Population response of rodents to control with rodenticides

Abstract

We summarize theoretical approaches and practice of rodent pest control in Russia and former USSR during last 50 years. We review literature as well as original data to understand mechanisms of rodent populations recovery after chemical control campaigns in urban areas, agricultural lands and natural foci of plague. Laboratory and field experiments indicate that inherent individual variation in behavioural, physiological and life-history traits provides survival of heterogeneous mix of individuals in residual population with increased resistance to poisonous baits and high reproductive potential that leads to fast recovery of a population. In a series of field experiments with various rodent and lagomorph species (Mus musculus, Rattus norvegicus, Meriones unguiculatus, M.meridianus, M.tamariscinus, Ochotona pallasii) we have shown that patterns of recolonization of depopulated area and mechanisms of population recovery vary among species and depend on species-specific social organization. After control territorial and group-living species demonstrated an increase in mobility and affiliative and marking behaviour and a decrease in intraspecific aggression. The rate of recolonization of treated areas was high due to redistribution of survived individuals and immigration by neighbors. Population recovered to original level due to increased breeding performance and fecundity of both survived residents and immigrants. In contrast socially-independent species exhibited minor changes in behaviour. Recolonization was mainly due to better survival and recruitment of youngs, so the rate of recolonization was low. Species-specificity of behavioural compensation mechanisms to control should be considered when developing ecologically based rodent management strategies.

Recovery of small rodent populations after population collapse

“…In addition, several studies have investigated the regeneration of fish species after overfishing (Myers et al 1997;Fabrizio et al 2001;Fu et al 2001). In contrast, studies on the population recovery of small rodents after the application of rodenticide are rare and have not been reviewed, apart from that of Shilova and Tchabovsky (2009) for Russia and the former USSR.…”

“…A few studies have suggested that recovery also strongly depends on the species and particular life history strategy, as well as social behaviour (Gardmark et al 2003;Shilova and Tchabovsky 2009).…”

“…Interestingly, this does not seem to be the case. Instead, the results of empirical studies strongly suggest that social behaviour and density-dependent population response play an important role in the recovery mechanism (Shilova and Tchabovsky 2009). Species that use r-selection start forming social breeding units after a collapse in the population density.…”

“…It was claimed that the mechanism of recovery after population control with rodenticides strongly depends on life history strategy and the social behaviour of the particular species (Shilova and Tchabovsky 2009). For example, the population responses of Mongolian gerbils (Meriones unguiculatus) and Midday gerbils (M. meridianus) to pest control with rodenticides differs markedly even though these two species belong to the same genus (Shilova and Tchabovsky 2009; Table 2).…”

“…For example, the population responses of Mongolian gerbils (Meriones unguiculatus) and Midday gerbils (M. meridianus) to pest control with rodenticides differs markedly even though these two species belong to the same genus (Shilova and Tchabovsky 2009; Table 2). The highly social group-living Mongolian gerbils form new breeding units after a population collapse, leading to rapid recolonisation due to intense reproduction and recruitment of young.…”