Evidence for a lacustrine faunal refuge in the Larsemann Hills, East Antarctica, during the Last Glacial Maximum

Abstract

Aim There is no previous direct evidence for the occurrence of lacustrine refuges for invertebrate fauna in Antarctica spanning the Last Glacial Maximum (LGM). In the absence of verified LGM lacustrine refuges many species are believed to result from Holocene dispersal from sub‐Antarctic islands and continents further north. If freshwater lake environments were present throughout the LGM, extant freshwater species may have been associated with Antarctica prior to this glacial period. This study looked at faunal microfossils in a sediment core from an Antarctic freshwater lake. This lake is unusual in that, unlike most Antarctic lakes, the sediment record extends to c. 130,000 yr bp, i.e. prior to the LGM. Location Lake Reid, Larsemann Hills, East Antarctica (76°23′ E; 69°23′ S). Methods Palaeofaunal communities in Lake Reid were identified through examination of faunal microfossils in a sediment core that extended to c. 130,000 yr bp. Results Ephippia and mandibles from the cladoceran Daphniopsis studeri and loricae of the rotifer Notholca sp. were found at all depths in the sediment, indicating that these two species have been present in the lake for up to 130,000 years. Copepod mandibles were also present in the older section of the core, yet were absent from the most recent sediments, indicating extinction of this species from Lake Reid during the LGM. Main conclusion The presence of D. studeri and Notholca sp. microfossils throughout the entire Lake Reid core is the first direct evidence of a glacial lacustrine refugium for invertebrate animals in Antarctica, and indicates the presence of a relict fauna on the Antarctic continent.

Hidden levels of phylodiversity in Antarctic green algae: further evidence for the existence of glacial refugia

“…In Prydz Bay, parts of the Larsemann Hills, less than 80 km away from the Rauer Islands and the Vestfold Hills, were ice-free during the LGM (Hodgson et al 2001). Some lakes in this region were shown to contain relict populations of diatoms and copepods (Hodgson et al 2005;Cromer et al 2006), while in other lakes taxa currently present in other Antarctic and sub-Antarctic regions became locally extinct during the LGM . In the Lü tzow Holm Bay region, ice-free conditions in some coastal areas during the LGM can be inferred from 14 C dates of in situ fossils in raised beach deposits (Miura et al 1998).…”

Spatial and temporal variability across life's hierarchies in the terrestrial Antarctic

“…Likewise, extensive fossil floras characterized the oldest of the sub-Antarctic islands on the Kerguelen Plateau (Chastain 1958;Quilty & Wheller 2000). Over shorter time-scales, palynological evidence has demonstrated compositional change in the floras of many sites (Scott 1985), and lake sediment cores have also revealed substantial variation in the abundances of terrestrial and freshwater invertebrates such as mites and crustaceans (Cromer et al 2006;. Interest in temporal variation in Antarctic terrestrial systems was initially focused on seasonal changes in the abundances, phenology and life histories of plants and animals, and on successional changes in plant communities (reviewed in Block 1984;Lewis Smith 1984;Convey 1996a).…”

“…Comprehensive phylogenetic assessments of taxa, using modern molecular methods, and incorporating ecological and biogeographic information, are curiously rare in the literature on Antarctic terrestrial biodiversity. Springtail sequences have been used to inform broader systematic questions ( Frati & Dell'Ampio 2000;D'Haese 2002), and only two recent studies have sought to investigate patterns of speciation across the Antarctic (Allegrucci et al 2006;Stevens et al 2006;§2b) (d) Assemblage and ecosystem levels Antarctic and sub-Antarctic assemblages have changed dramatically over the long term as is clear from the fossil record, and from palynological analyses that provide information on change at scales of several thousand years Cromer et al 2006;. In both the maritime Antarctic and sub-Antarctic, clear successional changes associated with glacial retreat, both in the past and in the present, have been documented, and form among the clearest examples of temporal variation in assemblages (Frenot et al 1998;.…”

Abundance and diversity of soil invertebrates in the Windmill Islands region, East Antarctica

“…For example, the nearest extensive ice-free area is the Bunger Hills (69°17 0 S, 100°47 0 E) that commenced deglaciation around 30,000-40,000 years ago (Mackintosh et al 2014) and is therefore unlikely to represent a long term refugia for soil fauna. Further afield, rotifer remains have been observed in lacustrine sediments dating back to around 130,000 years ago in Lake Reid in the Larsemann Hills (69°23 0 S, 76°26 0 E), indicating the presence of longerterm refugia in East Antarctica at least for aquatic animals (Cromer et al 2006). However, suitable refugia from which microarthropods could recolonize the Windmill Islands Region are less evident.…”