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Highly diverse, poorly studied and uniquely threatened by climate change: an assessment of marine biodiversity on South Georgia's continental shelf.

Hogg OT, Barnes DK, Griffiths HJ - PLoS ONE (2011)

Bottom Line: We attempt to quantify how significant the polar archipelago of South Georgia is as a source of regional and global marine biodiversity.Consequently, our data suggests the ecological implications of environmental change to the South Georgian marine ecosystem could be severe.If sea temperatures continue to rise, we suggest that changes will include depth profile shifts of some fauna towards cooler Antarctic Winter Water (90-150 m), the loss of some range-edge species from regional waters, and the wholesale extinction at a global scale of some of South Georgia's endemic species.

View Article: PubMed Central - PubMed

Affiliation: British Antarctic Survey, Natural Environmental Research Council, Cambridge, United Kingdom. olgg@bas.ac.uk

ABSTRACT
We attempt to quantify how significant the polar archipelago of South Georgia is as a source of regional and global marine biodiversity. We evaluate numbers of rare, endemic and range-edge species and how the faunal structure of South Georgia may respond to some of the fastest warming waters on the planet. Biodiversity data was collated from a comprehensive review of reports, papers and databases, collectively representing over 125 years of polar exploration. Classification of each specimen was recorded to species level and fully geo-referenced by depth, latitude and longitude. This information was integrated with physical data layers (e.g. temperature, salinity and flow) providing a visualisation of South Georgia's biogeography across spatial, temporal and taxonomic scales, placing it in the wider context of the Southern Hemisphere. This study marks the first attempt to map the biogeography of an archipelago south of the Polar Front. Through it we identify the South Georgian shelf as the most speciose region of the Southern Ocean recorded to date. Marine biodiversity was recorded as rich across taxonomic levels with 17,732 records yielding 1,445 species from 436 families, 51 classes and 22 phyla. Most species recorded were rare, with 35% recorded only once and 86% recorded <10 times. Its marine fauna is marked by the cumulative dominance of endemic and range-edge species, potentially at their thermal tolerance limits. Consequently, our data suggests the ecological implications of environmental change to the South Georgian marine ecosystem could be severe. If sea temperatures continue to rise, we suggest that changes will include depth profile shifts of some fauna towards cooler Antarctic Winter Water (90-150 m), the loss of some range-edge species from regional waters, and the wholesale extinction at a global scale of some of South Georgia's endemic species.

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Total species and sampling distribution on the South Georgia shelf.(A) shows species richness; (B) Sampling intensity and (C) Linear regression residuals recorded in 0.25×0.25° grid squares across the South Georgia Shelf.
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pone-0019795-g006: Total species and sampling distribution on the South Georgia shelf.(A) shows species richness; (B) Sampling intensity and (C) Linear regression residuals recorded in 0.25×0.25° grid squares across the South Georgia Shelf.

Mentions: Analysis of marine biodiversity recorded over increasing spatial scale identified South Georgia as having a very spatially heterogeneous dataset, as evident from the consistently large increases in overall biodiversity observed through a systematic doubling of sampling scale (Figure 4). Subdivision of the South Georgia shelf into 0.25×0.25 degree grid squares supported these assertions, revealing a very geographically uneven distribution of species richness ( = 57.2; σ = 75.2). The most speciose grid occurred adjacent to the north coast at Cumberland Bay East (see figure 5) and contained 577 different species. Neighbouring grid squares to the north and west including areas of Cumberland Bay West and Stromness Bay also had species richness levels >400. Many other grids, especially along the south coast of the island and across the south and eastern shelf however, contained far fewer species with 75 grids totaling less than 50 species each (figure 6a).


Highly diverse, poorly studied and uniquely threatened by climate change: an assessment of marine biodiversity on South Georgia's continental shelf.

Hogg OT, Barnes DK, Griffiths HJ - PLoS ONE (2011)

Total species and sampling distribution on the South Georgia shelf.(A) shows species richness; (B) Sampling intensity and (C) Linear regression residuals recorded in 0.25×0.25° grid squares across the South Georgia Shelf.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102052&req=5

pone-0019795-g006: Total species and sampling distribution on the South Georgia shelf.(A) shows species richness; (B) Sampling intensity and (C) Linear regression residuals recorded in 0.25×0.25° grid squares across the South Georgia Shelf.
Mentions: Analysis of marine biodiversity recorded over increasing spatial scale identified South Georgia as having a very spatially heterogeneous dataset, as evident from the consistently large increases in overall biodiversity observed through a systematic doubling of sampling scale (Figure 4). Subdivision of the South Georgia shelf into 0.25×0.25 degree grid squares supported these assertions, revealing a very geographically uneven distribution of species richness ( = 57.2; σ = 75.2). The most speciose grid occurred adjacent to the north coast at Cumberland Bay East (see figure 5) and contained 577 different species. Neighbouring grid squares to the north and west including areas of Cumberland Bay West and Stromness Bay also had species richness levels >400. Many other grids, especially along the south coast of the island and across the south and eastern shelf however, contained far fewer species with 75 grids totaling less than 50 species each (figure 6a).

Bottom Line: We attempt to quantify how significant the polar archipelago of South Georgia is as a source of regional and global marine biodiversity.Consequently, our data suggests the ecological implications of environmental change to the South Georgian marine ecosystem could be severe.If sea temperatures continue to rise, we suggest that changes will include depth profile shifts of some fauna towards cooler Antarctic Winter Water (90-150 m), the loss of some range-edge species from regional waters, and the wholesale extinction at a global scale of some of South Georgia's endemic species.

View Article: PubMed Central - PubMed

Affiliation: British Antarctic Survey, Natural Environmental Research Council, Cambridge, United Kingdom. olgg@bas.ac.uk

ABSTRACT
We attempt to quantify how significant the polar archipelago of South Georgia is as a source of regional and global marine biodiversity. We evaluate numbers of rare, endemic and range-edge species and how the faunal structure of South Georgia may respond to some of the fastest warming waters on the planet. Biodiversity data was collated from a comprehensive review of reports, papers and databases, collectively representing over 125 years of polar exploration. Classification of each specimen was recorded to species level and fully geo-referenced by depth, latitude and longitude. This information was integrated with physical data layers (e.g. temperature, salinity and flow) providing a visualisation of South Georgia's biogeography across spatial, temporal and taxonomic scales, placing it in the wider context of the Southern Hemisphere. This study marks the first attempt to map the biogeography of an archipelago south of the Polar Front. Through it we identify the South Georgian shelf as the most speciose region of the Southern Ocean recorded to date. Marine biodiversity was recorded as rich across taxonomic levels with 17,732 records yielding 1,445 species from 436 families, 51 classes and 22 phyla. Most species recorded were rare, with 35% recorded only once and 86% recorded <10 times. Its marine fauna is marked by the cumulative dominance of endemic and range-edge species, potentially at their thermal tolerance limits. Consequently, our data suggests the ecological implications of environmental change to the South Georgian marine ecosystem could be severe. If sea temperatures continue to rise, we suggest that changes will include depth profile shifts of some fauna towards cooler Antarctic Winter Water (90-150 m), the loss of some range-edge species from regional waters, and the wholesale extinction at a global scale of some of South Georgia's endemic species.

Show MeSH
Related in: MedlinePlus