Understanding resource partitioning in sympatric seabirds living in tropical marine environments

Pontón-Cevallos, José; Dwyer, Ross G.; Franklin, Craig E.; Bunce, Ashley

doi:10.1080/01584197.2016.1265431

Cited by 14 publications

(17 citation statements)

References 41 publications

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“…We conclude that divergent parental roles, environmental conditions, habitat preference and inter-specific competition could be mechanisms simultaneously underlying sexual segregation for BRBO during a period of co-existence. These results agree with the idea that BRBO boobies have a certain foraging ecology plasticity [13,43,84], capable of adapting to different circumstances of environmental conditions and competition. Foraging similarities in RFBO sexes, although confirmed in other studies, could possibly be related to the nonbreeding phase or even biased sex sampling [43].…”

Section: Discussionsupporting

confidence: 91%

“…These results agree with the idea that BRBO boobies have a certain foraging ecology plasticity [13,43,84], capable of adapting to different circumstances of environmental conditions and competition. Foraging similarities in RFBO sexes, although confirmed in other studies, could possibly be related to the nonbreeding phase or even biased sex sampling [43]. As such, inter-specific foraging differences, appear to be more affected by habitat preference and different breeding stages between species.…”

Section: Discussionsupporting

confidence: 91%

“…Foraging patterns of RFBO were also generally similar between sexes, following with the former literature on this species [12,17,20,108]. The similitude of these patterns might have been driven by low intra-specific competition due to the small population size of RFBO inhabiting Raso Islet [23,28], or more likely driven by an unbalanced female:male sample size (N = 4:17) [43]. Nevertheless, a difference in size does not seem to affect intra-specific foraging distributions here, and the lack of breeding seems to be a reasonable explanation for the low intra-specific competition.…”

Section: Plos Onesupporting

confidence: 82%

“…This sets the ideal scenario to investigate spatio-temporal foraging, trophic and dietary segregation within and between closely-related species, during different periods of the year, using GPS tracking and stable isotope analysis. Studies between sympatric boobies have long been performed around the world in tropical waters, with results being influenced by colony and species size [ 17 , 23 , 24 ], productivity and environmental conditions of surrounding waters [ 21 , 24 , 42 ], fish stock distributions and reproductive behaviour [ 21 , 42 , 43 ]. Most of these studies, however, have worked with sympatric breeding boobies, because it is much harder to retrieve tracking devices from non-breeding species.…”

Section: Introductionmentioning

confidence: 99%

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Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic

et al. 2021

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In the oligotrophic tropical marine environment resources are usually more patchily distributed and less abundant to top predators. Thus, spatial and trophic competition can emerge, especially between related seabird species belonging to the same ecological guild. Here we studied the foraging ecology of two sympatric species–brown booby (BRBO) Sula leucogaster (breeding) and red-footed boobies (RFBO) Sula sula (non-breeding)–at Raso islet (Cabo Verde), across different seasons. Sexual segregation was only observed during Jun-Oct, when RFBO were present, with larger females BRBO remaining closer to the colonies, while males and RFBO travelled further and exploited different habitats. Overall, species appeared to prefer areas with specific oceanic features, particularly those related with oceanic currents and responsible for enhancing primary productivity in tropical oceanic areas (e.g. Sea Surface Height and Ocean Mixed Layer Thickness). Female BRBOs showed high foraging-site fidelity during the period of sympatry, while exploiting the same prey species as the other birds. However, during the months of co-existence (Jun.-Oct.), isotopic mixing models suggested that female BRBO would consume a higher proportion of epipelagic fish, whereas female RFBO would consume more squid compared to the other birds, possibly due to habitat-specific prey availability and breeding energy-constraints for BRBO. We conclude that divergent parental roles, environmental conditions, habitat preference and competition could be mechanisms simultaneously underlying sexual segregation for BRBO during a period of co-existence, while inter-specific foraging differences appear to be more affected by habitat preference and different breeding stages. These results support previous statements that BRBO can adapt their foraging ecology to different circumstances of environmental conditions and competition, and that marine physical features play an important role in foraging decisions of boobies.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 91%

Section: Plos Onesupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic

et al. 2021

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“…Partitioning in diet can alleviate competitive pressures in communities [ 10 , 102 ], but we found weak evidence for this in our dietary data with both species targeting similar prey (see also [ 30 , 72 , 103 , 104 ]). In accordance with their neritic distribution, there was a higher diversity of prey in regurgitates of coastal BBs, including reef-associating species, and a higher incidence of squid in pelagic RFBs (consistent with [ 105 , 106 ]).…”

