Antarctic flora

Last updated
Nothofagus fusca, New Zealand NothofagusFusca.jpg
Nothofagus fusca , New Zealand

Antarctic flora are a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana. Presently, species of Antarctica flora reside on several now separated areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia, and New Caledonia. Joseph Dalton Hooker (1817 – 1911) was the first to notice similarities in the flora and speculated that Antarctica had served as either a source or a transitional point, and that land masses now separated might formerly have been adjacent. [1]

Contents

Based on the similarities in their flora, botanist Ronald D'Oyley Good identified a separate Antarctic Floristic Kingdom that included southern South America, New Zealand, and some southern island groups. In addition, Australia was determined to be its own floristic kingdom because of the influx of tropical Eurasian flora that had mostly supplanted the Antarctic flora and included New Guinea and New Caledonia in the Paleotropical floristic kingdom.

Origin

Millions of years ago the climate in Antarctica was warmer, and was able to support flora well into the Neogene. [2] This included forests of podocarps and southern beech. Antarctica was also part of the ancient supercontinent of Gondwana, which gradually broke up by plate tectonics starting 110 million years ago. The separation of South America from Antarctica 3035 million years ago allowed the Antarctic Circumpolar Current to form, which isolated Antarctica climatically and caused it to become much colder. The Antarctic flora subsequently died out in Antarctica, but is still an important component of the flora of southern Neotropic (South America) and Australasian realms, which were also former parts of Gondwana.

Some genera which originated in Antarctic Flora are still recognized as major components of New Caledonia, Tasmania, Madagascar, India, New Zealand, and southern South America.

South America, Madagascar, Africa, India, Australia, New Zealand, and Antarctica were all part of the supercontinent Gondwana, which started to break up in the early Cretaceous period (14566 million years ago). India was the first to break away, followed by Africa, and then New Zealand, which started to drift north. By the end of the Cretaceous, South America and Australia were still joined to Antarctica. Paleontologist Gilbert Brenner identified the emergence of a distinct southern Gondwanan flora by the late Cretaceous period in the cooler and humid southern hemisphere regions of Australia, southern South America, southern Africa, Antarctica, and New Zealand; it most resembled the flora of modern-day southern New Zealand. A drier northern Gondwanan flora had developed in northern South America and northern Africa.

Nothofagus antarctica, Chile and Argentina Nothofagus antarctica D.jpg
Nothofagus antarctica , Chile and Argentina

Africa and India drifted north into the tropical latitudes, became hotter and drier, and ultimately connected with the Eurasian continent. Today, the flora of Africa and India have few remnants of the Antarctic flora. Australia drifted north and became drier as well; the humid Antarctic flora retreated to the east coast and Tasmania, while the rest of Australia became dominated by Acacia, Eucalyptus , and Casuarina , as well as xeric shrubs and grasses. Humans arrived in Australia 5060,000 years ago and used fire to reshape the vegetation of the continent; as a result, the Antarctic flora, also known as the Rainforest flora in Australia, retreated to a few isolated areas composing less than 2% of Australia's land area.

The woody plants of the Antarctic flora include conifers in the families Podocarpaceae, Araucariaceae and the subfamily Callitroideae of Cupressaceae, and angiosperms such as the families Proteaceae, Griseliniaceae, Cunoniaceae, Atherospermataceae, and Winteraceae, and genera like southern beech ( Nothofagus ) and fuchsia ( Fuchsia ). Many other families of flowering plants and ferns, including the tree fern Dicksonia , are characteristic of the Antarctic flora.

Flora of Antarctica

Antarctic palaeoflora

A wide variety of plant life has resided in Antarctica throughout its history. Investigations of Upper Cretaceous and Early Tertiary sediments of Antarctica yield a rich assemblage of well-preserved fossil dicotyledonous angiosperm wood which provides evidence for the existence, since the Late Cretaceous, of temperate forests similar in composition to those found in present-day southern South America, New Zealand and Australia. It is suggested a paleobotanical habitat similar to the extant cool temperate Valdivian rainforests. [3] During the colder Neogene (17–2.5 Ma), a low diversity tundra ecosystem dominated by angiosperms replaced the rainforests. [2]

