*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*

*Marchantia* are those that present the largest gametophyte (**Figure 4**), although small species of other genera sometimes take very large areas. Large populations have been found recently, such as the rare *Hygrolembidium isophyllum* in Harmony Point - Nelson

**68**

**Figure 4.**

*Two Marchantiophyta, the thallose* Marchantia berteroana *(above) and the leafy* Cephalozia *sp. (below).*

Island [37]. *Marchantia* is thallose, reproducing basically by direct fragmentation of the thallus or by specialized structures, the propagules, formed in receptacles such as in the figure (called conceptacles). But the group most represented in species in the area are the leafy liverworts (about 22 species). They even have a relationship with other organisms, as in the case of *Cephaloziella varians*, which is associated with a mycorrhizal fungus *Rhizoscyphus ericae* (ericoid symbiosis) throughout Antarctica [38–40].

Many species of liverworts are associated with dominant species in the plant community, and this reflects an interdependence. If the dominant species are threatened, by climate change, for example, their dependents will also be [41].

Bryophyta, or mosses themselves, have so far collected 113 species, within 55 genera and 17 families [18, 42]. The mosses present two main forms of growth: the pleurocarpic, where the moss stalk is prostrate, forming continuous carpets and in general covering more extensive areas if they are available (**Figures 5** and **6**);

**Figure 5.** *A moss carpet moved by wind being fixed by a scientist.*

**Figure 6.**

*Two large carpet of* Sanionia uncinata *associated to* Warnstorfia sarmentosa *in the wettest areas.*

and the acrocarpic form, where the mosses grow upright, forming tufts or smaller cushions (**Figures 7**–**11**). The moss species with the highest occurrence and highest biomass in all ice-free spots is the pleurocarpic *Sanionia uncinata*, a carpet former with curved leaves, twisted like a scythe [18].

Antarctic moss fields can be very old and even deeper layers of growth can be alive even though they have been buried for over a thousand years by acrocarpic development. In 2014 research showed that the moss *Chorisodontium acyphyllum* remained alive after remaining frozen for more than 1500 years. A 1.4-meter-thick tuft was

#### **Figure 7.**

*Tufts of the moss* Syntrichia *sp. (red circles) growing among whale bones and a carpet of* Sanionia uncinata.

**71**

**Figure 10.**

**Figure 11.**

uncinata *(pleurocarpic).*

**Figure 9.**

Hennediella heimii *with sporophyte.*

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

Bartramia patens, *with sporophyte (left) and* Bryum palescens *(right).*

sectioned every 20 cm (layer by layer) and placed to germinate under ideal conditions. In up to 8 weeks everyone started growing. The deepest layer was dated by radiocarbon and estimated between 1533 and 1697 years [43]. Acrocarpic and pleurocarpic mosses buried under more than 600 years by a glacier were re-exposed by the retreat of the ice and parts of the moss were able to activate again and grow normally "in vitro" [44].

*Chorisodontium acyphyllum, dull green and acrocarpic surrounded by a light green carpet of* Sanionia

The most available substrate in Antarctica is rock, but there are species that grow in soil. *Andreaea*, with four acrocarpic species occurring in Antarctica, for example,

is exclusively saxicolous (name given to species that grow on rocks) [18].

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

**Figure 8.** Polytrichastrum alpinum*, one of the tallest moss (left) and* Pohlia cruda *(right).*

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

#### **Figure 9.**

*Glaciers and the Polar Environment*

with curved leaves, twisted like a scythe [18].

and the acrocarpic form, where the mosses grow upright, forming tufts or smaller cushions (**Figures 7**–**11**). The moss species with the highest occurrence and highest biomass in all ice-free spots is the pleurocarpic *Sanionia uncinata*, a carpet former

Antarctic moss fields can be very old and even deeper layers of growth can be alive even though they have been buried for over a thousand years by acrocarpic development. In 2014 research showed that the moss *Chorisodontium acyphyllum* remained alive after remaining frozen for more than 1500 years. A 1.4-meter-thick tuft was

*Tufts of the moss* Syntrichia *sp. (red circles) growing among whale bones and a carpet of* Sanionia uncinata.

