Effects of competitive pressure and habitat heterogeneity on niche partitioning between Arctic and boreal congeners

• Published in: Scientific Reports
• Main Authors: Anne-Sophie Bonnet-Lebrun, Thomas Larsen, Morten Frederiksen, Derren Fox, Fabrice le Bouard, Aude Boutet, Þorkell Lindberg Þórarinsson, Yann Kolbeinsson, Tanguy Deville, Norman Ratcliffe
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2021
• Subjects: Medicine; R; Science; Q; Arctic; common guillemot; Iceland; Uria aalge; Uria lomvia; uria
• Online Access: https://doi.org/10.1038/s41598-021-01506-w; https://doaj.org/article/7d097643ac3d4da88249e75f5a797fc2

Abstract The rapidly changing climate in the Arctic is expected to have a major impact on the foraging ecology of seabirds, owing to changes in the distribution and abundance of their prey but also that of competitors (e.g. southerly species expanding their range into the Arctic). Species can respond to interspecific competition by segregating along different niche axes. Here, we studied spatial, temporal and habitat segregation between two closely related seabird species: common guillemot Uria aalge (a temperate species) and Brünnich’s guillemot Uria lomvia (a true Arctic species), at two sympatric sites in Iceland that differ in their total population sizes and the availability of marine habitats. We deployed GPS and temperature-depth recorders to describe foraging locations and behaviour of incubating and chick-rearing adults. We found similar evidence of spatial segregation at the two sites (i.e. independent of population sizes), although segregation in environmental space was only evident at the site with a strong habitat gradient. Unexpectedly, temporal (and, to a limited extent, vertical) segregation appeared only at the least populated site. Overall, our results show complex relationships between the levels of inferred competition and that of segregation.