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Infaunal Benthic Communities from the Inner Shelf off Southwestern Africa Are Characterised by Generalist Species.

Steffani N, Sedick S, Rogers J, Gibbons MJ - PLoS ONE (2015)

Bottom Line: Although the fauna was dominated by polychaetes and peracarid crustaceans, patterns in community structure could only weakly be explained by the measured environment (~35%).This is attributed to the generalist nature of the species recovered, which were widely distributed amongst different sediments, water-depths and latitudes.The fauna is dominated by species that enjoy a widespread regional and global distribution and is characterised by relatively low diversity, which is discussed.

View Article: PubMed Central - PubMed

Affiliation: 21 Skippers End, Zeekoevlei, Cape Town, South Africa.

ABSTRACT
Infaunal communities of benthic macro-organisms (≥ 1mm length) were studied from 81 samples collected across nine sites to the north and south of the Orange River in the Benguela upwelling ecosystem in 2003, with a view to describing communities and understanding the drivers of regional community structure, as well as to document diversity and to examine geographic affinities. Although the fauna was dominated by polychaetes and peracarid crustaceans, patterns in community structure could only weakly be explained by the measured environment (~35%). This is attributed to the generalist nature of the species recovered, which were widely distributed amongst different sediments, water-depths and latitudes. The fauna is dominated by species that enjoy a widespread regional and global distribution and is characterised by relatively low diversity, which is discussed.

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Two dimensional visualisations of sediment environment.(A) PCA plot showing the distribution of the samples collected off southwestern Africa during 2003: vectors indicate the direction of increase of the different sediment size classes. (B) Multivariate multiple regression (dbRDA) performed on sediment data and predictor variables (water-depth, latitude and distance to the Orange River mouth): vectors indicate the direction and strength of the environmental gradients. The location of the samples, by site, is indicated by symbols.
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pone.0143637.g002: Two dimensional visualisations of sediment environment.(A) PCA plot showing the distribution of the samples collected off southwestern Africa during 2003: vectors indicate the direction of increase of the different sediment size classes. (B) Multivariate multiple regression (dbRDA) performed on sediment data and predictor variables (water-depth, latitude and distance to the Orange River mouth): vectors indicate the direction and strength of the environmental gradients. The location of the samples, by site, is indicated by symbols.

Mentions: Averages mask variability, however and it is clear from Fig 1 and S1 Fig that there was quite a bit of patchiness in the sediment textures of the different samples collected within each of the different sites. That said, the results of the PCA, the first two axes of which explain about 70% of the variability in the multivariate dataset (Fig 2A), clearly separate the sediment environment across the region and the marginal tests of the DistLM indicate that distance from the Orange River mouth (pseudo-F 16.03, p = 0.001), water-depth (pseudo-F 12.30, p = 0.001) and latitude (pseudo-F 12.50, p = 0.001) were approximately equally significant as predictors of sediment texture (Fig 2B). The final model (adj R2 0.299) included all predictors: distance (adj R2 0.16, pseudo-F 16.03, p = 0.001), latitude (adj R2 0.26, pseudo-F 11.79, p = 0.001) and depth (adj R2 0.0, pseudo-F 5.45, p = 0.002).


Infaunal Benthic Communities from the Inner Shelf off Southwestern Africa Are Characterised by Generalist Species.

Steffani N, Sedick S, Rogers J, Gibbons MJ - PLoS ONE (2015)

Two dimensional visualisations of sediment environment.(A) PCA plot showing the distribution of the samples collected off southwestern Africa during 2003: vectors indicate the direction of increase of the different sediment size classes. (B) Multivariate multiple regression (dbRDA) performed on sediment data and predictor variables (water-depth, latitude and distance to the Orange River mouth): vectors indicate the direction and strength of the environmental gradients. The location of the samples, by site, is indicated by symbols.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664413&req=5

pone.0143637.g002: Two dimensional visualisations of sediment environment.(A) PCA plot showing the distribution of the samples collected off southwestern Africa during 2003: vectors indicate the direction of increase of the different sediment size classes. (B) Multivariate multiple regression (dbRDA) performed on sediment data and predictor variables (water-depth, latitude and distance to the Orange River mouth): vectors indicate the direction and strength of the environmental gradients. The location of the samples, by site, is indicated by symbols.
Mentions: Averages mask variability, however and it is clear from Fig 1 and S1 Fig that there was quite a bit of patchiness in the sediment textures of the different samples collected within each of the different sites. That said, the results of the PCA, the first two axes of which explain about 70% of the variability in the multivariate dataset (Fig 2A), clearly separate the sediment environment across the region and the marginal tests of the DistLM indicate that distance from the Orange River mouth (pseudo-F 16.03, p = 0.001), water-depth (pseudo-F 12.30, p = 0.001) and latitude (pseudo-F 12.50, p = 0.001) were approximately equally significant as predictors of sediment texture (Fig 2B). The final model (adj R2 0.299) included all predictors: distance (adj R2 0.16, pseudo-F 16.03, p = 0.001), latitude (adj R2 0.26, pseudo-F 11.79, p = 0.001) and depth (adj R2 0.0, pseudo-F 5.45, p = 0.002).

Bottom Line: Although the fauna was dominated by polychaetes and peracarid crustaceans, patterns in community structure could only weakly be explained by the measured environment (~35%).This is attributed to the generalist nature of the species recovered, which were widely distributed amongst different sediments, water-depths and latitudes.The fauna is dominated by species that enjoy a widespread regional and global distribution and is characterised by relatively low diversity, which is discussed.

View Article: PubMed Central - PubMed

Affiliation: 21 Skippers End, Zeekoevlei, Cape Town, South Africa.

ABSTRACT
Infaunal communities of benthic macro-organisms (≥ 1mm length) were studied from 81 samples collected across nine sites to the north and south of the Orange River in the Benguela upwelling ecosystem in 2003, with a view to describing communities and understanding the drivers of regional community structure, as well as to document diversity and to examine geographic affinities. Although the fauna was dominated by polychaetes and peracarid crustaceans, patterns in community structure could only weakly be explained by the measured environment (~35%). This is attributed to the generalist nature of the species recovered, which were widely distributed amongst different sediments, water-depths and latitudes. The fauna is dominated by species that enjoy a widespread regional and global distribution and is characterised by relatively low diversity, which is discussed.

Show MeSH
Related in: MedlinePlus