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WEED THREAT TO BIODIVERSITY BEING IGNORED

Cooperative Research Centre for Australian Weed Management
Media Release

11 July 2007

WEED THREAT TO BIODIVERSITY BEING IGNORED

One of the best laws in the Western world on ecological protection,
Australia's Environment Protection and Biodiversity Conservation Act
(1999), is not being used when it comes to the widespread threat
posed to the environment by foreign plants, according to Dr Rachel
McFadyen, CEO of the Cooperative Research Centre for Australian Weed
Management.

Speaking at the Biodiversity Extinction Crisis Conference in Sydney
today, Dr McFadyen said that the EPBC Act allowed action once a 'key
threatening process' had been identified and declared. Examples of
official recognition so far included the rabbit, fox, goat, feral
cats, the root rot-fungus phytophthera, long-line fishing, climate
change and cane toads.

However, not a single invasive plant had been listed as posing a
significant threat, Dr McFadyen said.

'Yet we have plants from Central America forming one-species stands
over thousands of hectares, totally displacing the native flora and
fauna. Mimosa even prevents indigenous people from accessing their
country, and Kakadu National Park spends $0.5 million every year
just to keep it out, they see it as such a threat', she said.

Mesquite, olive hymenachne, lantana, blackberry and bitou bush are
all recognised as Weeds of National Significance under other federal
measures. All are very clearly rampant invaders of valuable natural
ecosystems, but none are listed under the EPBC Act, Dr McFadyen
said.

'One of the worst offenders is the African gamba grass, still being
promoted and planted as pasture for cattle in the north', Dr
McFadyen said.

'This is a monster of a grass that can grow over four metres high.
It seeds prolifically and invades surrounding woodland savannah
country - and when it burns the heat is just too much for the
eucalypts, which die.'

'The result is goodbye eucalypt woodland with its complex of
associated plants, birds and other animals, and hello African
grassland which allows very few of these species a look in', she
said.

'It does make me wonder what a foreign plant has to do to get
attention from conservationists. I sometimes think we are up against
a prevailing misinformed mindset that sees all green plants as
essentially the same - as passive, friendly and just part of
nature.'

'Try telling that to a landowner or park manager battling rubber
vine, cat's claw creeper, gorse, broom, boneseed, bridal creeper or
any of the dozens of highly invasive foreign plants that chew up
huge amounts of time and money on a daily basis around Australia.'

Dr McFadyen said that recent research was beginning to paint a
picture of how threatening weeds were to native plants and animals.

'There has been a serious underinvestment in this ecological impact
research for many years, but we are now starting to get a better
handle on it. We now know, for example, that weeds are a significant
threat to over one third of endangered species nationally, including
within 13 World Heritage Areas - and our international
responsibilities to protect them are very clear', she said.

'In NSW, where the Weeds CRC commissioned work in 2006, weeds are
known to be a direct threat to almost half of the threatened species
listed for that state. We know, for example, that the habitat of the
northern corroboree frog is directly threatened by blackberry
invasion, and the native rice flower by bitou bush and lantana.'

The lack of research and data for individual species makes it
difficult to pin-point specific threats with the precision that
scientists would like, Dr McFadyen said. But we do understand the
sorts of changes that weeds cause, and how these tend to affect
local flora and fauna.

'We know, for example, that nectar-feeding birds such as lorikeets
will abandon bushland when their food source is displaced by weeds
that do not produce nectar.'

That's something that's obvious, but there's a lot more going on.'

The reality is that such displacement of native plants, birds and
other animals is happening quietly on a vast scale across the
continent, as weeds gradually make their environment less attractive
and less supportive, Dr McFadyen said. Climate change will also add
real pressure.

'The really big weakness we have as custodians of this natural
heritage', Dr McFadyen said, 'is that too often we only address the
biodiversity issue at points or times of crisis, when certain
species are threatened with imminent extinction. That is reflected
in the language we use', she said.

In the meantime, Dr McFadyen said, we seem to be largely unaware of
the immense changes we have caused to this heritage, and which
continues to degrade wherever weeds get the upper hand.

'In fact, now that wholesale land clearing has largely stopped,
weeds constitute the number one threat to biodiversity. This is a
widely observed phenomenon around the world.'

The end point of this very long-term process of weed invasion is
hard to predict, but it is not likely to be good news for our native
flora and fauna, Dr McFadyen said.

'We need to understand this much better and plan and act
accordingly, not carry on as if all green plants are equal. The
nation is not a Peter Andrews production system.'

Contacts
Dr Rachel McFadyen, CEO, Weeds CRC, 0409 263

Images and further information
High resolution weed photos can be downloaded directly from
www.weeds.crc.org.au/publications/media.html
Most of the photos on the Weeds CRC's new image gallery are also
available in high resolution
www.weeds.crc.org.au/main/image_gallery_index.html Contact Jenny
Barker - 08 8303 7250 or jennifer.barker@adelaide.edu.au