Abstract
The Arctic and its adjacent ecosystems are undergoing rapid ecological reorganization in response to the effects of global climate change, and sentinel species provide critical updates as these changes unfold. This study leverages emerging remote sensing techniques to reveal fine-scale drivers of distribution and terrestrial habitat use of two sympatric sentinel species of the central Bering Sea, the Pacific harbor seal (Phoca vitulina richardii (Gray, 1864)) and the northern fur seal (Callorhinus ursinus (Linnaeus, 1758)), at non-breeding haul-outs in the Pribilof Islands. We surveyed these species using unoccupied aircraft systems with thermal and visible-light photography, and we applied distributional modeling techniques to quantify the relative influence of habitat characteristics and social dynamics on the local distributions of these species. Drone imagery yielded locations and population counts of each species, and spatial data products allowed quantitative characterization of occupied sites, revealing that conspecific attraction is a driver of local site selection for both species, and Pacific harbor seals and northern fur seals are differentially limited by terrain characteristics. These findings represent new applications of species distribution modeling at local scales, made possible by ultra-high resolution drone surveillance and photogrammetric techniques, which add new spatial context to past observations and future scenarios in this changing ecosystem.
Highlights
Global climate changes are driving major ecological shifts worldwide (Parmesan and Yohe 2003), and the Arctic is experiencing transformations with unprecedented environmental and biophysical disruptions (Box et al 2019)
Using UAS surveillance and photogrammetric techniques, we locate pinnipeds in the three-dimensional context of their haul-out sites, we characterize terrestrial habitat associations for each pinniped species, and we model how terrain and social factors might influence fine-scale site selection and distribution of the most abundant species, harbor seals and northern fur seals
UAS imagery was collected at a low enough groundsample distance (GSD) in each spectral range that individual seals could be discriminated against background substrates, classified to species by shape and color, located precisely within the landscape, and counted
Summary
Global climate changes are driving major ecological shifts worldwide (Parmesan and Yohe 2003), and the Arctic is experiencing transformations with unprecedented environmental and biophysical disruptions (Box et al 2019). Arctic marine ecological communities are restructuring around a poleward shift of species ranges (Kortsch et al 2015), and the Arctic-adjacent Bering–Chukchi Sea complex is increasingly stressed by anomalously warm water events (Carvalho et al 2021). These marine heatwaves can disrupt entire food webs from the bottom up, cascading into spatial redistributions, unusual mortality events, and body condition losses in top predator sentinel species, such as seabirds and pinnipeds (Jones et al 2019; Boveng et al 2020; Kuletz et al 2020; Romano et al 2020). Monitoring programs require spatial and temporal coverage sufficient to detect meaningful changes, alongside robust understandings of specific biology and natural history to accurately interpret those changes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
