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Gestoso A, Vidal M, Domínguez J. Use of Stable Isotopes (δ 13C and δ 15N) to Infer Post-Breeding Dispersal Strategies in Iberian Populations of the Kentish Plover. Animals (Basel) 2024; 14:1208. [PMID: 38672355 PMCID: PMC11047555 DOI: 10.3390/ani14081208] [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: 03/11/2024] [Revised: 04/10/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Beaches are among the habitats most frequented by migratory birds for breeding and/or wintering. However, threats such as human pressure and sea level rise can reduce the availability of these habitats for different species. The presence of alternative areas, such as salt pans and brackish habitats, is essential for many migratory shorebird populations. This study addresses the post-breeding dispersal of the Kentish plover (Charadrius alexandrinus) in the Iberian Peninsula by analysing C and N isotopes in feathers. The study was conducted at six locations along the Iberian coast, which were categorized into three areas: the NW Atlantic coast, the Atlantic coast of Andalusia, and the Mediterranean coast. Although linear mixed models did not reveal any significant effects of sex or coastal area on isotopic levels, the variability in the data suggests different habitat-use strategies in the post-reproductive period. Isotopic levels in birds from the northwest of the Iberian Peninsula exhibit greater fidelity to a single habitat type, while those from the Mediterranean coast and the Atlantic coast of Andalusia show greater variability, indicating different individual dispersal strategies. The lack of alternative habitats for the northwest Iberian population, the reduction in available habitat due to rising sea levels, and human pressure together pose a serious threat to the survival of this species, already with an unfavourable conservation status.
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Affiliation(s)
| | | | - Jesús Domínguez
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain; (A.G.); (M.V.)
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2
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Ramírez-Otarola N, Maldonado K, Valdés-Ferranty F, Newsome SD, Sabat P. Seasonal changes in diet, immune function, and oxidative stress in three passerines inhabiting a Mediterranean climate. Oecologia 2023; 203:395-405. [PMID: 37950102 DOI: 10.1007/s00442-023-05474-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 10/31/2023] [Indexed: 11/12/2023]
Abstract
Oxidative status and immune function are energy-demanding traits closely linked to diet composition, particularly resource availability and nutritional value. In seasonal environments, nutrient availability and diet quality fluctuate, potentially influencing these traits. However, limited evidence exists regarding these dietary effects on immune function in seasonal environments. In this study, we employed stable isotope analysis to assess the impact of seasonal changes in niche width and trophic level (i.e., δ15N) on two immune variables (hemolysis and hemagglutination scores) and two oxidative status parameters (lipid peroxidation and total antioxidant capacity) in three passerine species: Zonotrichia capensis (omnivorous), Troglodytes aedon (insectivorous), and Spinus barbatus (granivorous). We found that hemolysis scores varied seasonally in Z. capensis, with higher values in winter compared to summer. Total antioxidant capacity (TAC) also increased during the winter in Z. capensis and S. barbatus. The isotopic niche width for Z. capensis and S. barbatus was smaller in winter than in summer, with the omnivorous species exhibiting a decrease in δ15N. Despite the seasonal shifts in ecological and physiological traits in Z. capensis, we identified no correlation between immune response and TAC with trophic level. In contrast, in the granivorous S. barbatus, the lower trophic level resulted in an increase in TAC without affecting immunity. Our findings revealed that dietary shifts do not uniformly impact oxidative status and immune function across bird species, highlighting species-specific responses to seasonal changes. This underscores the importance of integrating ecological and evolutionary perspectives when examining how diet shapes avian immunity and oxidative balance.
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Affiliation(s)
- Natalia Ramírez-Otarola
- Escuela de Medicina Veterinaria, Facultad de Medicina y Ciencias de la Salud, Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago, Chile.
| | - Karin Maldonado
- Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Santiago, Chile
| | - Fernanda Valdés-Ferranty
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Pablo Sabat
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
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Enríquez-García AB, Cruz-Escalona VH, Carriquiry JD, Ehemann NR, Mejía-Falla PA, Marín-Enríquez E, Treinen-Crespo C, Vélez-Tacuri JR, Navia AF. Trophic assessment of three sympatric batoid species in the Southern Gulf of California. PeerJ 2023; 11:e16117. [PMID: 37753172 PMCID: PMC10519201 DOI: 10.7717/peerj.16117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 08/27/2023] [Indexed: 09/28/2023] Open
Abstract
The competitive exclusion principle establishes that the coexistence of closely related species requires a certain degree of resource partitioning. However, populations have individuals with different morphological or behavioral traits (e.g., maturity stages, sexes, temporal or spatial segregation). This interaction often results in a multi-level differentiation in food preferences and habits. We explored such resource partitioning between and within three batoid species: Hypanus dipterurus, Narcine entemedor, and Rhinoptera steindachneri in the southern Gulf of California, Mexico, using a combination of stomach content (excluding R. steindachneri) and stable isotope analyses. We found a clear differentiation between H. dipterurus and N. entemedor, where the latter exhibited more benthic habitats, supported by a greater association to infaunal prey and higher δ13C values. Though the degree and patterns of intra-specific segregation varied among species, there was a notable differentiation in both sex and stage of maturity, corresponding to changes in specialization (i.e., isotopic niche breadth) or trophic spectrum (varying prey importance and isotopic values per group). This work is a promising step towards understanding the dietary niche dynamics of these species in a potentially important feeding area within the southern Gulf of California, as well as the biological and ecological mechanisms that facilitate their coexistence.
