**1. Introduction**

The South Shetland Archipelago is located in the northern part of Antarctic Peninsula and is formed by 10 large islands (some reaching 100 km of lenght) and many smaller ones. The Maritime Antarctica, especially near the Antarctic Peninsula, have recorded the most significant temperature increases in the entire Southern Hemisphere, with 0.34° C per decade in the South Shetland Islands and between 1 and 1.4° C per decade (recorded since 1980) at the Rothera research station on the Antarctic Peninsula [1]. Data indicate that the marine water around the Antarctic Peninsula is up to 3° C warmer on average, contributing up to 50% of the ice melting already recorded [2].

The Antarctic Peninsula region had one of the most intense climatic warming trends over the last decades (increase of 0.56° C/decade in air temperature and 3°C in surface temperature since 1950) [3–5]. A statistically significant (at 3%) increasing trend in temperature was observed during the years 1944–1996, when the temperature increased by 1.6° C by analyzing the temperature in King George and in Deception Islands, from the South Shetland Archipelago. But in regions as the Admiralty Bay in King George Island the mean temperature was higher than 0.7° C, and the Wanda Glacier located there is retreating fast, having lost already 31% of its volume (compared to 1979) attributed to the regional warming [6].

The use of modeling proved that the ice river of the Thwaites Glacier that drains into the Amundsen Sea, in Western Antarctica, is already destabilized. The melting of these glaciers will raise the sea 1.2 meters on the planet, but the process will be very slow, probably hundreds of years [7].

Radar data proved that Pine Island Glacier retreated 31 km between 1992 and 2011, but has now reduced this speed. Until 2009 nothing was recorded about this retreat, when the melting and destabilization of glaciers suddenly began. The Larsen Glacier was one of the first to indicate a retreat (having persisted for 10,000 years), started to fall apart in 2002, collapsing in a period of 35 days and it is expected to disappear in 18 years [2].

In a reconstruction of changes in ice since the last glacial maximum, having studied at least 674 glacier data across the Antarctic Peninsula, it has been demonstrated as an environmental factor (the increase in the temperature of seawater rather than the atmosphere), was directly related to the retreat of glaciers [8]. The north–south gradient of increased retreat in the glaciers has a high correlation with ocean temperatures, since the water is cold in the Northwest and becomes progressively warmer at depths below 100 meters to the south. These waters of medium depth in the southernmost regions have been warming up since the 1990s, at the same time that the acceleration in the retreat of the glaciers began. And these waters are reaching lower and lower depths and affecting the emerged parts, as they heat up the platform. Almost all of the glaciers studied have declined since 1940.

The eastern region of the Antarctic continent, on the other hand, is slightly different from the region of the peninsula, since it is on dry land and has very thick ice. But because it is a more remote region, few scientists venture into the area and little data has been collected. However, data recently gathered from satellites and airplanes show another scenario. The Totten Glacier, for example, seems to be one of the most vulnerable, with the radar showing that there is a channel in the depths of it, which allows the entry of hot sea water that melts the ice and explains the loss of mass. This glacier can contribute to an increase of up to 3.5 meters in sea level [9].

Plant species on this continent are restricted to ice-free areas (except for microscopic algae that can grow directly on the ice) and are formations very threatened by climate change, as they do not support temperature changes very well. At the same time, plant communities are advancing in areas recently exposed by the retreat of ice and more favorable temperatures, resulting in the so-called "Antarctic greening". Analyzing five cores at three sites over 150 years, revealed increased biological activity over the past ca. 50 years, in response to climate change, suggesting that terrestrial ecosystems will alter rapidly under future warming, resulting in a greening similar to that registered to the Arctic [10].

It is important to note that a considerable carbon reservoir exists in cryobiont algae, which form extensive colonies directly on the ice. With the increase in temperature, it is expected that 62% of the blooms of small islands (like in the South Shetland archipelago) of low altitude will disappear [11].

