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Article Dans Une Revue Frontiers in Ecology and Evolution Année : 2022

Divergent post-breeding spatial habitat use of Laysan and black-footed albatross

Résumé

Understanding the at-sea movements of wide-ranging seabird species throughout their annual cycle is essential for their conservation and management. Habitat use and resource partitioning of Laysan ( Phoebastria immutabilis ) and black-footed ( Phoebastria nigripes ) albatross are well-described during the breeding period but are less understood during the post-breeding period, which represents ~40% of their annual cycle. Resource partitioning may be reduced during post-breeding, when birds are not constrained to return to the nest site regularly and can disperse to reduce competitive pressure. We assessed the degree of spatial segregation in the post-breeding distributions of Laysan ( n = 82) and black-footed albatrosses ( n = 61) using geolocator tags between 2008 and 2012 from two large breeding colonies in the Northwestern Hawaiian Islands, Midway Atoll, and Tern Island. We characterized the species-and colony-specific foraging and focal distributions (represented by the 95 and 50th density contours, respectively) and quantified segregation in at-sea habitat use between species and colonies. Laysan and black-footed albatross showed consistent and significant at-sea segregation in focal areas across colonies, indicating that resource partitioning persists during post-breeding. Within breeding colonies, segregation of foraging areas between the two species was more evident for birds breeding at Tern Island. Spatial segregation decreased as the post-breeding season progressed, when spatial distributions of both species became more dispersed. In contrast to studies conducted on breeding Laysan and black-footed albatross, we found that sea surface temperature distinguished post-breeding habitats of black-footed albatrosses between colonies, with black-footed albatrosses from Midway Atoll occurring in cooler waters (3.6°C cooler on average). Our results reveal marked at-sea segregation between Laysan and black-footed albatross breeding at two colonies during a critical but understudied phase in their annual cycle. The observed variation in species-environment relationships underscores the importance of sampling multiple colonies and temporal periods to more thoroughly understand the spatial distributions of pelagic seabirds.
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Dates et versions

hal-03990620 , version 1 (09-06-2023)

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Paternité

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Fredrick Dallas Jordan, Scott Shaffer, Melinda Conners, Julia Stepanuk, Morgan Gilmour, et al.. Divergent post-breeding spatial habitat use of Laysan and black-footed albatross. Frontiers in Ecology and Evolution, 2022, 10, ⟨10.3389/fevo.2022.1028317⟩. ⟨hal-03990620⟩
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