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Härer A, Rennison DJ. Gut Microbiota Uniqueness Is Associated with Lake Size, a Proxy for Diet Diversity, in Stickleback Fish. Am Nat 2024; 203:284-291. [PMID: 38306277 DOI: 10.1086/727703] [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] [Indexed: 02/04/2024]
Abstract
AbstractOrganismal divergence can be driven by differential resource use and adaptation to different trophic niches. Variation in diet is a major factor shaping the gut microbiota, which is crucial for many aspects of their hosts' biology. However, it remains largely unknown how host diet diversity affects the gut microbiota, and it could be hypothesized that trophic niche width is positively associated with gut microbiota diversity. To test this idea, we sequenced the 16S ribosomal RNA gene from intestinal tissue of 14 threespine stickleback populations from lakes of varying size on Vancouver Island, Canada, that have been shown to differ in trophic niche width. Using lake size as a proxy for trophic ecology, we found evidence for higher gut microbiota uniqueness among individuals from populations with broader trophic niches. While these results suggest that diet diversity might promote gut microbiota diversity, additional work investigating diet and gut microbiota variation of the same host organisms will be necessary. Yet our results motivate the question of how host population diversity (e.g., ecological, morphological, genetic) might interact with the gut microbiota during the adaptation to ecological niches.
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Fraleigh DC, Archer FI, Williard AS, Hückstädt LA, Fleming AH. Possible niche compression and individual specialization in Pacific Arctic beluga ( Delphinapterus leucas) from the 19th to 20th century. Ecol Evol 2023; 13:e10230. [PMID: 37408623 PMCID: PMC10318618 DOI: 10.1002/ece3.10230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 06/08/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023] Open
Abstract
Cetaceans have shown a potential to be used as sentinel species for tracking environmental change in marine ecosystems, yet our assessment of change is typically limited to recent decades and lacks ecological baselines. Using historical museum specimens, we compared community niche metrics and degree of individual dietary specialization in groups of Pacific Arctic beluga (Delphinapterus leucas) from the 1800s (n = 5) to 1900s (n = 10) using stable carbon and nitrogen isotopes drilled from teeth. Beluga occupied a broader trophic niche and demonstrated a higher degree of individual specialization in the 1800s than in the 1900s. The cause of this shift is difficult to confirm given long timescales and constraints of specimen-based research but could indicate changes in the prey base or competition. The scale and nature of this detected shift provide perspective for continued research on these climate-vulnerable species.
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Affiliation(s)
- Devin C. Fraleigh
- Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
| | - Frederick I. Archer
- Southwest Fisheries Science CenterNational Marine Fisheries Service, National Oceanic and Atmospheric AdministrationLa JollaCaliforniaUSA
| | - Amanda S. Williard
- Department of Biology and Marine BiologyUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
| | - Luis A. Hückstädt
- Department of Biology and Marine BiologyUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
- Centre for Ecology and ConservationUniversity of ExeterCornwallUK
| | - Alyson H. Fleming
- Center for Marine ScienceUniversity of North Carolina WilmingtonWilmingtonNorth CarolinaUSA
- Department of Forest & Wildlife EcologyUniversity of Wisconsin‐MadisonMadisonWisconsinUSA
- National Museum of Natural HistorySmithsonian InstitutionWashingtonDistrict of ColumbiaUSA
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Florko KRN, Shuert CR, Cheung WWL, Ferguson SH, Jonsen ID, Rosen DAS, Sumaila UR, Tai TC, Yurkowski DJ, Auger-Méthé M. Linking movement and dive data to prey distribution models: new insights in foraging behaviour and potential pitfalls of movement analyses. MOVEMENT ECOLOGY 2023; 11:17. [PMID: 36959671 PMCID: PMC10037791 DOI: 10.1186/s40462-023-00377-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 03/04/2023] [Indexed: 06/08/2023]
Abstract
BACKGROUND Animal movement data are regularly used to infer foraging behaviour and relationships to environmental characteristics, often to help identify critical habitat. To characterize foraging, movement models make a set of assumptions rooted in theory, for example, time spent foraging in an area increases with higher prey density. METHODS We assessed the validity of these assumptions by associating horizontal movement and diving of satellite-telemetered ringed seals (Pusa hispida)-an opportunistic predator-in Hudson Bay, Canada, to modelled prey data and environmental proxies. RESULTS Modelled prey biomass data performed better than their environmental proxies (e.g., sea surface temperature) for explaining seal movement; however movement was not related to foraging effort. Counter to theory, seals appeared to forage more in areas with relatively lower prey diversity and biomass, potentially due to reduced foraging efficiency in those areas. CONCLUSIONS Our study highlights the need to validate movement analyses with prey data to effectively estimate the relationship between prey availability and foraging behaviour.
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Affiliation(s)
- Katie R N Florko
- Aquatic Ecosystem Research Laboratory, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Courtney R Shuert
- Department of Integrative Biology, University of Windsor, Windsor, ON, Canada
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB, Canada
| | - William W L Cheung
- Aquatic Ecosystem Research Laboratory, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Steven H Ferguson
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Ian D Jonsen
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - David A S Rosen
- Aquatic Ecosystem Research Laboratory, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - U Rashid Sumaila
- Aquatic Ecosystem Research Laboratory, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Travis C Tai
- Pacific Climate Impacts Consortium, University of Victoria, Victoria, BC, Canada
| | - David J Yurkowski
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Marie Auger-Méthé
- Aquatic Ecosystem Research Laboratory, Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada
- Department of Statistics, University of British Columbia, Vancouver, BC, Canada
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Botha JA, Trueman CN, Kirkman SP, Arnould JPY, Lombard AT, Connan M, Hofmeyr GJG, Seakamela SM, Pistorius PA. Geographical, temporal, and individual-based differences in the trophic ecology of female Cape fur seals. Ecol Evol 2023; 13:e9790. [PMID: 36789339 PMCID: PMC9909003 DOI: 10.1002/ece3.9790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 02/11/2023] Open
Abstract
Information on resource use and trophic dynamics of marine predators is important for understanding their role in ecosystem functioning and predicting population-level responses to environmental change. Where separate populations experience different local environmental conditions, geographic variability in their foraging ecology is often expected. Within populations, individuals also vary in morphology, physiology, and experience, resulting in specialization in resource use. In this context, isotopic compositions of incrementally grown tissues such as keratinous hairs offer a valuable opportunity to study long-term variation in resource and habitat use. We investigated the trophic ecology of female Cape fur seals (Arctocephalus pusillus pusillus) using carbon and nitrogen isotopic compositions of serially sampled whiskers collected at four breeding sites along the coast of South Africa. Drawing on over 900 isotopic measurements, we assessed geographic variability in isotopic niche width between colonies and the degree of individual specialization. We found slight, but clear geographic differences in isotopic ratios and isotopic niche widths, seemingly related to ecological setting, with niche widths being proportional to the area of available shelf and shelf-slope habitat surrounding the colony. We further identified periodic oscillations in isotopic ratios, which likely reflect temporal patterns in foraging distribution and prey type, linked to shifts in the availability of prey resources and their interaction with constraints on individual females throughout their breeding cycle. Finally, individual specialization indices revealed that each of the study populations contain specialist individuals that utilize only a small subset of the total population niche width. The degree of individual specialization was, however, not consistent across colonies and may reflect an interactive influence between density-dependent effects and habitat heterogeneity. Overall, this study provides important information on the trophic ecology of Cape fur seals breeding in South Africa and highlights the need to consider geographic and individual variability when assessing the foraging ecology of marine predators.
