NZ Moss Flora: Adventives
Adventives
Adventive species continue to infiltrate the New Zealand flora. The northern hemisphere Sphagnum subnitens, first documented in New Zealand in 1975, is actively extending its range and is a weed in wetlands on the west coast of the South Island. In 1997 Rhytidiadelphus triquetrus was discovered in New Zealand, in second-growth native forest, and efforts are underway to eradicate this potentially invasive weed. In general, the number of moss adventives appears to be much lower than that among vascular plants and only 14 species are considered to be unquestionably introduced.
New Zealand's Vegetation
On the main islands, lowland forests have been highly depleted due to intensive, mainly agricultural, land use and only remnants of lowland forest remain in most regions. Montane and subalpine forests are extensive and relatively intact, largely dominated by various species of Nothofagus. Extensive areas of tussock grassland, largely dominated by Chionochloa species, occur naturally in the alpine zone and at lower elevations in drier districts of both main islands, as a result of deforestation and fire. Alpine regions are extensive, especially on the South Island, and have a diverse flora, including a disproportionate number of species of bipolar distribution.