Segregation in space and time explains the coexistence of two sympatric sub-Antarctic petrels

Granroth-Wilding, Hanna M. V.; Phillips, Richard A.. 2019 Segregation in space and time explains the coexistence of two sympatric sub-Antarctic petrels. Ibis, 161 (1). 101-116. 10.1111/ibi.12584

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Text This is the peer reviewed version of the following article: Granroth‐Wilding, H. M. and Phillips, R. A. (2019), Segregation in space and time explains the coexistence of two sympatric sub‐Antarctic petrels. Ibis, 161: 101-116, which has been published in final form at https://doi.org/10.1111/ibi.12584. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. PetrelsAccepted.pdf - Accepted Version Download (2MB) | Preview

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Text This is the peer reviewed version of the following article: Granroth‐Wilding, H. M. and Phillips, R. A. (2019), Segregation in space and time explains the coexistence of two sympatric sub‐Antarctic petrels. Ibis, 161: 101-116, which has been published in final form at https://doi.org/10.1111/ibi.12584. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. SympatricPetrelsSOM_Accepted.pdf - Supplemental Material Download (68kB) | Preview

Abstract/Summary

Biological communities are shaped by competition between and within species. Competition is often reduced by inter- and intraspecific specialization on resources, such as differencet foraging areas or time, allowing similar species to coexist and potentially contributing to reproductive isolation. Here, we examine the simultaneous role of temporal and spatial foraging segregation within and between two sympatric sister species of seabirds, Northern Macronectes halli and Southern Macronectes giganteus Giant Petrels. These species show marked sexual size dimorphism and allochrony (with earlier breeding by Northern Giant Petrels) but this is the first study to test for differences in foraging behaviours and areas across the entire breeding season both between the two species and between the sexes. We tracked males and females of both species in all breeding stages at Bird Island, South Georgia, to test how foraging distribution, behaviour and habitat use vary between and within species in biological time (incubation, brood-guard or post-brood stages) and in absolute time (calendar date). Within each breeding stage, both species took trips of comparable duration to similar areas, but due to breeding allochrony they segregated temporally. Northern Giant Petrels had a somewhat smaller foraging range than Southern Giant Petrels, reflecting their greater exploitation of local carrion and probably contributing to their recent higher population growth. Within species, segregation was spatial, with females generally taking longer, more pelagic trips than males, although both sexes of both species showed unexpectedly plastic foraging behaviour. There was little evidence of interspecific differences in habitat use. Thus, in giant petrels, temporal segregation reduces interspecific competition and sexual segregation reduces intraspecific competition. These results demonstrate how both specialization and dynamic changes in foraging strategies at different scales underpin resource division within a community.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1111/ibi.12584
ISSN:	00191019
Additional Keywords:	allochrony, interspecific competition, niche differentiation, Procellariiformes, resource partitioning, sexual segregation
Date made live:	23 Jan 2019 10:59 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/522079

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