A comparison of methods for estimating common vole (Microtus arvalis) abundance in agricultural habitats

摘要

Rodent outbreaks cause significant crop damages in agricultural areas worldwide, but routinely monitoring large areas at low cost remains a challenge. The common vole Microtus arvalis has recently colonized the agricultural plains of the northern Iberian Plateau, an area where it has started to produce population outbreaks with important impacts in agriculture, the environment and human health. Vole monitoring has become of prime importance to implement preventive management measures to control populations. In order to find a simple and reliable vole monitoring method to be applied in large areas, we compared abundance estimates derived from three methods: capture-mark-recapture (CMR), single capture events (SCE) and presence/absence of vole activity signs (VAS) during three seasons and on the main agricultural habitats in the study area. We show that an activity index based on the presence of fresh droppings and/or clippings had a similar performance to SCE in a large sample of plots (n=222) across habitats and seasons. Data obtained with both methods (SCE, VAS) were also well correlated with those obtained with CMR, despite a limited sample size (n= 23 CMR plots). We suggest that the VAS method, which is a cheaper and easier alternative to trapping methods, provides a promising tool for scientists and managers to implement large scale monitoring of common vole in agricultural areas.