J.R. Croft (jrc@anbg.gov.au) and M.M. Richardson (mark@anbg.gov.au), Australian National Botanic Gardens
In mid November 1989, JRC visited Macquarie Island for four days during the turn-around of the summer resupply voyage and collected living plant material and herbarium voucher specimens from the northern quarter of the island.
The project, proposed and planned by MMR, was to collect live material of subantarctic plants from Macquarie Island, ship them back to Australian as quickly as possible, and attempt to establish them in cultivation. The driving reasons for this project were to make this material, which is not commonly seen by the botanical community, readily and easily available for research, both taxonomic and horticultural, for education in the form of public displays and formal education programs, and to investigate the possibilities of ex situ cultivation and conservation of the species.
In particular we hoped to collect and establish material of the most striking plants on the island, Stilbocarpa polaris, Pleurophyllum hookeri and the dominant tussock grass, Poa foliosa. We were particularly anxious to collect the world's southernmost orchid, a Corybas previously known as C. macranthus, but believed by David L. Jones to be an undescribed species.
That most of the species collected are still alive, and actively growing, in Canberra indicates that the exercise was successful. [see nursery propagation report.]
The island was discovered in 1810 and its natural resources were intensively exploited by seekers of abundant animal fur and oil until well into second decade of this century. Tragically, the original populations of the fur seal were exterminated within 5 years of the discovery of the island. The introduction of vermin such as rats, cats and rabbits also had disastrous effects on the biota. Intensive scientific activity took place on the island with Australasian Anatarctic expedition of 1911-1914 led by Sir Douglas Mawson. Australian National Antarctic Research Expeditions (ANARE) have maintained a research and meteorological station on the island since 1948.
Politically and administratively the island is part of the state of Tasmania. The island itself is a Tasmanian Nature Reserve with Tasmanian park management and Tasmanian Rangers but the research station on a narrow isthmus at the northern end is maintained and run by the Commonwealth Antarctic Division. It is a successful example of Commonwealth-State co-operation.
The weather on Macquarie Island is both uniform and unpredicable, or uniform in its unpredictability. Rain can be expected on more than 300 days of the year (c. 900 mm/y) and the wind blows strongly and constantly from the west; the air temperature oscillates only a few degrees from 5 oC from day to day and throughout the year. While it is quite true to describe it as very windy, cold and wet, it is a common occurrence to experience all four seasons in one day.
As a geologically new island, and a subantarctic one at that, the flora of Macquarie is not particularly diverse. All vascular plants are herbs or prostrate sub-shrubs, 5 are pteridophytes and c. 45 are phanerogams; there are 5 introduced species and 2 endemics (the Azorella and the Corybas), both of which have very closely related sibling taxa on other southern islands. There are three times as many bryophyte species and over twice as many lichen species.
The vegetation cover on the island is rarely over 1 m tall and consists of tussock grasslands, herbfields, exposed feldmark, and wet and peaty fens and bogs.
The most striking feature of the island is of course its abundant bird and mammal fauna. Although exciting, walking and collecting near elephant seals has its problems.
The Antarctic Division has stringent requirements on training. Five days in October were spent being kitted out with quality cold weather gear and being trained in techniques of survival, rope work, search and rescue, first aid and in induction to the administrative and management arrangements of the Macquarie Island station. The Antarctic Division maintains a well appointed training centre at Bernacchi in the central highlands of Tasmania for this purpose, complete with appropriately cold, wet and windy weather. This may seem a bit excessive for a four-day excursion, but it was a valuable and productive learning exercise that enabled participants to start productive and safe work almost immediately after landing on the island.
The base is situated at the northern tip of the island and the limited time meant that our collecting was restricted to the northern quarter of the island (10 km). The main areas collected were Wireless Hill, Hasselborough Bay to the northern end of the 'Featherbed', Gadget Gulley and onto the plateau, Nuggets Point and Sandy Bay through to Bauer Bay and from Bauer Bay overland back to the station.
