Rita Reitano rita.reitano at adelaide.edu.au
Mon Sep 3 01:53:44 CEST 2007

3 September 2007

                      WEEDS THREATEN NATIVE BIRDS:
             new web-based tools target fleshy-fruited weeds

Invasive species are regarded as second only to habitat loss as a threat
to birds in Australia, so new web-based tools to help choose plants to
replace weeds with fleshy fruit will be a welcome relief to our
feathered friends.

Weeds are an important conservation and economic problem worldwide. They
directly threaten 16 native bird species on a national scale, although
this figure is considered to be a substantial underestimate. New
research suggests weeds threaten 25 bird species in NSW alone.

However birds contribute to this weed threat when they eat the fleshy
fruit from these weeds and distribute the seed wherever they next roost.
And so a new weed infestation can start up, many kilometres away from
the source of the weed.

Dr Carl Gosper and Dr Gabrielle Vivian-Smith’s Weeds CRC project,
Selecting weed replacement plants for use by frugivorous birds, has come
up with tools to help gardeners and land managers manage weeds but still
keep their birds.

“Weeds greatly modify the habitat of birds by contributing to changes in
fire regimes and vegetation structure, altering the quantity, quality
and/or seasonal availability of food and ensnaring birds,” says Dr

“Weeds are well known for these negative impacts,” he said, “but it is
important to consider that there are also cases where weeds appear to
benefit native species, or at least provide support for them, such as
providing a source of food.”

These positive ecological contributions by weeds can be a source of
conflict in conservation management. Should the weeds be removed, or
should they be retained because they support native birds and other

Providing alternative food resources for birds can balance the impact of
weed control, said Dr Gosper.

Providing alternative food resources aims to:
• conserve populations of native fruit-eating birds following the loss
of food resources from the removal of fleshy-fruited weeds
• favour the native plants’ seed dispersal and recruitment rather than
the weeds’
• reduce weed seed dispersal by promoting native plants that act as
effective competitors for seed dispersal services (ie those provided by
fruit-eating birds).

The tools developed by the Weeds CRC, for choosing native plants for
fruit-eating birds comes in three forms. And they are all available on
the web:

1. Replacement plant lists for target weeds:
Factsheets on Alternatives to bird-dispersed weeds in north-east NSW and
south-east Qld and Alternatives to bird-dispersed weeds for Weeds of
National Significance explain how fleshy-fruited weeds can be replaced
by fleshy-fruited native plants as a food source for birds.

2. How-to guide for plant selection:
This comprehensive guide assists with choosing native replacements for
weeds to support fruit-eating birds. This includes directions on
selection based on traits. A variety of plant and fruit traits, such as
fruit size and structure, fruit colour and fruiting season, are known to
affect the food choices of birds. Using these traits can help identify
which native plants have similar fruits to a selected weed, thus
providing alternative food to a similar suite of native fruit-eating

3. Native plant trait databases:
These databases have been provided as Excel spreadsheets, suitable for
searching, sorting and extracting data. There is a database each for
NSW, SA, Tasmania, Victoria and south-western WA.

“These tools will assist land managers, restoration practitioners,
gardeners, nursery industry personnel and others choose replacement
plants for these fleshy-fruited weeds,” Dr Gosper said.

To view the web-based tools visit:

Dr Carl Gosper
carl.gosper at yahoo.com.au
08 9333 6442
0408 424 559

Dr Tony Grice
Tony.Grice at csiro.au
07 4753 8543
0419 974 520

Images and further information
The following images can be downloaded from:

Camphor laurel (Cinnamomum camphora) is a particularly widespread and
problematic weed that is spread by birds eating the fruit.

Lantana (Lantana camara), a Weed of National Significance, can be
replaced by the flesh-fruited ruby saltbush (Enchylaena tomentosa).

The How-to guide for plant selection is a useful tool to help select
native fruiting plants to support fruit-eating birds like the topknot

The Weeds CRC was advised in November 2006 that its funding will not be
renewed, and that it will wind up in June 2008. Updates about the
situation are available at:

Rita Reitano
Science Communications Officer
CRC for Australian Weed Management
PMB 1, Waite Campus
Glen Osmond, SA 5064
tel  08 - 8303 6857
fax  08 - 8303 7311
mob  0419 184 153
e-mail: rita.reitano at adelaide.edu.au


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