A stochastic biodiversity model with overlapping niche structure

Abstract

The niche is a fundamental ecological concept that underpins many explanations of patterns of biodiversity. The complexity of niche processes in ecological systems, however, means that it is difficult to capture them accurately in theoretical models of community assembly. In this study, we build upon simple neutral biodiversity models by adding the important ingredient of overlapping niche structure. Our model is spatially implicit and contains a fixed number of equalsized habitats. Each species in the metacommunity arises through a speciation event; at which time, it is randomly assigned a fundamental niche or set of environments/habitats in which it can persist. Within each habitat, species compete with other species that have different but overlapping fundamental niches. Species abundances then change through ecological drift; each, however, is constrained by its maximum niche breadth and by the presence of other species in its habitats. Using our model, we derive analytical expressions for steady-state species abundance distributions, steady-state distributions of niche breadth across individuals and across species, and dynamic distributions of niche breadth across species. With this framework, we identify the conditions that produce the log-series species abundance distribution familiar from neutral models. We then identify how overlapping niche structure can lead to other species abundance distributions and, in particular, ask whether these new distributions differ significantly from species abundance distributions predicted by non-overlapping niche models. Finally, we extend our analysis to consider additional distributions associated with realized niche breadths. Overall, our results show that models with overlapping niches can exhibit behavior similar to neutral models, with the caveat that species with narrow fundamental niche breadths will be very rare. If narrow-niche species are common, it must be because they are in a non-overlapping niche or have countervailing advantages over broad-niche species. This result highlights the role that niches can play in establishing demographic neutrality.

Soil and vegetation conditions changes following the different sand dune restoration measures on the Zoige Plateau

“…Plant species survived under different restoration measures, and the population niche and interspecific relationships changed along the changed environment [49, 53–55]. Resource variations resulted in different ecological strategies among different plant populations, and these plants existed mutual effect with each other [50, 56, 57]. The E .…”

Soil and vegetation conditions changes following the different sand dune restoration measures on the Zoige Plateau

“…These changes stimulated the development of the sand dune community [49, 54, 55]. Resource variations cause populations to adopt different ecological strategies to intersect with other populations [50, 56, 57]. The E. nutans importance value improved in the sand barrier area, especially in the sandbag area.…”

Emergent niche structuring leads to increased differences from neutrality in species abundance distributions

“…Bewick et al. () recently considered a modification in which species can have membership in multiple niches, but interactions within niches are still neutral. Their model produced a surplus of rare species compared to the neutral case, even with a small number of niches.…”

“…Walker (2007) showed that when niches differed in their diversity, differences were produced in SADs, even in the high diversity limit. Bewick et al (2015) recently considered a modification in which species can have membership in multiple niches, but interactions within niches are still neutral. Their model produced a surplus of rare species compared to the neutral case, even with a small number of niches.…”