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Architecture of an antagonistic tree/fungus network: the asymmetric influence of past evolutionary history.

Vacher C, Piou D, Desprez-Loustau ML - PLoS ONE (2008)

Bottom Line: Unlike compartmentalization, nestedness did not reflect any consistent phylogenetic signal.Overall, our analyses emphasized how the current complexity of ecological networks results from the diversification of the species and their interactions over evolutionary times.They confirmed that the current architecture of ecological networks is not only dependent on recent ecological processes.

View Article: PubMed Central - PubMed

Affiliation: INRA [corrected] UMR1202 Biodiversité Gènes et Communautés, Villenave d'Ornon, France. cvacher@bordeaux.inra.fr

ABSTRACT

Background: Compartmentalization and nestedness are common patterns in ecological networks. The aim of this study was to elucidate some of the processes shaping these patterns in a well resolved network of host/pathogen interactions.

Methodology/principal findings: Based on a long-term (1972-2005) survey of forest health at the regional scale (all French forests; 15 million ha), we uncovered an almost fully connected network of 51 tree taxa and 157 parasitic fungal species. Our analyses revealed that the compartmentalization of the network maps out the ancient evolutionary history of seed plants, but not the ancient evolutionary history of fungal species. The very early divergence of the major fungal phyla may account for this asymmetric influence of past evolutionary history. Unlike compartmentalization, nestedness did not reflect any consistent phylogenetic signal. Instead, it seemed to reflect the ecological features of the current species, such as the relative abundance of tree species and the life-history strategies of fungal pathogens. We discussed how the evolution of host range in fungal species may account for the observed nested patterns.

Conclusion/significance: Overall, our analyses emphasized how the current complexity of ecological networks results from the diversification of the species and their interactions over evolutionary times. They confirmed that the current architecture of ecological networks is not only dependent on recent ecological processes.

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Related in: MedlinePlus

Relationship between the area covered by tree taxa (log-transformed) and their rank in the nested matrices after rearrangement for nestedness.Symbols correspond to tree phyla (gray circles: Magnoliophyta; black squares: Conipherophyta). (A) Largest connected component. (B) Compartment C5. (C) Compartment C6.
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pone-0001740-g005: Relationship between the area covered by tree taxa (log-transformed) and their rank in the nested matrices after rearrangement for nestedness.Symbols correspond to tree phyla (gray circles: Magnoliophyta; black squares: Conipherophyta). (A) Largest connected component. (B) Compartment C5. (C) Compartment C6.

Mentions: As expected, the correlation between the abundance and sampling intensity of tree species was significant and positive (Kendall's rank correlation test; τ = 0.59; p-value<0.001). The correlation between the abundance of given tree taxon and rank in the nested matrix (Fig. 5) was significant and negative for the largest component of the network (Kendall's rank correlation test; τ = −0.45; p-value<0.001) and for compartment C6 (Kendall's rank correlation test; τ = −0.68; p-value<0.001). A similar trend was found for compartment C5 (Kendall's rank correlation test; τ = −0.35; p-value = 0.067). Unsurprisingly, the correlation between the sampling intensity of a given tree taxon and rank in the nested matrix was also significant and negative for the largest component of the network (Kendall's rank correlation test; τ = −0.68; p-value<0.001), for compartment C5 (Kendall's rank correlation test; τ = −0.64; p-value<0.001) and for compartment C6 (Kendall's rank correlation test; τ = −0.76; p-value<0.001).


Architecture of an antagonistic tree/fungus network: the asymmetric influence of past evolutionary history.

Vacher C, Piou D, Desprez-Loustau ML - PLoS ONE (2008)

Relationship between the area covered by tree taxa (log-transformed) and their rank in the nested matrices after rearrangement for nestedness.Symbols correspond to tree phyla (gray circles: Magnoliophyta; black squares: Conipherophyta). (A) Largest connected component. (B) Compartment C5. (C) Compartment C6.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2254192&req=5

pone-0001740-g005: Relationship between the area covered by tree taxa (log-transformed) and their rank in the nested matrices after rearrangement for nestedness.Symbols correspond to tree phyla (gray circles: Magnoliophyta; black squares: Conipherophyta). (A) Largest connected component. (B) Compartment C5. (C) Compartment C6.
Mentions: As expected, the correlation between the abundance and sampling intensity of tree species was significant and positive (Kendall's rank correlation test; τ = 0.59; p-value<0.001). The correlation between the abundance of given tree taxon and rank in the nested matrix (Fig. 5) was significant and negative for the largest component of the network (Kendall's rank correlation test; τ = −0.45; p-value<0.001) and for compartment C6 (Kendall's rank correlation test; τ = −0.68; p-value<0.001). A similar trend was found for compartment C5 (Kendall's rank correlation test; τ = −0.35; p-value = 0.067). Unsurprisingly, the correlation between the sampling intensity of a given tree taxon and rank in the nested matrix was also significant and negative for the largest component of the network (Kendall's rank correlation test; τ = −0.68; p-value<0.001), for compartment C5 (Kendall's rank correlation test; τ = −0.64; p-value<0.001) and for compartment C6 (Kendall's rank correlation test; τ = −0.76; p-value<0.001).

Bottom Line: Unlike compartmentalization, nestedness did not reflect any consistent phylogenetic signal.Overall, our analyses emphasized how the current complexity of ecological networks results from the diversification of the species and their interactions over evolutionary times.They confirmed that the current architecture of ecological networks is not only dependent on recent ecological processes.

View Article: PubMed Central - PubMed

Affiliation: INRA [corrected] UMR1202 Biodiversité Gènes et Communautés, Villenave d'Ornon, France. cvacher@bordeaux.inra.fr

ABSTRACT

Background: Compartmentalization and nestedness are common patterns in ecological networks. The aim of this study was to elucidate some of the processes shaping these patterns in a well resolved network of host/pathogen interactions.

Methodology/principal findings: Based on a long-term (1972-2005) survey of forest health at the regional scale (all French forests; 15 million ha), we uncovered an almost fully connected network of 51 tree taxa and 157 parasitic fungal species. Our analyses revealed that the compartmentalization of the network maps out the ancient evolutionary history of seed plants, but not the ancient evolutionary history of fungal species. The very early divergence of the major fungal phyla may account for this asymmetric influence of past evolutionary history. Unlike compartmentalization, nestedness did not reflect any consistent phylogenetic signal. Instead, it seemed to reflect the ecological features of the current species, such as the relative abundance of tree species and the life-history strategies of fungal pathogens. We discussed how the evolution of host range in fungal species may account for the observed nested patterns.

Conclusion/significance: Overall, our analyses emphasized how the current complexity of ecological networks results from the diversification of the species and their interactions over evolutionary times. They confirmed that the current architecture of ecological networks is not only dependent on recent ecological processes.

Show MeSH
Related in: MedlinePlus