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Affiliation(s)
- Jonathan A. Botha
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - Clive N. Trueman
- Ocean and Earth Science, SouthamptonUniversity of SouthamptonSouthamptonUK
| | - Stephen P. Kirkman
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
- Oceans and Coast Research, Department of ForestryFisheries and the EnvironmentCape TownSouth Africa
| | - John P. Y. Arnould
- Faculty of Science, Engineering and Built EnvironmentDeakin UniversityBurwoodVictoriaAustralia
| | - Amanda T. Lombard
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - Maëlle Connan
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
| | - G. J. Greg Hofmeyr
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
- Port Elizabeth Museum at BayworldGqeberhaSouth Africa
| | - S. Mduduzi Seakamela
- Oceans and Coast Research, Department of ForestryFisheries and the EnvironmentCape TownSouth Africa
| | - Pierre A. Pistorius
- Marine Apex Predator Research Unit (MAPRU), Department of Zoology and Institute for Coastal and Marine ResearchNelson Mandela UniversityGqeberhaSouth Africa
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Teixeira CR, Botta S, Cremer MJ, Marcondes MCC, Pereira LB, Newsome SD, Jorge FGD, Simões-Lopes PC. Ecologically driven differences in individual diet specialization across three populations of Guiana dolphin. Oecologia 2023; 201:397-408. [PMID: 36650314 DOI: 10.1007/s00442-022-05312-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 12/29/2022] [Indexed: 01/19/2023]
Abstract
Populations usually considered foraging generalists may include specialized individuals that feed on a restricted subset of the prey spectrum consumed by the population. By analyzing the time series of δ13C and δ15N values in sequential growth layer groups within tooth dentin, we measured population- and individual-level variation in resource use of three populations of Guiana dolphins (Sotalia guianensis)-Caravelas River, Babitonga Bay, and Norte Bay-along a latitudinal gradient in the southwestern Atlantic Ocean. We show that the Guiana dolphin at Caravelas River is a generalist population consisting of individual dietary specialists, likely due to the absence of other resident dolphin populations thus allowing individuals to target prey across a wide range of habitats. The Babitonga Bay population is also composed of individual specialists potentially due to the selective foraging behavior of some individuals on high-quality prey sources within and near the bay. In contrast, the Norte Bay population comprises individual generalists, which likely reflects its distinctive cohesive social organization, coexistence with two other dolphin species, and an opportunistic foraging strategy in response to resource fluctuations inherent to the southern limit of the species distribution. Although the Guiana dolphin is generally considered to be a dietary generalist at the population level, our findings reveal that the total niche width of populations and the degree of individual diet specialization are highly context dependent, suggesting dietary plasticity that may be related to a latitudinal gradient in resource availability and environmental conditions.
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Affiliation(s)
- Clarissa R Teixeira
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil. .,Department of Fisheries, Wildlife, and Conservation Sciences, Marine Mammal Institute, Oregon State University, Newport, OR, USA.
| | - Silvina Botta
- Laboratório de Ecologia e Conservação da Megafauna Marinha (ECOMEGA), Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
| | - Marta J Cremer
- Laboratório de Ecologia e Conservação de Tetrápodes Marinhos e Costeiros (TetraMar), Unidade São Francisco do Sul, Universidade da Região de Joinville, São Francisco do Sul, Santa Catarina, Brazil
| | | | - Luiza B Pereira
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Fábio G Daura Jorge
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Paulo C Simões-Lopes
- Laboratório de Mamíferos Aquáticos (LAMAQ), Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
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Gobin J, Szumski CM, Roth JD, Murray DL. Patterns of dietary niche breadth and overlap are maintained for two closely related carnivores across broad geographic scales. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1059155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Ecological studies investigating niche breadth and overlap often have limited spatial and temporal scale, preventing generalizations across varying environments and communities. For example, it is not clear whether species having restricted diets maintain such patterns relative to closely related species and across their geographic range of co-occurrence. We used stable isotope analysis of hair and fur samples collected from four regions of sympatry for Canada lynx (Lynx canadensis) and bobcat (Lynx rufus) spanning southern Canada and the northern United States, to test the prediction that the more generalist species (bobcat) exhibits a wider dietary niche than the more specialist species (Canada lynx) and that this pattern is consistent across different regions. We further predicted that Canada lynx diet would consistently exhibit greater overlap with that of bobcat compared to overlap of bobcat diet with Canada lynx. We found that Canada lynx had a narrower dietary niche than bobcat, with a high probability of overlap (85–95%) with bobcat, whereas the bobcat dietary niche had up to a 50% probability of overlap with Canada lynx. These patterns of dietary niche breadth and overlap were consistent across geographic regions despite some regional variation in diet breadth and position, for both species. Such consistent patterns could reflect a lack of plasticity in species dietary niches. Given the increasingly recognized importance of understanding dietary niche breadth and overlap across large spatial scales, further research is needed to investigate the mechanisms by which broad-scale patterns are maintained across species and systems.
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Lunghi E, Cianferoni F, Corti C, Zhao Y, Manenti R, Ficetola GF, Mancinelli G. The trophic niche of subterranean populations of Speleomantes italicus. Sci Rep 2022; 12:18257. [PMID: 36309527 PMCID: PMC9617932 DOI: 10.1038/s41598-022-21819-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 10/04/2022] [Indexed: 12/31/2022] Open
Abstract
The determination of a species trophic niche can clarify its functional role within a food web and how prey resources are used in relation with the spatial and temporal variability of environmental conditions. This information may result particularly useful for the implementation of conservation plans of endangered species having a cryptic behaviour or living in places difficult to be surveyed. Here we present the first long-term study on the trophic niche of the Italian cave salamander Speleomantes italicus, a strictly protected facultative cave species that seasonally exploits surface environments (e.g., forested areas) as well as both natural and artificial subterranean environments. We analysed the diet variation of six populations of S. italicus inhabiting natural caves, surveyed 24 times in a full year. During the surveys, all sampled individuals were subjected to stomach flushing and the ingested prey were identified and enumerated; furthermore, salamanders' body condition was also evaluated. The results of the analyses provided the first comprehensive, year-round assessment of the diet for a Speleomantes species. Remarkable divergences in terms of trophic niche and body condition were observed between the studied populations. We found a discrepancy in the foraging activity of the populations located in different areas; specifically, the individuals that experienced sub-optimal microclimatic conditions poorly performed in foraging. Furthermore, we found temporal and spatial variability in the body condition of individuals. Our study highlighted a remarkably high spatial and temporal divergence in the trophic habits of conspecific populations, a feature that may represent one of the major factors promoting the variability of multiple population traits.
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Affiliation(s)
- Enrico Lunghi
- grid.9227.e0000000119573309Key Laboratory of the Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China ,grid.158820.60000 0004 1757 2611Dipartimento di Medicina clinica, sanità pubblica, scienze della vita e dell’ambiente (MESVA), University of L’Aquila, Coppito, L’Aquila Italy ,grid.8404.80000 0004 1757 2304Zoologia, “La Specola”, Museo di Storia Naurale, Università degli Studi di Firenze, Florence, Italy ,Natural Oasis, Prato, Italy ,Unione Speleologica Calenzano, Calenzano, Florence, Italy
| | - Fabio Cianferoni
- grid.8404.80000 0004 1757 2304Zoologia, “La Specola”, Museo di Storia Naurale, Università degli Studi di Firenze, Florence, Italy ,grid.5326.20000 0001 1940 4177Istituto di Ricerca Sugli Ecosistemi Terrestri (IRET), Consiglio Nazionale delle Ricerche (CNR), Sesto Fiorentino, Florence Italy
| | - Claudia Corti
- grid.8404.80000 0004 1757 2304Zoologia, “La Specola”, Museo di Storia Naurale, Università degli Studi di Firenze, Florence, Italy
| | - Yahui Zhao
- grid.9227.e0000000119573309Key Laboratory of the Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Raoul Manenti
- grid.4708.b0000 0004 1757 2822Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Milano, Italy ,Laboratorio di Biologia Sotterranea “Enrico Pezzoli”, Parco Regionale del Monte Barro, Galbiate, Italy
| | - Gentile Francesco Ficetola
- grid.4708.b0000 0004 1757 2822Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Milano, Italy ,grid.450308.a0000 0004 0369 268XLaboratoire d’Écologie Alpine (LECA), Université Grenoble Alpes, CNRS, Grenoble, France
| | - Giorgio Mancinelli
- grid.9906.60000 0001 2289 7785Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA), Università del Salento, Lecce, Italy ,grid.5326.20000 0001 1940 4177Istituto per le Risorse Biologiche e le Biotecnologie Marine (IRBIM), Consiglio Nazionale delle Ricerche (CNR), Lesina, Foggia Italy ,grid.10911.380000 0005 0387 0033CoNISMa, Consorzio Nazionale Interuniversitario per le Scienze del Mare, Roma, Italy
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Baker HK, Bruggeman CEF, Shurin JB. Population niche width is driven by within-individual niche expansion and individual specialization in introduced brook trout in mountain lakes. Oecologia 2022; 200:1-10. [PMID: 35661919 PMCID: PMC9547792 DOI: 10.1007/s00442-022-05201-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/21/2022] [Indexed: 11/02/2022]
Abstract
The width of a population's resource-use niche is determined by individual diet breadth ("within-individual component") and the degree of niche partitioning between individuals ("between-individual component"). The balance between these two factors affects ecological stability and evolutionary trajectories, and may shift as ecological opportunity permits broader population niches. Lakes in California's Sierra Nevada Mountains vary in resource diversity for introduced brook trout (Salvelinus fontinalis) due to elevation, lake morphometry, and watershed features. We compared the relative contributions of within- and between-individual niche components to two measures of the dietary niches of thirteen populations of brook trout: prey taxonomic composition and prey size distribution. For both taxonomic and size diversity of fish diets, population niche width was positively related to both the within- and between-individual components. For taxonomic diversity, the two components increased in parallel, while for size diversity, the between-individual component became more important relative to the within-individual component in populations with the greatest niche widths. Our results support the Niche Variation Hypothesis that populations with broader niches are more heterogeneous among individuals and show that individual niche width and individual specialization can operate in parallel to expand the population niche.