Polytrichastrum alpinum*, one of the tallest moss (left) and* Pohlia cruda *(right).*

**70**

**Figure 8.**

**Figure 7.**

Bartramia patens, *with sporophyte (left) and* Bryum palescens *(right).*

#### **Figure 10.** Hennediella heimii *with sporophyte.*

#### **Figure 11.**

*Chorisodontium acyphyllum, dull green and acrocarpic surrounded by a light green carpet of* Sanionia uncinata *(pleurocarpic).*

sectioned every 20 cm (layer by layer) and placed to germinate under ideal conditions. In up to 8 weeks everyone started growing. The deepest layer was dated by radiocarbon and estimated between 1533 and 1697 years [43]. Acrocarpic and pleurocarpic mosses buried under more than 600 years by a glacier were re-exposed by the retreat of the ice and parts of the moss were able to activate again and grow normally "in vitro" [44].

The most available substrate in Antarctica is rock, but there are species that grow in soil. *Andreaea*, with four acrocarpic species occurring in Antarctica, for example, is exclusively saxicolous (name given to species that grow on rocks) [18].

Mosses are capable to colonize areas such as those closest to the sea and even receiving splashes of salt water waves, to the interior of the continent and including areas of recent exposition by ice retreat. The species *Muelleriella crassifolia* P. Dusén requires at least some contact with marine spray to develop, which is achieved in some coastal rocks. Eventually it can be found with other groups that have species with this preference, called halophytes, such as some of the lichens of the genus *Verrucaria* [45, 46]. The alterations in sea level will affect directly this community.

The rise in temperature in Antarctic regions has been accelerating the growth of mosses in particular since the late half of the 20th century. A study of 5000 years old population of *Polytrichum strictum* (in Lazarev Bay, on Alexander Island), dated by radiocarbon millimeter by millimeter, demonstrated that the population accumulated around 1.25 mm/year in the 19th and early 20th century and then increased its growth from 1955 until reaching 5 mm per year until the end of 1970, currently reducing growth to 3,5 mm/year. The authors also found that the associated amoeba population also increased considerably over the same period [47].

Studying a 1500 km gradient from Antarctic Maritime to the south of the Antarctic Peninsula (in the region of Lazarev Bay, Alexander Island) the accumulation in the banks of moss began to increase around the 1950's, reaching peaks in the Lazarev Bay in the 1970's (about 0.1 g of dry matter/cm<sup>2</sup> /year) and Signy Island in the 1990s (0.06 g/DM cm<sup>2</sup> /year); the most recent measurements indicate around 0.04 g of dry matter/cm<sup>2</sup> . In continental Antarctica the growth of mosses is inversely proportional to the speed of the summer wind and proportional to the number of days above 0° C and the temperature of the summer [48].

Data collected in the Windmill Islands show evidence that the endemic moss *Schistidium antarctici* is likely to be more susceptible to climate change than the co-occurring and cosmopolitan species such as *Ceratodon purpureus* and *Bryum pseudotriquetrum.* And this in particular due to the habitat requirements, much more associated with water in the endemic species [49]. The rapid permanent icemelting in areas like the South Shetland can result in dryer areas and reduction of plant communities.

Antarctica was the last continent discovered and in the first botanical studies the samples revealed one main taxonomical difficulty: no fertile mosses were found. Among the Antarctic mosses only 22 are found commonly fertile [18] despite some of these species are relatively rare. Reproduction by spores is only possible with water in liquid form, since the antherozoid needs to swim to the correspondent archegonia, fertilize it to form sporophyte and then finely the spores are formed inside a capsule. Since Antarctica is known to have water mostly if form of ice and snow, and being called the biggest desert in the world, it is somewhat difficult and sometimes impossible in some areas to achieve fertilization.

