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Untangling the fungal niche: the trait-based approach.

Crowther TW, Maynard DS, Crowther TR, Peccia J, Smith JR, Bradford MA - Front Microbiol (2014)

Bottom Line: Given that the survival of a fungus in a given environment is contingent on its ability to tolerate antagonistic competitors, measuring variation in combat trait expression along environmental gradients provides a means of elucidating realized, from fundamental niche spaces.We conclude that, using a trait-based understanding of how niche processes structure fungal communities across time and space, we can ultimately link communities with ecosystem functioning.Our trait-based framework highlights fundamental uncertainties that require testing in the fungal system, given their potential to uncover general mechanisms in fungal ecology.

View Article: PubMed Central - PubMed

Affiliation: Yale School of Forestry and Environmental Studies, Yale University New Haven, CT, USA.

ABSTRACT
Fungi are prominent components of most terrestrial ecosystems, both in terms of biomass and ecosystem functioning, but the hyper-diverse nature of most communities has obscured the search for unifying principles governing community organization. In particular, unlike plants and animals, observational studies provide little evidence for the existence of niche processes in structuring fungal communities at broad spatial scales. This limits our capacity to predict how communities, and their functioning, vary across landscapes. We outline how a shift in focus, from taxonomy toward functional traits, might prove to be valuable in the search for general patterns in fungal ecology. We build on theoretical advances in plant and animal ecology to provide an empirical framework for a trait-based approach in fungal community ecology. Drawing upon specific characteristics of the fungal system, we highlight the significance of drought stress and combat in structuring free-living fungal communities. We propose a conceptual model to formalize how trade-offs between stress-tolerance and combative dominance are likely to organize communities across environmental gradients. Given that the survival of a fungus in a given environment is contingent on its ability to tolerate antagonistic competitors, measuring variation in combat trait expression along environmental gradients provides a means of elucidating realized, from fundamental niche spaces. We conclude that, using a trait-based understanding of how niche processes structure fungal communities across time and space, we can ultimately link communities with ecosystem functioning. Our trait-based framework highlights fundamental uncertainties that require testing in the fungal system, given their potential to uncover general mechanisms in fungal ecology.

No MeSH data available.


Related in: MedlinePlus

Biotic and abiotic filters differentially influence trait organization along environmental gradients. Similar shapes refer to individuals with similar stress-tolerance trait values, and the level of shading refers to relative combative ability of these individuals, with lighter individuals being less combative. On passage through the abiotic filter, stressful conditions reduce the survival and combative abilities of the most combative species, with negligible effects on the stress-tolerant species. Energetic costs of cell maintenance lead to reduced expression of combative traits, ultimately limiting the capacity of stress-intolerant species to compete under xeric conditions. However, the nature of the biotic filtering varies depending on the dominant interactive mechanism. Where combat (the direct killing of opponents) is the dominant interaction mechanism, the stress-intolerant individuals are capable of displacing the stress-tolerant individuals under mesic conditions, leading to under-dispersion of combative traits under mesic conditions. Conversely, competition for nutrients or refuges drives niche differentiation under optimal conditions, ultimately, resulting in trait over-dispersion in these optimal environments.
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Figure 5: Biotic and abiotic filters differentially influence trait organization along environmental gradients. Similar shapes refer to individuals with similar stress-tolerance trait values, and the level of shading refers to relative combative ability of these individuals, with lighter individuals being less combative. On passage through the abiotic filter, stressful conditions reduce the survival and combative abilities of the most combative species, with negligible effects on the stress-tolerant species. Energetic costs of cell maintenance lead to reduced expression of combative traits, ultimately limiting the capacity of stress-intolerant species to compete under xeric conditions. However, the nature of the biotic filtering varies depending on the dominant interactive mechanism. Where combat (the direct killing of opponents) is the dominant interaction mechanism, the stress-intolerant individuals are capable of displacing the stress-tolerant individuals under mesic conditions, leading to under-dispersion of combative traits under mesic conditions. Conversely, competition for nutrients or refuges drives niche differentiation under optimal conditions, ultimately, resulting in trait over-dispersion in these optimal environments.

Mentions: Along with spatial scale, the specific mechanisms through which organisms interact also require consideration when exploring how niche processes structure communities. Competition for resources, for example, generally promotes niche differentiation, but intense combat can select for the clustering of similar antagonistic or defensive traits (Mayfield and Levine, 2010; Herben and Goldberg, 2014). These opposing selection pressures can act simultaneously, leading to the over-dispersion of some traits and the under-dispersion of others within the same community (Figure 5; Herben and Goldberg, 2014). These dynamics could potentially contribute to the opposing patterns of community assembly observed between free-living, and mycorrhizal fungal communities in Australian sclerophyll forest (Beck et al., in preperation). Exploring trait dispersion across environments therefore requires consideration of the functional roles of those traits and the specific mechanisms through which they promote coexistence.


