Publications
48 results found
Gravel D, Bell T, Barbera C, et al., 2012, Phylogenetic constraints on ecosystem functioning, Nature Communications, Vol: 3
There is consensus that biodiversity losses will result in declining ecosystem functioning if species have different functional traits. Phylogenetic diversity has recently been suggested as a predictor of ecosystem functioning because it could approximate the functional complementarity among species. Here we describe an experiment that takes advantage of the rapid evolutionary response of bacteria to disentangle the role of phylogenetic and species diversity. We impose a strong selection regime on marine bacterial lineages and assemble the ancestral and evolved lines in microcosms of varying lineage and phylogenetic diversity. We find that the relationship between phylogenetic diversity and productivity is strong for the ancestral lineages but brakes down for the evolved lineages. Our results not only emphasize the potential of using phylogeny to evaluate ecosystem functioning, but also they warn against using phylogenetics as a proxy for functional diversity without good information on species evolutionary history
Lawrence D, Fiegna F, Behrends V, et al., 2012, Species interactions alter evolutionary responses to a novel environment., PLoS Biol, Vol: 10
Studies of evolutionary responses to novel environments typically consider single species or perhaps pairs of interacting species. However, all organisms co-occur with many other species, resulting in evolutionary dynamics that might not match those predicted using single species approaches. Recent theories predict that species interactions in diverse systems can influence how component species evolve in response to environmental change. In turn, evolution might have consequences for ecosystem functioning. We used experimental communities of five bacterial species to show that species interactions have a major impact on adaptation to a novel environment in the laboratory. Species in communities diverged in their use of resources compared with the same species in monocultures and evolved to use waste products generated by other species. This generally led to a trade-off between adaptation to the abiotic and biotic components of the environment, such that species evolving in communities had lower growth rates when assayed in the absence of other species. Based on growth assays and on nuclear magnetic resonance (NMR) spectroscopy of resource use, all species evolved more in communities than they did in monocultures. The evolutionary changes had significant repercussions for the functioning of these experimental ecosystems: communities reassembled from isolates that had evolved in polyculture were more productive than those reassembled from isolates that had evolved in monoculture. Our results show that the way in which species adapt to new environments depends critically on the biotic environment of co-occurring species. Moreover, predicting how functioning of complex ecosystems will respond to an environmental change requires knowing how species interactions will evolve.
Barrett LG, Bell T, Dwyer G, et al., 2011, Cheating, trade-offs and the evolution of aggressiveness in a natural pathogen population, Ecology Letters, Vol: 14, Pages: 1149-1157
The evolutionary dynamics of pathogens are critically important for disease outcomes, prevalence and emergence. In this study we investigate ecological conditions that may promote the long-term maintenance of virulence polymorphisms in pathogen populations. Recent theory predicts that evolution towards increased virulence can be reversed if less-aggressive social 'cheats' exploit more aggressive 'cooperator' pathogens. However, there is no evidence that social exploitation operates within natural pathogen populations. We show that for the bacterium Pseudomonas syringae, major polymorphisms for pathogenicity are maintained at unexpectedly high frequencies in populations infecting the host Arabidopsis thaliana. Experiments reveal that less-aggressive strains substantially increase their growth potential in mixed infections and have a fitness advantage in non-host environments. These results suggest that niche differentiation can contribute to the maintenance of virulence polymorphisms, and that both within-host and between-host growth rates modulate cheating and cooperation in P. syringae populations.