There are two conifer and at least seven angiosperm morphotypes recorded in the Antarctica palaeoflora. Conifers include Cupressinoxylon , which is the more common, and Podocarpoxylon . [3] The angiosperm component includes two species of Nothofagoxylon , one species of Myrceugenelloxylon (similar to Luma, in the extant family Myrtaceae), and one species of Weinmannioxylon (similar to Eucryphia in the extant family Cunoniaceae). [3] Two other species are assigned to genera Hedycaryoxylon (Monimiaceae) and Atherospermoxylon (Atherospermataceae). [4] A fossil water lily, Notonuphar (similar to Nuphar in the extant family Nympheaceae), was described from Eocene-aged sediments on Seymour Island in 2017. [5]

Present-day flora

Deschampsia antarctica at Collins Glacier, Antarctica. This species is one of only two flowering plants native to Antarctica, the other one being the Antarctic pearlwort (Colobanthus quitensis). D. antarctica.jpg
Deschampsia antarctica  at Collins Glacier, Antarctica. This species is one of only two flowering plants native to Antarctica, the other one being the Antarctic pearlwort ( Colobanthus quitensis ).

Antarctica's extant flora presently consists of around 250 lichens, 100 mosses, 25-30 liverworts, and around 700 terrestrial and aquatic algal species. Species of moss endemic to Antarctica include Grimmia antarctici , Schistidium antarctici , and Sarconeurum glaciale . Just two native flowering plants, Deschampsia antarctica (Antarctic hair grass) and Colobanthus quitensis (Antarctic pearlwort), are found on the northern and western parts of the Antarctic Peninsula. The continent of Antarctica itself has been too cold and dry to support any other vascular plants for millions of years. The scanty vegetation of Antarctica is a result of the chilling temperature, lack of sunlight, little rainfall, relatively poor soil quality, and a lack of moisture due to the inability of the plants to absorb water in the form of ice.

See also

Related Research Articles

<span class="mw-page-title-main">Geography of New Caledonia</span>

The geography of New Caledonia (Nouvelle-Calédonie), an overseas collectivity of France located in the subregion of Melanesia, makes the continental island group unique in the southwest Pacific. Among other things, the island chain has played a role in preserving unique biological lineages from the Mesozoic. It served as a waystation in the expansion of the predecessors of the Polynesians, the Lapita culture. Under the Free French it was a vital naval base for Allied Forces during the War in the Pacific.

<i>Nothofagus</i> Genus of plants

Nothofagus, also known as the southern beeches, is a genus of 43 species of trees and shrubs native to the Southern Hemisphere in southern South America and east and southeast Australia, New Zealand, New Guinea, and New Caledonia. The species are ecological dominants in many temperate forests in these regions. Some species are reportedly naturalised in Germany and Great Britain. The genus has a rich fossil record of leaves, cupules, and pollen, with fossils extending into the late Cretaceous period and occurring in Australia, New Zealand, Antarctica, and South America.

<span class="mw-page-title-main">Restionaceae</span> Family of flowering plants

The Restionaceae, also called restiads and restios, are a family of flowering plants native to the Southern Hemisphere; they vary from a few centimeters to 3 meters in height. Following the APG IV (2016): the family now includes the former families Anarthriaceae, Centrolepidaceae and Lyginiaceae, and as such includes 51 genera with 572 known species. Based on evidence from fossil pollen, the Restionaceae likely originated more than 65 million years ago during the Late Cretaceous period, when the southern continents were still part of Gondwana.

<span class="mw-page-title-main">Antarctic realm</span> One of Earths eight biogeographic realms

The Antarctic realm is one of eight terrestrial biogeographic realms. The ecosystem includes Antarctica and several island groups in the southern Atlantic and Indian oceans. The continent of Antarctica is so cold that it has supported only 2 vascular plants for millions of years, and its flora presently consists of around 250 lichens, 100 mosses, 25–30 liverworts, and around 700 terrestrial and aquatic algal species, which live on the areas of exposed rock and soil around the shore of the continent. Antarctica's two flowering plant species, the Antarctic hair grass and Antarctic pearlwort, are found on the northern and western parts of the Antarctic Peninsula. Antarctica is also home to a diversity of animal life, including penguins, seals, and whales.