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Affiliation(s)
- Arturo Bell Enríquez-García
- Departamento de Pesquerías y Biología Marina, Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | - Víctor Hugo Cruz-Escalona
- Departamento de Pesquerías y Biología Marina, Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | - José D. Carriquiry
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico
| | - Nicolás R. Ehemann
- Departamento de Pesquerías y Biología Marina, Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
- Department of Biology, University of Konstanz, Zoology and Evolutionary Biology, Konstanz, Germany
| | - Paola A. Mejía-Falla
- Wildlife Conservation Society, Cali, Colombia
- Fundación Colombiana para la Investigación y Conservación de Tiburones y Rayas, SQUALUS, Cali, Colombia
| | - Emigdio Marín-Enríquez
- Facultad de Ciencias del Mar, CONACyT, Universidad Autónoma de Sinaloa, Mazatlán, Sinaloa, Mexico
| | - Christina Treinen-Crespo
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Baja California, Mexico
| | - José R. Vélez-Tacuri
- Facultad Ciencias del Mar, Universidad Laica Eloy Alfaro de Manabí, Manabí, Ecuador
- Fundación RACSE, Red de Agentes por la Conservación y Sostenibilidad de los Ecosistemas, Manta, Manabí, Ecuador
| | - Andrés F. Navia
- Fundación Colombiana para la Investigación y Conservación de Tiburones y Rayas, SQUALUS, Cali, Colombia
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4
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Rader JA, Matute DR. Isotopic niches do not follow the expectations of niche conservatism in the bird genus Cinclodes. J Evol Biol 2023; 36:1185-1197. [PMID: 37428811 DOI: 10.1111/jeb.14197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 07/12/2023]
Abstract
Phenotypic traits are expected to be more similar among closely related species than among species that diverged long ago (all else being equal). This pattern, known as phylogenetic niche conservatism, also applies to traits that are important to determine the niche of species. To test this hypothesis on ecological niches, we analysed isotopic data from 254 museum study skins from 12 of the 16 species of the bird genus Cinclodes and measured stable isotope ratios for four different elements: carbon, nitrogen, hydrogen and oxygen. We find that all traits, measured individually, or as a composite measurement, lack any phylogenetic signal, which in turn suggests a high level of lability in ecological niches. We compared these metrics to the measurements of morphological traits in the same genus and found that isotopic niches are uniquely evolutionarily labile compared to other traits. Our results suggest that, in Cinclodes, the realized niche evolves much faster than expected by the constraints of phylogenetic history and poses the question of whether this is a general pattern across the tree of life.
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Affiliation(s)
- Jonathan A Rader
- Dept. of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Daniel R Matute
- Dept. of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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5
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Navarrete L, Lübcker N, Alvarez F, Nespolo R, Sanchez-Hernandez JC, Maldonado K, Sharp ZD, Whiteman JP, Newsome SD, Sabat P. A multi-isotope approach reveals seasonal variation in the reliance on marine resources, production of metabolic water, and ingestion of seawater by two species of coastal passerine to maintain water balance. Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1120271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Tracing how free-ranging organisms interact with their environment to maintain water balance is a difficult topic to study for logistical and methodological reasons. We use a novel combination of triple-oxygen stable isotope analyses of water extracted from plasma (δ16O, δ17O, δ18O) and bulk tissue carbon (δ13C) and nitrogen (δ15N) isotopes of feathers and blood to estimate the proportional contribution of marine resources, seawater, and metabolic water used by two species of unique songbirds (genus Cinclodes) to maintain their water balance in a seasonal coastal environment. We also assessed the physiological adjustments that these birds use to maintain their water balance. In agreement with previous work on these species, δ13C and δ15N data show that the coastal resident and invertivore C. nigrofumosus consumes a diet rich in marine resources, while the diet of migratory C. oustaleti shifts seasonally between marine (winter) to freshwater aquatic resources (summer). Triple-oxygen isotope analysis (Δ17O) of blood plasma, basal metabolic rate (BMR), and total evaporative water loss (TEWL) revealed that ~25% of the body water pool of both species originated from metabolic water, while the rest originated from a mix of seawater and fresh water. Δ17O measurements suggest that the contribution of metabolic water tends to increase in summer in C. nigrofumosus, which is coupled with a significant increase in BMR and TEWL. The two species had similar BMR and TEWL during the austral winter when they occur sympatrically in coastal environments. We also found a positive and significant association between the use of marine resources as measured by δ13C and δ15N values and the estimated δ18O values of ingested (pre-formed) water in both species, which indicates that Cinclodes do not directly drink seawater but rather passively ingest when consuming marine invertebrates. Finally, results obtained from physiological parameters and the isotope-based estimates of marine (food and water) resource use are consistent, supporting the use of the triple-oxygen isotopes to quantify the contribution of water sources to the total water balance of free-ranging birds.
