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Predicting the population consequences of acoustic disturbance, with application to an endangered gray whale population.

Authors :
McHuron EA
Aerts L
Gailey G
Sychenko O
Costa DP
Mangel M
Schwarz LK
Source :
Ecological applications : a publication of the Ecological Society of America [Ecol Appl] 2021 Dec; Vol. 31 (8), pp. e02440. Date of Electronic Publication: 2021 Sep 19.
Publication Year :
2021

Abstract

Acoustic disturbance is a growing conservation concern for wildlife populations because it can elicit physiological and behavioral responses that can have cascading impacts on population dynamics. State-dependent behavioral and life history models implemented via Stochastic Dynamic Programming (SDP) provide a natural framework for quantifying biologically meaningful population changes resulting from disturbance by linking environment, physiology, and metrics of fitness. We developed an SDP model using the endangered western gray whale (Eschrichtius robustus) as a case study because they experience acoustic disturbance on their summer foraging grounds. We modeled the behavior and physiological dynamics of pregnant females as they arrived on the feeding grounds and predicted the probability of female and offspring survival, with and without acoustic disturbance and in the presence/absence of high prey availability. Upon arrival in mid-May, pregnant females initially exhibited relatively random behavior before they transitioned to intensive feeding that resulted in continual fat mass gain until departure. This shift in behavior co-occurred with a change in spatial distribution; early in the season, whales were more equally distributed among foraging areas with moderate to high energy availability, whereas by mid-July whales transitioned to predominate use of the location that had the highest energy availability. Exclusion from energy-rich offshore areas led to reproductive failure and in extreme cases, mortality of adult females that had lasting impacts on population dynamics. Simulated disturbances in nearshore foraging areas had little to no impact on female survival or reproductive success at the population level. At the individual level, the impact of disturbance was unequally distributed across females of different lengths, both with respect to the number of times an individual was disturbed and the impact of disturbance on vital rates. Our results highlight the susceptibility of large capital breeders to reductions in prey availability, and indicate that who, where, and when individuals are disturbed are likely to be important considerations when assessing the impacts of acoustic activities. This model provides a framework to inform planned acoustic disturbances and assess the effectiveness of mitigation strategies for large capital breeders.<br /> (© 2021 by the Ecological Society of America.)

Details

Language :
English
ISSN :
1051-0761
Volume :
31
Issue :
8
Database :
MEDLINE
Journal :
Ecological applications : a publication of the Ecological Society of America
Publication Type :
Academic Journal
Accession number :
34374143
Full Text :
https://doi.org/10.1002/eap.2440