Effect of intensity and duration of anthropic noises on European mink locomotor activity and fecal cortisol metabolite levels

Abstract

Human activities involving noise emission can affect wild animals. European mink was exposed to road noise and human voice playbacks to analyse how sound intensity level and duration of both noises altered the time that individuals were active and if their faecal cortisol metabolite (FCM) levels varied. A Hierarchical Analysis Cluster was performed to established two mink groups with respect to both noise source type: short duration/low intensity (SL) and long duration/high intensity (LH). We performed General Linear Mixed Models to evaluate the variation in locomotor activity duration (s) and FCM (ng/g) levels, respectively. The results showed both road noise and human voices decreased locomotor activity duration in SL more sharply compared to LH, and human voices were the triggers that induced the most pronounced response to both exposure conditions. FCM levels increased in SL compared to LH during road noise while the opposite happened during human voices. Differences based on sex and age of individuals were observed. In conclusion, noise characteristics given by the sound type determined the variations in locomotor activity duration while noise exposure level determined the variations in FCM levels. Attention should be paid to noisy activities (e.g. recreational activities for visitors in protected natural areas) and loud groups of people to conserve wildlife, especially noise sensitive species.

Is reproductive management for oestrus detection a stressful routine for female European mink (Mustela lutreola)?

“…progesterone (involved in gestation) and oestradiol (involved in the ovulatory cycle). Faecal samples were classified as fresh if they showed no signs of dehydration and had a strong odour (Barja et al 2012, Ortiz-Jiménez et al 2022). All samples were stored in individually sealed bags and labelled with the date and name of the female.…”

“…The faecal samples were first dried at 90 °C in an oven for 24 h to eliminate any moisture (Ortiz-Jiménez et al 2022), and each was homogenised to prevent any potential bias caused by steroids being distributed unevenly throughout the faeces (Barja et al 2012). We weighed 0.5 g from each sample and added 2 ml of phosphate buffer and 2 ml of methanol.…”

“…The concentrations of cortisol, testosterone and progesterone metabolites in the faecal samples were determined using commercial enzyme immunoassays (EIAs; DEMEDITEC Diagnostics, Kiel, Germany), which had previously been validated for measuring faecal steroid metabolites in European mink (Ortiz-Jiménez et al 2022), i.e. each EIA was specifically validated for quantifying each faecal hormone metabolite (FHM) through parallelism, accuracy and precision tests (Goymann et al 1999, Young et al 2004).…”