Epsilon Archive for Student Projects

Abstract

European polecat (Mustela putorius) populations are reported to be declining in a large part of its range. The species is listed in Annex V of the Habitat Directive, which requires periodical monitoring and reporting of its conservation and distribution trends. However, many countries lack monitoring data for polecats and suitable monitoring methods are missing. In Sweden, the only available data comes from 1) hunters that report their bags and 2) sightings. Robust methods are missing. Therefore, a method for systematic monitoring is needed to get updated data about the polecat distribution and population size.
In this study I tested a newly developed tube-lure system (“polecam”) in four study sites in southern Sweden. I did this by placing 49 polecams during a period of two months in both spring (March-April) and fall (September-October) 2021. I related which landscape features influenced the detection probability: the distances from each polecam to the nearest buildings and main roads, the length of hedgerows in a 45m radius buffer around each polecam and a protective cover index (score 1-10) measured in the field. Furthermore I tested if the I3S-software was able to semi-automatically identify polecats in the study sites and were able to photograph their facial masks. However, it was not possible to identify individuals with the software I3S. My analyses of the landscape features showed, in contrast to my expectation, a high detection probability close to main roads, while other landscape features were not associated with the polecat detection. Further adaptions of the polecam and more studies about the landscape features, but also openness about alternative approaches is needed, to be able to develop a robust monitoring system.