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Ecological landscapes guide the assembly of optimal microbial communities

Fig 2

Niche overlap determines the linearity of ecological landscapes.

The top panels in (A) and (B) show the consumption matrices for species in each species pool. In (A), the niche overlap is low because the species are specialists and consume only a few resources. In (B), the niche overlap is high because the species are generalists and consume many resources. The bottom panels show how well a linear model (Eq 1) fits the steady-state abundances across all possible species combinations. Color bar quantifies the local density of points, as measured by gaussian kernel density estimation. The goodness of the model fit, quantified by , is higher when the niche overlap is lower. This conclusion is robust to varying the size of the community and the degree of niche overlap. (C) shows how varies with the number of species in the pool, S, and the average number of resources that they consume, M_consumed. The degree of niche overlap is determined by M_consumed/M_total. Letters indicate the parameters used in panels A and B. Note that was computed by averaging R² of the linear model fitted separately for each species, and the number of resources supplied was fixed to M_total = S. For each set of parameters, results were averaged over 10 independently generated species pools. Simulations were of consumer-resource models without leakage. Other simulation parameters are provided in Methods, and the robustness of the conclusions to certain modeling assumptions is further discussed in S1 Text and S2 Fig.

doi: https://doi.org/10.1371/journal.pcbi.1010570.g002