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van Oordt F, Cuba A, Choy ES, Elliott JE, Elliott KH. Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years. Sci Rep 2024; 14:7899. [PMID: 38570566 PMCID: PMC10991557 DOI: 10.1038/s41598-024-57339-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 03/18/2024] [Indexed: 04/05/2024] Open
Abstract
Hutchison's niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional space. The analysis of multiple stable isotopes can be used to test these ideas where each isotope can be considered a dimension of niche space. These hypervolumes may change over time in response to variation in behaviour or habitat, within or among species, consequently changing the niche space itself. Here, we use isotopic values of carbon and nitrogen of ten amino acids, as well as sulphur isotopic values, to produce multi-isotope models to examine niche segregation among an assemblage of five coexisting seabird species (ancient murrelet Synthliboramphus antiquus, double-crested cormorant Phalacrocorax auritus, Leach's storm-petrel Oceanodrama leucorhoa, rhinoceros auklet Cerorhinca monocerata, pelagic cormorant Phalacrocorax pelagicus) that inhabit coastal British Columbia. When only one or two isotope dimensions were considered, the five species overlapped considerably, but segregation increased in more dimensions, but often in complex ways. Thus, each of the five species occupied their own isotopic hypervolume (niche), but that became apparent only when factoring the increased information from sulphur and amino acid specific isotope values, rather than just relying on proxies of δ15N and δ13C alone. For cormorants, there was reduction of niche size for both species consistent with a decline in their dominant prey, Pacific herring Clupea pallasii, from 1970 to 2006. Consistent with niche theory, cormorant species showed segregation across time, with the double-crested demonstrating a marked change in diet in response to prey shifts in a higher dimensional space. In brief, incorporating multiple isotopes (sulfur, PC1 of δ15N [baselines], PC2 of δ15N [trophic position], PC1 and PC2 of δ13C) metrics allowed us to infer changes and differences in food web topology that were not apparent from classic carbon-nitrogen biplots.
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Affiliation(s)
- Francis van Oordt
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada.
| | | | - Emily S Choy
- Biology Department, McMaster University, Hamilton, ON, Canada
| | - John E Elliott
- Science & Technology Branch, Environment and Climate Change Canada, Delta, Canada
| | - Kyle H Elliott
- Department of Natural Resources Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
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Jordan FD, Shaffer SA, Conners MG, Stepanuk JEF, Gilmour ME, Clatterbuck CA, Hazen EL, Palacios DM, Tremblay Y, Antolos M, Foley DG, Bograd SJ, Costa DP, Thorne LH. Divergent post-breeding spatial habitat use of Laysan and black-footed albatross. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1028317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
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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Pereira JM, Ramos JA, Almeida N, Araújo PM, Ceia FR, Geraldes P, Marques AM, Matos DM, Rodrigues I, Dos Santos I, Paiva VH. Foraging costs drive within-colony spatial segregation in shearwaters from two contrasting environments in the North Atlantic Ocean. Oecologia 2022; 199:13-26. [PMID: 35044501 DOI: 10.1007/s00442-022-05109-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 12/07/2021] [Indexed: 11/24/2022]
Abstract
Foraging spatial segregation is frequent in central-place foragers during the breeding season, but very few studies have investigated foraging spatial segregation between adjacent sub-colonies. Here, we assessed for within-colony differences in the at-sea distribution, habitat use, trophic ecology and chick growth data of two Calonectris colonies differing in size, and breeding in two different environments in the North Atlantic Ocean. For this, we GPS tracked 52 Cory's shearwaters (Calonectris borealis) breeding in 2 small sub-colonies at Berlenga Island (Portugal) and 59 Cape Verde shearwaters (Calonectris edwardsii) breeding in 2 sub-colonies differing greatly in size at Raso Islet (Cabo Verde), over 2 consecutive breeding seasons (2017-2018), during chick-rearing. Cory's shearwaters from the two sub-colonies at Berlenga Island broadly overlapped in repeatedly used foraging patches close to the colony. In contrast, the foraging distribution of Cape Verde shearwaters was partially segregated in the colony surroundings, but overlapped at distant foraging areas off the west coast of Africa. Despite spatial segregation close to the colony, Cape Verde shearwaters from both sub-colonies departed in similar directions, foraged in similar habitats and exhibited mostly short trips within the archipelago of Cabo Verde. These results, corroborated with similar trophic ecology and chick growth rates between sub-colonies, support the idea that foraging spatial segregation in the colony surroundings was not likely driven by interference competition or directional bias. We suggest that high-quality prey patches are able to shape travel costs and foraging distribution of central-place foragers from neighbouring sub-colonies.
