Neutral assembly of bacterial communities

Abstract

Two recent, independent advances in ecology have generated interest and controversy: the development of neutral community models (NCMs) and the extension of biogeographical relationships into the microbial world. Here these two advances are linked by predicting an observed microbial taxa-volume relationship using an NCM and provide the strongest evidence so far for neutral community assembly in any group of organisms, macro or micro. Previously, NCMs have only ever been fitted using species-abundance distributions of macroorganisms at a single site or at one scale and parameter values have been calibrated on a case-by-case basis. Because NCMs predict a malleable two-parameter taxa-abundance distribution, this is a weak test of neutral community assembly and, hence, of the predictive power of NCMs. Here the two parameters of an NCM are calibrated using the taxa-abundance distribution observed in a small waterborne bacterial community housed in a bark-lined tree-hole in a beech tree. Using these parameters, unchanged, the taxa-abundance distributions and taxa-volume relationship observed in 26 other beech tree communities whose sizes span three orders of magnitude could be predicted. In doing so, a simple quantitative ecological mechanism to explain observations in microbial ecology is simultaneously offered and the predictive power of NCMs is demonstrated.

Host species as a strong determinant of the intestinal microbiota of fish larvae

“…2) also revealed significant differences (P<0.05) among the intestinal bacterial structures of the four species, suggesting that each had different relative abundances of dominant bacteria. Although the DGGE technique showed biases in the detection of bacterial taxa (Woodcock et al, 2007), band abundances as reflected by bacterial rank-abundance plots can indicate ecological shifts in the characteristics of bacterial communities (Loisel et al, 2006;van der Gast et al, 2006;Woodcock et al, 2007). Diet and the environment affect the intestinal microflora of fish and mammals (Holben et al, 2002;Savas et al, 2005;Ley et al, 2008), but the same environment and same natural food in the present study did not result in similar intestinal bacteria.…”

Regional synchrony in full-scale activated sludge bioreactors due to deterministic microbial community assembly

“…Traditional niche community assembly theory predicts that deterministic processes such as regional meteorological conditions and operational differences control assembly, whereas neutral theory predicts that trophically similar community members are ecologically similar and that stochastic processes such as immigration, birth and death lead to community differences (Hubbell, 2001;Woodcock et al, 2007). Community assembly theories such as the metacommunity framework incorporate both niche processes, such as species sorting and dispersal limitations, as well as neutral processes (Leibold et al, 2004).…”

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

“…It has been shown that bacterial communities can be assembled by species sorting (Beisner et al, 2006;Van der Gucht et al, 2007;Logue and Lindströ m, 2010) as well as mass effects (Lindströ m et al, 2006;Crump et al, 2007). It has also been demonstrated that frequency and abundance distributions in bacterial communities are, and often to a considerable extend, consistent with the neutral model (Sloan et al, 2006;Woodcock et al, 2007;Drakare and Liess, 2010;Ö stman et al, 2010). More recently, it has also become clear that several mechanisms co-occur and that communities are, for example, at the same time structured by species sorting and neutral processes (Ofiteru et al, 2010;Langenheder and Szekely, 2011).…”