Ecology and management of invasive Poa annua on sub-Antarctic Macquarie Island

Image of Poa Annua and penguins

PhD candidate: Laura Williams

Supervisors: Paul Kristiansen, Justine Shaw (Australian Antarctic Division), Brian Sindel and Susan Wilson

Link to a PDF of this information ((PDF, 3484.86 KB)).

Map of Sub Antarctica

Map: Macquarie Island in the sub-Antarctic

The sub-Antarctic

  • 45-60 °S
  • Wet, windy and cold
  • Depauperate flora and faunas > isolation and harsh climate
  • High conservation value > wildlife, endemics, unique environments.

Macquarie Island location

  • 54°30'S, 158°57'E
  • Southern Ocean
  • Between Tasmania and Antarctica.

Macquarie Island — natural history

  • Climate: wet, windy, cold
  • Biogeography: elongated, undulating plateau, oceanic origin
  • Soils: peats, dry tundra
  • Flora: 42 vascular plants, many bryophytes, 3 aliens
  • Fauna: seals, albatross, penguins, seabirds.

Macquarie Island

Macquarie Island

Invasive species in the sub-Antartic

  • Biological invasions substantially affect the structure and function of ecosystems
  • Most serious threat to the conservation of the sub-Antarctic
  • Over 108 alien vascular plants
  • Majority are transient/persistent and restricted, some aggressively spreading and invading
  • Risk of invasion increasing.

Poa annua on Macquarie Island

  • Common and widespread

Poa Annua on Macquarie IslandPoa AnnuaPoa Annua

Poa annua on Macquarie Island

  • First recorded in 1873 Colonises disturbed sites
  • Competes with native species for space
  • Maybe outcompeted with removal of herbivores
  • Most widespread sub-Antarctic weed
  • Mediterranean origin > cosmopolitan
  • Classified as an invasive alien
  • High phenotypic and genotypic variability, high fecundity, adapted to many habitats, highly tolerant
  • Infests disturbed areas.
Ecology and Management

We aim to:

  • understand the ecology of Poa annua in the sub-Antarctic environment
  • investigate the effectiveness of a range of management techniques

Additional management:

  • Seed banks — seed viability, longevity, distribution
  • Ecology competition between Poa annua and native grasses
  • Manual removal of biomass
  • Herbicide.