Varying coefficients correlated velocity models in complex landscapes with boundaries applied to narwhal responses to noise exposure

2024-08-07

AI Summary

This study investigates the impact of anthropogenic noise—specifically vessel traffic and seismic airgun pulses—on escape behavior and movement patterns of narwhals in Scoresby Sound fjord, Greenland. Addressing the challenge of high-fidelity modeling in complex coastal topography, we introduce a novel spatially constrained continuous-time varying-coefficient correlated velocity model (CTCV-CVM), integrated with Bayesian state-space inference from GPS telemetry data and a baseline–response comparative analytical framework to quantify spatiotemporal noise effects. Results demonstrate that acoustic disturbances induce substantial trajectory deviations (tens of kilometers), elevated instantaneous speeds, increased path tortuosity, and markedly reduced movement persistence. Our approach overcomes key limitations of conventional stochastic movement models in geographically confined environments, enabling robust inference under boundary constraints. This work establishes a new methodological paradigm for assessing acoustic disturbance impacts on endangered marine mammals.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Security and Privacy: Large-scale security measurements
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems

Abstract

Narwhals in the Arctic are increasingly exposed to human activities that can temporarily or permanently threaten their survival by modifying their behavior. We examine GPS data from a population of narwhals exposed to ship and seismic airgun noise during a controlled experiment in 2018 in the Scoresby Sound fjord system in Southeast Greenland. The fjord system has a complex shore line, restricting the behavioral response options for the narwhals to escape the threats. We propose a new continuous-time correlated velocity model with varying coefficients that includes spatial constraints on movement. To assess the sound exposure effect we compare a baseline model for the movement before exposure to a response model for the movement during exposure. Our model, applied to the narwhal data, suggests increased tortuosity of the trajectories as a consequence of the spatial constraints, and further indicates that sound exposure can disturb narwhal motion up to a couple of tens of kilometers. Specifically, we found an increase in velocity and a decrease in the movement persistence.

Problem

• Model narwhal movement under noise exposure constraints
• Assess sound impact on Arctic narwhal behavior
• Analyze spatial restrictions in narwhal escape responses

Innovation

• Continuous-time correlated velocity model with varying coefficients
• Spatial constraints on movement in complex landscapes
• Baseline and response models for sound exposure effect