Untangling the fungal niche: the trait-based approach.

Crowther TW, Maynard DS, Crowther TR, Peccia J, Smith JR, Bradford MA - Front Microbiol (2014)

Biotic and abiotic filters differentially influence trait organization along environmental gradients. Similar shapes refer to individuals with similar stress-tolerance trait values, and the level of shading refers to relative combative ability of these individuals, with lighter individuals being less combative. On passage through the abiotic filter, stressful conditions reduce the survival and combative abilities of the most combative species, with negligible effects on the stress-tolerant species. Energetic costs of cell maintenance lead to reduced expression of combative traits, ultimately limiting the capacity of stress-intolerant species to compete under xeric conditions. However, the nature of the biotic filtering varies depending on the dominant interactive mechanism. Where combat (the direct killing of opponents) is the dominant interaction mechanism, the stress-intolerant individuals are capable of displacing the stress-tolerant individuals under mesic conditions, leading to under-dispersion of combative traits under mesic conditions. Conversely, competition for nutrients or refuges drives niche differentiation under optimal conditions, ultimately, resulting in trait over-dispersion in these optimal environments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4215788&req=5

Figure 5: Biotic and abiotic filters differentially influence trait organization along environmental gradients. Similar shapes refer to individuals with similar stress-tolerance trait values, and the level of shading refers to relative combative ability of these individuals, with lighter individuals being less combative. On passage through the abiotic filter, stressful conditions reduce the survival and combative abilities of the most combative species, with negligible effects on the stress-tolerant species. Energetic costs of cell maintenance lead to reduced expression of combative traits, ultimately limiting the capacity of stress-intolerant species to compete under xeric conditions. However, the nature of the biotic filtering varies depending on the dominant interactive mechanism. Where combat (the direct killing of opponents) is the dominant interaction mechanism, the stress-intolerant individuals are capable of displacing the stress-tolerant individuals under mesic conditions, leading to under-dispersion of combative traits under mesic conditions. Conversely, competition for nutrients or refuges drives niche differentiation under optimal conditions, ultimately, resulting in trait over-dispersion in these optimal environments.
Mentions: Along with spatial scale, the specific mechanisms through which organisms interact also require consideration when exploring how niche processes structure communities. Competition for resources, for example, generally promotes niche differentiation, but intense combat can select for the clustering of similar antagonistic or defensive traits (Mayfield and Levine, 2010; Herben and Goldberg, 2014). These opposing selection pressures can act simultaneously, leading to the over-dispersion of some traits and the under-dispersion of others within the same community (Figure 5; Herben and Goldberg, 2014). These dynamics could potentially contribute to the opposing patterns of community assembly observed between free-living, and mycorrhizal fungal communities in Australian sclerophyll forest (Beck et al., in preperation). Exploring trait dispersion across environments therefore requires consideration of the functional roles of those traits and the specific mechanisms through which they promote coexistence.

Bottom Line: Given that the survival of a fungus in a given environment is contingent on its ability to tolerate antagonistic competitors, measuring variation in combat trait expression along environmental gradients provides a means of elucidating realized, from fundamental niche spaces.We conclude that, using a trait-based understanding of how niche processes structure fungal communities across time and space, we can ultimately link communities with ecosystem functioning.Our trait-based framework highlights fundamental uncertainties that require testing in the fungal system, given their potential to uncover general mechanisms in fungal ecology.

View Article: PubMed Central - PubMed

Affiliation: Yale School of Forestry and Environmental Studies, Yale University New Haven, CT, USA.

ABSTRACT
Fungi are prominent components of most terrestrial ecosystems, both in terms of biomass and ecosystem functioning, but the hyper-diverse nature of most communities has obscured the search for unifying principles governing community organization. In particular, unlike plants and animals, observational studies provide little evidence for the existence of niche processes in structuring fungal communities at broad spatial scales. This limits our capacity to predict how communities, and their functioning, vary across landscapes. We outline how a shift in focus, from taxonomy toward functional traits, might prove to be valuable in the search for general patterns in fungal ecology. We build on theoretical advances in plant and animal ecology to provide an empirical framework for a trait-based approach in fungal community ecology. Drawing upon specific characteristics of the fungal system, we highlight the significance of drought stress and combat in structuring free-living fungal communities. We propose a conceptual model to formalize how trade-offs between stress-tolerance and combative dominance are likely to organize communities across environmental gradients. Given that the survival of a fungus in a given environment is contingent on its ability to tolerate antagonistic competitors, measuring variation in combat trait expression along environmental gradients provides a means of elucidating realized, from fundamental niche spaces. We conclude that, using a trait-based understanding of how niche processes structure fungal communities across time and space, we can ultimately link communities with ecosystem functioning. Our trait-based framework highlights fundamental uncertainties that require testing in the fungal system, given their potential to uncover general mechanisms in fungal ecology.

No MeSH data available.


Related in: MedlinePlus