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Lal DM, Sreekanth GB, Soman C, Sharma A, Abidi ZJ. Delineating the food web structure in an Indian estuary during tropical winter employing stable isotope signatures and mixing model. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:49412-49434. [PMID: 36773262 DOI: 10.1007/s11356-023-25549-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 01/21/2023] [Indexed: 02/12/2023]
Abstract
The food and feeding links and sources in an impacted tropical estuary situated along India's western coast, the Ulhas River Estuary (URE) was analyzed employing the stable carbon and nitrogen isotopic signatures (δ13C and δ15N). Three basal carbon sources, such as mangrove leaves, particulate organic matter (phytoplankton), and detritus, were analyzed together with eight consumer groups from various trophic guilds. The δ13C varied from - 19.67 to - 24.61‰, whereas δ15N ranged from 6.31 to 15.39‰ from the primary consumer to the top predator species. The stable isotope mixing model developed for URE revealed a phytoplankton based pelagic food chain and detritus based benthic food chain in URE. The fairly larger value of SEA (Standard Ellipse Area) in the URE suggest a much broader food web structure and high trophic diversity in the ecosystem. Higher influence of detritus on the assimilated diet of majority of consumers and evidences of nitrogen enrichment in the basal sources such as detritus and particulate organic matter by anthropogenic activities in URE point towards nitrogen pollution and subsequent trophic disturbance in this tropical estuarine ecosystem.
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Affiliation(s)
- Dhanya Mohan Lal
- ICAR- Central Institute of Fisheries Education, Versova, Mumbai, 400061, India
| | | | - Chitra Soman
- ICAR- Central Institute of Fisheries Education, Versova, Mumbai, 400061, India
| | - Anupam Sharma
- Birbal Sahni Institute of Paleosciences, 53 University Road, Lucknow, 226007, India
| | - Zeba Jaffer Abidi
- ICAR- Central Institute of Fisheries Education, Versova, Mumbai, 400061, India
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7
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Aguiar-Santos J, deHart P, Forsberg B, Freitas C. Impacts of river fragmentation on limiting individual dietary specialization of Amazonian predatory fish. PeerJ 2022; 10:e14266. [PMID: 36540793 PMCID: PMC9760019 DOI: 10.7717/peerj.14266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/27/2022] [Indexed: 12/23/2022] Open
Abstract
Individual dietary specialization is one of the factors that promotes variation in resource use at the individual level. Here we used stable isotope analysis of multiple tissues with different turnover rates to examine the degree of individual specialization in two sub-populations of the predator Cichla temensis inhabiting both fragmented and undammed rivers within the Uatumã River basin of the Amazon. Our results showed that the undammed river provides better conditions to promote individual dietary specialization than the fragmented river. This study contributes to the understanding of how specific life history characteristics of populations of generalist predators are impacted by fragmentation within megadiverse environments such as the Amazon basin.
