Spatial ecology to strengthen invasive snake management on islands

Abstract

Abstract Knowledge on invasive predator spatial ecology positively contributes to optimizing their management, especially when involving cryptic and secretive species, such as snakes. However, this information is lacking for most invasive snakes, particularly on islands, where they are known to cause severe ecological and socio-economic impacts. We focused our research on compiling spatial ecology information of the California kingsnake in Gran Canaria to directly transfer our results to strengthen management actions. We monitored 15 radio-tagged individuals once per day during 9-11 days per month from July 2020 to June 2021 to calculate the species home range and describe annual activity patterns in the invaded range. We also performed a 3 consecutive days monitoring between January and May 2021 in four different time intervals each day to account for the species diel activity during the emergence period. We detected movement in 31.68 % of all detections, with a mean of 24.20 ± 12.00 moves for all individuals during the whole monitoring period. Most frequent movements detected were shorter than 20 m—82.24 % of the movements were shorter than 100 m—with a mean distance of 62.57 ± 62.62 m in 1-2 days. AKDE 95 % contour home range was 4.27 ± 5.35 ha, and was independent on SVL and sex. We detected an extremely low value of motion variance (0.76 ± 2.62 m), with a general inactivity period from November to February, January being the less active month. Diel activity was higher during central and evening hours than during early morning and night. These results allow to more robustly planning a trapping and capture strategy of this invasive snake in Gran Canaria and will guide the daily work of the management staff. Additionally, our research highlights the importance of gathering spatial information on the target species to enhance control strategies, which can contribute to the management of secretive invasive snakes worldwide.