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Affiliation(s)
- H K Baker
- Department of Ecology, Behavior, and Evolution, University of California San Diego, La Jolla, CA, 92093, USA.
| | - C E F Bruggeman
- Department of Ecology, Behavior, and Evolution, University of California San Diego, La Jolla, CA, 92093, USA
| | - J B Shurin
- Department of Ecology, Behavior, and Evolution, University of California San Diego, La Jolla, CA, 92093, USA
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Shaner PJL, Ke LH. Niche overlap in rodents increases with competition but not ecological opportunity: A role of inter-individual difference? J Anim Ecol 2022; 91:1679-1692. [PMID: 35633185 DOI: 10.1111/1365-2656.13750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/16/2022] [Indexed: 01/17/2023]
Abstract
Niche variation at population level mediates niche packing (i.e., patterns of species' spread within the niche space) and species coexistence at community level. Competition and ecological opportunity (resource diversity) are two of the main mechanisms underlying niche variation. Dense niche packing could occur through increased niche partitioning or increased niche overlap. In this study we used stable carbon and nitrogen isotope data of 635 individual rodents from 4 species across 9 sites in the montane region of a subtropical island to test the effects of competition and ecological opportunity on population isotope niche size, inter-individual niche difference within population, and inter-specific niche overlap within community. We used the Bayesian Standard Ellipse Area (SEAB, the ellipse area enclosed by carbon and nitrogen isotope values of organisms on a bi-plot) to estimate population niche size and inter-specific niche overlap. Inter-individual niche difference within population was quantified as isotopic divergence and isotopic uniqueness. We used rodent abundance (the number of unique individuals captured) to measure competition and plant isotope niche size (plant SEAB) to measure ecological opportunity. The rodents experienced competition as evidenced by a negative relationship between population change rate and conspecific abundance. Rodent population niche size increased with ecological opportunity but not competition. The inter-individual niche difference (isotopic uniqueness) increased with competition (inter-specific competition only) but not ecological opportunity. At community level, inter-specific niche overlap (herbivore-omnivore pair only) increased with competition (the combined abundance of the pair) but not ecological opportunity. This study demonstrated that isotope niche variation of the rodents could be hierarchically influenced by ecological opportunity and competition, with the former setting the limit of population niche size across communities and the latter shaping inter-individual niche difference and inter-specific niche overlap within communities. Under strong intra-specific competition and limited ecological opportunity for niche expansion, individuals may choose to increase their isotopic uniqueness from conspecifics at the cost of overlapping with heterospecifics of different trophic roles within the community niche space as overall competition increases. Denser niche packing of these rodent communities might be achieved through increased niche overlap.
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Affiliation(s)
- Pei-Jen L Shaner
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ling-Hua Ke
- Wildervalley Environmental Consultants Ltd., Pingtung, Taiwan
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10
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Ogloff WR, Anderson RA, Yurkowski DJ, Debets CD, Anderson WG, Ferguson SH. OUP accepted manuscript. J Mammal 2022; 103:1208-1220. [PMID: 36262800 PMCID: PMC9562108 DOI: 10.1093/jmammal/gyac047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 05/06/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
| | | | - David J Yurkowski
- Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
- Department of Biological Sciences, University of Manitoba, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
| | - Cassandra D Debets
- Department of Biological Sciences, University of Manitoba, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
| | - Steven H Ferguson
- Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
- Department of Biological Sciences, University of Manitoba, 66 Chancellors Circle, Winnipeg, MB R3T 2N2, Canada
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11
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Smith RA, Yurkowski DJ, Parkinson KJL, Fort J, Hennin HL, Gilchrist HG, Hobson KA, Mallory ML, Danielsen J, Garbus SE, Hanssen SA, Jónsson JE, Latty CJ, Magnúsdóttir E, Moe B, Parsons GJ, Sonne C, Tertitski G, Love OP. Environmental and life-history factors influence inter-colony multidimensional niche metrics of a breeding Arctic marine bird. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 796:148935. [PMID: 34274678 DOI: 10.1016/j.scitotenv.2021.148935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/05/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
Human industrialization has resulted in rapid climate change, leading to wide-scale environmental shifts. These shifts can modify food web dynamics by altering the abundance and distribution of primary producers (ice algae and phytoplankton), as well as animals at higher trophic levels. Methylmercury (MeHg) is a neuro-endocrine disrupting compound which biomagnifies in animals as a function of prey choice, and as such bioavailability is affected by altered food web dynamics and adds an important risk-based dimension in studies of foraging ecology. Multidimensional niche dynamics (MDND; δ13C, δ15N, THg; total mercury) were determined among breeding common eider (Somateria mollissima) ducks sampled from 10 breeding colonies distributed across the circumpolar Arctic and subarctic. Results showed high variation in MDND among colonies as indicated by niche size and ranges in δ13C, δ15N and THg values in relation to spatial differences in primary production inferred from sea-ice presence and colony migratory status. Colonies with higher sea-ice cover during the pre-incubation period had higher median colony THg, δ15N, and δ13C. Individuals at migratory colonies had relatively higher THg and δ15N, and lower δ13C, suggesting a higher trophic position and a greater reliance on phytoplankton-based prey. It was concluded that variation in MDND exists among eider colonies which influenced individual blood THg concentrations. Further exploration of spatial ecotoxicology and MDND at each individual site is important to examine the relationships between anthropogenic activities, foraging behaviour, and the related risks of contaminant exposure at even low, sub-lethal concentrations that may contribute to deleterious effects on population stability over time. Overall, multidimensional niche analysis that incorporates multiple isotopic and contaminant metrics could help identify those populations at risk to rapidly altered food web dynamics.
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Affiliation(s)
- Reyd A Smith
- University of Windsor, Windsor, Ontario N9B 3P4, Canada.
| | | | | | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS - La Rochelle University, La Rochelle FR-17000, France
| | - Holly L Hennin
- Environment and Climate Change Canada, Ottawa, Ontario K0A 1H0, Canada
| | - H Grant Gilchrist
- Environment and Climate Change Canada, Ottawa, Ontario K0A 1H0, Canada
| | | | - Mark L Mallory
- cadia University, Wolfville, Nova Scotia B4P 2R6, Canada
| | | | | | | | - Jón Einar Jónsson
- University of Iceland's Research Centre at Snæfellsnes, Hafnargata 3, 340 Stykkishólmur, Iceland
| | - Christopher J Latty
- Arctic National Wildlife Refuge, U.S. Fish and Wildlife Service, Fairbanks, AK 99701, United States
| | - Ellen Magnúsdóttir
- University of Iceland's Research Centre at Snæfellsnes, Hafnargata 3, 340 Stykkishólmur, Iceland
| | - Børge Moe
- Norwegian Institute for Nature Research, Tromsø N-9296, Norway
| | - Glen J Parsons
- Nova Scotia Department of Lands and Forestry, Kentville, Nova Scotia B4N 4E5, Canada
| | | | - Grigori Tertitski
- Institute of Geography of the Russian Academy of Sciences, Moscow 119017, Russia
| | - Oliver P Love
- University of Windsor, Windsor, Ontario N9B 3P4, Canada
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12
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Application of Combined Analyses of Stable Isotopes and Stomach Contents for Understanding Ontogenetic Niche Shifts in Silver Croaker ( Pennahia argentata). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18084073. [PMID: 33924310 PMCID: PMC8070473 DOI: 10.3390/ijerph18084073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 11/17/2022]
Abstract
Stable isotope analysis (SIA) and stomach content analysis (SCA) were conducted to understand ontogenetic niche shifts in silver croaker Pennahia argentata inhabiting the southern coastal waters of the Korean peninsula. Sampled P. argentata were classified into three groups based on their total length (TL; 60-80 mm TL, 80-120 mm TL, and 120-210 mm TL). Carbon isotope (δ13C) ratios were distinguishable, whereas nitrogen isotope (δ15N) ratios were not significantly different among size classes, and Standard Ellipse Area (SEA), estimated by δ13C and δ15N, was expanded with increasing TL from 0.2 ‰2 (60-80 mm TL) to 2.0 ‰2 (120-210 mm TL). SCA results showed variable contribution of dietary items to each size class. In particular, higher dietary contribution of Polychaeta to P. argentata of 80-120 mm TL than 120-210 mm TL mirrored variation in δ13C values of P. argentata in those size classes. Based on the combined analyses involving SIA and SCA, we concluded that P. argentata underwent ontogenetic niche shifts, particularly dietary shifts, with growth stages. Ontogenetic niche shifting is a representative survival strategy in fish, and, therefore, represents essential information for managing fisheries. The present study demonstrated applicability of combined SIA and SCA analyses, not only for dietary resource tracing, but also for ecological niche studies.
