The impact of resource dependence of the mechanisms of life on the spatial population dynamics of an in silico microbial community

Abstract

Biodiversity has a critical impact on ecosystem functionality and stability, and thus the current biodiversity crisis has motivated many studies of the mechanisms that sustain biodiversity, a notable example being non-transitive or cyclic competition. We therefore extend existing microscopic models of communities with cyclic competition by incorporating resource dependence in demographic processes, characteristics of natural systems often oversimplified or overlooked by modellers. The spatially explicit nature of our individual-based model of three interacting species results in the formation of stable spatial structures, which have significant effects on community functioning, in agreement with experimental observations of pattern formation in microbial communities. Published by AIP Publishing.[http://dx.doi.org/10.1063/1.4972788]Biodiversity plays a crucial role in promoting and preserving the proper functioning of ecosystems.1 As a result, significant attention has been devoted to understanding the mechanisms that maintain biodiversity, 2 in particular, the role of cyclic competition. Existing microscopic models of communities with cyclic competition often significantly oversimplify or even neglect the resource-dependent nature of demographic processes. 3-6We therefore extend existing models by considering this key factor in a spatially heterogeneous landscape, to align them more closely with real-world microbial ecosystems, and to investigate how this more realistic approach affects community productivity and biodiversity. We demonstrate the consequent dramatic effects on the population dynamics of this community of three species, consistent with other modelling and experimental studies. These results have implications for the maintenance and development of natural ecosystems, as well as for pattern formation in microbial communities.

Individual-Based Modelling of Invasion in Bioaugmented Sand Filter Communities

“…These patterns also qualitatively resemble those observed in in vitro experiments where a similar synthetic community of SFIs was co-cultured with MSH1 in the presence of BAM [18]. The spiral formations also enable spatial refuges, which have been observed to support species coexistence by allowing vulnerable species to persist at low but still significant levels [44]. Such refuges can be observed for example in Figure 7b for multiple species.…”

Untangling the mechanisms of cryptic species coexistence in a nematode community through individual‐based modelling

“…Scramble and contest are two different forms of competition for a limiting resource. Scramble competition occurs when all species have access to a communal resource, so that population growth rates decline with population density as said resource is depleted, whereas contest competition occurs when one species monopolizes the resource, at the expense of its weaker competitors (Daly et al 2016). Hence contest competition involves an unequal partitioning of the resource between species, so that some can persist at the expense of others, while scramble competition involves an equal competition for resources between the species.…”