<span class="mw-page-title-main">Winteraceae</span> Family of flowering plants

Winteraceae is a primitive family of tropical trees and shrubs including 93 species in five genera. It is of particular interest because it is such a primitive angiosperm family, distantly related to Magnoliaceae, though it has a much more southern distribution. Plants in this family grow mostly in the southern hemisphere, and have been found in tropical to temperate climate regions of Malesia, Oceania, eastern Australia, New Zealand, Madagascar and the Neotropics, with most of the genera concentrated in Australasia and Malesia. The five genera, Takhtajania, Tasmannia, Drimys, Pseudowintera, and Zygogynum s.l. all have distinct geographic extant populations. Takhtajania includes a single species, T. perrieri, endemic only to Madagascar, Tasmannia has the largest distribution of genera in Winteraceae with species across the Philippines, Borneo, New Guinea, Eastern Australia, and Tasmannia, Drimys is found in the Neotropical realm, from southern Mexico to the subarctic forests of southern South America, Pseudowintera is found only in New Zealand, and Zygogynum has species in New Guinea and New Caledonia.

<span class="mw-page-title-main">Atherospermataceae</span> Family of flowering plants

The Atherospermataceae, commonly known as the southern sassafrases, are a family of broadleaf evergreen trees and shrubs. The family includes 14 species in seven genera. The atherosperms are today mostly distributed in the Southern Hemisphere, with two species native to southern Chile and 12 species native to Australasia. Wood is commercially harvested from rainforest species of this family, and is used both in construction and in fine cabinet making.

<span class="mw-page-title-main">South Polar region of the Cretaceous</span> Animals that lived below the Antarctic circle in the Cretaceous

The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia, Zealandia, and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much warmer than it is today, ranging from perhaps 4–8 °C (39–46 °F) in the latest Cretaceous Maastrichtian in what is now southeastern Australia. This prevented permanent ice sheets from developing and fostered polar forests, which were largely dominated by conifers, cycads, and ferns, and relied on a temperate climate and heavy rainfall. Major fossil-bearing geological formations that record this area are: the Santa Marta and Sobral Formations of Seymour Island off the Antarctic Peninsula; the Snow Hill Island, Lopez de Bertodano, and the Hidden Lake Formations on James Ross Island also off the Antarctic Peninsula; and the Eumeralla and Wonthaggi Formations in Australia.

<span class="mw-page-title-main">Monimiaceae</span> Family of flowering plants

The Monimiaceae is a family of flowering plants in the magnoliid order Laurales. It is closely related to the families Hernandiaceae and Lauraceae. It consists of shrubs, small trees, and a few lianas of the tropics and subtropics, mostly in the southern hemisphere. The largest center of diversity is New Guinea, with about 75 species. Lesser centres of diversity are Madagascar, Australia, and the neotropics. Africa has one species, Xymalos monospora, as does Southern Chile. Several species are distributed through Malesia and the southwest Pacific.

<span class="mw-page-title-main">Biodiversity of New Caledonia</span> Variety of life in the New Caledonia archipelago and its seas

The biodiversity of New Caledonia is of exceptional biological and paleoecological interest. It is frequently referred to as a biodiversity hotspot. The country is a large South Pacific archipelago with a total land area of more than 18,000 square kilometres (6,900 sq mi). The terrain includes a variety of reefs, atolls, small islands, and a variety of topographical and edaphic regions on the largest island, all of which promote the development of unusually concentrated biodiversity. The region's climate is oceanic and tropical.

<i>Glossopteris</i> Genus of extinct seed ferns

Glossopteris is the largest and best-known genus of the extinct Permian order of seed plants known as Glossopteridales. The name Glossopteris refers only to leaves, within the framework of form genera used in paleobotany.

<span class="mw-page-title-main">New Caledonia rain forests</span>

The New Caledonia rain forests are a terrestrial ecoregion, located in New Caledonia in the South Pacific. It is a tropical moist broadleaf forest ecoregion, part of the Australasian realm.

The natural history of Australia has been shaped by the geological evolution of the Australian continent from Gondwana and the changes in global climate over geological time. The building of the Australian continent and its association with other land masses, as well as climate changes over geological time, have created the unique flora and fauna present in Australia today.