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Affiliation(s)
- Jamerson Aguiar-Santos
- Graduate Program in Ecology, National Institute of Amazonian Research, Manaus, Amazonas, Brazil
| | - Pieter deHart
- Office of Graduate Studies, University of Wisconsin-Green Bay, Green Bay, WI, United States of America
| | - Bruce Forsberg
- Department of Environmental Conservation, Vermont Agency of Natural Resources, Montpelier, VT, United States of America
| | - Carlos Freitas
- Department of Fishery Sciences, Federal University of Amazonas, Manaus, Amazonas, Brazil
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Navarro AB, Magioli M, Moreira MZ, Silveira LF. Perspectives and challenges on isotopic ecology of terrestrial birds in Brazil. ZOOLOGIA 2022. [DOI: 10.1590/s1984-4689.v39.e21023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
| | - Marcelo Magioli
- Instituto Pró-Carnívoros, Brazil; Instituto Chico Mendes de Conservação da Biodiversidade, Brazil
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10
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Ancin‐Murguzur FJ, Tarroux A, Bråthen KA, Bustamante P, Descamps S. Using near-infrared reflectance spectroscopy (NIRS) to estimate carbon and nitrogen stable isotope composition in animal tissues. Ecol Evol 2021; 11:10483-10488. [PMID: 34367590 PMCID: PMC8328452 DOI: 10.1002/ece3.7851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/03/2021] [Accepted: 06/07/2021] [Indexed: 11/15/2022] Open
Abstract
Stable isotopes analysis (SIA) of carbon and nitrogen provides valuable information about trophic interactions and animal feeding habits.We used near-infrared reflectance spectroscopy (NIRS) and support vector machines (SVM) to develop a model for screening isotopic ratios of carbon and nitrogen (δ 13C and δ 15N) in samples from living animals. We applied this method on dried blood samples from birds previously analyzed for δ 13C and δ 15N to test whether NIRS can be applied to accurately estimate isotopic ratios.Our results show a prediction accuracy of NIRS (R 2 > 0.65, RMSEP < 0.28) for both δ 13C and δ 15N, representing a 12% of the measurement range in this study.Our study suggests that NIRS can provide a time- and cost-efficient method to evaluate stable isotope ratios of carbon and nitrogen when substantial differences in δ 13C or δ 15N are expected, such as when discriminating among different trophic levels in diet.
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Affiliation(s)
| | | | - Kari Anne Bråthen
- Department of Arctic and Marine BiologyUniversity of Tromsø – The Arctic University of NorwayTromsøNorway
| | - Paco Bustamante
- Littoral Environnement et Sociétés (LIENSs)UMR 7266 CNRS‐La Rochelle UniversitéLa RochelleFrance
- Institut Universitaire de France (IUF)ParisFrance
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Agostinho KFF, Monteiro LR, Beneditto APMD. Individual niche trajectories in nesting green turtles on Rocas Atoll, Brazil: an isotopic tool to assess diet shifts over time. BIOTA NEOTROPICA 2021. [DOI: 10.1590/1676-0611-bn-2020-1099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abstract In this study, multi-tissue (yolk and carapace) stable isotope analysis was used to assess individual isotopic niche trajectories of nesting green turtles on Rocas Atoll, off northeastern Brazil, and to reveal a diet shift in the temporal dimension. The diet trajectories of individual green turtles were highly directional, with a stronger component towards decreasing values of δ15N from carapace to yolk. When the green turtles are in their foraging sites (temporal window measured by the yolk samples), they are more herbivores. Conversely, in a broader temporal window, the green turtles demonstrate a carnivore-omnivore strategy, such as represented by heavier δ15N values in the carapace. This finding confirms a temporal diet shift. This is the first study that applies trophic niche trajectories for sea turtles, adding a new isotopic tool to understand the trophic ecology of these migrant animals.
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Agostinho KFF, Pestana IA, Carvalho CEVD, Di Beneditto APM. Trace elements and stable isotopes in egg yolk of green turtles on Rocas Atoll, Brazil. MARINE POLLUTION BULLETIN 2021; 162:111821. [PMID: 33162056 DOI: 10.1016/j.marpolbul.2020.111821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/26/2020] [Accepted: 10/28/2020] [Indexed: 06/11/2023]
Abstract
This study analyzed trace elements (As, Ba, Cd, Cu, Fe, Mn, Pb, Zn) and stable isotopes of carbon and nitrogen in egg yolk samples of female green turtles that nested in Rocas Atoll, Brazil, in 2017 and 2018. The trace elements concentration varied between years, with higher concentrations in 2017, suggesting that the nesting groups come from different foraging sites. The isotopic data indicated high overlap between years (73%), leading to an ambiguous interpretation on the turtles' foraging site. The Normalized Total Load presented a low association (0.01 < R2 < 0.41) with the stable isotopes. The Normalized Total Load that represents the trace element load in egg yolk is a holistic approach that can be applied elsewhere to predict ecotoxicology pathways in any animal species. We recommend a continuous monitoring to verify how the trace elements load behave in the nesting green turtles on Rocas Atoll.
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Affiliation(s)
- Karoline Fernanda Ferreira Agostinho
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, CBB, Laboratório de Ciências Ambientais, Av. Alberto Lamego 2000, Campos dos Goytacazes 28013-602, RJ, Parque Califórnia, Brazil.
| | - Inácio Abreu Pestana
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, CBB, Laboratório de Ciências Ambientais, Av. Alberto Lamego 2000, Campos dos Goytacazes 28013-602, RJ, Parque Califórnia, Brazil.
| | - Carlos Eduardo Veiga de Carvalho
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, CBB, Laboratório de Ciências Ambientais, Av. Alberto Lamego 2000, Campos dos Goytacazes 28013-602, RJ, Parque Califórnia, Brazil
| | - Ana Paula Madeira Di Beneditto
- Universidade Estadual do Norte Fluminense Darcy Ribeiro, CBB, Laboratório de Ciências Ambientais, Av. Alberto Lamego 2000, Campos dos Goytacazes 28013-602, RJ, Parque Califórnia, Brazil.
