Spatial distribution of freshwater crustaceans in Antarctic and Subantarctic lakes

Abstract

Antarctic and Subantarctic lakes are unique ecosystems with relatively simple food webs, which are likely to be strongly affected by climate warming. While Antarctic freshwater invertebrates are adapted to extreme environmental conditions, little is known about the factors determining their current distribution and to what extent this is explained by biogeography or climate. We explored the distribution of freshwater crustaceans (one of the most abundant and diverse group of organisms in Antarctic and Subantarctic lakes) across four biogeographic provinces (Continental Antarctic, CA; Maritime Antarctic, MA; Subantarctic islands, SA; and Southern Cool Temperate, SCT) based on the literature, predicting that species distribution would be determined by biogeography, spatial autocorrelation among regions (in relation to dispersal) and climate. We found that variation in species composition was largely explained by the joint effect of spatial autocorrelation and climate, with little effect of biogeography – only regions within the SA province had a clearly distinct species composition. This highlights a plausible main influence of crustacean dispersal – mainly through migratory seabirds – and suggests that some regions will be more affected by climate warming than others, possibly in relation to the existence of nearby sources of colonists.

Diatoms define a novel freshwater biogeography of the Antarctic

“…3D, Supporting information; Chown andConvey 2007, Van der Putten et al 2010). This pronounced biogeographic structuring therefore closely resembles that of terrestrial free-living invertebrates (Pugh andConvey 2008, Chown andConvey 2016), but contradicts the presumed Antarctic-wide distribution observed in most freshwater crustaceans (Díaz et al 2019). Partitioning of beta diversity (Baselga 2010) confirms the strong regional-scale structuring of diatom floras (Supporting information).…”

“…For lakes, compilations of distributional data in the Antarctic to date only exist for crustaceans (Dartnall 2017). Based on this dataset, it was concluded that the majority of species probably have an Antarctic wide distribution, and that there is limited evidence for biogeographic structuring (Díaz et al 2019). By contrast, several studies documenting new species of for example chlorophytes (De Wever et al 2009), bdelloid rotifers (Iakovenko et al 2015) and cyclopoid copepods (Karanovic et al 2014) suggest that endemism and narrower ranges may be more widespread among freshwater organisms of the Antarctic than hitherto assumed.…”

Historical biogeography of the Gondwanan freshwater genus Boeckella (Crustacea): Timing and modes of speciation in the Southern Hemisphere

“…The species B . poppei (Mrázek, 1901) has the broadest distribution and is the only representative of the genus in Antarctica today (Bayly et al., 2003; Díaz et al., 2019; Maturana et al., 2019; Menu‐Marque et al., 2000), where it is restricted to freshwater bodies in seasonally or permanently snow‐ or ice‐free areas, on glacier surfaces and epishelf lakes (Laybourn‐Parry & Pearce, 2007). It has been reported in lakes in continental Antarctica (King Charles Mountains, Bayly et al., 2003; Gibson & Bayly, 2007), Alexander Island, the Antarctic Peninsula, the South Shetland and South Orkney Islands in maritime Antarctica and sub‐Antarctic South Georgia, as well as in southern South America and the Falkland/Malvinas Islands (Bayly et al., 2003; Maturana et al., 2019; Menu‐Marque et al., 2000).…”

Population features of Boeckella poppei in Lake Wujka, King George Island

“…The copepod genus Boeckella Guerne & Richard, 1889 consists of 42 species distributed throughout Australia, New Zealand, South America, Antarctica, and sub-Antarctic islands (Menu-Marque et al, 2000;Dartnall, 2017;Díaz et al, 2019;. Some species, including Boeckella poppei (Mrázek, 1901) (Сentropagidae), were originally described in the genus Pseudoboeckella Mrázek, 1901, but were transferred to Boeckella (Bayly, 1992).…”