Pherosphaera hookeriana
 | This article includes a list of general references, but it lacks sufficient corresponding inline citations. (March 2022) |
| Pherosphaera hookeriana | |
|---|---|
| |
| Pherosphaera hookeriana | |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Araucariales
|
| Family: | Podocarpaceae |
| Genus: | Pherosphaera |
| Species: | P. hookeriana
|
| Binomial name | |
| Pherosphaera hookeriana W.Archer bis
| |
Pherosphaera hookeriana, or Mount Mawson pine (previously known as Microstrobos niphophilus), is a dwarf
dolerite derived soils. The species is highly fire sensitive and an increase in fire events associated with climate change may lead to local extinction
and fragmentation of habitat.
Description
Pherosphaera hookeriana is a densely-branched erect
keel
.
Male flowers form in compressed, terminal globular abaxial
surface.
Female flowers occur in cones on short branches that usually droop (hence the old common name). The flowers are globular, 2–4 mm long and have 3-8 fertile scales, with a single ovule on the upper surface of each. When the glossy
brown coat and is approximately 1 mm in diameter (Curtis & Morris 1975, Hill 1998).
Identification and ecology
Pherosphaera hookeriana is a dwarf conifer that has been recorded to grow up to 5 meters, but in exposed and harsh environments it may only attain a height of 0.5 meters (Minchin 1983). The foliage of Pherosphaera hookeriana is well adapted to the high altitudinal ranges it occupies, with small imbricate scale leaves, the
dioecious
, with the reproductive organs occurring on specialised leaves arranged in cone like structures.
Pollen is wind dispersed and seed ripening occurs by late April (Wood & Rudman 2015). It is unclear if the plant produces seed annually or produces mass seed every few years (lycopods
, with narrow spreading leaves. The seeds drop within a few meters of the parent plant. It has been suggested that dispersal over long distances via water is possible for plants occurring near lakes and rivers. Pherosphaera hookeriana may form extensive clonal colonies via vegetative growth (Fitzgerald 2011).
Like most endemic Diselma archeri
.
Distribution and habitat
Pherosphaera hookeriana is endemic to Tasmania's west, southwest and central plateau, the current distribution of the species is most likely to be a reflection of post-glacial expansion from
Sphagnum bogs, the common element through the environments the species inhabits is the high soil moisture content and annual rainfall. Confirmed records indicate that the species ranges from the Walls of Jerusalem National Park in the north to Mt La Perouse in Southwest National Park (Tasmanian threatened species guide 2016) – about 12 kilometers from Tasmania's south coast. Most populations of the species occurs on soils derived from Jurassic dolerite, with an exception being a stand in Artichoke Valley near Frenchmans Cap
, which grows on sedimentary deposits.
Population
Mount Field National Park has long been recognized as the stronghold for the species with areas of coniferous heath being dominated or co-dominated by the species. There are approximately 30 known stands with an estimated population of 20,000 individuals. There is a high likelihood that stands of the species undiscovered, particularly in the Walls of Jerusalem National Park.
Conservation
Pherosphaera hookeriana is listed under the old name Microstrobos niphophilus as
Threatened species protection act of 1995, after having its classification updated from rare in 2001. The chance of the whole species being lost in a single disaster is very unlikely, given its wide geographic range, however the chance of local extinction in individual stands or subpopulations appears to be increasing (the Lake Mackenzie fire in early 2016 is evidence of the threat fire poses to montane conifers). Populations at lower altitudes closer to more flammable vegetation communities are considered to be at extreme risk of fire damage over the coming decades. Another prominent issue is that anecdotal reports suggest that the rate of seedling germination and establishment is extremely low. The possibility that many of the stands of this species are clonal
in combination with the breeding strategy, could potentially set a limit on viable seeds in some areas. Climate change and the trends towards a warmer climate, with a greater chance of extreme events such as drought and fires, are likely to have a direct and adverse effect on populations of Pherosphaera hookeriana. Severe declines or local extinctions in more susceptible regions are predicted to occur by the end of the century.
References
- Curtis, W.M. & Morris, D.I. (1975). The Students Flora of Tasmania, Part 1. Second edition. Government Printer, Hobart.
- De Salas, M.F. & Baker, M.L. (2016) A Census of the Vascular Plants of Tasmania, Including Macquarie Island. (Tasmanian Herbarium, Tasmanian Museum and Art Gallery. Hobart) www.tmag.tas.gov.au
- Fitzgerald, N. (2011). Establishment Report for Tasmanian Wilderness World Heritage Area Climate Change Monitoring Program: Montane Conifers. Nature Conservation Report Series 11/06, Resource Management and Conservation Division, DPIPWE, Hobart.
- Hill, R. S. & Brodribb, T. J. (1999). Southern conifers in time and space. Australian Journal of Botany 47: 639–696.
- Kirkpatrick, J.B. & Dickinson, K.J.M. (1984). The impact of fire on Tasmanian alpine Listing Statement for Pherosphaera hookeriana (mount mawson pine) vegetation and soils. Australian Journal of Botany 32: 613–629.
- Minchin, P.R. (1983). A Comparative Evaluation of Techniques for Ecological Ordination using Simulated Vegetation Data and An Integrated Ordination –Classification Analysis of the Alpine and Subalpine Plant Communities of the Mt. Field Plateau, Tasmania. Ph.D. Thesis, University of Tasmania, Hobart.
- Wood, J. & Rudman, T. (2015). Montane Conifer Seed Collection Project. Internal Report to the Royal Tasmanian Botanical Gardens and the Natural Values Conservation Branch, Department of Primary Industries, Parks, Water and Environment, Hobart.
- https://www.naturalvaluesatlas.tas.gov.au/downloadattachment?id=16151