Multiscale environmental determinants of rats' infestation on households in a subtropical urban to rural gradient in Latin America

Abstract

Strategies for the prevention and control of commensal rodents would improve with better knowledge of their response to environmental factors from different spatial scales. In this research we evaluated which different scales environmental characteristics determine rodent infestation levels in a subtropical urban to rural landscape gradient in Misiones, Argentina. A total of 87 households from an urban, a periurban and a rural landscape were surveyed at least once, with nine households surveyed repeatedly along five consecutive seasons. Rodent infestation levels were estimated using nontoxic bait stations set up in the backyard and garden of each household. Different environmental characteristics at several spatial scales were obtained from field surveys and land cover classification based on a satellite image. Rattus spp. was detected in 42.5% of the households. The lowest rodent infestations occurred in winter. Infestation levels showed spatial dependence up to 2500 m. Rodent infestation was associated with landscape types and environmental characteristics at the macro and microhabitat scales. Macrohabitat characteristics explained 53.7% of the variation of rodent infestation levels, whereas microscale explained 28.0% and landscape type only 2%. This multiscale study provides evidence that households’ characteristics may not be the most important factor to explain variations in the abundance of commensal rodents’ around human dwellings. As a consequence, prevention and control measures would be more effective if applied at the neighborhood level and during winter, since it is a critical time for preventing compensatory population responses in rodent infestations.