Ecological landscapes guide the assembly of optimal microbial communities

TL;DR

This paper explores how ecological landscapes influence the assembly of optimal microbial communities, demonstrating that landscape ruggedness affects the success of heuristic search methods in community design.

Contribution

It introduces measures of ecological landscape ruggedness that predict the effectiveness of heuristic community assembly strategies.

Findings

Ruggedness of ecological landscapes impacts search efficacy.

Identified ruggedness measures are predictive and robust.

Validated approach with experimental soil microbial data.

Abstract

Assembling optimal microbial communities is key for various applications in biofuel production, agriculture, and human health. Finding the optimal community is challenging because the number of possible communities grows exponentially with the number of species, and so an exhaustive search cannot be performed even for a dozen species. A heuristic search that improves community function by adding or removing one species at a time is more practical, but it is unknown whether this strategy can discover an optimal or nearly optimal community. Using consumer-resource models with and without cross-feeding, we investigate how the efficacy of search depends on the distribution of resources, niche overlap, cross-feeding, and other aspects of community ecology. We show that search efficacy is determined by the ruggedness of the appropriately-defined ecological landscape. We identify specific ruggedness measures that are both predictive of search performance and robust to noise and low sampling density. The feasibility of our approach is demonstrated using experimental data from a soil microbial community. Overall, our results establish conditions necessary for the success of the heuristic search and provide concrete design principles for building high-performing microbial consortia.