Buffel grass (Cenchrus ciliaris) also threatens the
environmental integrity of landmarks like Uluru
(Ayers Rock), NT.
Photo: Rick Davies 

Invasive species from other countries spreading across Australia are the most immediate threat to Australia's own flora and fauna, according to CRC for Australian Weed Management (Weeds CRC) scientist and President of the Council of Australasian Weed Societies Dr John Virtue.

With the historical period of large-scale land clearing for agriculture now over, invasive weed species continue to expand in cleared country and bushland remnants, Dr Virtue said, threatening the survival of native plants and animals already stressed by severe habitat loss and changing rainfall and temperature patterns.

'Much of the current focus is on establishing biodiversity corridors to enable native plants and animals to migrate in the future, to more suitable climates. Yet this won't happen if exotic weeds destroy the remnants of natural habitat we still have left. We need to actively manage weed threats now as a fundamental part of our response to climate change', he said.

Launching a new series of weed management guides for Australian landholders and bushland managers by the Weeds CRC, at the inaugural SA Weeds Conference in Adelaide, Dr Virtue said the plight of Australia's native plants and animals under these pressures is poorly recognised.

'Research by the Weeds CRC shows that invasive foreign weeds now threaten the survival of almost half the 945 native plants and animals on the threatened species list for NSW alone', he said.

'We think this pattern of threat to native biodiversity by invasive weeds is likely to be widespread across Australia, especially for patches of remnant vegetation near cities, towns and farmhouses where ex-garden plants have jumped the fence.'

Dr Virtue said the weeds chosen for these new management guides were selected after a survey of Australia's NRM regions.

'They are high impact environmental weeds, seen as a priority by a significant number of regional bodies. The perennial grasses, shrubs and vines all have the capacity to out-compete our native plants and deny food and shelter to our native animals. Some also pose fire risks.

Dr Virtue said that for the first time plainly written yet detailed colour brochures suitable for use by local weed managers and community groups had been brought together for this important but overlooked suite of problem weeds.

The eight species covered in the series are:

1.      Lycium ferocissimum (African boxthorn)
2.      Hyparrhenia hirta (Coolatai grass)
3.      Cenchrus ciliaris (buffel grass)
4.      Vinca major (periwinkle)
5.      Erica lusitanica and other Erica spp. (spanish heath etc.)
6.      Cytisus scoparius, Genista monspessulana and related species (brooms)
7.      Macfadyena unguis-cati (cat's claw creeper)
8.      Pennisetum spp. (some foxtails and fountain grasses)

Printed copies of the management guides will be distributed at the SA Weeds Conference this week and are available online.