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Juárez-Rodríguez M, Heckel G, Herguera-García JC, Elorriaga-Verplancken FR, Herzka SZ, Schramm Y. Trophic ecology of Mexican Pacific harbor seal colonies using carbon and nitrogen stable isotopes. PLoS One 2020; 15:e0225889. [PMID: 31967988 PMCID: PMC6975529 DOI: 10.1371/journal.pone.0225889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 11/14/2019] [Indexed: 11/28/2022] Open
Abstract
There is limited information that provides a comprehensive understanding of the trophic ecology of Mexican Pacific harbor seal (Phoca vitulina richardii) colonies. While scat analysis has been used to determine the diet of some colonies, the integrative characterization of its feeding habits on broader temporal and spatial scales remains limited. We examined potential feeding grounds, trophic niche width, and overlap, and inferred the degree of dietary specialization using stable carbon and nitrogen isotope ratios (δ13C and δ15N) in this subspecies. We analyzed δ13C and δ15N on fur samples from pups collected at five sites along the western coast of the Baja California Peninsula, Mexico. Fur of natal coat of Pacific harbor seal pups begins to grow during the seventh month in utero until the last stage of gestation. Therefore pup fur is a good proxy for the mother's feeding habits in winter (~December to March), based on the timing of gestation for the subspecies in this region. Our results indicated that the δ13C and δ15N values differed significantly among sampling sites, with the highest mean δ15N value occurring at the southernmost site, reflecting a well-characterized north to south latitudinal 15N-enrichment in the food web. The tendency identified in δ13C values, in which the northern colonies showed the most enriched values, suggests nearshore and benthic-demersal feeding habits. A low variance in δ13C and δ15N values for each colony (<1‰) and relatively small standard ellipse areas suggest a specialized foraging behavior in adult female Pacific harbor seals in Mexican waters.
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Affiliation(s)
- Maricela Juárez-Rodríguez
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Gisela Heckel
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Juan Carlos Herguera-García
- Departamento de Ecología Marina, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Fernando R. Elorriaga-Verplancken
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, Departamento de Pesquerías y Biología Marina, La Paz, Baja California Sur, México
| | - Sharon Z. Herzka
- Departamento de Oceanografía Biológica, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, México
| | - Yolanda Schramm
- Facultad de Ciencias Marinas, Universidad Autónoma de Baja California, Ensenada, Baja California, México
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14
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Costa‐Pereira R, Toscano B, Souza FL, Ingram T, Araújo MS. Individual niche trajectories drive fitness variation. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13389] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Raul Costa‐Pereira
- Instituto de Biociências Universidade Estadual Paulista (UNESP) Rio Claro Brazil
- McMaster University Hamilton Ontario Canada
| | | | - Franco L. Souza
- Instituto de Biociências Universidade Federal de Mato Grosso do Sul Campo Grande Brazil
| | - Travis Ingram
- Department of Zoology University of Otago Dunedin New Zealand
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15
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Foraging strategies of individual silky pocket mice over a boom-bust cycle in a stochastic dryland ecosystem. Oecologia 2019; 190:569-578. [PMID: 31190119 DOI: 10.1007/s00442-019-04432-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 06/07/2019] [Indexed: 01/19/2023]
Abstract
Small mammals use multiple foraging strategies to compensate for fluctuating resource quality in stochastic environments. These strategies may lead to increased dietary overlap when competition for resources is strong. To quantify temporal contributions of high (C3) versus low quality (C4) resources in diets of silky pocket mice (Perognathus flavus), we used stable carbon isotope (δ13C) analysis of 1391 plasma samples collected over 2 years. Of these, 695 samples were from 170 individuals sampled ≥ 3 times across seasons or years, allowing us to assess changes in dietary breadth at the population and individual levels across a boom-bust population cycle. In 2014, the P. flavus population increased to 412 captures compared to 8 captures in prior and subsequent years, while populations of co-occurring small mammals remained stable. As intraspecific competition increased, the population-wide dietary niche of P. flavus did not change, but individual specialization increased significantly. During this period, ~ 27% (41/151) of individuals sampled specialized on C3 resources, which were abundant during the spring and previous fall seasons. Most of the remaining individuals were C3-C4 generalists (64%) (96/151), and only 9% (14/151) specialized on C4 resources. In 2015, P. flavus population density and resource availability declined, individual dietary breadth expanded (84% generalists), no C3 specialists were found, and specialization on C4 resources increased (16%). Our results demonstrate a high degree of inter-individual plasticity in P. flavus foraging strategies, which has implications for how this species will respond to environmental change that is predicted to decrease C3 resources in the future.
