Project Leader: Dr Tony Grice, CSIRO Sustainable Ecosystems,
Application of research | Research Progress | Interactions between fire and grazing | Effect of fire on fauna | Effect
of fire on riparian vegetation | Future
directions | Publications |
Project Team |
Towers of rubbervine shroud trees alongside the
Burdekin River, north Queensland
Photo: Kate O'Donnell
Rubber vine ( Cryptostegia grandiflora ) is an exotic
woody weed that poses a significant threat to northern Australian
savanna landscapes. It has already invaded a large portion of
northern and eastern Queensland and bio-climatic analysis suggests
that it is capable of growing across northern sections of the
Northern Territory and Western Australia. The species poses a major
problem for pastoral industries and presents a considerable threat
to conservation values. It is particularly prevalent in riparian
Experimental work since the early 1990s has demonstrated that
rubber vine is prone to fire. Intense fires kill most seedlings and
juvenile plants and a large proportion of adults, as well as
causing seed mortality. These results indicate that fire has
general potential as a tool for the management of rubber vine. Its
specific potential for riparian environments must be examined
further. In particular it is necessary to document the impacts of
riparian burning on both rubber vine and non-target species and
This project addressed three questions:
- What are the short- and medium-term effects of fire on rubber
vine in riparian habitats?
- What are the effects of fire on representative plant and animal
taxa of north Queensland riparian environments?
- How does rubber vine affect the structure and composition of
the native plant and animal communities of riparian
This project will help delineate how invasive species influence
landscape health. It will also provide recommendations regarding
the use of fire for the large-scale management of rubber vine in
riparian landscape zones. Recommendations will be built on an
understanding of the responses of rubber vine to different fire
regimes and knowledge of the impacts of prescribed burning on
non-target plant and animal species.
Weed management in extensive savannas present particular
challenges. Rubber vine occupies very large areas of northern
Queensland and there are few economic management options for
This project has been able to demonstrate the application of one
technique - fire - for managing rubber vine in the all-important
riparian environment. It is especially significant because of the
scale of the demonstrations involved. The approach is particularly
relevant to Burdekin Catchment where the vegetation is structurally
and compositionally similar to that of the study sites. Several
landholders in the vicinity of the study area have begun to use
fire specifically to control rubber vine.
The research would not have been possible without the
collaboration of members of the Seventy Mile Range Landcare Group
and the Mount Cooper Bushfire Brigade. Linkages with these groups
facilitated effective communication of the work's results to
landholders who are confronted by the practical challenges of weed
management in the region.
The project will also feed outputs into the Information
Clearinghouse, the Graduate Diploma and Master of Tropical
Environmental Management, and modules of the extension project.
These will be coordinated under the Human Capability Development
Research findings will also feed into the North Australia
Landscape, Ecosystem Management and Landscape Processes themes.
This will allow us to produce integrated research findings into an
overview of savanna health and how to manage savanna landscapes.
The findings from the project will also play a role in the Burdekin
Catchment Management Study.
The project is assessing the impact of using
fire to control rubbervine Photo: CSIRO
This experiment was designed to incorporate burning treatments
at a scale that is relevant to the practical management of rubber
vine. To achieve this, each of the three replicate experimental
sites encompasses 2-3 km of creek line and the adjacent uplands.
Each site is located on a separate tributary of the Burdekin River.
At each site, five plots were established in 1999 and, following
collection of baseline data, prescribed fires were imposed. The
experimental design allowed for each of five burning regimes to be
imposed on one of the five plots at each site. These treatments
- burned once on the dry season;
- burned once in the wet season;
- burned twice in successive dry seasons;
- burned twice in successive wet seasons.
For the sake of this work, 'wet' and 'dry' seasons were defined
in terms of the phenological status of the rubber vine; namely,
whether rubber vine was in leaf (wet season) or leafless (dry
season, taking into account defoliation by biological control
agents). The woody and herbaceous composition of each plot was
Initial burning treatments were imposed in the 1999-2000 wet
season and the 2000 dry season. Fuel loads prior to these fires
were 3000-4000 kg/ha though not evenly distributed, resulting in a
variation of fire intensity in different areas. At least some of
this variation in fire intensity is attributable to the presence
(and uneven distribution of) rubber vine itself. Low-intensity
fires especially will often not penetrate dense stands of rubber
vine and in this way the weed can reduce land-management options
and so impinge upon landscape health.
In spite of the differing character of the prescribed fires,
their overall impact on rubber vine was considerable. For example,
a single wet-season fire reduced the density of rubber vine from
2147 to 1165 plants per hectare. These fires did not cause
significant changes in the densities of most species of native
trees and shrubs. Most shrub species sprouted from the base even
when they had been subjected to intense fires. The fires stimulated
germination of Acacia spp., notably Acacia holosericea. After
burning, the herbaceous layer remained dominated by the exotic
stoloniferous grass Bothriochloa pertusa (Indian couch) and native
perennial tussock grasses, though there was an increase in the
abundance of native legumes. In the dry season after burning,
herbaceous biomass was lower on burned plots than on unburnt
There were obvious interactions between the effects of burning
and the effects of grazing. These interactions would need to be
considered in developing practical fire-management strategies for
rubber vine fire. Importantly, the concentration of cattle on the
unfenced experimentally burnt plots meant that the annual burning
regimes of the design could not be followed. Although the paddocks
carried sufficient fuel to support a fire, the low fuel loads meant
that the fires would not have been effective against rubber vine.
