Inter-annual changes in oceanic conditions drives spatial and trophic consistency of a tropical marine predator

Cerveira, Lara Rodrigues; Ramos, Jaime A.; Rodrigues, Isabel; Almeida, Nathalie; Araújo, Pedro M.; Santos, Ivo dos; Vieira, Cristiana; Pereira, Jorge M.; Ceia, Filipe R.; Geraldes, Pedro; Melo, Tommy; Paiva, Vítor H.

doi:10.1016/j.marenvres.2020.105165

Cited by 22 publications

(11 citation statements)

References 92 publications

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“…However, only a very restricted number of studies have tracked individual tropical seabirds on multiple migrations [ 25 , 44 ], and typically in such small sample sizes that quantifying within-individual variability has not yet been possible. So far for tropical seabirds, studies have mainly focused on variation in behaviours at breeding grounds, when individuals are constrained to a central location, and have revealed no consistent patterns in foraging site-fidelity [ 11 , 40 ]. Consequently, it remains unclear whether consistent individual migratory behaviours occur in less predictable, tropical environments.…”

Section: Introductionmentioning

confidence: 99%

Individual consistency in migration strategies of a tropical seabird, the Round Island petrel

et al. 2022

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Background In migratory species, the extent of within- and between-individual variation in migratory strategies can influence potential rates and directions of responses to environmental changes. Quantifying this variation requires tracking of many individuals on repeated migratory journeys. At temperate and higher latitudes, low levels of within-individual variation in migratory behaviours are common and may reflect repeated use of predictable resources in these seasonally-structured environments. However, variation in migratory behaviours in the tropics, where seasonal predictability of food resources can be weaker, remains largely unknown. Methods Round Island petrels (Pterodroma sp.) are tropical, pelagic seabirds that breed all year round and perform long-distance migrations. Using multi-year geolocator tracking data from 62 individuals between 2009 and 2018, we quantify levels of within- and between-individual variation in non-breeding distributions and timings. Results We found striking levels of between-individual variation in at-sea movements and timings, with non-breeding migrations to different areas occurring across much of the Indian Ocean and throughout the whole year. Despite this, repeat-tracking of individual petrels revealed remarkably high levels of spatial and temporal consistency in within-individual migratory behaviour, particularly for petrels that departed at similar times in different years and for those departing in the austral summer. However, while the same areas were used by individuals in different years, they were not necessarily used at the same times during the non-breeding period. Conclusions Even in tropical systems with huge ranges of migratory routes and timings, our results suggest benefits of consistency in individual migratory behaviours. Identifying the factors that drive and maintain between-individual variation in migratory behaviour, and the consequences for breeding success and survival, will be key to understanding the consequences of environmental change across migratory ranges.

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Section: Introductionmentioning

confidence: 99%

Individual consistency in migration strategies of a tropical seabird, the Round Island petrel

et al. 2022

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“…This clearly demonstrates that BRBO can modify their intra-specific foraging behaviour to counterbalance possible competition for feeding resources. In our study, although the breeding peak of BRBO occurs between December-February, it is undeniable that the overall seabird breeding peak at Raso occurs during the summer period (Jun-Oct) [ 41 , 104 – 107 ]. Adding that a second colony of breeding Cape Verde shearwater and other species occur at less than 6.5 km away, in Branco islet [ 41 , 105 ], is enough to suppose that competition is a possibility between species.…”

Section: Discussionmentioning

confidence: 99%

“…In our study site, however, regardless of its tropical location and its less productive waters compared to the first period ( S3 Fig ), foraging bigger-sized female BRBOs seem to have relied on locations near the colony during both study periods, while smaller male BRBO and RFBO individuals foraged farther from the colony, in a more diverse array of areas, and exhibited lower repeatability in their foraging behaviour. From June to October, female BRBOs foraging probability increased with decreasing SST and OMLT, depicting good environmental conditions in areas closer to the colonies and a thinner mixed layer, which should allow prey fish to be closer to the surface and more accessible to predators [ 88 , 107 , 110 – 112 ]. Contrastingly, male BRBO and both sexes of RFBO preferred areas with higher gradients of SST (i.e.…”

