How long do anti-predator interventions remain effective? Patterns, thresholds and uncertainty

• Main Authors: Igor Khorozyan, Matthias Waltert
• Format: Article
• Language: English
• Published: The Royal Society 2019-09-01
• Series: Royal Society Open Science
• Subjects: carnivore; habituation; livestock; non-invasive intervention; nuisance animal
• Online Access: https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.190826

Human–predator conflicts are globally widespread, and effective interventions are essential to protect human assets from predator attacks. As effectiveness also has a temporal dimension, it is of importance to know how long interventions remain most effective and to determine time thresholds at which effectiveness begins to decrease. To address this, we conducted a systematic review of the temporal changes in the effectiveness of non-invasive interventions against terrestrial mammalian predators, defining a temporal trend line of effectiveness for each published case. We found only 26 cases from 14 publications, mainly referring to electric fences (n = 7 cases) and deterrents (n = 7 cases). We found electric fences and calving control to remain highly effective for the longest time, reducing damage by 100% for periods between three months and 3 years. The effectiveness of acoustical and light deterrents as well as guarding animals eroded quite fast after one to five months. Supplemental feeding was found to be counter-productive by increasing damage over time instead of reducing it. We stress that it is vital to make monitoring a routine requirement for all intervention applications and suggest to standardize periods of time over which monitoring can produce meaningful and affordable information.