coexistence of many species becomes possible by the minute differences in microhabitats. This mechanism should be applicable to many vegetation types, such as temperate forests and grasslands.

Resistance of a terrestrial plant community to local microhabitat changes

“…Similar to the previous lattice coexistence model (Tubay et al., ), lattice size or carrying capacity has a positive effect on coexistence. Simulations were conducted using difference lattice sizes from 50 × 50 to 500 × 500 with increments of 50 to where microhabitat locality changes in every generation.…”

“…We have previously shown that microhabitat locality in a plant lattice community guarantees the coexistence of many species (Tubay et al., ). The results of this new simulation model show that even dynamic microhabitat locality can still lead to species coexistence.…”

“…To reach the stable state of the populations quickly, variations between the basic fecundity B i among species are introduced, where for . The parameter a is the fecundity of B 1 , the most superior species in terms of basic fecundity and minimum difference between fecundity among species is set to , where p is the upper bound of the fecundity difference (Tubay et al., ).…”

“…previous paper, we showed that even minuscule differences in microhabitat composition can promote coexistence in a lattice competition model. This model is different from other coexistence models as the lattice model presented in our previous work can maintain stable coexistence of more than 10 species while most coexistence models are based on lottery models which can only maintain at most four species with strict stability requirements (Tubay et al, 2015).…”

“…Even soils that are used for agriculture are never homogeneous (Adamchuk, Ferguson, & Hergert, ). However, micro‐spatial heterogeneity in soils has not been incorporated in previous models until recently (Tubay et al., ). These changes in microhabitats can be induced by an increase in temperature due to global warming but are generally applicable to yearly and gradual changes in microhabitats.…”