February 26, 2020
12:00pm The Hershey Hall Grand Salon, Room 158, Hershey Hall
Canada Research Chair, Microbial Evolutionary Genomics, Department of Biological Sciences, Université de Montréal
Microbes are embedded in complex communities where they engage in a wide array of intra- and inter-specific interactions. The extent to which these interactions drive or impede microbiome diversity is not well understood. Two contrasting hypotheses have been put forward to explain how species interactions could influence diversity. ‘Ecological Controls’ (EC) predicts a negative relationship, where the evolution or migration of novel types is constrained as available niches become filled. In contrast, ‘Diversity Begets Diversity’ (DBD) predicts a positive relationship, with existing diversity promoting the accumulation of further diversity via niche construction and other interactions. Using the Earth Microbiome Project, the largest standardized survey of global biodiversity to date, we provide support for DBD as a widespread driver of microbiome diversity. In diverse biomes such as soil, DBD reaches a plateau, which is consistent with increasingly saturated niche space and a greater importance of abiotic factors relative to biotic interactions in limiting diversity. Resident genera that are strongly associated with a particular biome show a stronger DBD relationship than generalists or migrants, presumably because niches were already filled by residents. Genera with larger genomes exhibit a stronger DBD response, which could be due to a higher potential for metabolic interactions and niche construction offered by more diverse gene repertoires. Our results demonstrate a general scaling between levels of community diversity, with broad implications for modelling and predicting microbial ecosystem function and stability.
Refreshments will be served at 11:40 a.m.
Host: Nandita Garud