There are at least 3 ways in which organisms can adapt to changes in the environment: 1- they can use the margins of physiological flexibility and then support changes. 2- can change the range of biological capacity which is highly dependent on the magnitude and rate of change. This ability is linked to the organism's reproductive capacity, but mutation rates, number of reproductive events and generation time are also linked. 3- they can migrate to have more favorable conditions. For Antarctic plants, the problems to be faced are greater to adapt, as they do not have an efficient disperser except the wind for lichen and moss spores, and must compensate locally for the differences to survive. And perhaps one of the big problems is getting nutrients. These are brought to the continent basically by animals, from their diet consisting of marine organisms [12]. A schematic of the flow of nutrients to the terrestrial environment can be seen in **Figure 1**.

Penguins are climate indicators and changes in their populations have been described over the past 50 years, mainly associated with changes in ice dynamics [13, 14]. *Pygoscelis adeliae* (Adélie penguin) is the most dependent on ice and the most

**65**

**Figure 1.**

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

widely distributed species, occurring throughout the continent, as it is circumpolar. *P. antarctica* (the Antarctic Penguin) is found almost exclusively in the Antarctic Peninsula [15] and *P. papua* (the Papua Penguin) occurs in both the Antarctic peninsula and sub-Antarctic islands. The latter species has been showing its Antarctic populations expanding rapidly in the last 50 years, which is being associated with the increase in temperature in the region. Changes in ice dynamics have allowed the species to move further south, while *P. adeliae* and *P. antarctica* had a decrease in their populations mainly because availability of Krill, its main food. Adélie penguin populations are decreasing throughout the Antarctic Peninsula but they have remained stable on the east side of the continent, where the influences are still not so felt. In the past this species seems to have resisted climate change better. If it continues at this rate, it is estimated that populations can be reduced by 30% by 2060 and 60% by 2099 [16]. Fewer penguins means less availability of nutrients as they are one of the main sources of guano for the continent. Therefore, changes in plant communities that depend on this input may not happen. The melting of glaciers ends up exposing areas with rocks and sediments that will allow the installation of terrestrial vegeta-

*Schematic view of the contribution of nutrients for the terrestrial ecosystems (adapted from [12]).*

tion, but nutrients must be available specially for the nitrophilic species.

existing vegetation in an area of about 80 hectares [18–21].

**2. Plants with flower from Antarctica**

Even cryobiont algae are found in ice, because it receives a spray of nutrients from penguins existing at least 5 km away [11]. The melting of the ice allows the melting water flows to carry these nutrients to the plants that grow on its banks, especially species like *Wanstorfia* spp., *Brachythecium* spp. and *Sanionia* spp. [17]. The Pinnipedia also have their contribution to the terrestrial environment, especially during periods when they are on land to rest. The deposition of feces and urine helps to nitrify the ground, but trampling can be harmful. A case described for the Signy Islands exemplifies this aspect, where the population of *Arctocephalus gazella* (fur seal) has greatly increased in recent years, completely destroying the

Antarctica has only two native plants forming flowers: *Deschampsia antarctica* Desv. (Poaceae - **Figure 2**) and *Colobanthus quitensis* Kunth. (a Caryophyllaceae - **Figure 3**). There are already records of other Angiosperms occurring in the region, but these have been introduced by man, such as *Poa annua* L., and climate change can contribute to

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

*The Vegetation of the South Shetland Islands and the Climatic Change DOI: http://dx.doi.org/10.5772/intechopen.94269*

#### **Figure 1.**

*Glaciers and the Polar Environment*

expected to disappear in 18 years [2].

Radar data proved that Pine Island Glacier retreated 31 km between 1992 and 2011, but has now reduced this speed. Until 2009 nothing was recorded about this retreat, when the melting and destabilization of glaciers suddenly began. The Larsen Glacier was one of the first to indicate a retreat (having persisted for 10,000 years), started to fall apart in 2002, collapsing in a period of 35 days and it is

In a reconstruction of changes in ice since the last glacial maximum, having studied at least 674 glacier data across the Antarctic Peninsula, it has been demonstrated as an environmental factor (the increase in the temperature of seawater rather than the atmosphere), was directly related to the retreat of glaciers [8]. The north–south gradient of increased retreat in the glaciers has a high correlation with ocean temperatures, since the water is cold in the Northwest and becomes progressively warmer at depths below 100 meters to the south. These waters of medium depth in the southernmost regions have been warming up since the 1990s, at the same time that the acceleration in the retreat of the glaciers began. And these waters are reaching lower and lower depths and affecting the emerged parts, as they heat up the platform. Almost all of the glaciers studied have declined since 1940.

