Project Leader: Dr Brian Cooke, Invasive Animals CRC
Aim: To assess the impact of rabbits on biodiversity in pastoral lands and farmlands, including on road reserves, stock routes and public amenities.
This project examines the impacts of rabbits on biodiversity. It looks beyond the impacts of rabbits on land that is used for wool and meat production and considers areas adjacent to farms such as roadside vegetation, water reserves and recreational areas of value to the broader community. It helps gauge the long-term loss of trees or shrubs, damage to pasture and weed invasion and competition with native fauna. Results will provide insight into the ways in which rabbits cause losses, such as over-grazing pasture, digging or scratching, or selective grazing in summer.
The project will provide a detailed review of the nature and severity of biodiversity losses. The review will help in developing a simple method of scoring rabbit abundance for use by people contributing to pest management.
The project uses desk-top research, a series of site surveys and involves testing of the rabbit abundance scoring method:
- A literature review documents the nature of rabbit impacts on biodiversity across a wide range of habitats in south-eastern Australia in different seasons. The review makes comparative studies between states and defining areas where the risk of rabbit damage is highest.
- The site surveys also provide an opportunity to evaluate proposed rabbit abundance assessment methods to ensure that they can be readily used by people who have no specific training or experience in rabbit management, and so that the results are consistent with more complex assessment methods.
- The assessment tool was tested on nine sites with a range of rabbit infestations and levels of damage. At least four people from a range of background tested the tool on each site and despite different levels of experience with assessing rabbit problems, all participants arrived at similar conclusions.
Alongside this work, the project manager is providing input to another project to measure the direct and indirect impacts of pest animals. The project results enabled researchers to conduct an economic assessment of the costs of rabbits on agricultural producers, measuring the production losses from rabbits. The work contributes to estimating future losses that may occur as a result of the decline in effectiveness of current management strategies.
- A simple method of scoring rabbit abundance was developed to estimate densities which are independent of seasonal variation in rabbit numbers or plant growth. A means of scoring biodiversity ‘risk’ using damage indices helped quantify the relationship between rabbit abundance and risk to natural biodiversity.
- A survey of 220 adjacent to farmlands in south-eastern Australia indicated that rabbits were present in 54 per cent of sites visited and were causing noticeable vegetation damage in about half the infested sites.
- The project demonstrated that low numbers of rabbits (1-2/ha) are capable of removing all seedlings of the more palatable native tree and shrubs and exacerbating weed competition with native flora.
- ‘Rabbits: A threat to conservation and natural resource management’ provides a guide on how to rapidly assess a rabbit problem and take action.
- Both the method and the guide were applied in the 2009 community mapping survey, RabbitScan (www.rabbitscan.net.au)
- Rabbits were demonstrated as costing $206 million annually to agricultural producers in production loss alone.
IA CRC, Australian Wool Innovation, Victorian Department of Primary Industries.
For further information, contact us.