Bushland Weeds Manual - Environmental Weeds Action Network

iv
Introduction
The Banksia, Tuart and Jarrah woodlands, the
shrublands and the species-rich heathlands of the Swan
Coastal Plain and Darling Plateau are wonderful places.
They contribute to Perth’s unique natural landscapes,
provide a window into the natural world, habitat for
native fauna and support an extraordinarily diverse
flora. They are fast disappearing though, mostly under
urban development. Those bushlands that remain face
a range of threats; one of the most serious is invasion
by environmental weeds.
The concept of environmental weeds is still relatively
new. Although the weediness of plants like Bridal
Creeper and Watsonia have become entrenched in the
public psyche, there is some way to go before the wider
community accepts the extent of the problem. For
example, Harlequin Flower (Sparaxis bulbifera) threatens
one of the last remaining clay-based wetlands on the
eastern side of the coastal plain and yet the species was
available this year from a fundraising catalogue in at
least one local primary school. Still, it is evident that
many people do recognise the threats. Increasingly,
community volunteers and state and local governments
are involved in on-ground actions to protect bushland
from the impacts of environmental weeds.
With few resources available, maximising the positive
outcomes of these professional and voluntary efforts is
critical. For those working on the ground, information
on identification and control is available from a number
of good books: Managing Perth’s Bushlands (Scheltema
and Harris 1995), Southern Weeds and their control
(Moore and Wheeler 2002), Bush Invaders of South-East
Australia (Muyt 2001), Western Weeds. A guide to the
weeds of Western Australia (Hussey et al. 1997) and
Environmental weeds: a field guide for SE Australia
(Blood 2001). Importantly, this kind of information
needs to be taken and applied in the context of
particular bushland areas. There are no simple
formulas and effective management begins with an
understanding and a knowledge of each site.
It was with this in mind that, in 1998, the Environmental
Weeds Action Network (EWAN), with funding from the
Natural Heritage Trust, employed a project officer to
work with community volunteers and local and state
government land managers at bushland sites across
Perth’s Swan Coastal Plain. The underlying objective
was to help the various land managers to develop
strategies for effective weed management in their
bushlands. This manual has grown out of that project.
The aim of the manual is firstly to bring together
information on the biology and known control methods
for the serious weeds of bushlands of the Swan Coastal
Plain and Jarrah Forest. Secondly, it is to illustrate,
with examples and case studies, how this sort of
information can be used to manage weeds in the
context of particular sites. Hopefully this will provide
the reader with the basic knowledge and the
framework needed to begin effectively managing the
weeds in their own bushlands.
Chapter one provides descriptions of bushlands from
where the case studies and examples throughout the
text are drawn. Chapter two covers some general
principles that should guide weed management in
bushland, including the kind of area-specific information
required before setting weed management priorities.
The next four chapters each cover a different group or
lifeform of weeds. The first three groups are all herbs –
green non-woody plants: Chapter three covers the
grasses, chapter four herbs that die back to corms,
bulbs or tubers over summer (geophytes) and chapter
five broadleaf herbs, sedges and succulents. The final
group, chapter six, includes all the woody plants and a
few climbers that are technically herbs, but have
control strategies in common with woody climbers.
Individual chapters look at the general biology of each
weed group and how it relates to dispersal, spread,
control and management. Case studies examine control
of certain species at particular sites and discuss the
management approach taken. They often describe the
set-up of trials and monitoring programs. Each weed
group has a corresponding table containing a summary
of information, gathered from a wide range of sources,
on the biology and control of weeds occurring in
bushland of the Swan Coastal Plain and Jarrah Forest.
The list is based on ‘A Checklist of the naturalised
vascular plants of Western Australia’ (Keighery 1999a)
and includes species that can have an impact on
biodiversity and hamper restoration and regeneration
efforts. Finally there are chapters on how to map weed
populations in urban bushland, an integral part of weed
management and on the issues arising from the use of
herbicides in bushland.
Ideally, this manual will impart enough information for
the reader to devise a strategy for management of their
serious bushland weeds. At the same time the authors
want to highlight the complexities involved in working
in Perth’s bushlands; diverse and wonderful places to
get to know and understand. The following chapter
provides detailed descriptions of some of those
bushlands along with the serious weeds that threaten
them and the people who are managing them.