There is a huge difference in precipitation from Dry Valleys at 77,8° S (50 mm) to Livingston Island at 62.6° S (80 mm) [50]. An increase in precipitation was found at Faraday Station, according to data collected from 1956 to 1992 in the Antarctic Peninsula. This increase is connected with the diminishing sea ice and the intensification of evaporation, a higher humidity of the air and more dynamic cyclonic activity, especially in the winter season [51]. All these aspects can affect directly Antarctic plants, contributing also to mosses achieve fertilization.

In tropical and temperate areas ca. 75 ± 90% of the mosses are found fertile. In the maritime Antarctic the value reduces to approximately 25 ± 33% and in

**73**

**Table 1.**

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

continental Antarctica to only 10%. In Margerite Bay fertility of 43% was found (19 species: 17 mosses, 2 liverworts) and in Alexander Island 47% (17 species; 16 mosses, 1 liverwort). 51 sterile species were found among 111 known from

It is interesting that mostly saxicolous mosses are found fertile (**Table 1**), and this is probably because the rock surface is hottest than the environment, melting the snow deposited and resulting in liquid water available more frequently than on other surfaces. As the species usually grow on cracks, the water is piped over

There is also some preference for the availability of nutrients, especially the presence or proximity to nesting points or with the presence of birds or mammals. These species are called ornithocoprophylous or nitrophilous and often growing on slopes bathed in the excrement of the animals that occur above. Species such as *Synchitria magellanica* and *Henediella heimii* (**Figure 10**), among others, have this preference. With the reduction of penguin populations, already mentioned above,

Another group is represented by species that do not support high levels of nitrogen and therefore occur away from places where birds or mammals occur. They are called ornithocoprophobic or nitrophobic. Examples are *Pohlia cruda* and *Bartramia patens* (**Figure 9**). These classifications can be used for lichens as well

Mosses can be useful for Antarctic biodiversity, serving as food, as material for making nests or as a resting place for fauna. As food, they are used for this purpose mainly by arthropods, who are permanent residents of the South Pole, as there is no way out of there in winter. In this context, several other groups of microscopic

**SPECIES ON ROCK ON FINE SEDIMENTS FERTILITY** *Andreaea regularis* X Frequent *Andreaea gainii* X Frequent *Schistidium cupulare* X Rare *Schistidium amblyophyllum* X Frequent *Schistidium deceptionensis* X Rare *Schistidium leptoneuron* X Rare *Schistidium antarctici* X X Frequent *Schistidium hialinae* X Frequent *Schistidium urnulaceum* X Frequent *Schistidium steerei* Not truly saxicolous X Frequent *Schistidium andinum* X X Frequent *Schistidium praemorsum* X Rare *Schistidium rivulare* X X near water Frequent *Schistidium lewis-smithii* X X Rare *Hymenoloma grimmiaceum* X Frequent *Hymenoloma crispulum* X Frequent *Hymenoloma antarcticum* X Frequent

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

Antarctica (46% with sporophyte) [18, 35].

the unavailability of nutrients will affect these species.

and both mosses and lichens can grow associated in these places.

*List of saxicolous/soil growing mosses frequently found fertile in Antarctica.*

them [52].

### *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*

community.

period [47].

summer [48].

plant communities.

Mosses are capable to colonize areas such as those closest to the sea and even receiving splashes of salt water waves, to the interior of the continent and including areas of recent exposition by ice retreat. The species *Muelleriella crassifolia* P. Dusén requires at least some contact with marine spray to develop, which is achieved in some coastal rocks. Eventually it can be found with other groups that have species with this preference, called halophytes, such as some of the lichens of the genus *Verrucaria* [45, 46]. The alterations in sea level will affect directly this

