Population Dynamics of Rodent Pest Species in Upland Farming Systems of Lao PDR

Abstract

Rodents are a significant problem to farmers in upland agricultural systems in Lao PDR. They are considered as the second most important pest after insects because they are the least controlled. There is little known about the factors that influence the breeding activity or changes in population numbers of the main rodent pest species in Lao PDR. There are a minimum of 21 species of murid rodents in Lao PDR, with six considered as important crop pests, among them being Rattus rattus. The other species generally cause little crop damage and are important for their conservation value in the upland forests. Trapping data revealed that the population abundance and breeding activity of rats changed over time in response to the availability of food resources. Peaks in population abundance in the field occurred during the harvest of wet season crops. Rodents then moved into village habitats, where population abundance was high during the fallow and early growing stages. Breeding activity was evident at all stages in the village, with a peak during the fallow stage, when abundant food was available in village stores. Little breeding was observed in the field during the fallow period, increasing to only moderate levels during the growing and harvesting stages. The village habitat is considered as an important habitat for rodents. Management needs to be focussed on limiting the movement of rodents between villages and fields and this needs to be conducted prior to the onset of breeding activity in the field.