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13
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Pahl KB, Yurkowski DJ, Wintner SP, Cliff G, Dicken ML, Hussey NE. Determining the appropriate pretreatment procedures and the utility of liver tissue for bulk stable isotope (δ 13 C and δ 15 N) studies in sharks. JOURNAL OF FISH BIOLOGY 2021; 98:829-841. [PMID: 33251592 DOI: 10.1111/jfb.14635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 11/11/2020] [Accepted: 11/27/2020] [Indexed: 06/12/2023]
Abstract
Stable-isotope analysis (SIA) provides a valuable tool to address complex questions pertaining to elasmobranch ecology. Liver, a metabolically active, high turnover tissue (~166 days for 95% turnover), has the potential to reveal novel insights into recent feeding/movement behaviours of this diverse group. To date, limited work has used this tissue, but ecological application of SIA in liver requires consideration of tissue preparation techniques given the potential for high concentrations of urea and lipid that could bias δ13 C and δ15 N values (i.e., result in artificially lower δ13 C and δ15 N values). Here we investigated the effectiveness of (a) deionized water washing (WW) for urea removal from liver tissue and (b) chloroform-methanol for extraction of lipids from this lipid rich tissue. We then (a) established C:N thresholds for deriving ecologically relevant liver isotopic values given complications of removing all lipid and (b) undertook a preliminary comparison of δ13 C values between tissue pairs (muscle and liver) to test if observed isotopic differences correlated with known movement behaviour. Tests were conducted on four large shark species: the dusky (DUS, Carcharhinus obscurus), sand tiger (RAG, Carcharias taurus), scalloped hammerhead (SCA, Sphyrna lewini) and white shark (GRE, Carcharodon carcharias). There was no significant difference in δ15 N values between lipid-extracted (LE) liver and lipid-extracted/water washed (WW) treatments, however, WW resulted in significant increases in %N, δ13 C and %C. Following lipid extraction (repeated three times), some samples were still biased by lipids. Our species-specific "C:N thresholds" provide a method to derive ecologically viable isotope data given the complexities of this lipid rich tissue (C:N thresholds of 4.0, 3.6, 4.7 and 3.9 for DUS, RAG, SCA and GRE liverLEWW tissue, respectively). The preliminary comparison of C:N threshold corrected liver and muscle δ13 C values corresponded with movement/habitat behaviours for each shark; minor differences in δ13 C values were observed for known regional movements of DUS and RAG (δ13 CDiffs = 0.24 ± 0.99‰ and 0.57 ± 0.38‰, respectively), while SCA and GRE showed greater differences (1.24 ± 0.63‰ and 1.08 ± 0.71‰, respectively) correlated to large-scale movements between temperate/tropical and pelagic/coastal environments. These data provide an approach for the successful application of liver δ13 C and δ15 N values to examine elasmobranch ecology.
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Affiliation(s)
- K Blue Pahl
- Department of Integrative Biology, University of Windsor, Windsor, Ontario, Canada
| | - David J Yurkowski
- Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, Manitoba, Canada
| | - Sabine P Wintner
- KwaZulu-Natal Sharks Board, Maritime Centre of Excellence, Umhlanga Rocks, Umhlanga, South Africa
- Biomedical Resource Unit, University of KwaZulu-Natal, Durban, South Africa
- College of Agriculture, Engineering and Science, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Geremy Cliff
- KwaZulu-Natal Sharks Board, Maritime Centre of Excellence, Umhlanga Rocks, Umhlanga, South Africa
- Biomedical Resource Unit, University of KwaZulu-Natal, Durban, South Africa
- College of Agriculture, Engineering and Science, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Matthew L Dicken
- KwaZulu-Natal Sharks Board, Maritime Centre of Excellence, Umhlanga Rocks, Umhlanga, South Africa
- Department of Development Studies, School of Economics, Development and Tourism, Nelson Mandela University, Port Elizabeth, South Africa
- College of Agriculture, Engineering and Science, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Nigel E Hussey
- Department of Integrative Biology, University of Windsor, Windsor, Ontario, Canada
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14
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Lang AR, Boveng P, Quakenbush L, Robertson K, Lauf M, Rode KD, Ziel H, Taylor BL. Re-examination of population structure in Arctic ringed seals using DArTseq genotyping. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Although Arctic ringed seals Phoca hispida hispida are currently abundant and broadly distributed, their numbers are projected to decline substantially by the year 2100 due to climate warming. While understanding population structure could provide insight into the impact of environmental changes on this subspecies, detecting demographically important levels of exchange can be difficult in taxa with high abundance. We used a next-generation sequencing approach (DArTseq) to genotype ~5700 single nucleotide polymorphisms in 79 seals from 4 Pacific Arctic regions. Comparison of the 2 most geographically separated strata (eastern Bering vs. northeastern Chukchi-Beaufort Seas) revealed a statistically significant level of genetic differentiation (FST = 0.001, p = 0.005) that, while small, was 1 to 2 orders of magnitude greater than expected based on divergence estimated for similarly sized populations connected by low (1% yr-1) dispersal. A relatively high proportion (72 to 88%) of individuals within these strata could be genetically assigned to their stratum of origin. These results indicate that demographically important structure may be present among Arctic ringed seals breeding in different areas, increasing the risk that declines in the number of seals breeding in areas most negatively affected by environmental warming could occur.
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Affiliation(s)
- AR Lang
- Ocean Associates, Inc., Arlington, VA 22207, USA, under contract to the Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, CA 92037, USA
| | - P Boveng
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA Fisheries, Seattle, WA 98115, USA
| | - L Quakenbush
- Arctic Marine Mammal Program, Alaska Department of Fish and Game, Fairbanks, AK 99701, USA
| | - K Robertson
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, CA 92037, USA
| | - M Lauf
- Ocean Associates, Inc., Arlington, VA 22207, USA, under contract to the Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, CA 92037, USA
| | - KD Rode
- Alaska Science Center, US Geological Survey, Anchorage, AK 99508, USA
| | - H Ziel
- Marine Mammal Laboratory, Alaska Fisheries Science Center, NOAA Fisheries, Seattle, WA 98115, USA
| | - BL Taylor
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, CA 92037, USA
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Liang D, Yang S, Pagani-Núñez E, He C, Liu Y, Goodale E, Liao WB, Hu J. How to Become a Generalist Species? Individual Niche Variation Across Habitat Transformation Gradients. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.597450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Species in transformed habitats, frequently labeled as environmental generalists, tend to show broader niches than species in natural habitats. However, how population niche expansion translates into changes in the niches of individual organisms remains unclear, particularly in the context of habitat transformation. Niche expansion could be a product of individuals having broader niches, greater distances among individuals’ niches, or a combination of both processes. This would challenge the traditional conceptions on niche dynamics, which emphasize the role played by individual specialization (IS). Here, using stable isotopes, we computed total niche width (TNW), its within- and between-individual components (WIC and BIC), and IS (the ratio WIC/TNW), in 13 populations of 6 bird species and 8 populations of 3 frog species in natural and transformed habitats. We confirmed that species had broader niche width in transformed than in natural habitats, yet population niche expansion across habitats was mainly a product of increased distance between individuals. Within each habitat type, increases in TNW were linked to increases in WIC for all habitat types, while relationships between TNW and BIC were found in transformed but not in natural habitats. Hence, both increased individual niche width and increased distance among individuals were apparent within habitats, particularly in transformed ones, where increases in WIC dominated. Neither across or within habitats was niche expansion associated with increasing IS. Therefore, our results overturn traditional conceptions associated with the niche variation hypothesis and illustrate that niche expansion is not invariably associated with increased IS, because the distance between individual’s niches (BIC) can increase, as well as the breadth of those niches (WIC).
