A contribution for the calibration of an abundance index useful for large-scale monitoring of common vole

Resumen del póster presentado a la 10th European Vertebrate Pest Management Conference, celebrada en Sevilla (España) del 21 al 25 de septiembre de 2015.-- et al.Common vole (Microtus arvalis Pallas) recurrent population outbreaks have led to significant crop damages in the agricultural areas of Castilla y León (Spain), where over 5 million hectares are devoted to crops, meadows and pastures. Monitoring abundance changes, essential to efficiently implement preventive actions, in such a large area requires reliable but simple, cheap and quick monitoring tools. Methods based on activity signs can cover this need, but do not provide estimates of population density unless they are calibrated for specific environments. Capture-recapture trapping methods are considered the best way for estimating vole population density, so are useful for calibrating other methods, but results could be influenced by many factors: differences in individual capture probability according to sex, age or previous capture history; weather conditions; capture effort; home range size and shape in relation to trap distribution, etc. Careful flooding of burrows in a controlled surface provokes a disturbance for the individuals inside burrows, which they thus tend to flee; this behavior is independent of the factors affecting trapping methods mentioned above. If well done, mortality due to flooding is negligible and individuals trying to go outside are easily captured. In this contribution, an abundance index based in activity signs, usable for large scale-common vole monitoring, is calibrated with the minimum number of individuals alive provided by parallel controlled burrow flooding. A significant polynomial relationship between both methods has been detected (R2=0.79). We use this relationship to establish confidence limits to estimates of population density in relation to abundance levels.Peer Reviewe