The rise in temperature in Antarctic regions has been accelerating the growth of mosses in particular since the late half of the 20th century. A study of 5000 years old population of *Polytrichum strictum* (in Lazarev Bay, on Alexander Island), dated by radiocarbon millimeter by millimeter, demonstrated that the population accumulated around 1.25 mm/year in the 19th and early 20th century and then increased its growth from 1955 until reaching 5 mm per year until the end of 1970, currently reducing growth to 3,5 mm/year. The authors also found that the associated amoeba population also increased considerably over the same

Studying a 1500 km gradient from Antarctic Maritime to the south of the Antarctic Peninsula (in the region of Lazarev Bay, Alexander Island) the accumulation in the banks of moss began to increase around the 1950's, reaching

growth of mosses is inversely proportional to the speed of the summer wind and proportional to the number of days above 0° C and the temperature of the

Data collected in the Windmill Islands show evidence that the endemic moss *Schistidium antarctici* is likely to be more susceptible to climate change than the co-occurring and cosmopolitan species such as *Ceratodon purpureus* and *Bryum pseudotriquetrum.* And this in particular due to the habitat requirements, much more associated with water in the endemic species [49]. The rapid permanent icemelting in areas like the South Shetland can result in dryer areas and reduction of

Antarctica was the last continent discovered and in the first botanical studies the samples revealed one main taxonomical difficulty: no fertile mosses were found. Among the Antarctic mosses only 22 are found commonly fertile [18] despite some of these species are relatively rare. Reproduction by spores is only possible with water in liquid form, since the antherozoid needs to swim to the correspondent archegonia, fertilize it to form sporophyte and then finely the spores are formed inside a capsule. Since Antarctica is known to have water mostly if form of ice and snow, and being called the biggest desert in the world, it is somewhat difficult and

There is a huge difference in precipitation from Dry Valleys at 77,8° S (50 mm) to Livingston Island at 62.6° S (80 mm) [50]. An increase in precipitation was found at Faraday Station, according to data collected from 1956 to 1992 in the Antarctic Peninsula. This increase is connected with the diminishing sea ice and the intensification of evaporation, a higher humidity of the air and more dynamic cyclonic activity, especially in the winter season [51]. All these aspects can affect directly Antarctic plants, contributing also to mosses achieve

In tropical and temperate areas ca. 75 ± 90% of the mosses are found fertile. In the maritime Antarctic the value reduces to approximately 25 ± 33% and in

/year)

/year); the most recent measure-

. In continental Antarctica the

peaks in the Lazarev Bay in the 1970's (about 0.1 g of dry matter/cm<sup>2</sup>

and Signy Island in the 1990s (0.06 g/DM cm<sup>2</sup>

ments indicate around 0.04 g of dry matter/cm<sup>2</sup>

sometimes impossible in some areas to achieve fertilization.

**72**

fertilization.

continental Antarctica to only 10%. In Margerite Bay fertility of 43% was found (19 species: 17 mosses, 2 liverworts) and in Alexander Island 47% (17 species; 16 mosses, 1 liverwort). 51 sterile species were found among 111 known from Antarctica (46% with sporophyte) [18, 35].

It is interesting that mostly saxicolous mosses are found fertile (**Table 1**), and this is probably because the rock surface is hottest than the environment, melting the snow deposited and resulting in liquid water available more frequently than on other surfaces. As the species usually grow on cracks, the water is piped over them [52].

There is also some preference for the availability of nutrients, especially the presence or proximity to nesting points or with the presence of birds or mammals. These species are called ornithocoprophylous or nitrophilous and often growing on slopes bathed in the excrement of the animals that occur above. Species such as *Synchitria magellanica* and *Henediella heimii* (**Figure 10**), among others, have this preference. With the reduction of penguin populations, already mentioned above, the unavailability of nutrients will affect these species.

Another group is represented by species that do not support high levels of nitrogen and therefore occur away from places where birds or mammals occur. They are called ornithocoprophobic or nitrophobic. Examples are *Pohlia cruda* and *Bartramia patens* (**Figure 9**). These classifications can be used for lichens as well and both mosses and lichens can grow associated in these places.