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16
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Houde M, Taranu ZE, Wang X, Young B, Gagnon P, Ferguson SH, Kwan M, Muir DC. Mercury in Ringed Seals (Pusa hispida) from the Canadian Arctic in Relation to Time and Climate Parameters. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2020; 39:2462-2474. [PMID: 33025637 PMCID: PMC7756774 DOI: 10.1002/etc.4865] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/16/2020] [Accepted: 08/19/2020] [Indexed: 05/05/2023]
Abstract
Mercury is found in Arctic marine mammals that are important in the diet of northern Indigenous peoples. The objectives of the present long-term study, spanning a 45-yr period, were to 1) investigate the temporal trends of total mercury (THg; muscle and liver) and selenium (Se; liver) in ringed seals (Pusa hispida) from different regions of the Canadian Arctic; and 2) examine possible relationships with age, diet, and climate parameters such as air temperature, precipitation, climatic indices, and ice-coverage. Ringed seals were collected by hunters in northern communities in the Beaufort Sea, Central Arctic, Eastern Baffin Island, Hudson Bay, and Ungava/Nunatsiavut regions (Canada) between 1972 and 2017. Mercury levels did not change through time in seal liver, but THg levels in muscle decreased in seals from Hudson Bay (-0.91%/yr) and Ungava/Nunatsiavut (-1.30%/yr). Carbon stable isotope values in seal muscle decreased significantly through time in 4 regions. Selenium-to-THg ratios were found to be >1 for all years and regions. Variation partitioning analyses across regions indicated that THg trends in seals were mostly explained by age (7.3-21.7%), climate parameters (3.5-12.5%), and diet (up to 9%); climate indices (i.e., Arctic and North Atlantic Oscillations, Pacific/North American pattern) explained the majority of the climate portion. The THg levels had a positive relationship with Arctic Oscillation for multiple regions. Associations of THg with air temperature, total precipitation, and sea-ice coverage, as well as with North Atlantic Oscillation and Pacific/North American pattern were found to vary with tissue type and geographical area. Environ Toxicol Chem 2020;39:2462-2474. © 2020 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Fisheries and Oceans Canada.
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Affiliation(s)
- Magali Houde
- Environment and Climate Change CanadaMontrealQuebecCanada
| | | | - Xiaowa Wang
- Environment and Climate Change CanadaBurlingtonOntarioCanada
| | - Brent Young
- Arctic Aquatic Research DivisionDepartment of Fisheries and OceansWinnipegManitobaCanada
| | - P. Gagnon
- Environment and Climate Change CanadaMontrealQuebecCanada
| | - Steve H. Ferguson
- Arctic Aquatic Research DivisionDepartment of Fisheries and OceansWinnipegManitobaCanada
| | | | - Derek C.G. Muir
- Environment and Climate Change CanadaBurlingtonOntarioCanada
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17
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Broad feeding niches of capelin and sand lance may overlap those of polar cod and other native fish in the eastern Canadian Arctic. Polar Biol 2020. [DOI: 10.1007/s00300-020-02738-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Lunghi E, Manenti R, Cianferoni F, Ceccolini F, Veith M, Corti C, Ficetola GF, Mancinelli G. Interspecific and interpopulation variation in individual diet specialization: Do environmental factors have a role? Ecology 2020; 101:e03088. [PMID: 32320485 DOI: 10.1002/ecy.3088] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 03/13/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022]
Abstract
Individual diet specialization (IS) has important community- and population-level implications and its ecological drivers are actively investigated. Here, to test the hypothesis that local environmental conditions may influence IS in wild populations, we analyzed the stomach contents of 395 individuals from eight populations of five allopatric species of European cave salamanders (genus Hydromantes). We assessed whether their degree of individual diet specialization (1) scaled positively with the respective niche widths, in agreement with Van Valen's niche variation hypothesis (NVH), and (2) could be predicted by satellite-derived climatic and vegetation characteristics of the sites where the populations live. Consistent with the NVH, the degree of individual diet specialization increased with the populations' total niche width. Furthermore, two variables describing local nonarboreal vegetation cover and habitat heterogeneity successfully predicted the variation in individual specialization across the eight populations. Climatic factors had a generally low predictive power, with individual specialization in low- and high-elevation populations showing contrasting patterns of co-variation with air temperature in the warmest quarter of the year. However, independently from elevation, specialization peaked under conditions of high nonarboreal vegetation cover and high precipitation regimes. We discussed the results against two mutually nonexclusive scenarios hypothesizing different mechanisms linking environmental factors to salamanders' trophic strategy at an individual and population level. We concluded that satellite-derived climatic and vegetation variables to date generally adopted to model Grinnellian niches might also be useful in predicting spatial variations in dietary habits of populations, that is, their Eltonian niches.
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Affiliation(s)
- Enrico Lunghi
- Key Laboratory of the Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beichen West Road 1, Beijing, 100101, China.,Museo di Storia Naturale "La Specola" dell'Università degli Studi di Firenze, Via Romana 17, Firenze, 50125, Italy.,Biogeographie, Universität Trier Fachbereich VI Raum-und Umweltwissenschaften, Universitätsring 15, Trier, 54286, Germany
| | - Raoul Manenti
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26, Milano, 20133, Italy
| | - Fabio Cianferoni
- Museo di Storia Naturale "La Specola" dell'Università degli Studi di Firenze, Via Romana 17, Firenze, 50125, Italy.,Istituto di Ricerca sugli Ecosistemi Terrestri (IRET), Consiglio Nazionale delle Ricerche (CNR), Via Madonna del Piano, Sesto Fiorentino (Firenze), 50019, Italy
| | - Filippo Ceccolini
- Museo di Storia Naturale "La Specola" dell'Università degli Studi di Firenze, Via Romana 17, Firenze, 50125, Italy
| | - Michael Veith
- Biogeographie, Universität Trier Fachbereich VI Raum-und Umweltwissenschaften, Universitätsring 15, Trier, 54286, Germany
| | - Claudia Corti
- Museo di Storia Naturale "La Specola" dell'Università degli Studi di Firenze, Via Romana 17, Firenze, 50125, Italy
| | - Gentile Francesco Ficetola
- Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, via Celoria 26, Milano, 20133, Italy.,Laboratoire d'Écologie Alpine (LECA), Université Grenoble Alpes, CNRS, CS 40700, Grenoble, 38058, France
| | - Giorgio Mancinelli
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA), Università del Salento, Centro Ecotekne, S.P. Lecce-Monteroni, Lecce, 73100, Italy.,Istituto per le Risorse Biologiche e le Biotecnologie Marine (IRBIM), Consiglio Nazionale delle Ricerche (CNR), Via Pola, 4, Lesina (Foggia), 71010, Italy.,CoNISMa, Consorzio Nazionale Interuniversitario per le Scienze del Mare, Piazzale Flaminio, 9, Roma, 00196, Italy
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19
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Boucher NP, Derocher AE, Richardson ES. Spatial and temporal variability in ringed seal ( Pusa hispida) stable isotopes in the Beaufort Sea. Ecol Evol 2020; 10:4178-4192. [PMID: 32489588 PMCID: PMC7246210 DOI: 10.1002/ece3.6186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/14/2020] [Accepted: 02/17/2020] [Indexed: 12/02/2022] Open
Abstract
Arctic ecosystem dynamics are shifting in response to warming temperatures and sea ice loss. Such ecosystems may be monitored by examining the diet of upper trophic level species, which varies with prey availability. To assess interannual variation in the Beaufort Sea ecosystem, we examined spatial and temporal trends in ringed seal (Pusa hispida) δ13C and δ15N in claw growth layers grown from 1964 to 2011. Stable isotopes were correlated with climate indices, environmental conditions, seal population productivity, and geographic location. Sex and age did not influence stable isotopes. Enriched 13C was linked to cyclonic circulation regimes, seal productivity, and westward sampling locations. Higher δ15N was linked to lower sea surface temperatures, a higher percentage of pups in the subsistence harvest, and sample locations that were eastward and further from shore. From the 1960s to 2000s, ringed seal niche width expanded, suggesting a diversification of diet due to expansion of prey and/or seal space use. Overall, trends in ringed seal stable isotopes indicate changes within the Beaufort Sea ecosystem affected by water temperatures and circulation regimes. We suggest that continued monitoring of upper trophic level species will yield insights into changing ecosystem structure with climate change.
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Affiliation(s)
- Nicole P. Boucher
- Department of Biological SciencesUniversity of AlbertaEdmontonABCanada
| | | | - Evan S. Richardson
- Wildlife Research Division, Science and Technology BranchEnvironment and Climate Change CanadaWinnipegMBCanada
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20
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Rodríguez-Malagón MA, Camprasse ECM, Angel LP, Arnould JPY. Geographical, temporal and individual factors influencing foraging behaviour and consistency in Australasian gannets. ROYAL SOCIETY OPEN SCIENCE 2020; 7:181423. [PMID: 32537184 PMCID: PMC7277272 DOI: 10.1098/rsos.181423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
Foraging is a behaviour that can be influenced by multiple factors and is highly plastic. Recent studies have shown consistency in individual foraging behaviour has serious ecological and evolutionary implications within species and populations. Such information is crucial to understand how species select habitats, and how such selection might allow them to adapt to the environmental changes they face. Five foraging metrics (maximum distance from the colony, bearing from the colony to the most distal point, tortuosity index, total number of dives and mean vectorial dynamic body acceleration were obtained using GPS tracking and accelerometry data in adult Australasian gannets (Morus serrator) from two colonies in southeastern Australia. Individuals were instrumented over two breeding seasons to obtain data to assess factors influencing foraging behaviour and behavioural consistency over multiple timescales (consecutive trips, breeding stages and years) and habitats (pelagic, mixed pelagic and inshore, and inshore). Colony, breeding stage and year were the factors which had the greatest influence on foraging behaviour, followed by sex. Behavioural consistency, measured as the contribution of the individual to the observed variance, was low to moderate for all foraging metrics (0.0-27.05%), with the higher values occurring over shorter timescales. In addition, behavioural consistency was driven by spatio-temporal factors rather than intrinsic characteristics. Behavioural consistency was higher in individuals foraging in inshore than pelagic habitats or mixed pelagic/inshore strategy, supporting suggestions that consistency is favoured in stable environments.
