Ecologically Based Rodent Management (EBRM)

Ecologically based rodent management has now taken center stage in Asia, Australia, and eastern Africa for management of rats in agricultural systems. This has not always been the case. In the 1960s, a wide range of chemical rodenticides became available on the global market. Research then focused on the toxicity of the poisons, on making them more palatable to the pests and less attractive to non-target species. Ecological studies of rodent pest species were an exception. With the development of resistance and increased tolerance of rodents to the rodenticides, and an increased awareness of ecological and human health issues associated with their use, attention in the mid-1990s turned back to ecology. People realized that we knew so little about the behavior, breeding ecology and habitat use of rodents that together drove their population dynamics.

The ecology of rodent pests is strongly influenced by the agricultural practices of smallholder farmers. And rodents are highly mobile, so if only a few farmers implemented good management practices, their crops would soon be reinvaded by rats from neighboring fields. Effective and sustainable ecologically-based rodent management therefore requires communities to become involved. Moreover, our understanding of the ecology of major pest species indicates that community management must be conducted much earlier than whatever farmers had been doing. We provide one example of EBRM for the ricefield rat, Rattus argentiventer; a species for which we have a reasonable understanding of its ecology in lowland rice-based landscapes. EBRM practices will vary for different species because their biology and ecology in specific agricultural landscapes are different.

Click here to view rodent ecologist Grant Singleton as he talks about EBRM and its uptake in Asia and soon Europe, and more.

Integrated actions to manage the ricefield rat, Rattus argentiventer, in lowland irrigated rice

In Indonesia, ecological studies in lowland irrigated rice fields provide the following MUST DO activities at a community level for effective management of the ricefield rat in rice.

• Synchronize planting of crops within 2 weeks of one another; otherwise the breeding season of the ricefield rat is extended, leading to exponential population growth; 
• Conduct community campaigns before the ricefield rat breeding season using local methods, such as trapping and fumigation, to control rats within 3 weeks of planting the crop; these community actions usually focus on village gardens, main irrigation channels, and roadsides; 
• Keep irrigation banks less than 30 cm wide to make it difficult for rats to build nests; 
• Clean up any grain spills at harvest and practice good hygiene around houses and gardens. 

Additional technology if chronic losses are greater than 10%

One simple technology added to the armory of rice farmers is a trap-and-fence system known as the Community Trap Barrier System. It comprises a plastic fence surrounding a small rice crop (20 x 20 m) planted 2-3 weeks earlier than the surrounding crop, with traps set into the plastic. At night, rats follow the line of the plastic until they reach a hole, which they enter to reach the rice but instead are caught in a trap.