Ecological importance of bryophyte.

 

Ecological importance of bryophyte.        

          Bryophytes are the amphibian member of plant kingdom, which are also known as moss. Unlike most of the higher plants bryophytes are found in groups of individual  and they never form any mechanical tissue. Bryophyte often play in the economy of nature, as ecological indicator, medicinal raw materials and many other aspects.  Bryophytes are important constituent of ecosystem in temperate and tropical region  of earth. They are ecologically important because of following reasons

1.Bryophytes and plant succession: Among the bryophytes the mosses are considered to potent forms of successional process. They colonize over  the nutrient poor  sides, where no other plant can survive. After death and decay they form humus and increase  the soil fertility.Some important species under this category are- Cephalozia media, Lepidozia septans, Pellia epiphylla etc.      

2.Bryophytes and anatomical succession:In association of plant succession, they participate in faunal succession.For  example moss cushions developing  on rock, first colonized by Rhizopods, Rotifers, Nematodes and Ciliates. As a thicker decomposition of the fauna become similar  to that of the soil fauna.

3.Bryophytes a ovipositor: The animals which feed on bryophyte also deposits their egg in bryophyte thallus.  Slugs and snails are frequently depositing their eggs upon gametophores. Some water beetles spent their dormancy period  within the leaves of bryophytes.

4. Bryophytes as ion exchanger: The cell wall of  Sphagnum, functions  as ion exchanger . They  rapidly absorb cation such as Ca⁺², Mg⁺² etc, supplied by rain water and in exchange  release hydrogen ions in to the water. Hydrogen ion make the soil acidic and maintain the acidic  environment of soil.

5.Maintanance  of water balance in forest: In forest, especially in the tropical forest Sphagnum and few other bryophytes absorb huge  amount of water and maintain humidity over dry period and thus preventing rapid run off  and folding.

6.Conservation of soil and prevention of soil erosion: On bare and disturbed soil, bryophytes act as pioneer community and they have the ability to stabilize soil.The soil in semi arid regions are held in place by crusts predominantly composed of  bryophytes and thus preventing the soil from blowing  away. N. G. Miller (1981) found that bryophytes increase the buffering capacity of soil, particularly against the changes normally caused by addition of fertilizer. The slow decomposition of many bryophyte taxa makes them suitable for long-lasting mulch. When Sphagnum is spread over the ground or mixed with soil, it retains moisture and prevents weed growth; it also discourages damping-off fungi (H. Miller and N. G. Miller 1979).

 

7.Nitrogen Fixation:Nitrogen is often a limiting nutrient for plant growth, especially in agriculture. Bryophyte crusts, endowed with nitrogen-fixing Cyanobacteria, can contribute considerable soil nitrogen, particularly to dry rangeland soils. Some of these Cyanobacteria behave symbiotically in Anthoceros (D. K. Saxena 1981), taking nitrogen from the atmosphere and converting it to ammonia and amino acids. The excess fixed nitrogen is released to the substrate where it can be used by other organisms. K. T. Harper and J. R. Marble (1988) found that bryophyte crusts not only help protect soil from wind and water erosion, and provide homes for nitrogen-fixing organisms, but they facilitate absorption and retentionof water as well.

 

8. UV-B Radiation: The moss Bryum argenteum is being used to monitor the thickness of the ozone layer over Antarctica (L. Hedenas 1991). As the ozone layer decreased, increased exposure to UV-B radiation stimulated production of flavonoids in this species. But, as with ozone exposure, responses vary considerably among species. In Sphagnum magellanicum there were no significant differences in chlorophyll or carotenoid concentrations following UV-B exposure; nevertheless, exposure increased its growth in height without a corresponding increase in voltric density, resulting in no effect on biomass (P. S. Searles et al. 2002).