Mouse Ecology Project

The challenge

The changes in Australian farming systems may have inadvertently increased problems caused by mice

Farming systems in Australia have changed significantly over the last 10-20 years, bringing in advances in conservation agriculture such as minimum tillage, stubble retention and diversified crop rotations. These practices increase profitability, break disease cycles and benefit soil properties (improving soil organics, soil structure, soil moisture and soil nutrients from crop residues and nitrogen from legumes). No tillage farming practices have led to significant benefits for Australian grain growers. Farming systems are more resilient to a variable climate and more sustainable.

These changes in Australia farming systems may have inadvertently increased problems caused by mice. House mice undergo periodic and irregular outbreaks and sometime mouse plagues cause widespread damage. The new farming systems provide more cover (from retention of crop residues), more food (from increased cropping intensity) and less disturbance (from reduced tillage) meaning that mice are now living permanently in undisturbed mouse 'warrens' in crops rather than retreating to crop margins (like fencelines and scrub habitats) as they did in the past under conventional tillage systems when multiple ploughings were common.

These zero- or no-till farming systems have implications for the management of mice, as they appear to be more prevalent than in the past. There is now an increasing reliance on the use of zinc phosphide grain baits for control of mouse populations, to such an extent that some growers are baiting mice at sowing each year irrespective of mouse numbers.

Our response

Gaining a better understanding of the ecology of mice

To gain a better understanding of the ecology of mice in no tillage cropping systems we need to know:

1. How to reduce food supply? This might include, seed destroyers, windrows and burning, chaff lines, strategic ploughing, and a better understanding of caching and foraging behaviour.
2. How to reduce favourable habitat? This might include rolling and slashing stubble, grazing sheep, windrows and burning.
3. How important are mouse burrows? How do they persistent over time and how do they affect the way mice use the habitat around the burrows?
4. How to improve mouse management? This might be through a better understanding of how mice use different habitat components in the farming systems, where they breed, where they feed and how they respond to management efforts.

The results

A range of methods to monitor mice

We are using a range of methods to monitor mice and their interaction with crops, including:

• breeding dynamics, survival, recruitment of mouse populations
• predation risk (measured through 'giving up densities')
• dispersal and movement patterns (using spool-and-line tracking technique and radio telemetry to measure burrow use, foraging areas and home range size)
• distribution and survival of mouse burrows over time
• food availability (how much grain is left on the ground over time)
• mouse damage to crops (using caged enclosures to measure mouse damage).

This project is funded by GRDC: 'Understanding mouse biology and ecology in zero- and no-till cropping systems to inform best practice crop production and mouse management practices'.