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Wyatt AS, Matsumoto R, Chikaraishi Y, Miyairi Y, Yokoyama Y, Sato K, Ohkouchi N, Nagata T. Enhancing insights into foraging specialization in the world's largest fish using a multi-tissue, multi-isotope approach. ECOL MONOGR 2019. [DOI: 10.1002/ecm.1339] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Alex S.J. Wyatt
- Atmosphere and Ocean Research Institute; The University of Tokyo; 5-1-5 Kashiwanoha Kashiwa Chiba 277-8564 Japan
| | - Rui Matsumoto
- Okinawa Churaumi Aquarium; 424 Ishikawa Motobu Kunigami, Okinawa 905-0206 Japan
| | - Yoshito Chikaraishi
- Japan Agency for Marine-Earth Science and Technology; 2-15 Natsushima Yokosuka Kanagawa 237-0061 Japan
| | - Yosuke Miyairi
- Atmosphere and Ocean Research Institute; The University of Tokyo; 5-1-5 Kashiwanoha Kashiwa Chiba 277-8564 Japan
| | - Yusuke Yokoyama
- Atmosphere and Ocean Research Institute; The University of Tokyo; 5-1-5 Kashiwanoha Kashiwa Chiba 277-8564 Japan
| | - Keiichi Sato
- Okinawa Churashima Research Center; Okinawa Churashima Foundation; 888 Ishikawa Motobu Kunigami, Okinawa 905-0206 Japan
| | - Nao Ohkouchi
- Japan Agency for Marine-Earth Science and Technology; 2-15 Natsushima Yokosuka Kanagawa 237-0061 Japan
| | - Toshi Nagata
- Atmosphere and Ocean Research Institute; The University of Tokyo; 5-1-5 Kashiwanoha Kashiwa Chiba 277-8564 Japan
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17
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Verreault J, Letcher RJ, Gentes ML, Braune BM. Unusually high Deca-BDE concentrations and new flame retardants in a Canadian Arctic top predator, the glaucous gull. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 639:977-987. [PMID: 29929336 DOI: 10.1016/j.scitotenv.2018.05.222] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 06/08/2023]
Abstract
Despite a sustained effort in surveying flame retardants (FRs) in wildlife from industrialized regions, their occurrence in birds or any other wildlife species spanning the Arctic regions, particularly in North America, has received limited attention. This study investigated in the top predator glaucous gull (Larus hyperboreus) breeding in the Eastern Canadian Arctic (Cape Dorset, Nunavut) a comprehensive suite of FRs including unstudied halogenated and non-halogenated FRs of potential health concern, along with legacy organochlorines and mercury. The influence of diet acquired locally and in wintering areas on the tissue contaminant profiles was also investigated using δ15N and δ13C signatures in liver and feathers. The principal constituent in the Deca-brominated diphenyl ether (BDE) mixture, BDE-209, was remarkably the most concentrated PBDE congener determined in liver samples of Eastern Canadian Arctic glaucous gulls. This suggests dietary exposure from the local marine food web and perhaps also from nearby community landfills. Moreover, this study revealed for the first time the presence of 16 emerging halogenated and non-halogenated FRs in glaucous gulls from this Arctic region including HBB, DDC-CO (anti and syn isomers), PBEB, EHTBB, BEHTBP as well as a series of organophosphate esters (OPEs) (TCEP, TCIPP, TPP, TDCIPP, TDBPP, TBNP, TBOEP, TBEP, TCrP, EHDPP, and TEHP). With the exception of BDE-209, concentrations of other halogenated FRs and organochlorines were found to be in the lower range in liver of Eastern Canadian Arctic glaucous gulls compared to individuals from other circumpolar populations (Svalbard and Greenland). Mercury and methylmercury concentrations, however, were greater than reported elsewhere for glaucous gull populations.
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Affiliation(s)
- Jonathan Verreault
- Centre de recherche en toxicologie de l'environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montreal, QC H3C 3P8, Canada.