The eastern region of the Antarctic continent, on the other hand, is slightly different from the region of the peninsula, since it is on dry land and has very thick ice. But because it is a more remote region, few scientists venture into the area and little data has been collected. However, data recently gathered from satellites and airplanes show another scenario. The Totten Glacier, for example, seems to be one of the most vulnerable, with the radar showing that there is a channel in the depths of it, which allows the entry of hot sea water that melts the ice and explains the loss of mass. This

Plant species on this continent are restricted to ice-free areas (except for microscopic algae that can grow directly on the ice) and are formations very threatened by climate change, as they do not support temperature changes very well. At the same time, plant communities are advancing in areas recently exposed by the retreat of ice and more favorable temperatures, resulting in the so-called "Antarctic greening". Analyzing five cores at three sites over 150 years, revealed increased biological activity over the past ca. 50 years, in response to climate change, suggesting that terrestrial ecosystems will alter rapidly under future warming, resulting in

It is important to note that a considerable carbon reservoir exists in cryobiont algae, which form extensive colonies directly on the ice. With the increase in temperature, it is expected that 62% of the blooms of small islands (like in the South

There are at least 3 ways in which organisms can adapt to changes in the environment: 1- they can use the margins of physiological flexibility and then support changes. 2- can change the range of biological capacity which is highly dependent on the magnitude and rate of change. This ability is linked to the organism's reproductive capacity, but mutation rates, number of reproductive events and generation time are also linked. 3- they can migrate to have more favorable conditions. For Antarctic plants, the problems to be faced are greater to adapt, as they do not have an efficient disperser except the wind for lichen and moss spores, and must compensate locally for the differences to survive. And perhaps one of the big problems is getting nutrients. These are brought to the continent basically by animals, from their diet consisting of marine organisms [12]. A schematic of the flow of nutrients

Penguins are climate indicators and changes in their populations have been described over the past 50 years, mainly associated with changes in ice dynamics [13, 14]. *Pygoscelis adeliae* (Adélie penguin) is the most dependent on ice and the most

glacier can contribute to an increase of up to 3.5 meters in sea level [9].

a greening similar to that registered to the Arctic [10].

Shetland archipelago) of low altitude will disappear [11].

to the terrestrial environment can be seen in **Figure 1**.

**64**

*Schematic view of the contribution of nutrients for the terrestrial ecosystems (adapted from [12]).*

widely distributed species, occurring throughout the continent, as it is circumpolar. *P. antarctica* (the Antarctic Penguin) is found almost exclusively in the Antarctic Peninsula [15] and *P. papua* (the Papua Penguin) occurs in both the Antarctic peninsula and sub-Antarctic islands. The latter species has been showing its Antarctic populations expanding rapidly in the last 50 years, which is being associated with the increase in temperature in the region. Changes in ice dynamics have allowed the species to move further south, while *P. adeliae* and *P. antarctica* had a decrease in their populations mainly because availability of Krill, its main food. Adélie penguin populations are decreasing throughout the Antarctic Peninsula but they have remained stable on the east side of the continent, where the influences are still not so felt. In the past this species seems to have resisted climate change better. If it continues at this rate, it is estimated that populations can be reduced by 30% by 2060 and 60% by 2099 [16].

Fewer penguins means less availability of nutrients as they are one of the main sources of guano for the continent. Therefore, changes in plant communities that depend on this input may not happen. The melting of glaciers ends up exposing areas with rocks and sediments that will allow the installation of terrestrial vegetation, but nutrients must be available specially for the nitrophilic species.

Even cryobiont algae are found in ice, because it receives a spray of nutrients from penguins existing at least 5 km away [11]. The melting of the ice allows the melting water flows to carry these nutrients to the plants that grow on its banks, especially species like *Wanstorfia* spp., *Brachythecium* spp. and *Sanionia* spp. [17].

