Assessing the disturbance potential of small unoccupied aircraft systems (UAS) on gray seals ( Halichoerus grypus ) at breeding colonies in Nova Scotia, Canada

PeerJ

article

Lauren Arona¹  Julian Dale¹  Susan G. Heaslip¹  Michael O. Hammill²  David W. Johnston¹ 

[1] Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University Marine Laboratory;Institut Maurice-Lamontagne/Maurice Lamontagne Institute

关键词: Disturbance;    Marine mammals;    Grey seal;    UAS;    Drone;    Unoccupied aircraft system;    Acoustic;    Noise;    Abundance estimation;    Aerial surveys;   

DOI  :  10.7717/peerj.4467

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The use of small unoccupied aircraft systems (UAS) for ecological studies and wildlife population assessments is increasing. These methods can provide significant benefits in terms of costs and reductions in human risk, but little is known if UAS-based approaches cause disturbance of animals during operations. To address this knowledge gap, we conducted a series of UAS flights at gray seal breeding colonies on Hay and Saddle Islands in Nova Scotia, Canada. Using a small fixed-wing UAS, we assessed both immediate and short-term effects of surveys using sequential image analysis and between-flight seal counts in ten, 50 m2 random quadrats at each colony. Counts of adult gray seals and young-of-the-year animals between first and second flights revealed no changes in abundance in quadrats (matched pair t-test p 0.69) and slopes approaching 1 for linear regression comparisons (r2 0.80). Sequential image analysis revealed no changes in orientation or posture of imaged animals. We also assessed the acoustic properties of the small UAS in relation to low ambient noise conditions using sound equivalent level (Leq) measurements with a calibrated U-MIK 1 and a 1/3 octave band soundscape approach. The results of Leq measurements indicate that small fixed-wing UAS are quiet, with most energy above 160 Hz, and that levels across 1/3 octave bands do not greatly exceed ambient acoustic measurements in a quiet field during operations at standard survey altitudes. As such, this platform is unlikely to acoustically disturb gray seals at breeding colonies during population surveys. The results of the present study indicate that the effects of small fixed-wing UAS on gray seals at breeding colonies are negligible, and that fixed-wing UAS-based approaches should be considered amongst best practices for assessing gray seal colonies.

【 授权许可】

CC BY