Figure 1.
The position of South Georgia relative to the Polar Front (white line), and the Antarctic Circumpolar Current (black dashes).
Figure 2.
South Georgia Shelf sampling locations.
(A) prior to the current study; (B) including data assimilated during this study (dots denoted in red).
Table 1.
Species abundance and record counts across 22 recorded phyla.
Figure 3.
Species frequency on the South Georgian shelf.
Species are ranked according to the number of distinct locations at which samples were records with the vast majority of species recording low record counts.
Table 2.
Levels of endemism, and the proportion of species occurring at their northern and southern range limits at South Georgia.
Figure 4.
Marine Biodiversity over spatial scale.
South Georgia data is denoted by filled black squares and presented in the format of 0.25×0.25° grid squares randomised through 999 iterations. Each successive point represents a doubling in shelf area from (1) a single 0.25×0.25° grid square, through to (2) the entire South Georgia Shelf. The combined biodiversity data from the South Georgian shelf and the South Orkney Islands (Barnes et. al. 2009), is represented by the filled grey square, point 3. Data for comparison was obtained from Barnes et. al. (2009) and includes biodiversity sampling from Reunion (Reu), Mauritius (Mus), Rodrigues (Rod), and South Africa (SAfr). Sampling from the Russian arctic seas (Sirenko et al., 2001) is denoted by two tone diamonds. Grey circles denote data presented by Barnes et. al. (2009) for the South Orkney Islands, the first point representing biodiversity recorded from a randomly selected single trawl. Subsequent points record species richness for the entire BIOPEARL 1 expedition, total biodiversity for the South Orkney Islands (SOI) and finally reported species richness for the whole Southern Ocean (Clarke & Johnston, 2003).
Figure 5.
Map of South Georgia showing the main bays and islets around the island.
The area of Cumberland Bay is enlarged in inset and includes the locations of King Edward Point (KP) and Moraine Fjord (MF).
Figure 6.
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.
Figure 7.
Relationship between sampling intensity and species richness.
Each point represents a single 0.25×0.25° spatial grid on the South Georgia shelf. The regression line is shown in solid black, 95% regression confidence interval as dot/dash lines and 95% sample confidence lines as broad black dashing. Grid square with large residuals outside or approaching the 95% prediction line are represented by hollow circles.
Figure 8.
Species and sampling distribution of 8 phyla on the South Georgia shelf.
(1) shows sampling intensity; (2) Species richness and (3) Linear regression residuals recorded in 0.25×0.25° grid squares across the South Georgia Shelf for (A) Bryozoans; (B) Cnidarians; (C) Chordates; (D) Echinoderms; (E) Molluscs; (F) Crustaceans; (G) Annelids and (H) sponges.
Figure 9.
Rarefaction curves showing the rate of species accumulation with increasing sample effort in eight major taxa.
Sample effort is defined by number of sampling sites. Inset presents the same data scaled to show trending of Crustaceans and Chordates over their entire sampling effort.
Figure 10.
Species richness of eight major phyla on the South Georgia shelf.
Dark grey bars show actual number of species recorded for each taxa; Light grey bars represent an estimated total species richness extrapolated using Chao 1(left hand column for each phyla) and Jacknife 2 (right hand column).