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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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Abundance of those taxa characteristic of each site.Histogram showing the average abundance per site, of those macro-infaunal taxa identified by the SIMPER routine in PRIMER 6 as being responsible for a minimum of 50% of the identity of each of the sites sampled off southern Namibia and off Namaqualand during 2003.
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pone.0143637.g004: Abundance of those taxa characteristic of each site.Histogram showing the average abundance per site, of those macro-infaunal taxa identified by the SIMPER routine in PRIMER 6 as being responsible for a minimum of 50% of the identity of each of the sites sampled off southern Namibia and off Namaqualand during 2003.

Mentions: In an attempt to understand the relatively low proportion of the variability in infaunal structure explained by the environmental predictors, we have looked at the results of the SIMPER analysis and the average abundance per sample of those species responsible for 50% of the similarity within sites. These data are shown in Fig 4, from which it is clear that many of the “identifiers” are shared across sites. For example, the polychaete Nepthys hombergi was common at five sites, whilst the polychaete Paraprionospio pinnata and the gastropod Nassarius vinctus were common at four. Indeed, almost 50% of identified species were recovered at, and dominant at, three or more of the sites (S2A Fig). The results of a similar analysis conducted with respect to water-depth and sediment are shown in S4 and S5 Tables, from which it can be seen, especially with respect to water-depth (S4 Table), that although there were clear patterns in species distribution across the shelf, relatively few species were restricted to single habitats. In other words, the fauna of the region appears to be dominated by habitat generalists and differences between sites largely reflect differences in relative abundance.


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)

Abundance of those taxa characteristic of each site.Histogram showing the average abundance per site, of those macro-infaunal taxa identified by the SIMPER routine in PRIMER 6 as being responsible for a minimum of 50% of the identity of each of the sites sampled off southern Namibia and off Namaqualand during 2003.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0143637.g004: Abundance of those taxa characteristic of each site.Histogram showing the average abundance per site, of those macro-infaunal taxa identified by the SIMPER routine in PRIMER 6 as being responsible for a minimum of 50% of the identity of each of the sites sampled off southern Namibia and off Namaqualand during 2003.
Mentions: In an attempt to understand the relatively low proportion of the variability in infaunal structure explained by the environmental predictors, we have looked at the results of the SIMPER analysis and the average abundance per sample of those species responsible for 50% of the similarity within sites. These data are shown in Fig 4, from which it is clear that many of the “identifiers” are shared across sites. For example, the polychaete Nepthys hombergi was common at five sites, whilst the polychaete Paraprionospio pinnata and the gastropod Nassarius vinctus were common at four. Indeed, almost 50% of identified species were recovered at, and dominant at, three or more of the sites (S2A Fig). The results of a similar analysis conducted with respect to water-depth and sediment are shown in S4 and S5 Tables, from which it can be seen, especially with respect to water-depth (S4 Table), that although there were clear patterns in species distribution across the shelf, relatively few species were restricted to single habitats. In other words, the fauna of the region appears to be dominated by habitat generalists and differences between sites largely reflect differences in relative abundance.

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