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Affiliation(s)
- Jorge M Pereira
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal. .,Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK.
| | - Jaime A Ramos
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Nathalie Almeida
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.,Biosfera Cabo Verde, Rua de Moçambique 28, Mindelo, Caixa Postal 233, São Vicente, Cabo Verde
| | - Pedro M Araújo
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.,CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
| | - Filipe R Ceia
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Pedro Geraldes
- SPEA-Sociedade Portuguesa para o Estudo das Aves, Av. Columbano Bordalo Pinheiro, 87, 3º Andar, 1070-062, Lisbon, Portugal
| | - Ana M Marques
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Diana M Matos
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Isabel Rodrigues
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal.,Biosfera Cabo Verde, Rua de Moçambique 28, Mindelo, Caixa Postal 233, São Vicente, Cabo Verde
| | - Ivo Dos Santos
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Vitor H Paiva
- Department of Life Sciences, MARE-Marine and Environmental Sciences Centre, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
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Lourie E, Schiffner I, Toledo S, Nathan R. Memory and Conformity, but Not Competition, Explain Spatial Partitioning Between Two Neighboring Fruit Bat Colonies. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.732514] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spatial partitioning between neighboring colonies is considered a widespread phenomenon in colonial species, reported mainly in marine birds. Partitioning is suspected to emerge due to various processes, such as competition, diet specialization, memory, information transfer, or even “foraging cultures.” Yet, empirical evidence from other taxa, and studies that tease apart the relative contribution of the processes underlying partitioning, remain scarce, mostly due to insufficiently detailed movement data. Here, we used high-resolution movement tracks (at 0.125 Hz) of 107 individuals belonging to two neighboring colonies of the Egyptian fruit bat (Rousettus aegyptiacus), a highly gregarious central-place forager, using the ATLAS reverse-GPS system in the Hula Valley, Israel. Based on comparisons between agent-based mechanistic models and observed spatial partitioning patterns, we found high levels of partitioning of both area and tree resources (<11% overlap) that were stable across different fruiting seasons. Importantly, partitioning could not have emerged if the bats’ movement was only limited by food availability and travel distances, as most commonly hypothesized. Rather than density-dependent or between-colony competition, memory, and, to a lesser extent, conformity in tree-use explain how partitioning develops. Elucidating the mechanisms that shape spatial partitioning among neighboring colonies in the wild under variable resource conditions is important for understanding the ecology and evolution of inter-group coexistence, space use patterns and sociality.
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Oceans of stimuli: an individual-based model to assess the role of olfactory cues and local enhancement in seabirds' foraging behaviour. Anim Cogn 2020; 23:629-642. [PMID: 32152923 DOI: 10.1007/s10071-020-01368-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 01/01/2023]
Abstract
Oceans are extremely dynamic environments, which poses challenges for top-predators such as seabirds to find food resources. Yet, seabirds evolved sensorial abilities (olfactory senses) along with complex behaviours (social information transfer through local enhancement) to improve foraging efficiency. Using the Cory's shearwater (Calonectris borealis) as a model species, we developed an individual-based model to explore the complementary role of different searching mechanisms (olfactory foraging and local enhancement) for the optimal foraging behaviour of pelagic seabirds during 1-day foraging trips around breeding colonies. Model outputs were compared with observed patterns of Cory's shearwaters distribution during local foraging trips. Also, the foraging efficiency of virtual individuals was analysed considering hypothetical scenarios of foraging conditions and densities of foraging individuals around breeding colonies. The results support the use of a combination of searching strategies by Cory's shearwaters, which produced representative patterns of space use from tracked individuals, including spatial foraging segregation of neighbouring sub-colonies. Furthermore, while the mechanisms underpinning local enhancement played a key role in mitigating sub-optimal foraging conditions, the use of olfactory senses conferred great adaptive foraging advantages over a wide range of environmental conditions. Our results also indicate a synergistic effect between the two strategies, which suggests that a multimodal foraging strategy is useful to forage in extremely dynamic environments. The developed model provides a basis for further investigation regarding the role of foraging mechanisms in the population dynamics of colonial animals, including the adaptive foraging behaviour of marine top predators to dynamic environmental conditions.