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21
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Differential effects of habitat loss on occupancy patterns of the eastern green lizard Lacerta viridis at the core and periphery of its distribution range. PLoS One 2020; 15:e0229600. [PMID: 32134932 PMCID: PMC7058328 DOI: 10.1371/journal.pone.0229600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/10/2020] [Indexed: 11/19/2022] Open
Abstract
The effects of habitat loss on the distribution of populations are often linked with species specialization degree. Specialist species can be more affected by changes in landscape structure and local patch characteristics compared to generalist species. Moreover, the spatial scale at which different land covers (eg. habitat, cropland, urban areas) affect specialist species can be smaller. Specialization is usually assumed as a constant trait along the distribution range of species. However, for several taxa, there is evidence of higher specialization degree in peripheral populations compared with populations in the core. Hence, peripheral populations should have a higher sensitivity to habitat loss, and strongest effects should be found at a smaller spatial scale. To test these expectations, we implemented a patch-landscape approach at different spatial scales, and compared effects of landscape structure and patch characteristics on occupancy probability among northern peripheral, more specialized populations (Czech Republic) and core populations (Bulgaria) of the eastern green lizard Lacerta viridis. We found that landscape structure and patch characteristics affect differently the occupancy probability of Lacerta viridis in each region. Strongest effects of habitat loss were found at a spatial scale of 150m around patches in the periphery, but at a scale of 500m in the core. In the periphery occupancy probability of populations was principally affected by landscape composition, and the effect of habitat quality was stronger compared to core populations. In the core, persistence of populations was mainly explained by characteristics of the spatial configuration of habitat patches. We discuss possible ecological mechanisms behind the relationship between sensitivity to habitat loss, populations' specialization degree and position in the distribution range, and suggest conservation measures for L. viridis.
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22
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Yurkowski DJ, Richardson ES, Lunn NJ, Muir DCG, Johnson AC, Derocher AE, Ehrman AD, Houde M, Young BG, Debets CD, Sciullo L, Thiemann GW, Ferguson SH. Contrasting Temporal Patterns of Mercury, Niche Dynamics, and Body Fat Indices of Polar Bears and Ringed Seals in a Melting Icescape. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2780-2789. [PMID: 32046488 DOI: 10.1021/acs.est.9b06656] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Polar bears (Ursus maritimus) and ringed seals (Pusa hispida) have a strong predator-prey relationship and are facing climate-associated Arctic habitat loss and harmful dietary exposure to total mercury (THg) and other pollutants. However, little is known about whether both species inhabiting the same area exhibit similar temporal patterns in Hg concentration, niche dynamics, and body fat indices. We used THg, δ13C, and δ15N values of western Hudson Bay polar bear hair (2004-2016) and ringed seal muscle samples (2003-2015) to investigate temporal trends of these variables and multidimensional niche metrics, as well as body fat indices for both species. We found a decline in THg concentration (by 3.8% per year) and δ13C (by 1.5‰) in ringed seals suggesting a change in feeding habits and carbon source use over time, whereas no significant changes occurred in polar bears. In contrast, the polar bear 3-dimensional niche size decreased by nearly half with no change in ringed seal niche size. The δ13C spacing between both species increased by approximately 1.5× suggesting different responses to annual changes in sympagic-pelagic carbon source production. Ringed seal body fat index was higher in years of earlier sea ice breakup with no change occurring in polar bears. These findings indicate that both species are responding differently to a changing environment suggesting a possible weakening of their predator-prey relationship in western Hudson Bay.
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Affiliation(s)
- David J Yurkowski
- University of Manitoba, Winnipeg, Manitoba MB R3T 2N2, Canada
- Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada
| | - Evan S Richardson
- Environment and Climate Change Canada, Winnipeg, Manitoba MB R3B 2B4, Canada
| | - Nicholas J Lunn
- Environment and Climate Change Canada, Edmonton, Alberta AB T5J 0J4, Canada
| | - Derek C G Muir
- Environment and Climate Change Canada, Burlington, Ontario ON L7S 1A1, Canada
| | - Amy C Johnson
- University of Alberta, Edmonton, Alberta AB T6G 2R3, Canada
| | | | - Ashley D Ehrman
- Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada
| | - Magali Houde
- Environment and Climate Change Canada, Montreal, Quebec QC H2Y 2E7, Canada
| | - Brent G Young
- Fisheries and Oceans Canada, Winnipeg, Manitoba MB R3T 2N6, Canada
| | | | - Luana Sciullo
- York University, Toronto, Ontario ON M3J 1P3, Canada
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23
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Bolnick DI, Ballare KM. Resource diversity promotes among-individual diet variation, but not genomic diversity, in lake stickleback. Ecol Lett 2020; 23:495-505. [PMID: 31919988 PMCID: PMC7325224 DOI: 10.1111/ele.13448] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/07/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022]
Abstract
Many generalist species consist of specialised individuals that use different resources. This within-population niche variation can stabilise population and community dynamics. Consequently, ecologists wish to identify environmental settings that promote such variation. Theory predicts that environments with greater resource diversity favour ecological diversity among consumers (via disruptive selection or plasticity). Alternatively, niche variation might be a side-effect of neutral genomic diversity in larger populations. We tested these alternatives in a metapopulation of threespine stickleback. Stickleback consume benthic and limnetic invertebrates, focusing on the former in small lakes, the latter in large lakes. Intermediate-sized lakes support generalist stickleback populations using an even mixture of the two prey types, and exhibit greater among-individual variation in diet and morphology. In contrast, genomic diversity increases with lake size. Thus, phenotypic diversity and neutral genetic polymorphism are decoupled: trophic diversity being greatest in intermediate-sized lakes with high resource diversity, whereas neutral genetic diversity is greatest in the largest lakes.
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Effects of urbanization on resource use and individual specialization in coyotes (Canis latrans) in southern California. PLoS One 2020; 15:e0228881. [PMID: 32023321 PMCID: PMC7001990 DOI: 10.1371/journal.pone.0228881] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/24/2020] [Indexed: 11/30/2022] Open
Abstract
Urban environments are unique because fragments of natural or semi-natural habitat are embedded within a potentially permeable matrix of human-dominated areas, creating increased landscape and, potentially, habitat heterogeneity. In addition, urban areas can provide diet subsidies for wildlife species in the form of fruiting ornamental plants, trash, and domestic animals. Ecological opportunity in the forms of habitat and food heterogeneity are thought to be important mechanisms in maintaining individual specialization. Identifying which contexts, traits, and mechanisms determine the success or failure of individuals within an urban wildlife population could potentially provide predictions about which populations may succeed in human-dominated landscapes and which may experience local extinction. We used both scat and stable isotope analysis of whiskers to investigate the degree to which coyotes (Canis latrans) utilized anthropogenic subsidies and exhibited individual diet specialization across the urban-rural gradient in southern California. Land use surrounding scat and isotope sample locations was also evaluated to determine the effect of land cover on diet. Human food constituted a significant portion of urban coyote diet (22% of scats, 38% of diet estimated by stable isotope analysis). Domestic cats (Felis catus) and ornamental fruit and seeds were also important items in urban coyote diets. Consumption of anthropogenic items decreased with decreasing urbanization. In suburban areas, seasonality influenced the frequency of occurrence of anthropogenic subsidies with increased consumption in the dry season. The amount of altered open space (areas such as golf courses, cemeteries, and landscaped parks) nearby had a negative effect on the consumption of anthropogenic items in both urban and suburban areas. Contrary to our hypothesis, urban coyotes displayed reduced between-individual variation compared to suburban and rural coyotes. It is possible that the core urban areas of cities are so densely developed and subsidized that wildlife inhabiting these areas actually have reduced ecological opportunity. Suburban animals had the broadest isotopic niches and maintained similar individual specialization to rural coyotes. Wildlife in suburban areas still have access to relatively undisturbed natural areas while being able to take advantage of anthropogenic subsidies in neighboring residential areas. Therefore, areas with intermediate urban development may be associated with increased ecological opportunity and specialization.