Mosses can be useful for Antarctic biodiversity, serving as food, as material for making nests or as a resting place for fauna. As food, they are used for this purpose mainly by arthropods, who are permanent residents of the South Pole, as there is no way out of there in winter. In this context, several other groups of microscopic


#### **Table 1.**

*List of saxicolous/soil growing mosses frequently found fertile in Antarctica.*

beings are also inserted, with nematodes or even the smaller rotifers. Another important aspect is the associated microalgae communities.

There is also important associations with large animals, such as birds, which use plants to make their nests. The most used material can be moss (**Figure 12**), there may be mixtures with lichens in different proportions or even with flowering plants, but in some cases lichens (**Figure 14**) and phanerogams may predominate. There are, of course, birds that use other materials, such as rocks, in the case of giant petrels and penguins (**Figure 13**), mud with algae as is the case of *Phalacrocorax atriceps*, etc. [53].

#### **Figure 12.**

*Skua nest build using the moss* Polytrichastrum alpinum *(above) and another using* Sanionia uncinata *(below).*

**75**

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

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

**4. The lichenized fungi: lichens**

**Figure 14.**

Lichens are the most representative land group in Antarctica, despite they are not truly plants. They are formed by the symbiosis between a fungus plus an alga (most), a fungus plus a bacterium (case of *Leptogium puberulum,* as for example) or a fungus plus an alga and a bacterium (case of *Placopsis contortuplicata*). There are even lichenized mushrooms such as in *Lichenomphalia* spp. In the relationship, the photobiont provides the carbon source to the fungus, which can be polybasic alcohol (if it is green algae) or glucose (cyanobacteria). The fungus protects the algae from radiation and desiccation. The fungus still manages to reproduce in most cases through sexually formed spores or conidia (asexual), to fragments of the thallus or

To grow like a lichen, the spore needs to find the compatible algae that is rare in nature and lichenize. About 17,500 species of lichenized fungi and about 200 species of associated algae (100 green and 100 cyanobacteria) have been described. In this way, all of these fungi use algae in common and even different algae are used by the same species, in most cases even to adapt better to certain environments [55]. There are approximately between 386 to 427 species of lichens cited for Antarctica [55, 56] numbers that implies the most biodiverse group among terrestrials. In Antarctica in addition to the climate, limiting factors for lichens are the availability of substrate, which in most cases are rocks (in saxicolous species) or mosses (when species are muscicolous) and the presence of a source of nutrients, which can be originating from resting places or breeding animals, as already mentioned in the topic about mosses, above. These species are also starting competition with introduced ones which are being more and more frequent due climatic change.

In natural environments on the planet a succession is expected to occur. But these environments generally have trees. How is the succession of species in a

Perhaps one of the most ignored formation in Antarctica is that of the lichen/ moss association. Mosses colonize an environment first and, to be replaced, must be

soredia. The algae reproduction is inhibited or suppressed [54].

Larus dominicanus *(kelp gull) nest build with mosses and the lichen Usnea.*

**5. Plant species associated with lichens**

mainly cryptogamic community like in Antarctica?

*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*

beings are also inserted, with nematodes or even the smaller rotifers. Another

*Skua nest build using the moss* Polytrichastrum alpinum *(above) and another using* Sanionia uncinata

There is also important associations with large animals, such as birds, which use plants to make their nests. The most used material can be moss (**Figure 12**), there may be mixtures with lichens in different proportions or even with flowering plants, but in some cases lichens (**Figure 14**) and phanerogams may predominate. There are, of course, birds that use other materials, such as rocks, in the case of giant petrels and penguins (**Figure 13**), mud with algae as is the case of *Phalacrocorax atriceps*, etc. [53].

important aspect is the associated microalgae communities.

**74**

**Figure 13.**

*Giant petrel nest (*Macronectes giganteus*) build using rock fragments.*

**Figure 12.**

*(below).*

**Figure 14.** Larus dominicanus *(kelp gull) nest build with mosses and the lichen Usnea.*