It was seen as preferable to delay the second round of fires to
give two years between fires. A regime consisting of fires in years
one and three of a 10-year cycle would allow for two fires of
adequate intensity and sufficiently close in time to be very
effective against rubber vine. For rubber vine management on
pastoral properties it will always be essential link a fire
management program with a grazing management plan.
The impacts of riparian burning for rubber vine management on
two important faunal groups, birds and reptiles, are also being
examined by James Cook University Masters student Leonie
Preliminary faunal surveys indicate that reptiles may be useful
indicator species to address impacts of burning. This is because of
the micro-scale of their habitat requirements and their key
position as major predators of another major element of
biodiversity, the arthropods. An additional question to be
addressed is what effect rubber vine itself has on biodiversity.
Early observations suggest that there was less reptile diversity in
dense rubber vine infestations than elsewhere in riparian
To the extent that data have been analysed so far, it is
apparent that the side-effects of individual fires on non-target
components of the riparian communities are tolerable. This
observation must be interpreted in the light of the fact that
effects were of single fires in a single type of riparian
vegetation. The results should not be interpreted to mean that
riparian vegetation in general is tolerant of fire or that the
specific riparian communities that were studied would be resilient
in the face of frequent burning.
At present this project will end in December 2001. By December
2001, the full complement of planned wet season experimental fires
will have been imposed; our current plan is to complete dry-season
burning by October 2002. Their effects should be documented over
the subsequent 12 months.
The results of this project raise the importance of the
interactions between grazing and fire. This lies in the impact that
grazing has on the landholders capacity to impose fires of a type
that will have a useful impact on populations of rubber vine.
Another issue that should be considered involves the
interactions between weed species. Most savanna systems are under
threat from more than one weed species. Management that targets one
species may open opportunities for invasion by others. This demands
that attention be given to understanding and managing 'weed
complexes' that may include species of a variety of growth forms
and functional responses.
Grice, A.C., Radford, I.J and Abbott, B.N.
2000, 'Landscape and regional-scale patterns of shrub invasion in
tropical savannas,' Biological Invasions, 2:187-205.
Grice, A.C. and Campbell, S.D. 2000, 'Weeds in
pasture ecosystems: symptom or disease', Tropical Grasslands,
Campbell, S.D. and Grice, A.C. 2000, 'Weed
biology: a foundation for weed management,' Tropical Grasslands,
Grice, A.C., Campbell, S.D. and Vitelli, J.S.
2000, 'The principles and practice of weed control for northern
Australia', Proceedings of the Northern Grassy Landscapes
Conference, Tropical Savannas CRC, Darwin.
Dr Tony Grice, CSIRO Sustainable
Dr Ian Radford, CSIRO Sustainable Ecosystems
Lindsay Whiteman, CSIRO Sustainable Ecosystems
Michael Nicholas, CSIRO Sustainable Ecosystems
Dr Shane Campbell, Queensland Dept Natural Resources and Mines
John McKenzie, Queensland Dept Natural Resources and Mines
Tony Johnson, Queensland Dept Natural Resources and Mines
Exotic grass species in tropical savannas of northern Australia
Fire and weeds: what works, what doesn't
Article on the impact of fire on woody weeds and how it affects management decisions. From Savanna Links, Issue 19, July - Sept 2001 [read more...
Fire burns out large-scale riparian threat
Rubbervine research in Queensland has shown fire to be an effective control method. From Savanna Links, Issue 22, May - July 2002 [read more...
Biosecurity Queensland potential distribution map for Rubber Vine Cryptostegia grandiflora (Queensland)
This map, on the Biosecurity Queensland Website, predicts the potential distribution of Rubber Vine Cryptostegia grandiflora throughout Queensland (PDF file, 405 kB)
Control methods and case studies – Rubber Vine management
Link to a PDF file outlining control methods and case studies of Rubber Vine - published May 2004 by Qld Department of Natural Resource Management, Natural Heritage Trust and the National Rubber Vine Management Group.
Fire management of Rubber Vine
Link to an article outlining fire management techniques for the control of rubber vine.
Management Guide for Rubber Vine Cryptostegia grandiflora
This colourful weed management guide for Rubber Vine Cryptostegia grandiflora has information about why Rubber Vine is a problem; how it spreads; where it grows; how to control it; and the legislative requirements for controlling it in each of the states or territories in which it occurs. It is well illustrated, and has an example of where control has been attempted. (PDF file, 506 kB)
Rubber Vine - Queensland Government information
Description of Rubber Vine: Source, Distribution (source, spread, current and potential)& Control, by the Queensland Department of Natural Resources, Mines and Water, Pest Status Review Series - Land Protection Branch.
Weeds of National Significance:Rubber Vine
Links to downloadable Management Manuals, Management Guides, Strategic Plans and Distribution Maps.