| | - Robert J Letcher
- Environment and Climate Change Canada, Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, ON K1A 0H3, Canada
| | - Marie-Line Gentes
- Centre de recherche en toxicologie de l'environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-ville, Montreal, QC H3C 3P8, Canada
| | - Birgit M Braune
- Environment and Climate Change Canada, Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, ON K1A 0H3, Canada
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18
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Terrestrial birds in coastal environments: metabolic rate and oxidative status varies with the use of marine resources. Oecologia 2018; 188:65-73. [PMID: 29948312 DOI: 10.1007/s00442-018-4181-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/30/2018] [Indexed: 01/21/2023]
Abstract
Life in saline environments represents a major physiological challenge for birds, particularly for passerines that lack nasal salt glands and hence are forced to live in environments that do not contain salty resources. Increased energy costs associated with increased salt intake, which in turn increases the production of reactive oxygen species, is likely a major selection pressure for why passerines are largely absent from brackish and marine environments. Here we measured basal metabolic rates (BMR) and oxidative status of free-ranging individuals of three species of Cinclodes, a group of passerine birds that inhabit marine and freshwater habitats in Chile. We used a combination of carbon, nitrogen, and hydrogen isotope data from metabolically active (blood) and inert (feathers) tissues to estimate seasonal changes in marine resource use and infer altitudinal migration. Contrary to our expectations, the consumption of marine resources did not result in higher BMR values and higher oxidative stress. Specifically, the marine specialist C. nigrofumosus had lower BMR than the other two species (C. fuscus and C. oustaleti), which seasonally switch between terrestrial and marine resources. C. fuscus had significantly higher total antioxidant capacity than the other two species (C. nigrofumosus and C. oustaleti) that consumed a relatively high proportion of marine resources. Nearly all studies examining the effects of salt consumption have focused on intraspecific acclimation via controlled experiments in the laboratory. The mixed results obtained from field- and lab-based studies reflect our poor understanding of the mechanistic link among hydric-salt balance, BMR, and oxidative stress in birds.
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19
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Cloyed CS, Eason PK, Dell AI. The thermal dependence of carbon stable isotope incorporation and trophic discrimination in the domestic cricket, Acheta domesticus. JOURNAL OF INSECT PHYSIOLOGY 2018; 107:34-40. [PMID: 29432766 DOI: 10.1016/j.jinsphys.2018.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/12/2018] [Accepted: 02/08/2018] [Indexed: 06/08/2023]
Abstract
Stable isotopes are valuable tools in physiological and ecological research, as they can be used to estimate diet, habitat use, and resource allocation. However, in most cases a priori knowledge of two key properties of stable isotopes is required, namely their rate of incorporation into the body (incorporation rate) and the change of isotope values between consumers and resources that arises during incorporation of the isotopes into the consumer's tissues (trophic discrimination). Previous studies have quantified these properties across species and tissue types, but little is known about how they vary with temperature, a key driver of many biological rates and times. Here, we explored for the first time how temperature affects both carbon incorporation rate and trophic discrimination via growth rates, using the domestic cricket, Acheta domesticus. We raised crickets at 16 °C, 21 °C, and 26 °C and showed that temperature increased carbon isotope incorporation rate, which was driven by both an increased growth rate and catabolism at higher temperatures. Trophic discrimination of carbon isotopes decreased at higher temperatures, which we attributed to either lower activation energies needed to synthesize non-essential amino acids at higher temperatures or the increased utilization of available resources of consumers at higher temperatures. Our results demonstrate that temperature is a key driver of both carbon isotope incorporation rate and trophic discrimination, via mechanisms that likely persist across all ectotherms. Experiments to determine incorporation rates and trophic discrimination factors in ectotherms must include temperature as a major factor, and natural variation in temperature might have significant effects on these isotopic properties that then can affect inferences made from isotope values.
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Affiliation(s)
- Carl S Cloyed
- National Great Rivers Research and Education Center, East Alton, IL 62024, United States; Washington University in St. Louis, Department of Biology, St. Louis, MO 63130, United States.
| | - Perri K Eason
- University of Louisville, Department of Biology, Louisville, KY 40292, United States
| | - Anthony I Dell
- National Great Rivers Research and Education Center, East Alton, IL 62024, United States; Washington University in St. Louis, Department of Biology, St. Louis, MO 63130, United States
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20
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Voigt CC, Krofel M, Menges V, Wachter B, Melzheimer J. Sex‐specific dietary specialization in a terrestrial apex predator, the leopard, revealed by stable isotope analysis. J Zool (1987) 2018. [DOI: 10.1111/jzo.12566] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. C. Voigt
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
- Department of Animal Behavior Institute of Biology Berlin Germany
| | - M. Krofel
- Department of Forestry and Renewable Forest Resources Biotechnical Faculty University of Ljubljana Ljubljana Slovenia
| | - V. Menges
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - B. Wachter
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
| | - J. Melzheimer
- Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Berlin Germany
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21
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Cherel Y, Parenteau C, Bustamante P, Bost C. Stable isotopes document the winter foraging ecology of king penguins and highlight connectivity between subantarctic and Antarctic ecosystems. Ecol Evol 2018; 8:2752-2765. [PMID: 29531692 PMCID: PMC5838085 DOI: 10.1002/ece3.3883] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/11/2017] [Accepted: 01/02/2018] [Indexed: 11/30/2022] Open
Abstract
The poorly known winter foraging ecology of the king penguin, a major Southern Ocean consumer, was investigated at the subantarctic Crozet Islands where the largest global population breeds. Blood δ13C and δ15N values were used as proxies of the birds' foraging habitat and diet, respectively, and circulating prolactin levels helped in determining the birds' reproductive status. Plasma prolactin concentrations showed that king penguin adults of unknown breeding status (n = 52) that were present at the colony in winter were in fact breeders and failed breeders, but were not non -breeders. Circulating prolactin was neither related to δ13C nor δ15N values, thus suggesting that both breeders and failed breeders used the same foraging habitats and fed on the same prey. Plasma and blood cell isotopic values depicted four new relevant biological features on the feeding strategies of king penguins during the critical winter period: (1) 42% of the birds foraged in the distant Antarctic Zone, but 58% fed primarily in subantarctic waters (δ13C), (2) they preyed upon myctophids in both zones (δ15N), (3) individuals were consistent in their foraging strategies over the winter months (δ13C and δ15N), and (4) a higher proportion of females (77%-80%) than males (27%-31%) favored feeding in distant Antarctic waters (δ13C). This study highlights trophic connectivity between subantarctic and Antarctic ecosystems and hence the key role of energy export from Antarctic waters to sustain breeding populations of subantarctic predators, including during the Austral winter.