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Hamilton CD, Vacquié-Garcia J, Kovacs KM, Ims RA, Kohler J, Lydersen C. Contrasting changes in space use induced by climate change in two Arctic marine mammal species. Biol Lett 2019; 15:20180834. [PMID: 30836888 DOI: 10.1098/rsbl.2018.0834] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Global warming is inducing major environmental changes in the Arctic. These changes will differentially affect species owing to differences in climate sensitivity and behavioural plasticity. Arctic endemic marine mammals are expected to be impacted significantly by ongoing changes in their key habitats owing to their long life cycles and dependence on ice. Herein, unique biotelemetry datasets for ringed seals (RS; Pusa hispida) and white whales (WW; Delphinapterus leucas) from Svalbard, Norway, spanning two decades (1995-2016) are used to investigate how these species have responded to reduced sea-ice cover and increased Atlantic water influxes. Tidal glacier fronts were traditionally important foraging areas for both species. Following a period with dramatic environmental change, RS now spend significantly more time near tidal glaciers, where Arctic prey presumably still concentrate. Conversely, WW spend significantly less time near tidal glacier fronts and display spatial patterns that suggest that they are foraging on Atlantic fishes that are new to the region. Differences in levels of dietary specialization and overall behavioural plasticity are likely reasons for similar environmental pressures affecting these species differently. Climate change adjustments through behavioural plasticity will be vital for species survival in the Arctic, given the rapidity of change and limited dispersal options.
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Affiliation(s)
| | | | - Kit M Kovacs
- 1 Norwegian Polar Institute, Fram Centre , Tromsø , Norway
| | - Rolf A Ims
- 2 University of Tromsø, The Arctic University of Norway , Tromsø , Norway
| | - Jack Kohler
- 1 Norwegian Polar Institute, Fram Centre , Tromsø , Norway
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Abstract
Niche expansion is attained by adaptations in two generalized phenotypical traits-niche position and niche width. This gives room for a wide range of conceptual ways of niche filling. The niche variation hypothesis reduces the range by predicting that expansion occurs by increasing variation in niche position, which has been debated on empirical and theoretical grounds as also other options seem possible. Here, we propose a general theory of niche expansion. We review empirical data and show with an eco-evolutionary model how resource diversity and a trade-off in resource acquisition steer niche evolution consistent with observations. We show that the range can be reduced to a discrete set of two orthogonal ways of niche filling, through (1) strict phenotypical differentiation in niche position or (2) strict individual generalization. When individual generalization is costly, niche expansion undergoes a shift from (2) to (1) at a point where the resource diversity becomes sufficiently large. Otherwise, niche expansion always follows (2), consistent with earlier results. We show that this either-or response can operate at both evolutionary and short-term time scales. This reduces the principles of niche expansion under environmental change to a notion of orthogonality, dictated by resource diversity and a resource-acquisition trade-off.
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Affiliation(s)
- Henrik Sjödin
- Theoretical Population Ecology and Evolution Group (ThePEG), Department of Biology, Lund University , 22362 Lund , Sweden
| | - Jörgen Ripa
- Theoretical Population Ecology and Evolution Group (ThePEG), Department of Biology, Lund University , 22362 Lund , Sweden
| | - Per Lundberg
- Theoretical Population Ecology and Evolution Group (ThePEG), Department of Biology, Lund University , 22362 Lund , Sweden
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Pedro S, Fisk AT, Ferguson SH, Hussey NE, Kessel ST, McKinney MA. Limited effects of changing prey fish communities on food quality for aquatic predators in the eastern Canadian Arctic in terms of essential fatty acids, methylmercury and selenium. CHEMOSPHERE 2019; 214:855-865. [PMID: 30317166 DOI: 10.1016/j.chemosphere.2018.09.167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/24/2018] [Accepted: 09/28/2018] [Indexed: 06/08/2023]
Abstract
We determined concentrations of eicosapentaenoic and docosahexaenoic acids (EPA + DHA), Σomega-3, polyunsaturated fatty acids (ΣPUFA), selenium, methylmercury, and selenium:methylmercury (Se:Hg) ratios in native and northward-redistributing sub-Arctic marine fish and invertebrates from low, mid-, and high Canadian Arctic latitudes. There was no clear latitudinal trend in nutrient or contaminant concentrations. Among species, EPA + DHA concentrations in native Arctic cod (Boreogadus saida) were similar to concentrations in sub-Arctic capelin (Mallotus villosus) and sand lance (Ammodytes spp.) (444-658 mg.100 g-1), and higher than in most other species. Concentrations of EPA + DHA were related to lipid content, but to a greater extent for higher trophic position species (R2 = 0.83) than for species at lower trophic positions (R2 = 0.61). Selenium concentrations were higher in sand lance (1.15 ± 0.16 μg g-1) than in all other species (0.30-0.69 μg g-1), which was significantly, but weakly, explained by more pelagic feeding in sand lance. Methylmercury concentrations were similar (and Se:Hg ratios were higher) in capelin, sand lance, and Arctic cod (0.01-0.03 μg g-1 wet weight (ww)) and lower than in other prey (0.12-0.26 μg g-1 ww), which was significantly explained by the smaller size of these species and more pelagic feeding habits than other fish. These results suggested that a shift in prey fish composition from Arctic cod to capelin and/or sand lance is unlikely to reduce the food quality of the prey available to marine predators at least with respect to concentrations of essential fatty acids, selenium, and Se:Hg ratios.
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Affiliation(s)
- Sara Pedro
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA.
| | - Aaron T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Steven H Ferguson
- Fisheries and Oceans Canada, Central and Arctic Region, Winnipeg, MB R3T 2N6, Canada
| | - Nigel E Hussey
- Department of Biological Sciences, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Steven T Kessel
- Daniel P. Haerther Center for Conservation and Research, John G. Shedd Aquarium, Chicago, IL 60605, USA
| | - Melissa A McKinney
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the Environment and Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT 06269, USA; Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
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28
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Prieto‐Ramirez AM, Pe’er G, Rödder D, Henle K. Realized niche and microhabitat selection of the eastern green lizard ( Lacerta viridis) at the core and periphery of its distribution range. Ecol Evol 2018; 8:11322-11336. [PMID: 30519446 PMCID: PMC6262924 DOI: 10.1002/ece3.4612] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/16/2018] [Accepted: 09/19/2018] [Indexed: 12/05/2022] Open
Abstract
The available range of habitats and suitable abiotic conditions like temperature and radiation tends to be narrower toward the periphery of the distribution range of species. Peripheral populations of generalist species could then be more specialized and have a smaller and differentiated realized niche (habitat niche in our study) compared to populations at the core. Likewise, patterns of microhabitat selection can differ between periphery and core. In our study, we compared niche size and microhabitat selection among core (Bulgaria) and northern peripheral (Germany, Czech Republic) populations of Lacerta viridis and estimated niche differentiation among regions. We collected data on vegetation structure and abiotic parameters at the microhabitat scale in each region. In order to compare niche size among regions and estimate niche differentiation, we built multidimensional niche hypervolumes. We applied generalized linear mixed models and model averaging, accounting for spatial autocorrelation when necessary, to analyze microhabitat differences among regions and microhabitat selection in each region. Peripheral populations were more specialized, having a smaller niche than core ones, and their niche differed from that in the core (Sørensen overlap in all comparisons <0.3). Microhabitats at the periphery had lower radiation and soil compaction and less structured vegetation. Microhabitat selection at the core depended solely on abiotic parameters, while at the periphery it was defined by only vegetation structure (Czech Republic) or a combination of both, vegetation structure, and abiotic factors (Germany). Thus, peripheral populations seem to compensate for overall harsher climatic conditions by responding to different parameters of the microhabitat compared to core populations. We suggest specific conservation measures for L. virids in each studied region and point out the general implications of a higher specialization degree of peripheral populations in relation to climate change and habitat fragmentation.