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Wege M, de Bruyn PJN, Hindell MA, Lea MA, Bester MN. Preferred, small-scale foraging areas of two Southern Ocean fur seal species are not determined by habitat characteristics. BMC Ecol 2019; 19:36. [PMID: 31510989 PMCID: PMC6739983 DOI: 10.1186/s12898-019-0252-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 09/03/2019] [Indexed: 11/29/2022] Open
Abstract
Background To understand and predict the distribution of foragers, it is crucial to identify the factors that affect individual movement decisions at different scales. Individuals are expected to adjust their foraging movements to the hierarchical spatial distribution of resources. At a small local scale, spatial segregation in foraging habitat happens among individuals of closely situated colonies. If foraging segregation is due to differences in distribution of resources, we would expect segregated foraging areas to have divergent habitat characteristics. Results We investigated how environmental characteristics of preferred foraging areas differ between two closely situated Subantarctic fur seal (Arctocephalus tropicalis) colonies and a single Antarctic fur seal (A. gazella) colony that forage in different pelagic areas even though they are located well within each other’s foraging range. We further investigated the influence of the seasonal cycle on those environmental factors. This study used tracking data from 121 adult female Subantarctic and Antarctic fur seals, collected during summer and winter (2009–2015), from three different colonies. Boosted Regression Tree species distribution models were used to determine key environmental variables associated with areas of fur seal restricted search behaviour. There were no differences in the relative influence of key environmental variables between colonies and seasons. The variables with the most influence for each colony and season were latitude, longitude and magnitude of sea-currents. The influence of latitude and longitude is a by-product of the species’ distinct foraging areas, despite the close proximity (< 25 km) of the colonies. The predicted potential foraging areas for each colony changed from summer to winter, reflecting the seasonal cycle of the Southern Ocean. The model predicted that the potential foraging areas of females from the three colonies should overlap, and the fact they do not in reality indicates that factors other than environmental are influencing the location of each colony’s foraging area. Conclusions The results indicated that small scale spatial segregation of foraging habitats is not driven by bottom-up processes. It is therefore important to also consider other potential drivers, e.g. competition, information transfer, and memory, to understand animal foraging decisions and movements.
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Affiliation(s)
- Mia Wege
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa.
| | - P J Nico de Bruyn
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
| | - Mark A Hindell
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Hobart, TAS, 7004, Australia.,Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, TAS, 7004, Australia
| | - Mary-Anne Lea
- Institute for Marine and Antarctic Studies, University of Tasmania, 20 Castray Esplanade, Battery Point, Hobart, TAS, 7004, Australia
| | - Marthán N Bester
- Mammal Research Institute, Department of Zoology & Entomology, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
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Mott R, Herrod A, Clarke RH. Interpopulation resource partitioning of Lesser Frigatebirds and the influence of environmental context. Ecol Evol 2016; 6:8583-8594. [PMID: 28031809 PMCID: PMC5167043 DOI: 10.1002/ece3.2565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/22/2016] [Accepted: 10/01/2016] [Indexed: 11/21/2022] Open
Abstract
Conspecific individuals inhabiting nearby breeding colonies are expected to compete strongly for food resources owing to the constraints imposed by shared morphology, physiology, and behavior on foraging strategy. Consequently, colony‐specific foraging patterns that effectively partition the available resources may be displayed. This study aimed to determine whether intraspecific resource partitioning occurs in two nearby colonies of Lesser Frigatebirds (Fregata ariel). A combination of stable isotope analysis and GPS tracking was used to assess dietary and spatial partitioning of foraging resources during the 2013 and 2014 breeding seasons. These results were compared to vessel‐derived estimates of prey availability, local primary productivity, and estimates of reproductive output to suggest potential drivers and implications of any observed partitioning. Isotopic data indicated a more neritic source of provisioned resources for near‐fledged chicks at an inshore colony, whereas their offshore counterparts were provisioned with resources with a more pelagic signal. Deep pelagic waters (>200 m) had higher availability of a preferred prey type despite a trend for lower primary productivity. Differences in foraging ecology between the two populations may have contributed to markedly different reproductive outputs. These findings suggest environmental context influences dietary and spatial aspects of foraging ecology. Furthermore, the effect of colony‐specific foraging patterns on population demography warrants further research.
