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Entangled effects of allelic and clonal (genotypic) richness in the resistance and resilience of experimental populations of the seagrass Zostera noltii to diatom invasion.

Massa SI, Paulino CM, Serrão EA, Duarte CM, Arnaud-Haond S - BMC Ecol. (2013)

Bottom Line: They also show that at the low genotypic (i.e. clonal) richness levels used in prior experimental approaches, the effects of genotypic and allelic richness could not be disentangled and allelic richness was a likely hidden treatment explaining at least part of the effects hitherto attributed to genotypic richness.Altogether, these results emphasize the need to acknowledge and take into account the interdependency of both genotypic and allelic richness in experimental designs attempting to estimate their importance alone or in combination.These results, on the key species structuring of one of the most threatened coastal ecosystem worldwide, seagrass meadows, support the need to better take into account the distinct compartments of clonal and genetic diversity in management strategies, and in possible restoration plans in the future.

View Article: PubMed Central - HTML - PubMed

Affiliation: IFREMER, Bd Jean Monnet, BP 171, Sète 34203, France. Sophie.Arnaud@ifremer.fr.

ABSTRACT

Background: The relationship between species diversity and components of ecosystem stability has been extensively studied, whilst the influence of the genetic component of biodiversity remains poorly understood. Here we manipulated both genotypic and allelic richness of the seagrass Zostera noltii, in order to explore their respective influences on the resistance of the experimental population to stress. Thus far intra-specific diversity was seldom taken into account in management plans, and restoration actions showed very low success. Information is therefore needed to understand the factors affecting resistance and resilience of populations.

Results: Our results show a positive influence of both allelic and genotypic richness on the resistance of meadows to environmental perturbations. They also show that at the low genotypic (i.e. clonal) richness levels used in prior experimental approaches, the effects of genotypic and allelic richness could not be disentangled and allelic richness was a likely hidden treatment explaining at least part of the effects hitherto attributed to genotypic richness.

Conclusions: Altogether, these results emphasize the need to acknowledge and take into account the interdependency of both genotypic and allelic richness in experimental designs attempting to estimate their importance alone or in combination. A positive influence of allelic richness on resistance to perturbations, and of allelic richness combined with genotypic richness on the recovery (resilience) of the experimental populations is supported by differential mortality. These results, on the key species structuring of one of the most threatened coastal ecosystem worldwide, seagrass meadows, support the need to better take into account the distinct compartments of clonal and genetic diversity in management strategies, and in possible restoration plans in the future.

Show MeSH
Path analysis of allelic and genotypic richness. Path analysis showing the direct effects, equivalent to correlation coefficients, of allelic richness (A) and genotypic richness (G) on the resistance to perturbation (as the number of shoots having survived the perturbation). The coefficient linking A and G is the correlation coefficient between these two components of genetic diversity. Path coefficients calculated after Alvin and Hauser (1975), and all are supported by p-values < 0.05.
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Figure 4: Path analysis of allelic and genotypic richness. Path analysis showing the direct effects, equivalent to correlation coefficients, of allelic richness (A) and genotypic richness (G) on the resistance to perturbation (as the number of shoots having survived the perturbation). The coefficient linking A and G is the correlation coefficient between these two components of genetic diversity. Path coefficients calculated after Alvin and Hauser (1975), and all are supported by p-values < 0.05.

Mentions: Finally, path analysis confirmed that the strong correlation between A and G inflated the apparent effect of G on seagrass resistance to stress due to the hidden effect of changes in A with increasing G (Figure 2). Indeed, allelic richness had a stronger effect on resistance to disturbance, directly accounting for 25% of the variance (0.492) on the number of surviving shoots following stress, stronger therefore than genotypic diversity, which explained 15% of the variance (0.392; Figure 4). No significant effect was detected however on resilience, i.e. on shoot numbers 10 months after the algal bloom.


Entangled effects of allelic and clonal (genotypic) richness in the resistance and resilience of experimental populations of the seagrass Zostera noltii to diatom invasion.

Massa SI, Paulino CM, Serrão EA, Duarte CM, Arnaud-Haond S - BMC Ecol. (2013)

Path analysis of allelic and genotypic richness. Path analysis showing the direct effects, equivalent to correlation coefficients, of allelic richness (A) and genotypic richness (G) on the resistance to perturbation (as the number of shoots having survived the perturbation). The coefficient linking A and G is the correlation coefficient between these two components of genetic diversity. Path coefficients calculated after Alvin and Hauser (1975), and all are supported by p-values < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3818440&req=5

Figure 4: Path analysis of allelic and genotypic richness. Path analysis showing the direct effects, equivalent to correlation coefficients, of allelic richness (A) and genotypic richness (G) on the resistance to perturbation (as the number of shoots having survived the perturbation). The coefficient linking A and G is the correlation coefficient between these two components of genetic diversity. Path coefficients calculated after Alvin and Hauser (1975), and all are supported by p-values < 0.05.
Mentions: Finally, path analysis confirmed that the strong correlation between A and G inflated the apparent effect of G on seagrass resistance to stress due to the hidden effect of changes in A with increasing G (Figure 2). Indeed, allelic richness had a stronger effect on resistance to disturbance, directly accounting for 25% of the variance (0.492) on the number of surviving shoots following stress, stronger therefore than genotypic diversity, which explained 15% of the variance (0.392; Figure 4). No significant effect was detected however on resilience, i.e. on shoot numbers 10 months after the algal bloom.

Bottom Line: They also show that at the low genotypic (i.e. clonal) richness levels used in prior experimental approaches, the effects of genotypic and allelic richness could not be disentangled and allelic richness was a likely hidden treatment explaining at least part of the effects hitherto attributed to genotypic richness.Altogether, these results emphasize the need to acknowledge and take into account the interdependency of both genotypic and allelic richness in experimental designs attempting to estimate their importance alone or in combination.These results, on the key species structuring of one of the most threatened coastal ecosystem worldwide, seagrass meadows, support the need to better take into account the distinct compartments of clonal and genetic diversity in management strategies, and in possible restoration plans in the future.

View Article: PubMed Central - HTML - PubMed

Affiliation: IFREMER, Bd Jean Monnet, BP 171, Sète 34203, France. Sophie.Arnaud@ifremer.fr.

ABSTRACT

Background: The relationship between species diversity and components of ecosystem stability has been extensively studied, whilst the influence of the genetic component of biodiversity remains poorly understood. Here we manipulated both genotypic and allelic richness of the seagrass Zostera noltii, in order to explore their respective influences on the resistance of the experimental population to stress. Thus far intra-specific diversity was seldom taken into account in management plans, and restoration actions showed very low success. Information is therefore needed to understand the factors affecting resistance and resilience of populations.

Results: Our results show a positive influence of both allelic and genotypic richness on the resistance of meadows to environmental perturbations. They also show that at the low genotypic (i.e. clonal) richness levels used in prior experimental approaches, the effects of genotypic and allelic richness could not be disentangled and allelic richness was a likely hidden treatment explaining at least part of the effects hitherto attributed to genotypic richness.

Conclusions: Altogether, these results emphasize the need to acknowledge and take into account the interdependency of both genotypic and allelic richness in experimental designs attempting to estimate their importance alone or in combination. A positive influence of allelic richness on resistance to perturbations, and of allelic richness combined with genotypic richness on the recovery (resilience) of the experimental populations is supported by differential mortality. These results, on the key species structuring of one of the most threatened coastal ecosystem worldwide, seagrass meadows, support the need to better take into account the distinct compartments of clonal and genetic diversity in management strategies, and in possible restoration plans in the future.

Show MeSH