<span class="mw-page-title-main">Antarctic Floristic Kingdom</span> Geographic area with a relatively uniform composition of plant species in the Antarctic

The Antarctic Floristic Kingdom, also the Holantarctic Kingdom, is a floristic kingdom that includes most areas of the world south of 40°S latitude. It was first identified by botanist Ronald Good, and later by Armen Takhtajan. The Antarctic Floristic Kingdom is a classification in phytogeography, different from the Antarctic realm classification in biogeography, and from Antarctic flora genera/species classifications in botany.

<span class="mw-page-title-main">Paleotropical Kingdom</span> One of the Earths six floristic kingdoms

The Paleotropical Kingdom (Paleotropis) is a floristic kingdom composed of the tropical areas of Africa, Asia and Oceania, as proposed by Ronald Good and Armen Takhtajan. Part of its flora is inherited from the ancient supercontinent of Gondwana or exchanged later. These Gondwanan lineages are related to those in the Neotropical Kingdom, composed of the tropical areas of Central and South America. Flora from the Paleotropical Kingdom influenced the tropical flora of the Australian Kingdom. The kingdom is subdivided into five floristic subkingdoms according to Takhtajan and about 13 floristic regions. In this article the floristic subkingdoms and regions are given as delineated by Takhtajan.

The natural history of New Zealand began when the landmass Zealandia broke away from the supercontinent Gondwana in the Cretaceous period. Before this time, Zealandia shared its past with Australia and Antarctica. Since this separation, the New Zealand landscape has evolved in physical isolation, although much of its current biota has more recent connections with species on other landmasses. The exclusively natural history of the country ended in about 1300 AD, when humans first settled, and the country's environmental history began. The period from 1300 AD to today coincides with the extinction of many of New Zealand's unique species that had evolved there.

<span class="mw-page-title-main">Flora of Australia</span> Plant species of Australia

The flora of Australia comprises a vast assemblage of plant species estimated to over 21,000 vascular and 14,000 non-vascular plants, 250,000 species of fungi and over 3,000 lichens. The flora has strong affinities with the flora of Gondwana, and below the family level has a highly endemic angiosperm flora whose diversity was shaped by the effects of continental drift and climate change since the Cretaceous. Prominent features of the Australian flora are adaptations to aridity and fire which include scleromorphy and serotiny. These adaptations are common in species from the large and well-known families Proteaceae (Banksia), Myrtaceae, and Fabaceae.

<span class="mw-page-title-main">Gondwana</span> Neoproterozoic to Cretaceous landmass

Gondwana was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the Indian Subcontinent.

<i>Richea pandanifolia</i> Species of tree

Richea pandanifolia, the pandani or giant grass tree, is a distinctive endemic Tasmanian angiosperm. It is dicot of the family Ericaceae and is found in central, western and south west Tasmania. It is a favourite among hikers and nature lovers.

<span class="mw-page-title-main">Ecology of Tasmania</span>

The biodiversity of Tasmania is of exceptional biological and paleoecological interest. A state of Australia, it is a large South Pacific archipelago of one large main island and a range of smaller islands. The terrain includes a variety of reefs, atolls, many small islands, and a variety of topographical and edaphic regions on the largest island, all of which promote the development of unusually concentrated biodiversity. During long periods geographically and genetically isolated, it is known for its unique flora and fauna. The region's climate is oceanic.

<i>Trinisaura</i> Extinct genus of dinosaurs

Trinisaura is a genus of ornithopod dinosaur that lived during the late Campanian stage of the Upper Cretaceous, around 73 to 72 million years ago in what is now James Ross Island off the coast of northern Antarctica near Patagonia. It is known from a single, incomplete postcranial skeleton that includes several vertebrae, a partial pelvis, and nearly complete right hindlimb. The fossils were collected in 2008 by paleontologists Juan Moly and Rodolfo Coria from the sandstone of the Snow Hill Island Formation. It remained undescribed in the collections of the Museo de La Plata until its description by Coria and colleagues in 2013, being the basis of the novel genus and species Trinisaura santamartaensis. The genus name is to commemorate the efforts of Argentine geologist Trinidad "Trini" Diaz and the Latin root -sauros, meaning "lizard". The species name is after Santa Marta Cove, where the fossils were collected.

References

Works cited

Further reading