The Pinnipedia also have their contribution to the terrestrial environment, especially during periods when they are on land to rest. The deposition of feces and urine helps to nitrify the ground, but trampling can be harmful. A case described for the Signy Islands exemplifies this aspect, where the population of *Arctocephalus gazella* (fur seal) has greatly increased in recent years, completely destroying the existing vegetation in an area of about 80 hectares [18–21].

## **2. Plants with flower from Antarctica**

Antarctica has only two native plants forming flowers: *Deschampsia antarctica* Desv. (Poaceae - **Figure 2**) and *Colobanthus quitensis* Kunth. (a Caryophyllaceae - **Figure 3**). There are already records of other Angiosperms occurring in the region, but these have been introduced by man, such as *Poa annua* L., and climate change can contribute to

**Figure 2.** Deschampsia antarctica*, the Antarctic grass. Scale = 20 cm.*

#### **Figure 3.**

Colobanthus quitensis *among mosses and rock fragments.*

the occurrence of more plants in the region [22]. These two plants compete for space with all other species, but because they are larger and more complex, they need a large availability of nutrients and water. Therefore, they are usually found close to sources of nitrogen, such as in the vicinity of penguin rockeries or nests of other birds. Both have a chemical arsenal to survive the conditions of the Antarctic cold, especially a reasonable concentration of sugars in their cells: there is at least ten times more sugar in vacuoles

**67**

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

of sugar is a protection against very cold periods in Antarctica [23].

than in sugarcane, foreseeing a potential use of this source in future. This accumulation

to mention their occurrence in almost all the South Shetland Islands and areas of the Antarctic Peninsula free of ice. They can occur as small isolated tufts of a maximum of 15 cm, or forming fields of a few meters, but almost always associated with different Bryophyta and Marchantiophyta. Carpets even seem to stimulate

Regarding the distribution of these phanerogams in the study area, it is possible

There are studies reporting the photoprotective effect of *Deschampsia antarctica* and *Colobanthus quitensis* extracts against UVB. The photoprotective properties have been attributed to several molecules, such as flavonoids and carotenoids,

It is possible that changes in temperature may interfere with the growth and development of populations of these species as has been shown experimentally [27, 28]. In the Argentine Islands, an increase of 25 times for *D. antarctica* and 5 times for *C. quitensis* was recorded in 30 years of observation [29]. Data collected in 2009 and historical data since the 1960s on the distribution of the two Antarctic vascular plants on Signy Island revealed that *D. antarctica* increased its coverage by 191% and the number of occurrence sites by 104%. *C. quitensis* increased its coverage by 208% and the number of occurrence sites by 35%. All due to the increase of 1.2° C in the air temperature and all the changes that this caused in the region [30]. Studying the formations of these phanerogams in the Fildes and Coppermine Peninsulas, in addition to locations in the Antarctic Peninsula in order to assess their responses to the increase in local temperatures, it was discovered that the populations of *D. antarctica* are expanding in the South Shetland Islands, but this expansion is not continuous in the Antarctic Peninsula, as the plants disappeared at 3 points, suggesting that there are other biotic and abiotic factors involved [31]. The fauna and flora associated with these plants is also very rich. There are bacteria, fungi and microscopic animals, many with a symbiotic or survival relationship with these plants. A high mortality of terrestrial microbial communities was detected along the South Shetland Islands. These communities are said to be dying from physiological problems and lack of nitrogen, in addition to changes in their microstructure, which seems to be associated with the rupture of the biogeochemical gradient of the microbial ecosystem. Caused by a strange but high abundance (explosion) of the associated fungi and the physical changes caused by them. All of these changes are related to the high temperatures recorded in the region. Some new diseases have been registered, especially for Antarctic grass, indicating that something is making possible the occurrence of these phytopathologies, but more studies are needed [32, 33]. There are also birds, of which at least the skuas (*Catharacta* spp.) and the gulls (*Larus dominicanus*) use these plants more frequently to make their nests. In a survey, scientists identified the seagull's preference for *Deschampsia antarctica* at Cierva Point in the Antarctic Peninsula [34]. More or less availability of this raw material

These plants can be found in reproduction, but in general they are sterile. But higher average temperatures can contribute to increasing seed maturation, germination and seedling survival, although this has not yet been proven experimentally [35, 36].

