**8. The Antarctic ice-free areas and their potential for the evaluation of climatic changes**

Antarctica, despite having the largest number of superlatives, as it is considered the coldest (−89.2° C), the driest (average annual precipitation not exceeding 100 mm), the highest (average height 2300 m), the windiest (wind speed can reach 327 Km/h), is the most unknown and the most preserved continent. However, it is isolated from the rest of the world due to its geography and ocean currents. From this isolation the populations are very different, facilitating the study of biological models, whose data can help in the explanation of global biological problems. Global climate change has been a feature in polar regions and continues to be. When discussing climate change on Earth, references are always made to glaciations and ice records [66].

The environmental superlatives of Antarctica, which determine extreme abiotic conditions for the biota, led to the evolution of fragile and unique communities, which are mainly characterized have high specialization and adaptation to environmental conditions, in addition to being very sensitive to environmental impacts of anthropic origin or caused by natural phenomena.

The climatic phenomena that occur in Antarctica are the basis for describing the climate of the Southern Hemisphere, and what happens in many countries is in part also a reflection of the phenomena that occur in the South Pole. In Antarctica the so-called "fronts" are frequent, numerous and of constant formation, these are mostly ephemeral, but many reach the southern areas of South America. In addition, the Antarctic ice is considered as a climatic archive. Air bubbles found in glacial ice can identify the composition of air from past eras. Snow samples can currently demonstrate the types of gases and particles that existed in atmospheric air many years ago. This means that through isotopes, it is possible to evaluate the activity of the sun in several eras, in addition to the biological activity, obtained by the analysis of molecules of organic origin [66].

Pollution was believed to be almost exclusively a product of the Industrial Age, but ice samples demonstrated lead pollution, dating from the Roman Empire period. The snow when deposited carries with it the characteristics of the chemical composition of the atmosphere at the moment it was formed, deposited on the continent's surface air bubbles, salts, dust, volcanic ash, pollutants, among others. As snow does not melt on glaciers, the layers are deposited and compacted, keeping the record of climatic phenomena that occur over time preserved.

One of the global changes that can affect the Antarctic ecosystems is the so-called "hole in the Ozone layer", which is located at the south pole, because

**79**

*The Vegetation of the South Shetland Islands and the Climatic Change*

easily detected due to the simplicity of polar ecosystems [25].

changes consequences can be justified by facts such as:

and 22 species of liverworts [18].

*Colobanthus quitensis* [45].

such environmental conditions.

it brings together the coldest regions of the planet and for having a very localized circulation of air masses. This despite being on Antarctica also reaches the southern tip of South America. This phenomenon contributes to the increase in ultraviolet radiation (UV-B), which, because it is mutagenic, contributes to the genetic alteration of species. Since this radiation is very intense in Antarctica, great mutation rates are expected, but it was observed that this does not occur, since these species have mechanisms that prevent DNA damage by the formation of secondary metabolites, at least in plants, whose photoprotector effects were

The retreat of the glaciers and the reduction of snow fields expand and the consequent exposure of new habitats for colonization, and the increase in the populations of plants, has been documented. Small changes in the physiology of the Antarctic organisms can affect their life histories, with indirect effects on the dynamics of the ecosystem and trophic chains. These subtle effects can be more

The use of plant communities in Antarctic ice-free areas to assess climatic

1.These have a small number of species when compared to periglacial and subtropical regions, since among the species mentioned and described so far there are: two species of Magnoliophyta, *Deschampsia antarctica* Desv. (Poaceae) and *Colobanthus quitensis* (Kunth.) Bart. (Caryophyllaceae), approximately 360 species of lichens [55]. Bryophytes comprise approximately 113 species of moss

2.As biodiversity is small, populations are very numerous, facilitating their delimitation and the identification of interspecific relationships.

3.The presence of soil is an important factor, since there are species of mosses such as, for example, *Sanionia uncinata* (Hedw.) Loeske and *Chorisodontium aciplhyllum* (Hook. F et Wils.) Broth. that grow in areas where rock fragments occur, as the soil is formed these populations are replaced by other moss species such as, for example, *Polytrichum juniperinum* Hedw. and *Polytrichastrum alpinum* (Hedw.) G.L.Smith, often associated with *Deschampsia antarctica* and

4.Most of the species that grow in these areas, evolved under extreme environmental conditions and under intense stress, making them very well adapted to

5.Antarctica is still a continent with an insignificant anthropic impact, so the changes that occur in communities are the result of environmental changes arising from natural phenomena. This fact is important, since environmental variables that are selected can be evaluated based on natural phenomena.

6.The importance of studying plant species that grow in ice-free areas in Antarctica are strongly related to the environment, so it constitutes a potential source for assessing global changes. It is expected that climate change will have a major impact on Antarctic land biota. Studies suggest that the increase in temperature and greater availability of water can extend periods favorable to growth, increase the rates of development and reduce the duration of the life

cycle, which can alter the distribution of species [5].

*DOI: http://dx.doi.org/10.5772/intechopen.94269*

experimentally proven [25, 26].
