Flora of the Antarctic

Lichens such as these beard lichen make up the majority of Antarctica's vegetation. Click to enlarge
Lichens such as these beard lichen make up the majority of Antarctica's vegetation.
Source: Cornelius Braun/UBA

It is hard to believe but plants do in fact grow in the Antarctic! A few species have adapted to the austere conditions and have colonised areas which are ice-free. However, these highly specialised plants are threatened when foreign subpolar species are introduced or human activities cause other types of damage.

What grows in the perpetual ice?

There are few favourable conditions in the Antarctic which promote vegetation in light of thick ice cover, little light, dry and very saline soil, and extremely short vegetation periods. A few plants have nevertheless found a way to adapt to these extreme conditions: terrestrial plant growth is limited in ice-free areas, and the diversity of species is low. The only two species of flowering plants in the Antarctic, Antarctic hair grass (Deschampsia antarctica) and Antarctic pearlwort (Colobanthus crassifolius), a small umbelliferous plant, are present mainly on the Antarctic Peninsula.

Predominantly flowerless organisms

Non-flowering plants like mosses and algae and additionally lichen and fungi comprise most of the vegetation in the Antarctic,of which there are more than a thousand known species. These species and their biocoenoses are adapted exceptionally well to the exceptional living conditions of cold temperatures, little light and few nutrients. Lichens – composite organisms which are an association of algae and cyanobacteria (symbiosis) – are the singlemost widespread plant group (more than 750 species in Antarctica). Rock is their preferred substrate: rocky surfaces, debris or boulders. Lichen have adapted very well to conditions in the Antarctic, and some species can even photosynthesise at temperatures below -10°C. The most favourable locations for lichen are in the marine West Antarctic with its adequate humidity.

Highly adapted and highly sensitive

Plants grow and spread at an extraordinarily slow rate because of the climate conditions. They rest for most of the year. Growth phases are short, and many plants live for hundreds of years. The diameter of many lichen increases by only 10 to 16 millimetres in one hundred years. Footprints made on moss can still be visible decades later. It is this sensitivity that makes it important to protect the Antarctic ecosystem, because even the slightest interference can lead to lasting and irreversible damage to nature.

Another grave problem is the introduction of non-native species by man. Plant seeds in the clothing and equipment of travellers to the Antarctic may come from further away than any subpolar region: in some cases they travel from the Arctic all the way to the other end of the world. Cruise trips in particular, that visit several points onshore in the Antarctic, multiply the risk of further increasing the spread of species which have already been introduced.