**5. Plant species associated with lichens**

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 mainly cryptogamic community like in Antarctica?

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 annihilated. Who does that? If not an animal, mostly a set of lichens. If we look at the work already done with phytosociology in Antarctica, we see that lichens have figured as one of the most important when considering the ecological significance index [17].

**Figure 15** illustrates how different species are associated with a lichen which in this case is fruticose: *Sphaerophorus globosus*, which forms groups up to 10 cm in height and is generally parasitic on mosses (muscicolous). In this 20 x 30 square in the figure, there are associated eight other species, of which 3 are mosses and 5 are other lichens, demonstrating how the lichen community settles on mosses and needs them to develop, even if it results in its death. In succession, it is to be expected, therefore, that lichens from the vegetation damage or kill a previously installed moss and then gradually disappear, also due to the lack of a host.

In this community the mosses are at a disadvantage, as they are being attacked by various parasites of the lichen group. These parasites do not even care about the moss species, but it looks like the *Chorisodontium acyphyllum* moss is surviving well and unscathed. This is also noticed in other parts and perhaps indicates that this moss ends up taking the place of the other parasitized and previously killed. This may show a stage of plant succession in Antarctica, which is still poorly studied.

Lichens can also occur on rock fragments and in **Figure 16** there is a schematic drawing of the cover of round rocks, very common in uplifted areas. There are

#### **Figure 15.**

*Biodiversity surrounding the fruticose lichen* Spaerophorus globosus.

**Figure 16.** *Biodiversity in a 20 x 20 cm square of rounded rocks in Henequin point, King George Island, with 18 species.*

**77**

Antarctica.

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

disturbance, imagine the effects of climatic change.

17 species of lichens and one of moss occurring on the fragments. At some distance and to the unsuspecting it seems that the rocks have no vegetation, but it has adapted very well to this surface. Vegetation-free areas are in most cases rocks turned over by an animal or researcher who passed the site. So even small areas can group a considerable richness and the Antarctica is very sensitive to any

*Prasiola* is the macroscopic alga that occurs in terrestrial environments in the Antarctic region with greater frequency. Only two species were being cited for the area: *P. crispa* (nitrophilous) and *P. calophylla* (nitrophobous) (Putzke & Pereira, 2013). Studying the molecular phylogeny of these algae in Antarctica, the presence of *P. crispa* was confirmed, that *P. calophylla* is different from the same species mentioned for Europe, changing its name to *P. glacialis* and that *Prasiola antarctica*

These species are among the largest primary producers in Antarctica and studies have shown that *P. crispa* is very resistant to desiccation and hypersaline

In general, nitrophilic species occur near or inside bird colonies and nitrophobic in areas in contact with them. Often, some shallow pools of water have groups of *Prasiola* that prevent the growth of the surrounding mosses, demonstrating that

In several places it can be seen that the alga is lichenized, forming a different, more blackened and dotted thallus. It is the association with the fungus *Mastodia tesselata*, whose relationship is still controversial, as some authors believe it is parasitism and not a symbiosis. The lichen appears close to Verrucaria, a lichen with

In some cases, during the collections it can be seen that part of the algae stem is green and part is associated with the fungus and is already blackened, showing that the association may not be complete. Further studies are needed to elucidate what is

*P. crispa* produces secondary metabolites with high toxicity and insecticidal power, and some studies on the subject have already been published [63, 64].

Birds can contribute to the long-distance dispersion of spores and seeds. In the first case, they can carry diaspores of fungi, mosses and pteridophytes transcontinentally (the latter group does not yet occur in Antarctica). Seeds in general can be carried via the digestive tract even. Some first evidences of dispersion of microscopic bryophyte spores have been published, where the case studied presents a transequatorial dispersion, with species carrying diaspores from one pole to the other or at least from the southern part of South America to the North Pole. Algae cells, fragments of moss leaves, elatheria and fungal spores have been found [65]. With the temperature registered due to climate changes, it is expected that new mosses may occur from introductions with the participation of birds in

Many birds carry these structures passively, as they can land on the fields, brush against them, use plants from these groups as material for their nests and even ingest material when transporting the food that is taken to the nests, or when

is an independent species, morphologically identical *P. crispa* [57].

the relationship between these two very different organisms.

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

**6. Macroscopic terrestrial algae**

conditions [58–61].

marine affinities [62].

they are somewhat allelopathic.

**7. Dispersion of land plants**

17 species of lichens and one of moss occurring on the fragments. At some distance and to the unsuspecting it seems that the rocks have no vegetation, but it has adapted very well to this surface. Vegetation-free areas are in most cases rocks turned over by an animal or researcher who passed the site. So even small areas can group a considerable richness and the Antarctica is very sensitive to any disturbance, imagine the effects of climatic change.