Among the species that most stand out on more consolidated areas and even on Antarctic rocks, are mosses. The group that represents the bryophytes also has some liverworts occurring, but in this text, all will be commonly called mosses. There are, therefore, Marchantiophyta, popularly called hepatics, and the representatives of the genus

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

grass development, but not its survival [24].

can affect the reproduction of these birds.

**3. Mosses and hepatics**

which absorb UV and act as antioxidants [25, 26].

#### *The Vegetation of the South Shetland Islands and the Climatic Change DOI: http://dx.doi.org/10.5772/intechopen.94269*

*Glaciers and the Polar Environment*

**66**

**Figure 3.**

**Figure 2.**

Colobanthus quitensis *among mosses and rock fragments.*

Deschampsia antarctica*, the Antarctic grass. Scale = 20 cm.*

the occurrence of more plants in the region [22]. These two plants compete for space with all other species, but because they are larger and more complex, they need a large availability of nutrients and water. Therefore, they are usually found close to sources of nitrogen, such as in the vicinity of penguin rockeries or nests of other birds. Both have a chemical arsenal to survive the conditions of the Antarctic cold, especially a reasonable concentration of sugars in their cells: there is at least ten times more sugar in vacuoles

than in sugarcane, foreseeing a potential use of this source in future. This accumulation of sugar is a protection against very cold periods in Antarctica [23].

Regarding the distribution of these phanerogams in the study area, it is possible to mention their occurrence in almost all the South Shetland Islands and areas of the Antarctic Peninsula free of ice. They can occur as small isolated tufts of a maximum of 15 cm, or forming fields of a few meters, but almost always associated with different Bryophyta and Marchantiophyta. Carpets even seem to stimulate grass development, but not its survival [24].

There are studies reporting the photoprotective effect of *Deschampsia antarctica* and *Colobanthus quitensis* extracts against UVB. The photoprotective properties have been attributed to several molecules, such as flavonoids and carotenoids, which absorb UV and act as antioxidants [25, 26].

It is possible that changes in temperature may interfere with the growth and development of populations of these species as has been shown experimentally [27, 28]. In the Argentine Islands, an increase of 25 times for *D. antarctica* and 5 times for *C. quitensis* was recorded in 30 years of observation [29]. Data collected in 2009 and historical data since the 1960s on the distribution of the two Antarctic vascular plants on Signy Island revealed that *D. antarctica* increased its coverage by 191% and the number of occurrence sites by 104%. *C. quitensis* increased its coverage by 208% and the number of occurrence sites by 35%. All due to the increase of 1.2° C in the air temperature and all the changes that this caused in the region [30].

Studying the formations of these phanerogams in the Fildes and Coppermine Peninsulas, in addition to locations in the Antarctic Peninsula in order to assess their responses to the increase in local temperatures, it was discovered that the populations of *D. antarctica* are expanding in the South Shetland Islands, but this expansion is not continuous in the Antarctic Peninsula, as the plants disappeared at 3 points, suggesting that there are other biotic and abiotic factors involved [31].

The fauna and flora associated with these plants is also very rich. There are bacteria, fungi and microscopic animals, many with a symbiotic or survival relationship with these plants. A high mortality of terrestrial microbial communities was detected along the South Shetland Islands. These communities are said to be dying from physiological problems and lack of nitrogen, in addition to changes in their microstructure, which seems to be associated with the rupture of the biogeochemical gradient of the microbial ecosystem. Caused by a strange but high abundance (explosion) of the associated fungi and the physical changes caused by them. All of these changes are related to the high temperatures recorded in the region. Some new diseases have been registered, especially for Antarctic grass, indicating that something is making possible the occurrence of these phytopathologies, but more studies are needed [32, 33].

There are also birds, of which at least the skuas (*Catharacta* spp.) and the gulls (*Larus dominicanus*) use these plants more frequently to make their nests. In a survey, scientists identified the seagull's preference for *Deschampsia antarctica* at Cierva Point in the Antarctic Peninsula [34]. More or less availability of this raw material can affect the reproduction of these birds.

These plants can be found in reproduction, but in general they are sterile. But higher average temperatures can contribute to increasing seed maturation, germination and seedling survival, although this has not yet been proven experimentally [35, 36].