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Affiliation(s)
- Ana M. Prieto‐Ramirez
- Department of Conservation BiologyHelmholtz Center for Environmental Research UFZLeipzigGermany
- Department of HerpetologyZoological Research Museum Alexander König ZFMKBonnGermany
| | - Guy Pe’er
- Department of Economics and Department of Ecosystem ServicesUFZ LeipzigLeipzigGermany
- German Center for Integrative Biodiversity (iDiv)Halle‐Jena‐LeipzigLeipzigGermany
- Universität LeipzigLeipzigGermany
| | - Dennis Rödder
- Department of HerpetologyZoological Research Museum Alexander König ZFMKBonnGermany
| | - Klaus Henle
- Department of Conservation BiologyHelmholtz Center for Environmental Research UFZLeipzigGermany
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Ferguson SH, Zhu X, Young BG, Yurkowski DJ, Thiemann GW, Fisk AT, Muir DC. Geographic variation in ringed seal (Pusa hispida) growth rate and body size. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0213] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We summarize geographical patterns in ringed seal (Pusa hispida (Schreber, 1775)) body length and girth growth using 3012 samples collected by Inuit hunters in the eastern Canadian Arctic from 1990 to 2016. Spatial structure was detected using cluster analysis of environmental variables separating a northern region in the eastern Canadian High Arctic and a southern region in Hudson Bay. The north was characterized by more fast ice, multiyear ice, greater snow depth, colder temperatures, and greater sea-ice concentration in the spring seal breeding season. Hierarchical Bayesian models described length and axillary girth growth of northern seals as slower than in the south, reaching asymptotic size 5–7 years later. Northern females were larger than males (asymptotic length of 149 versus 140 cm, respectively) and both were larger than southern seals (males and females 126 cm). We conclude that environmental variation was best represented by regions rather than latitude, regional body size differences were driven by differential growth rates, and northern ringed seals may be characterized by reverse sexual size dimorphism.
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Affiliation(s)
- Steven H. Ferguson
- Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Xinhua Zhu
- Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
| | - Brent G. Young
- Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
| | - David J. Yurkowski
- Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, MB R3T 2N6, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Gregory W. Thiemann
- Faculty of Environmental Studies, York University, Toronto, ON M3J 1P3, Canada
| | - Aaron T. Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON N9B 3P4, Canada
| | - Derek C.G. Muir
- Environment Climate Change Canada, Aquatic Contaminants Research Division, Burlington, ON L7S 1A1, Canada
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30
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Colborne SF, Fisk AT, Johnson TB. Tissue-specific turnover and diet-tissue discrimination factors of carbon and nitrogen isotopes of a common forage fish held at two temperatures. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:1405-1414. [PMID: 28590512 DOI: 10.1002/rcm.7922] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 05/26/2017] [Accepted: 06/05/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE The application of stable isotopes to foraging ecology is dependent on understanding life-history and environmental factors unrelated to diet that may influence isotopic composition. Diet-tissue discrimination factors (DTDFs) and turnover rates will increase the accuracy of isotope-based studies. Furthermore, little consideration has been given to the effects of temperature or life-history stage on isotopic ratios despite the prevalence of variation in temperature and growth rates throughout life. METHODS We measured δ13 C and δ15 N values with an elemental analyzer coupled to a continuous flow isotope ratio mass spectrometer. These values were used to estimate turnover and DTDFs for Emerald Shiners (Notropis atherinoides), a common North American freshwater forage fish. Fish were assigned to a temperature treatment, either 10°C (Low) or 20°C (High), and provided one of three diets (commercial pellet, Artemia salina, or Hemimysis anomala). At regular intervals fish were sampled and the isotopic compositions of whole body and liver tissues were determined. RESULTS Tissue turnover rates for fish fed Artemia were faster for liver than for whole body, but were also influenced by temperature. Turnover occurred faster at higher temperatures for body and liver δ15 N values, but not for δ13 C values. The pellet and Hemimysis treatments were in isotopic equilibrium from the start of the experiment and estimated DTDFs based on these treatments were lower than assumed for Δ15 N (+0.6 to 2.7‰) and variable, but within expected ranges for Δ13 C (-1.9 to +1.5‰). CONCLUSIONS The results for Emerald Shiners differed from commonly made assumptions for applying stable isotopes to ecological questions, possibly related to a bias in the use of juveniles in studies of turnover and DTDFs and assumptions regarding thermal-independence of isotopic relationships. The species-specific DTDF and tissue turnover estimates provided here will inform interpretations of stable isotope data for smaller fish species and improve food-web studies.
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Affiliation(s)
- S F Colborne
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada
| | - A T Fisk
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada
| | - T B Johnson
- Ontario Ministry of Natural Resources and Forestry, Glenora Fisheries Station, Picton, ON, Canada
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31
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Houde M, Wang X, Ferguson SH, Gagnon P, Brown TM, Tanabe S, Kunito T, Kwan M, Muir DCG. Spatial and temporal trends of alternative flame retardants and polybrominated diphenyl ethers in ringed seals (Phoca hispida) across the Canadian Arctic. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 223:266-276. [PMID: 28131476 DOI: 10.1016/j.envpol.2017.01.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 06/06/2023]
Abstract
Concentrations of alternative flame retardants and polybrominated diphenyl ethers (PBDEs) were analyzed in ringed seal (Phoca hispida) blubber collected across the Canadian Arctic during subsistence hunts between 1998 and 2013. More than 80% of sampled animals were females and juvenile males. The highest mean ΣPBDE concentrations (sum of 13 congeners) were found in seals from Nain (Nunatsiavut) as well as Inukjuaq and Arviat (Hudson Bay) and the lowest mean levels were found in seals from Lancaster Sound. BDE-47 and -99 were the predominant PBDE congeners quantified in ringed seals. The most frequently detected non-PBDE flame retardants were polybrominated biphenyl 101 (BB-101, 57% of samples analyzed for this chemical), hexabromocyclododecane (HBCDD; 38%), hexabromobenzene (HBB, 30%), and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTeBB, 23%). The relative trophic position of seals, estimated using stable isotopes, did not vary over time and did not influence flame retardant blubber concentrations. The relative carbon source increased over time at Arviat and Resolute Bay and weak relationships were observed with ΣPBDEs in blubber of seals. ΣPBDEs increased significantly from 1998 to 2008 in ringed seals from East Baffin and subsequently decreased in recent years. PBDE levels at other sites fluctuated slightly over time. HBCDD concentrations increased at several sites over the past decade. The presence of flame retardants in ringed seals suggests their persistence and their continuous inputs in the Canadian Arctic environment. Monitoring and research on the effects of these contaminants in seals are warranted given the importance of this species in Arctic marine food webs and for local communities.
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Affiliation(s)
- M Houde
- Environment and Climate Change Canada, 105 McGill Street, Montreal, QC H2Y 2E7, Canada.
| | - X Wang
- Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, ON L7S 1A1, Canada
| | - S H Ferguson
- Department of Fisheries and Oceans, Arctic Aquatic Research Division, Winnipeg, MB R3T 2N6, Canada
| | - P Gagnon
- Environment and Climate Change Canada, 105 McGill Street, Montreal, QC H2Y 2E7, Canada
| | - T M Brown
- Memorial University, St. John's, NL A1B 3X9, Canada
| | - S Tanabe
- Ehime University, Center for Marine Environmental Studies (CMES), Matsuyama 790-8566, Japan
| | - T Kunito
- Shinshu University, Department of Environmental Sciences, Matsumoto 390-8621, Japan
| | - M Kwan
- Nunavik Research Centre, Kuujjuaq, QC J0M 1C0, Canada
| | - D C G Muir
- Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, ON L7S 1A1, Canada
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Ferguson SH, Young BG, Yurkowski DJ, Anderson R, Willing C, Nielsen O. Demographic, ecological, and physiological responses of ringed seals to an abrupt decline in sea ice availability. PeerJ 2017; 5:e2957. [PMID: 28168119 PMCID: PMC5292026 DOI: 10.7717/peerj.2957] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/04/2017] [Indexed: 01/19/2023] Open
Abstract
To assess whether demographic declines of Arctic species at the southern limit of their range will be gradual or punctuated, we compared large-scale environmental patterns including sea ice dynamics to ringed seal (Pusa hispida) reproduction, body condition, recruitment, and stress in Hudson Bay from 2003 to 2013. Aerial surveys suggested a gradual decline in seal density from 1995 to 2013, with the lowest density occurring in 2013. Body condition decreased and stress (cortisol) increased over time in relation to longer open water periods. The 2010 open water period in Hudson Bay coincided with extremes in large-scale atmospheric patterns (North Atlantic Oscillation, Arctic Oscillation, El Nino-Southern Oscillation) resulting in the earliest spring breakup and the latest ice formation on record. The warming event was coincident with high stress level, low ovulation rate, low pregnancy rate, few pups in the Inuit harvest, and observations of sick seals. Results provide evidence of changes in the condition of Arctic marine mammals in relation to climate mediated sea ice dynamics. We conclude that although negative demographic responses of Hudson Bay seals are occurring gradually with diminishing sea ice, a recent episodic environmental event played a significant role in a punctuated population decline.
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Affiliation(s)
- Steven H. Ferguson
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
- Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, Canada
| | - Brent G. Young
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - David J. Yurkowski
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Randi Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Cornelia Willing
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada
- Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB, Canada
| | - Ole Nielsen
- Fisheries and Oceans Canada, Winnipeg, MB, Canada
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