Poroyko V, Morowitz M, Bell T, et al., 2011, Diet creates metabolic niches in the "inmature gut" that shape microbial communities, NUTRICION HOSPITALARIA, Vol: 26, Pages: 1283-1295, ISSN: 0212-1611
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- Citations: 55
Gravel D, Bell T, Barbera C, et al., 2011, Experimental niche evolution alters the strength of the diversity-productivity relationship, Vol: 469, Pages: 89-92, ISSN: 0028-0836
The relationship between biodiversity and ecosystem functioning (BEF) has become a cornerstone of community and ecosystem ecology(1-3) and an essential criterion for making decisions in conservation biology and policy planning(4,5). It has recently been proposed that evolutionary history should influence the BEF relationship because it determines species traits and, thus, species' ability to exploit resources(6,7). Here we test this hypothesis by combining experimental evolution with a BEF experiment. We isolated 20 bacterial strains from a marine environment and evolved each to be generalists or specialists(8). We then tested the effect of evolutionary history on the strength of the BEF relationship with assemblages of 1 to 20 species constructed from the specialists, generalists and ancestors(9). Assemblages of generalists were more productive on average because of their superior ability to exploit the environmental heterogeneity(10). The slope of the BEF relationship was, however, stronger for the specialist assemblages because of enhanced niche complementarity. These results show how the BEF relationship depends critically on the legacy of past evolutionary events.
Griffiths RI, Thomson BC, James P, et al., 2011, The bacterial biogeography of British soils, Vol: 13, Pages: 1642-1654, ISSN: 1462-2920
Gluecksman E, Bell T, Griffiths RI, et al., 2010, Closely related protist strains have different grazing impacts on natural bacterial communities, ENVIRONMENTAL MICROBIOLOGY, Vol: 12, Pages: 3105-3113, ISSN: 1462-2912
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- Citations: 91
Bell T, 2010, Experimental tests of the bacterial distance-decay relationship, Vol: 4, Pages: 1357-1365, ISSN: 1751-7362
Bell T, Bonsall MB, Buckling A, et al., 2010, Protists have divergent effects on bacterial diversity along a productivity gradient, Vol: 6, Pages: 639-642, ISSN: 1744-9561
Productivity and predation are thought to be crucial drivers of bacterial diversity. We tested how the productivity-diversity of a natural bacterial community is modified by the presence of protist predators with different feeding preferences. In the absence of predators, there was a unimodal relationship between bacterial diversity and productivity. We found that three protist species (Bodo, Spumella and Cyclidium) had widely divergent effects on bacterial diversity across the productivity gradient. Bodo and Cyclidium had little effect on the shape of the productivity-diversity gradient, while Spumella flattened the relationship. We explain these results in terms of the feeding preferences of these predators.
Hector A, Bell T, Connolly J, et al., 2009, The analysis of biodiversity experiments: from pattern toward mechanism, Pages: 94-104
Srivastava DS, Bell T, 2009, Reducing horizontal and vertical diversity in a foodweb triggers extinctions and impacts functions, Vol: 12, Pages: 1016-1028
Bell T, Gessner MO, Griffiths RI, et al., 2009, Microbial biodiversity and ecosystem functioning under controlled conditions and in the wild, Biodiversity, Ecosystem Functioning, and Human Wellbeing: An Ecological and Economic Perspective, Editors: Naeem, Bunker, Hector, Oxford, Publisher: Oxford University Press
Bell T, Lilley AK, Hector A, et al., 2009, A linear model method for biodiversity-ecosystem functioning experiments, Vol: 174
Woodcock S, van der Gast CJ, Bell T, et al., 2007, Neutral assembly of bacterial communities, Joint Symposium of the Environmental-Microbiology-Group/British-Ecological-Society/Society-for-General-Microbiology, Publisher: OXFORD UNIV PRESS, Pages: 171-180, ISSN: 0168-6496
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- Citations: 133
Brockhurst MA, Hochberg ME, Bell T, et al., 2006, Character displacement promotes cooperation in bacterial biofilms, CURRENT BIOLOGY, Vol: 16, Pages: 2030-2034, ISSN: 0960-9822
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- Citations: 74
Bell T, Newman JA, Thompson IP, et al., 2005, Bacteria and island biogeography - Response, SCIENCE, Vol: 309, Pages: 1998-1999, ISSN: 0036-8075
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- Citations: 11
Bell T, Newman JA, Silverman BW, et al., 2005, The contribution of species richness and composition to bacterial services, NATURE, Vol: 436, Pages: 1157-1160, ISSN: 0028-0836
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- Citations: 657
Bell T, Ager D, Song JI, et al., 2005, Larger islands house more bacterial taxa, SCIENCE, Vol: 308, Pages: 1884-1884, ISSN: 0036-8075
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- Citations: 190
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