The 'Featherbed' was a deep spongy peat bog of low herbs and grasses and pockets of free water. Juvenile plants of Stilbocarpa and Pleurophyllum were collected here. It was easy, but not pleasant, to extract the plants from the cold soft wet peat. The silky-silver-leaved Pleurophyllum had a large swollen carrot-like tuber and long roots that descended deep into the peat.
The cryptic Corybas orchid was found in full flower in similarly wet peat conditions on the north side of Bauer Bay. It was difficult to find due to its size and the fact that the leaves looked not unlike a very young Pleurophyllum.
Pleurophyllum also occured high on the plateau in well drained sandy gravel. With this wide tolerance of altitude, exposure, soils and water levels it was anticipated that this species would be extremely hardy and easy to establish in cultivation. This was not to be the case.
Throughout the island, the Pleurophyllum especially and other species generally, were copiously in flower and there was no trouble finding fertile voucher specimens. Regular visitors to the island stated that often the flowering is poor or non-existant, so we were fortunate in this regard.
We were also fortunate in the weather which was mild by Macquarie standards allowing four days collecting with virtually no rain, moderate winds and hardly any mist or low cloud. Another advantage of summer field work on Macquarie Island are the very long daylight hours; you can work from 4 am to 9 pm in full daylight.
Herbarium voucher specimens were collected for each of the live samples. As there is no woody vegetation on Macquarie Island to speak of, most plants were collected as whole plants, clumps, or juvenile plants of the larger species. To satisfy quarantine regulations, soil was removed from the specimens and they were wrapped in moist newspaper and placed in plastic bags. Some specimens were potted directly in moist vermiculite, but this was a very time consuming process and was abandoned in the later stages.
The environmental control at the ANBG was by means of 2 evaporative coolers and maintained minimum air temperatures of 13.6-15.1 oC and maximum air temperatures of 20.6-22.7 oC over the summer months. The environmental cabinets at the ANU were set at 8 oC by day and 5 oC by night with a photoperiod of 16 hours. All watering was done by hand.
It was interesting to note that for those species in both the ANBG and the ANU a given regime did not favour all taxa, some doing better in the warmer conditions of the ANBG and others in the harsher conditions of the growth cabinets; subjectively, 6 taxa did better in warmer conditions, 6 in the cooler and 7 showed no differences.
The following species are currently being cultivated at the ANBG nursery:
Blechnum penna-marina Polystichum vestitum Stilbocarpa polaris Pleurophyllum hookeri Epilobium pedunculare Epilobium brunnescens Ranunculus biternatus Montia fontana Colobanthus muscoides Colobanthus sp Luzula crinita var. crinita Poa foliosa Poa cookii Acaena magellanica Cotula plumosa Isolepis aucklandica Coprosma perpusilla ssp. antarctica Puccinellia macquariensis Hydrocotyle novae-zealandiae Corybas sp. nov. Azorella macquariensisClumps of the minute fern Grammitis poeppigeana were also brought back but did not survive. This genus is renowned for its difficulty of cultivation. Plants of Poa annua were also collected from the island but were culled due their potential problem as a weed in the collection; they are now stored as seed collections.
At the time of writing the Stilbocarpa polaris was growing extremely well in Canberra and had even flowered. Unfortunately the Pleurophyllum hookeri did not take kindly to being moved and nearly all plants have regressed and died; it is unlikely that the collections of this species will survive in captivity.
As many of the species are mat-forming, some plants will be grown in trays rather than in pots, both for cultivation and display purposes.
Many of the Macquarie Island plants had not previously been brought into cultivation; they are now available for study and display. By varying the cultivation regimes, we have shown that the plants can survive in conditions milder than those experienced in their native habitat.
A facility is to be constructed in the nursery to provide cool conditions for the collections sover the summer months and a permanent display of the Macquarie Island flora. Attempts will be made to have those taxa that did not establish well recollected by future expeditions to Maccquarie Island. The ANBG will be distributing those species that have been established and repropagated to other Australian and international botanic gardens with facilities to maintain alpine and subpolar plants.