Section: Discussionmentioning

confidence: 99%

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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“…Seabirds, as marine apex predators, are sensitive to changes at lower trophic levels, e.g., oscillations in prey availability caused by shifts in oceanographic conditions (Becker et al 2007;Chimienti et al 2017), and many are seen as optimal sentinel organisms for monitoring environmental and trophic changes in marine ecosystems worldwide (Furness and Camphuysen 1997;Scopel et al 2017). In their foraging choices, seabirds are driven by extrinsic factors (i.e., environmental conditions) and also by intrinsic traits, such as sex, breeding stage or age (Votier et al 2017;Sztukowski et al 2018;Cerveira et al 2020). The combined effect of such factors may explain the inter-and intraspecies partitioning of food resources (Schoener 1974;Paiva et al 2017), which is particularly meaningful when resources are more unpredictable and patchily distributed, as happens in tropical regions (Weimerskirch 2007).…”

Section: Introductionmentioning

confidence: 99%

“…To the best of our knowledge only two studies tracked the movements and trophic ecology of Boyd's shearwater using light-sensing geolocators (Zajková et al 2017;Ramos et al 2020). Additionally, the trophic ecology of Boyd's shearwater during the breeding season is also less known when compared to its closest-related counterpart, the Macaronesian shearwater Pu nus baroli (Neves et al 2012;Ramos et al 2015), and other larger breeding seabirds of Cabo Verde (Cerveira et al 2020;Almeida et al 2021). Here, we tracked the foraging movements of Boyd's shearwater using high-precision mini-GPS loggers and studied the trophic ecology during the breeding season at Raso islet, Cabo Verde.…”

Section: Introductionmentioning

confidence: 99%

Sexual segregation in the foraging distribution, behaviour, and trophic niche of the endemic Boyd’s shearwater (Puffinus lherminieri boydi)

et al. 2022

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Studies on sex-speci c segregation in foraging and trophic niche have been focused on large and dimorphic seabirds, with less information on small monomorphic species. Here, we used mini-GPS loggers, habitat suitability models, and stable isotopes to assess the foraging movements, at-sea spatial distribution, and trophic ecology of male and female Boyd's shearwaters Pu nus lherminieri boydi in Raso Islet (16°36' N, 24°35' W), Cabo Verde, during the breeding seasons of 2018-2019. The existence of sexual foraging segregation was tested in short and long foraging trips. Females engaged on longer foraging trips, travelling towards more distant and northward regions from the colony when compared to males, especially during long foraging excursions. Spatial overlap within and between sexes was generally low, indicating a sex-speci c pattern in the foraging behaviour and spatial distribution of adult breeders. Habitat suitability models revealed a higher importance for chlorophyll a concentration in explaining females' at-sea distribution during long foraging trips when compared to males, although the most important predictors in explaining adults' distribution were sea surface temperature and height for short and long excursions, respectively. Stable isotope analysis revealed that both sexes occupied similar isotopic niches and stable isotope mixing models revealed no diet differences. This indicates that Boyd's shearwaters segregate at the spatial level while foraging but rely on similar food resources. Our results suggest that female-biased nutritional requirements at the onset of chick-rearing may be driving sexual foraging segregation in this population, which depends upon resources from a rather oligotrophic environment.

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Inter-annual changes in oceanic conditions drives spatial and trophic consistency of a tropical marine predator

Cited by 22 publications

References 92 publications

Individual consistency in migration strategies of a tropical seabird, the Round Island petrel

Individual consistency in migration strategies of a tropical seabird, the Round Island petrel

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

Sexual segregation in the foraging distribution, behaviour, and trophic niche of the endemic Boyd’s shearwater (Puffinus lherminieri boydi)

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