Rodent Management Research Focus
The Challenge
- More than 40% of the world’s mammal species are rodents.
- About 10% of rodent species are significant pests in agricultural and urban environments.
- About 90% of rodent species play an important role in ecosystems:
- as prey for native species,
- limiting growth in invertebrate populations,
- as ecological engineers through influencing water infiltration (eg. burrows, dams) and flow of nutrients,
- as seed dispersers.
Our Research Focus
- Whole of systems approaches in complex landscapes - incorporating agricultural production, conservation, wildlife and pest management.
- Managing rodents as pests, or for conservation, through understanding the ecology of particular species.
- Identifying factors that influence rodent pest populations.
- Devising sustainable management strategies to significantly reduce pest economic and social impact.
Background
>> The mouse problem in Australia
>> The rat problem in Asia
We have 20 years of research experience in the biology and management of rodents and other invasive mammal species. The team undertakes research in conservation biology and systematics of small mammals (see Projects & Activities). We are actively engaged in collaboration and consultancies to solve specific rodent management problems (see Skills and Expertise).
The mouse problem in Australia
House Mouse Plagues
Mouse plagues are characterised by a concurrent widespread increase in mouse densities (over 750 mice per hectare). The density of mice in between plagues is generally < 10 mice/ha. Mouse plagues occur as a result of high quality food , good nesting sites and good breeding conditions . The role of diseases, predation and social structure are also important.
There have been mouse plagues in the grain-growing regions of south-eastern Australia since the turn of the century. Until about ten years ago, a mouse plague occurred somewhere in southern or eastern Australia on average every fourth year.
In recent years, farm management practices have changed to incorporate farming techniques which conserve soil, water, energy and labour. This conservation farming favours continuous, rotational cropping, greater diversity of crops, extended crop season, minimum tillage and stubble retention.
These activities may favour mice by providing more food and shelter, resulting in an increase in the intensity and frequency of plagues. Since 1980, there have been a staggering 7 outbreaks of mice in southeast Queensland, 3 in southern New South Wales, 3 in South Australia and 4 in Victoria.
Significance of Mouse Plagues
During plagues, mice are responsible for severe economic, social and environmental damage to the agricultural community. During an outbreak in southern Australia in 1993, mice caused estimated losses of more than $AU100 million. Grain-growers suffered significant crop loss and damage to stored grain, intensive livestock farmers experienced markedly reduced production levels, rural businesses endured mice spoiling stock and destroying electrical equipment.
Environmental problems arise through increased use of pesticides and the use of unregistered chemicals to control mice. There is also the obvious social burden and health risks associated with sharing a house, school or hospital with hordes of mice for periods of up to 6 months.
CSIRO Research on Mouse Plagues
Research by CSIRO since 1983 has provided a better understanding of the processes that lead to a mouse plague and of how mice use different habitats at different stages of plague formation. This knowledge of their ecology underpins our current research on mouse plague management in Australia.
We aim for a suitable balance between long and short term research, and we are fortunate to have the input of growers, agricultural departments and other researchers from around the country and from overseas.
The rat problem in southeast Asia
The problem of rodents, specifically rats, damaging crops has been with Southeast Asian farmers for centuries. With no effective sustainable method for control, farmers have had to adopt a level of tolerance of the pest. Progress is now being made by:
- managing the rodent problem by understanding the ecology of the pest species, and by
- working closely with farmers in a range of countries.
While rats cause damage to many agricultural and horticultural crops, probably the greatest impact is on rice crops.
With Asia's population likely to increase from 3.6 billion in 2004 to 4 billion by 2025, there is increasing pressure to reduce the impact of rats on the region's primary food source.
A current conservative estimate is that rodents in rice-growing regions typically cause annual pre-harvest losses of between 5 and 17%. A loss of 6% of rice production amounts to approximately 36 tonnes, enough rice to feed 215 million people (roughly the population of Indonesia) for one year. Rat damage is generally patchy, so it is not unusual for families or even villages to lose more than 50% of their crop to rats. Rats and Disease
There is a rise in concern over rodents as a health risk in rice agroecosystems because of the increase in travel of people between rural and urban areas and between countries; increased population density that amplifies the ability of a disease to spread through a population; and increased clearance of natural habitats that promotes rodent-human contact. In poorer communities, if a rodent zoonotic causes disability for a poor farmer for a month at a key time, then it may lead to no crop, a late crop, or reduced crop yield. Each can lead to debt treadmill.
For more information see the fact sheet "Rodents in SE Asia" (pdf file 524 Kb)
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