The Relationships Between Rodent Control Efforts, Abundance, Damage, and Outcomes.

Rodents cause damage to agricultural crops and biodiversity. Rodent control occurs to reduce damage and ideally increase crop yield and biodiversity. So, do control efforts increase outcomes, such as yield? The sequence of relationships between control, rodents, damage, and outcomes is examined for empirical evidence of each. Simple, general models of relationships are described and elaborated for control effort-outcome relationships. Two models, the logarithmic and inverse models, assume diminishing returns and accelerated losses, and one model, the linear model, assumes no diminishing returns and no accelerated losses. The results show there are many studies of rodent control and rodent damage; however, few empirical studies of relationships between rodent control efforts and outcomes, such as crop yield. The rodent control effort-outcome relationship should be estimated more frequently, ideally using randomized regression-design experiments and diminishing returns and accelerated losses evaluated as part of causal inference.