Temporal variation of β-diversity and assembly mechanisms in a bacterial metacommunity

Abstract

The turnover of community composition across space, b-diversity, is influenced by different assembly mechanisms, which place varying weight on local habitat factors, such as environmental conditions and species interactions, and regional factors such as dispersal and history. Several assembly mechanisms may function simultaneously; however, little is known about how their importance changes over time and why. Here, we implemented a field survey where we sampled a bacterial metacommunity consisting of 17 rock pools located at the Swedish Baltic Sea coast at 11 occasions during 1 year. We determined to which extent communities were structured by different assembly mechanisms using variation partitioning and studied changes in b-diversity across environmental gradients over time. b-Diversity was highest at times of high overall productivity and environmental heterogeneity in the metacommunity, at least partly due to species sorting, that is, selection of taxa by the prevailing environmental conditions. In contrast, dispersal-driven assembly mechanisms were primarily detected at times when b-diversity was relatively low. There were no indications for strong and persistent differences in community composition or b-diversity between permanent and temporary pools, indicating that the physical disturbance regime is of relatively minor importance. In summary, our study clearly suggests that there are temporal differences in the relative importance of different assembly mechanisms related to abiotic factors and shows that the temporal variability of those factors is important for a more complete understanding of bacterial metacommunity dynamics.

Bacterial structures and ecosystem functions in glaciated floodplains: contemporary states and potential future shifts

“…Landscape features such as glaciers have the potential to create strong landscape heterogeneity by dictating coarse-scale physicochemical characteristics of habitats over time and space. Hydrogeochemical conditions, disturbance as well as spatial connectivity between aquatic systems can be altered by glaciers, and it has been shown that these mechanisms can influence BCC (Sekar et al, 2002;Frey et al, 2009;Langenheder et al, 2011). In contrast, lake outlet streams or groundwater-fed streams provide more spatiotemporal stability and a more homogeneous landscape (Tockner et al, 1997;Brown et al, 2003), and the smaller fluctuations in physicochemical characteristics in such habitats cause reduced variability in bacterial communities.…”

Lifestyles of rarity: understanding heterotrophic strategies to inform the ecology of the microbial rare biosphere

“…There is growing evidence that many microorganisms have different abundances across many connected environments and gradients (e.g. Langenheder et al 2012, Ruiz González et al 2015, and, of course, different habitats vary in their productivity. For example, an oligotroph in a soil habitat may, with no fundamental alteration to its physiology, fall more along the copiotrophic end of a trophic continuum than it would in a neighboring wetland habitat, though it may naturally occur in both localities.…”

Geochemical and Temporal Influences on the Enrichment of Acidophilic Iron-Oxidizing Bacterial Communities

“…For example, pH (1)(2)(3)(4), temperature (5), organic carbon (6,7), and salinity (8,9) have all been identified as major drivers of microbial niche differentiation in a variety of natural habitats. Spatial distance (10)(11)(12)(13) and temporal distance (14)(15)(16) can also structure microbial communities due to environmental heterogeneity, dispersal limitation, historical contingency, stochastic events, and disturbances. Extreme environments, such as acidic systems, can be useful as model systems for the analysis of microbial niches because of the limited biological diversity and available number of energy-deriving reactions (17)(18)(19).…”