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Affiliation(s)
- Rowan Mott
- School of Biological Sciences Monash University Clayton Vic. Australia
| | - Ashley Herrod
- School of Biological Sciences Monash University Clayton Vic. Australia
| | - Rohan H Clarke
- School of Biological Sciences Monash University Clayton Vic. Australia
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Kirkman SP, Yemane DG, Lamont T, Meÿer MA, Pistorius PA. Foraging Behavior of Subantarctic Fur Seals Supports Efficiency of a Marine Reserve's Design. PLoS One 2016; 11:e0152370. [PMID: 27163373 PMCID: PMC4862747 DOI: 10.1371/journal.pone.0152370] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/14/2016] [Indexed: 11/18/2022] Open
Abstract
Foraging behaviour of marine top predators is increasingly being used to identify areas of ecological importance. This is largely enabled by the ability of many such species to forage extensively in search of prey that is often concentrated in oceanographically productive areas. To identify important habitat in the Southern Indian Ocean within and around South Africa’s Prince Edward Islands’ Marine Protected Area (MPA), satellite transmitters were deployed on 12 lactating Subantarctic fur seals Arctocephalus tropicalis at Prince Edward Island (PEI) itself. Switching state space models were employed to correct ARGOS tracks and estimate behavioural states for locations along predicted tracks, namely travelling or area restricted search (ARS). A random forest model showed that distance from the study colony, longitude and distance from the Subantarctic Front were the most important predictors of suitable foraging habitat (inferred from ARS). Model-predicted suitable habitat occurred within the MPA in relatively close access to the colony during summer and autumn, but shifted northwards concurrently with frontal movements in winter and spring. The association of ARS with the MPA during summer-autumn was highly significant, highlighting the effectiveness of the recently declared reserve’s design for capturing suitable foraging habitat for this and probably other marine top predator species.
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Affiliation(s)
- Stephen P. Kirkman
- Department of Environmental Affairs, Branch Oceans and Coasts, Cape Town, South Africa
- * E-mail:
| | - Dawit G. Yemane
- Fisheries Management, Department of Agriculture, Forestry and Fisheries, Cape Town, South Africa
| | - Tarron Lamont
- Department of Environmental Affairs, Branch Oceans and Coasts, Cape Town, South Africa
| | - Michael A. Meÿer
- Department of Environmental Affairs, Branch Oceans and Coasts, Cape Town, South Africa
| | - Pierre A. Pistorius
- Department of Zoology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
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Corman AM, Mendel B, Voigt CC, Garthe S. Varying foraging patterns in response to competition? A multicolony approach in a generalist seabird. Ecol Evol 2016; 6:974-86. [PMID: 26941940 PMCID: PMC4761771 DOI: 10.1002/ece3.1884] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/13/2015] [Accepted: 11/25/2015] [Indexed: 11/11/2022] Open
Abstract
Reducing resource competition is a crucial requirement for colonial seabirds to ensure adequate self‐ and chick‐provisioning during breeding season. Spatial segregation is a common avoidance strategy among and within species from neighboring breeding colonies. We determined whether the foraging behaviors of incubating lesser black‐backed gulls (Larus fuscus) differed between six colonies varying in size and distance to mainland, and whether any differences could be related to the foraging habitats visited. Seventy‐nine incubating individuals from six study colonies along the German North Sea coast were equipped with GPS data loggers in multiple years. Dietary information was gained by sampling food pellets, and blood samples were taken for stable isotope analyses. Foraging patterns clearly differed among and within colonies. Foraging range increased with increasing colony size and decreased with increasing colony distance from the mainland, although the latter might be due to the inclusion of the only offshore colony. Gulls from larger colonies with consequently greater density‐dependent competition were more likely to forage at land instead of at sea. The diets of the gulls from the colonies furthest from each other differed, while the diets from the other colonies overlapped with each other. The spatial segregation and dietary similarities suggest that lesser black‐backed gulls foraged at different sites and utilized two main habitat types, although these were similar across foraging areas for all colonies except the single offshore island. The avoidance of intraspecific competition results in colony‐specific foraging patterns, potentially causing more intensive utilization of terrestrial foraging sites, which may offer more predictable and easily available foraging compared with the marine environment.
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Affiliation(s)
- Anna-Marie Corman
- Research and Technology Centre (FTZ) University of Kiel Hafentörn 1 25761 Büsum Germany
| | - Bettina Mendel
- Research and Technology Centre (FTZ) University of Kiel Hafentörn 1 25761 Büsum Germany
| | - Christian C Voigt
- Leibniz Institute for Zoo and Wildlife Research (IZW) Alfred-Kowalke-Straße 16 10315 Berlin Germany
| | - Stefan Garthe
- Research and Technology Centre (FTZ) University of Kiel Hafentörn 1 25761 Büsum Germany
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