There are three different types of mosses:
- true mosses
- sphagnums (peat mosses)
- granite mosses.
The true mosses (with over 500 species) make up 95% of all New Zealand mosses. New Zealand has nine species of sphagnum. The granite mosses are rarest, with five species.
New Zealand boasts some 550 species of moss in more than 200 genera – a rich variety for such a small area. Only about one-fifth are endemic – meaning they are found nowhere else. In comparison, four-fifths of the country’s flowering plants are endemic. There are relatively fewer endemic mosses because their lightweight spores are dispersed far and wide by the wind. As well, new plants can sprout from even tiny fragments carried on the feet and feathers of migrating birds.
Some endemic species are peculiar enough to entice botanists from around the world. Among them is Epipterygium opararense, known only from individual stems growing on a boulder in the Kahurangi National Park, in the north-west of the South Island.
The world’s most valuable moss is peat moss (Sphagnum species). One per cent of the earth’s land surface – half the area of Australia – is peat bog. Sphagnum is harvested for fuel, garden mulch and packaging. In New Zealand, sphagnum is harvested from Westland and Southland swamps for export as a horticultural growing medium. Most is sent to Japan, where it is used for growing orchids. However, peat moss is most valuable as a colossal carbon sink – it stores 400 billion tonnes of carbon (14% of the world’s total), which could otherwise be converted to atmospheric carbon dioxide, which is a greenhouse gas and worsens global warming.
New Zealand mosses in Europe
Two New Zealand mosses, Campylopus introflexus and Orthodontium lineare, were accidentally introduced into Europe, where they have become noxious weeds, spreading quickly and displacing native mosses. Campylopus smothers the ground so completely that it interferes with the germination of seeds of trees and shrubs.
Two other moss exports are Calomnion complanatum and Leptotheca gaudichaudii.These are not a threat.
At least 14 species of moss are recent introductions to New Zealand. Rhytidiadelphus squarrosus was first recorded in the 1970s, and has become common along roadsides in the South Island. A related northern hemisphere species, shaggy moss (R. triquetrus), grows in scrub at Nelson Lakes, and has the potential to establish itself in the nearby National Park.
Māori decorated and insulated some of their traditional flax garments with two species of hair-cap moss, Polytrichum commune and Polytrichadelphus magellanicus. The flax strands were woven so tightly that the moss could not be poked in as an afterthought, but had to be carefully inserted during weaving.