Section: Discussionmentioning

confidence: 79%

Interspecific and intraspecific foraging differentiation of neighbouring tropical seabirds

et al. 2021

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Background Social interactions, reproductive demands and intrinsic constraints all influence foraging decisions in animals. Understanding the relative importance of these factors in shaping the way that coexisting species within communities use and partition resources is central to knowledge of ecological and evolutionary processes. However, in marine environments, our understanding of the mechanisms that lead to and allow coexistence is limited, particularly in the tropics. Methods Using simultaneous data from a suite of animal-borne data loggers (GPS, depth recorders, immersion and video), dietary samples and stable isotopes, we investigated interspecific and intraspecific differences in foraging of two closely-related seabird species (the red-footed booby and brown booby) from neighbouring colonies on the Cayman Islands in the Caribbean. Results The two species employed notably different foraging strategies, with marked spatial segregation, but limited evidence of interspecific dietary partitioning. The larger-bodied brown booby foraged within neritic waters, with the smaller-bodied red-footed booby travelling further offshore. Almost no sex differences were detected in foraging behaviour of red-footed boobies, while male and female brown boobies differed in their habitat use, foraging characteristics and dietary contributions. We suggest that these behavioural differences may relate to size dimorphism and competition: In the small brown booby population (n < 200 individuals), larger females showed a higher propensity to remain in coastal waters where they experienced kleptoparasitic attacks from magnificent frigatebirds, while smaller males that were never kleptoparasitised travelled further offshore, presumably into habitats with lower kleptoparasitic pressure. In weakly dimorphic red-footed boobies, these differences are less pronounced. Instead, density-dependent pressures on their large population (n > 2000 individuals) and avoidance of kleptoparasitism may be more prevalent in driving movements for both sexes. Conclusions Our results reveal how, in an environment where opportunities for prey diversification are limited, neighbouring seabird species segregate at-sea, while exhibiting differing degrees of sexual differentiation. While the mechanisms underlying observed patterns remain unclear, our data are consistent with the idea that multiple factors involving both conspecifics and heterospecifics, as well as reproductive pressures, may combine to influence foraging differences in these neighbouring tropical species.

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Variations in inter‐specific and sex‐related niche partitioning in pelagic boobies during their annual cycle

Lerma,

Dehnhard,

Castillo‐Guerrero

et al. 2024

Ecology and Evolution

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Animals that co‐occur in a region (sympatry) may share the same environment (syntopy), and niche differentiation is expected among closely related species competing for resources. The masked booby (Sula dactylatra) and smaller congeneric red‐footed booby (Sula sula) share breeding grounds. In addition to the inter‐specific size difference, females of both species are also larger than the respective males (reversed sexual size dimorphism). Although both boobies consume similar prey, sometimes in mixed‐species flocks, each species and sex may specialize in terms of their diet or foraging habitats. We examined inter‐ and intra‐specific differences in isotopic values (δ13C and δ15N) in these pelagically feeding booby species during the incubation period at Clarion Island, Mexico, to quantify the degrees of inter‐ and intra‐specific niche partitioning throughout the annual cycle. During incubation, both species preyed mainly on flyingfish and squid, but masked boobies had heavier food loads than red‐footed boobies. There was no overlap in isotopic niches between masked and red‐footed boobies during breeding (determined from whole blood), but there was slight overlap during the non‐breeding period (determined from body feathers). Female masked boobies had a higher trophic position than conspecific males during breeding; however, no such pattern was detected in red‐footed boobies. These results provide evidence of inter‐ and intra‐specific niche partitioning in these tropical seabird species, particularly during the breeding period and in the more‐dimorphic species. Our results suggest that these closely related species use different strategies to cope with the same tropical marine environment.

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Understanding resource partitioning in sympatric seabirds living in tropical marine environments

Cited by 14 publications

References 41 publications

Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic

Year-round at-sea distribution and trophic resources partitioning between two sympatric Sulids in the tropical Atlantic

Interspecific and intraspecific foraging differentiation of neighbouring tropical seabirds

Variations in inter‐specific and sex‐related niche partitioning in pelagic boobies during their annual cycle

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