Antarctic Paleobiology: Glacial refugia and constraints on past ice-sheet reconstructions

Many boreal and polar lichens occupy bipolar distributional ranges that frequently extend into high mountains at lower latitudes. Although such disjunctions are more common among lichens than in other groups of organisms, the geographic origin of bipolar lichen taxa, and the way and time frame in which they colonized their ranges have not been studied in detail. We used the predominantly vegetative, widespread lichen Cetraria aculeata as a model species. We surveyed the origin and history of its bipolar pattern using population genetics, phylogenetic and genealogical reconstruction methods. Cetraria aculeata originated in the Northern Hemisphere and dispersed southwards during the Pleistocene. The genetic signal suggests a Pleistocene dispersive burst in which a population size expansion concurred with the acquisition of a South-American range that culminated in the colonization of the Antarctic.

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“…; Newman et al . ). This would have been facilitated by a 80–120 m drop in sea level during this period (Ritz et al .…”

Section: Discussionmentioning

confidence: 97%

Pleistocene expansion of the bipolar lichen Cetraria aculeata into the Southern hemisphere

Fernández-Mendoza

Printzen

2013

Molecular Ecology

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“…The refugia near Campbell Plateau and Bouvet Island were not identified in a previous study by Dambach et al (2012) due to their more limited data. Molecular studies on Antarctic isopods, amphipods, and bivalves have indicated similar re-colonization events in nearby shelf and slope from glacial refugia in several taxa since the LGM ( Rogers, 2007 ; Newman et al, 2009 ). The shrimp refugia found in this study complement these molecular studies and provide a geographic context of how species ranges adjust to environmental change by moving up and down the continental slope and on and off the continental shelf ( Fig.…”

Section: Discussionmentioning

confidence: 99%

The past, present and future distribution of a deep-sea shrimp in the Southern Ocean

Basher

Costello

2016

PeerJ

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Shrimps have a widespread distribution across the shelf, slope and seamount regions of the Southern Ocean. Studies of Antarctic organisms have shown that individual species and higher taxa display different degrees of sensitivity and adaptability in response to environmental change. We use species distribution models to predict changes in the geographic range of the deep-sea Antarctic shrimp Nematocarcinus lanceopes under changing climatic conditions from the Last Glacial Maximum to the present and to the year 2100. The present distribution range indicates a pole-ward shift of the shrimp population since the last glaciation. This occurred by colonization of slopes from nearby refugia located around the northern part of Scotia Arc, southern tip of South America, South Georgia, Bouvet Island, southern tip of the Campbell plateau and Kerguelen plateau. By 2100, the shrimp are likely to expand their distribution in east Antarctica but have a continued pole-ward contraction in west Antarctica. The range extension and contraction process followed by the deep-sea shrimp provide a geographic context of how other deep-sea Antarctic species may have survived during the last glaciation and may endure with projected changing climatic conditions in the future.

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“…However, unlike terrestrial species, many of the Southern Ocean seabirds, which breed on small, isolated islands, could not simply move further north. Suitable breeding habitat was severely reduced or non-existent, and many of their prey likely experienced range shifts tied to changes in ocean currents (De Dinechin et al 2009;Newman et al 2009;Wakefield et al 2009).…”

Section: Refugia and Postglacial Colonisationmentioning

confidence: 99%

A review of historical and contemporary processes affecting population genetic structure of Southern Ocean seabirds

Munro

Burg

2017

Emu - Austral Ornithology

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Genetic signatures of historical, behavioural and environmental processes are evident in contemporary seabird populations. Molecular markers have allowed us to determine historical patterns of gene flow, relationships among taxa, and contemporary dispersal barriers. The Southern Ocean contains a number of small, isolated islands that are home to four families of seabirds: albatrosses, petrels, penguins and skuas, which have been the focus of a number of population genetic studies. While capable of travelling large distances, many seabirds have restricted dispersal and exhibit high levels of population structure; typically in northern areas and areas with high endemism (e.g. New Zealand). We reviewed 29 studies of 25 Southern Ocean seabird species comparing biogeographic patterns, glacial history and barriers to gene flow, especially at-sea distribution and ocean currents. Despite diversity in behaviour and life history, our review demonstrates that population genetic structure of the seabirds corresponds to the same barriers. For penguins, currents are the major impediment to dispersal whereas at-sea distribution and island location influence population structure for many seabirds with genetically distinct populations on islands at the periphery of their range. As environmental conditions change, it will become more important to assess how seabirds respond and how these changes influence both dispersal and population structure. It is particularly important as a disproportionately high number of Southern Ocean seabirds are threatened or near threatened. Future studies need to focus on adaptive genetic markers, range-wide comprehensive sampling, influence of behaviour on genetic structure and lesser studied seabirds such as terns and cormorants.

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Antarctic Paleobiology: Glacial refugia and constraints on past ice-sheet reconstructions

Cited by 11 publications

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Pleistocene expansion of the bipolar lichen Cetraria aculeata into the Southern hemisphere

Pleistocene expansion of the bipolar lichen Cetraria aculeata into the Southern hemisphere

The past, present and future distribution of a deep-sea shrimp in the Southern Ocean

A review of historical and contemporary processes affecting population genetic structure of Southern Ocean seabirds

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