Impacts of rodent outbreaks on food security in Asia Grant R. Singleton A,D , Steven Belmain B , Peter R. Brown C , Ken Aplin C and Nyo Me Htwe A A International Rice Research Institute, Crop and Environmental Sciences Division, DAPO, Box 7777, Metro Manila, Philippines. B Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK. C CSIRO Sustainable Ecosystems, GPO Box 284, Canberra, ACT 2601, Australia. D Corresponding author. Email: g.singleton@cgiar.org Abstract. Since 2007, a spate of rodent outbreaks has led to severe food shortages in Asia, affecting highly vulnerable and food-insecure families. Little has been documented about wildlife-management issues associated with these outbreaks. The aims of the present study were to synthesise what we know about rodent outbreaks in Asia, and identify important gaps in our knowledge. We compiled information from agencies of the United Nations, non-government organisations and the authors. The authors conducted site visits to areas affected by outbreaks of rodent populations, and convened an international conference in October 2009 to share knowledge. Bamboo masting is clearly implicated as the primary cause of the rodent- population outbreaks that led to severe food shortages in Mizoram (India), Chin State (Myanmar), Chittagong Hill Tracts (Bangladesh) and upland provinces of Lao PDR. In Laos, emergency food assistance was required for 85 000–145 000 people. In 2009, high rodent losses occurred also in lowland irrigated rice-based systems in the Philippines, Myanmar and Indonesia, not related to bamboo masting. Asynchronous or aseasonal growing of rice crops was a common element in these outbreaks. In the Ayeyarwaddy delta, Myanmar, 2.6 million rats were collected in 3 months through community activities; this outbreak appeared to be related to an extreme climatic event, Cyclone Nargis. There are two key features of rodent outbreaks that make the future uncertain. First, climate change and extreme climatic events will increase impacts of rodents on agricultural production. Second, there is food-security pressure in some countries to grow three crops per year. Increased cropping intensity will reduce fallow periods and create ideal conditions for rodents to breed nearly continuously. Implications of the research are as follows: (i) rodent outbreaks are a consequence of enhanced reproduction and natural mortality is of minor importance, particularly with rapidly increasing populations; therefore, we need to focus more on methods for disrupting reproduction; (ii) a stronger understanding of the ecology of pest species and community dynamics will enable ecologically sustainable management; (iii) we need landscape approaches that focus on crop synchrony, and timely coordinated community action to manage pest species and conserve desirable species; and (iv) a simple monitoring system can help implement ecologically based rodent management. Rodents – a continuing menace to food security ‘Nature has sent the rats to our homesteads by thousands, and farmers are being eaten off the face of the earth by them.’ This quote from H. C. Bartley (1911) appeared in his book Studies in the art of rat catching. After a career spent catching rats and rabbits in England for a living he wrote this book as a reference for teaching this profession at schools. The book was dedicated to the Headmasters of Eton, Harrow, Westminster and Rugby. A modern version of this book is urgently needed in Asia, where rodents are continuing to cause both chronic and acute impacts to the livelihoods of smallholder farmers (Singleton 2003; Palis et al. 2008; Jacob et al., in press), and there is a dearth of people with the skills to assist farmers manage the problem (Singleton 2003). These farmers typically have holdings of less than 1.5 ha in the intensive lowland agro-ecosystems (Maclean et al. 2002) or 5–10 ha of marginal cropping lands in the sloping uplands (Brown and Khamphoukeo 2010). In Asia, more than 640 million people suffer from chronic hunger (FAO 2009) and the majority rely on agriculture for their subsistence. Globally, in countries where under-nourishment is prevalent, the total cereal production is almost 1.4 billion tonnes. A recent analysis indicated that what rodents eat and spoil globally could feed ~280 million people in developing countries for a year (Meerburg et al. 2009a). In Asia, rodents cause, on average, annual pre-harvest losses of 5–10% in rice crops (Singleton 2003). However, occasional outbreaks of rodent populations can lead to severe crop losses, particularly in upland environments where such losses can lead to major food shortages (Aplin et al. 2006; Normile 2010). Not included in these estimates of rodent impacts are the substantial economic and human hardships associated with debilitating rodent-borne diseases (Meerburg et al. 2009b). Diseases such as leptospirosis, murine typhus and scrub typhus are readily treated if diagnosed early. However, in many Asian and Pacific countries diagnosis is often too late and the death rate in some instances is greater than for higher- profile illnesses such as HIV-AIDS (Table 1). In 2008 in Fiji, CSIRO PUBLISHING Viewpoint www.publish.csiro.au/journals/wr Wildlife Research, 2010, 37, 355–359 Ó CSIRO 2010 10.1071/WR10084 1035-3712/10/050355