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Ecology of Tasmanian cool temperate rainforest bryophytes

A diverse range of cool temperate rainforest bryophyte species in Mt Field

Tasmania cool temperate rainforest

callidendrous type rainforest with a diverse bryophyte community

Tasmania's rainforest are classified as cool temperate rainforests where it is defined when the annual rainfall exceeds 1400 mm per year or when the summer rainfall exceeds 50 mm per month which occurs mainly in the western half of Tasmania and in the northen-eastern highlands, however it can be found in small isolated patches where it is moist enough; fire-protected gullies, ridges and hills tops where mist and clouds gathered. Rainforest in Tasmania are additionally defined as being dominated by a range of species which includes Nothofagus cunninghamii, Atherosperma moschatum, Eucryphia lucida, Phyllocladus aspleniifolius, Athrotaxis selaginoides, Athrotaxis cupressoides, Lagarostrobos franklinii. One could find up to 70-80 different vascular species on top of the dominating species but about two-thirds of the trees and shrubs are endemic to Tasmania rainforest Lastly, Fire isn't required as extensively for species in the rainforest as compared to savanna and heathland.

Tasmanian rainforests are further divided into four main types:

• callidendrous; tall trees with an open, park-like understorey
• thamnic; shrubby understorey
• implicate; short, tangled vegetation
• montane; woodlands and forests at high altitude

Tasmania rainforest covers about 760,000 ha of the State's land area. In any given rainforest site, the amount of vascular plants ranges from 3-6 species whereas non-vascular plants ranges from 30-70 species

Geological history

Australia was part of Gondwana, which compromises of South America, Africa, Madagascar, India, New Zealand and Antartica around 200 million years ago , which resulted in a similar vegetation both in the fossils and present day species even though these countries are so far apart today. The current state of similar vegetation in Tasmania and Victoria, Australia was due to the Last Glacial Maximum where Tasmania was a single land mass with Australia called Sahulland. After the Last glacial maximum, Tasmania got separated from Australia by a shallow sea known as Bass Strait today

Further information: [[:geologic time scale]]

Bryophyte diversity and ecological role

A diverse range of cool temperate rainforest bryophyte species in Mt Field

Bryophytes are ancient true land plants that consist of mosses, liverworts and hornworts and are found in a huge range of enviroment from deserts, artic, antarctic, rainforest, caves, acidic bogs, urban areas, decomposing animal bodies, dung and even on old cars<. Bryophytes are called "non-vascular plants" because of the lack internal vessels(xylem and phloem) for conducting fluids however many bryophyte species have conducting structures; hydroids, within the stems and sometimes leaves, often bryophytes have leaves that are one cell thick, hence the need for complex transport systems. They do not have roots but are anchored by fine, hair-like rhizomes.

Further information: [[:Bryophytes]]

There are at about 13,000-22,000 or so species of bryophytes in the world today with a variable 10,000 - 15,000 species of mosses, 5,000 - 7,500 species of liverworts and 100 - 236 species of hornworts. Although it does not compare to the minimum 223,300 species of flowering vascular plants About 643 species are recognised in Tasmania with about 230 bryophyte species recorded in Tasmanian rainforest alone, For any given site, the difference in species richness between vascular plant (3-6 species) and bryophyte (30-70 species) diversity is huge ). It occurs throughout the forest mainly in moist and very shady enviroment, from ground level to canopy with it being the most abundant in the understory as epiphytes on living wood, dead wood, leaves of plants and exposed rocks.

The ecological role of bryophytes in Tasmania rainforest isn't well studied as compared to other fields of study, hence the suggestion is that

• Bryophyte increase water holding capacity of vegetation which might other wise be lost as run-off
• Reduces evaporation from soil, preventing or reducing erosion of soil
• Slow releases of water during dry spells which influences and reduces fluctuations in humdity
• Maintain a stable environment for other cryptogams and invertebrate animals
• May play an important role in nutrient cycling
• pioneering plants on converting unfavourable substrate into suitables ones for other plants

Anthocerotophyta (Hornworts)

Hornworts are a group of bryophytes comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant. There are about 100 known species so far but new species are still being discovered. A common example of hornwort found in tasmania is Phaeoceros carolinianus

Further information: [[:Hornwort]]

Bryophyta (Moss)

Mosses are a group of bryophytes comprising the division Bryophyta. Commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like capsules borne aloft on thin stalks. There are about 12,000 species of moss at the moment. A common example of moss in tasmania is Thamnobryum sp.

Further information: [[:Moss]]

Marchantiophyta (Liverworts)

Liverworts or hepatics are a group of bryophytes comprising the division are a division Marchantiophyta. Like other bryophytes, they have a gametophyte-dominant life cycle. Leafy liverwort specuies can be mistaken for a moss, however liverwort do not posses a costa in their leaves and may bear marginal cilia which are rare in mosses. Other differences are not universal for all mosses and liverworts, but the occurrence of leaves arranged in three ranks, the presence of deep lobes or segmented leaves, or a lack of clearly differentiated stem and leaves all point to the plant being a liverwort. There are about 9000 species of liverworts. A common example of liverwort in tasmania is Marchantia sp

Further information: [[:Liverwort]]

Bryophyte examples spotted in Mt. Field

Liverwort

• 
  Liverwort, Tylimanthus pseudosaccatus
• 
  Liverwort, Riccardia sp

Moss

• 
  Moss, Dicranoloma menziesii
• 
  Moss, Hypnodendron comosum & Hypnodendron vitiense
• 
  Moss, Ptychomnion aciculare

Further Reading

Kantvilas, G., & JARMAN, S. J. (2012). Lichens and bryophytes in Tasmanian wet eucalypt forest: floristics, conservation and ecology.

Kantvilas, G., & Jarman, S. J. (2008). The cryptogamic flora of an isolated rainforest fragment in Tasmania. Botanical journal of the Linnean Society, 111(2), 211-228.

Pharo, E. J., & Beattie, A. J. (2002). The association between substrate variability and bryophyte and lichen diversity in eastern Australian forests. The Bryologist, 105(1), 11-26.

Pharo, E. J., & BEATTIE, A. J. (2006). Bryophyte and lichen diversity: a comparative study. Australian Journal of Ecology, 22(2), 151-162

Tng, Y.P.D., Dalton, P.J. & Jordan, G.J., (2009). Does moisture affect the partitioning of bryophytes between terrestrial and epiphytic substrates within cool temperate rain forests? A Journal of Bryology and Lichenology, The Bryologist, vol 112, pp.506–519.

Turner, P. A., & Pharo, E. J. (2005). Influence of substrate type and forest age on bryophyte species distribution in Tasmanian mixed forest. The Bryologist, 108(1), 67-85.

Williams J.E. (2012). The Evolutionary Significance of Tasmania’s Rainforests and Associated Vegetation. A report to the Independent Verification Group, Tasmania, February 2012.

External links

B.Goffinet (2012), Australian Mosses Online 53. Splachnaceae. Australian Biological Resources Study, Canberra. Version 22 June 2012.

McCarthy, P.M. (2006), Checklist of Australian Liverworts and Hornworts. Australian Biological Resources Study, Canberra. Version 6 April 2006.

Key to Tasmanian Dicots. 2011 http://www.utas.edu.au/dicotkey/dicotkey/key.htm Viewed on March 9 2013

Glime, Janice M. 2007. Bryophyte Ecology. Volume 1. Physiological Ecology. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. accessed on March 9 2013 at <http://www.bryoecol.mtu.edu/>.