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Affiliation(s)
- Yves Cherel
- Centre d'Etudes Biologiques de Chizé (CEBC)UMR 7372 du CNRS‐Université de La RochelleVilliers‐en‐BoisFrance
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé (CEBC)UMR 7372 du CNRS‐Université de La RochelleVilliers‐en‐BoisFrance
| | - Paco Bustamante
- Littoral, Environnement et Sociétés (LIENSs)UMR 7266 du CNRS‐Université de la RochelleLa RochelleFrance
| | - Charles‐André Bost
- Centre d'Etudes Biologiques de Chizé (CEBC)UMR 7372 du CNRS‐Université de La RochelleVilliers‐en‐BoisFrance
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22
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Intraspecific variation in exploratory behavior and elevational affinity in a widely distributed songbird. Oecologia 2018; 186:931-938. [PMID: 29388024 DOI: 10.1007/s00442-018-4076-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 01/16/2018] [Indexed: 10/18/2022]
Abstract
Populations of the same species can vary substantially in their behavioral and morphometric traits when they are subject to different environmental pressures, which may lead to the development of different adaptive strategies. We quantified variation in exploratory behavior and morphometric traits among two rufous-collared sparrow populations that occur at low and high elevations in central Chile. Moreover, we used census and δ2H values of feather and blood to evaluate migration. We found that individual sparrows inhabiting high elevations were larger and showed more intense exploratory behavior in comparison with those that were captured at lower elevation. Moreover, we observed a steady decline in sparrow abundance during the winter and similar δ2H values for blood collected in the winter and summer at this site, which were significantly lower than blood δ2H values observed at low elevation. This pattern suggests that individuals do not move long distances during winter, and likely they remain at similar elevations in refuge habitats. As predicted, our results support the existent of different adaptive strategies among populations of the same species, and suggest that the combination of behavioral, morphometric, and stable isotope data is a novel and robust integrative approach to assess differences in adaptation across environmental gradients.
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23
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O’Brien SL, Cook JA, Newsome SD. Niche differentiation among small mammals of the Alexander Archipelago in southeastern Alaska. J Mammal 2017. [DOI: 10.1093/jmammal/gyx141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shannon L O’Brien
- Museum of Southwestern Biology and Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Joseph A Cook
- Museum of Southwestern Biology and Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Seth D Newsome
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
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24
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Stanek AE, Wolf N, Hilderbrand GV, Mangipane B, Causey D, Welker JM. Seasonal foraging strategies of Alaskan gray wolves (Canis lupus) in an ecosystem subsidized by Pacific salmon (Oncorhynchus spp.). CAN J ZOOL 2017. [DOI: 10.1139/cjz-2016-0203] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Despite frequent observations of gray wolves (Canis lupus L., 1758) using nonungulate prey, the seasonal and interannual variation in the use and relative importance of alternative prey sources to gray wolf diets have not been studied at the individual scale. We used stable isotope analysis (δ13C and δ15N) of guard hair and blood components (clot and serum) collected over 4 years to examine the occurrence, extent, and temporal variation of Pacific salmon (genus Oncorhynchus Suckley, 1861) as a food resource by both individual wolves and social groups in Lake Clark National Park and Preserve in southwestern Alaska, USA. Our results demonstrate substantial variability in the use of salmon over time. During summer, diets of five wolves consisted of at least 50% salmon, while the diets of 17 wolves consisted of primarily terrestrial prey. Over 3 years, one group of wolves consistently consumed salmon in summer and switched to terrestrial prey in winter. Prey choices were generally similar within social groups; however, the degree to which individuals consumed salmon was highly variable. The use of salmon as exhibited by wolves in Lake Clark is likely widespread where salmon are abundant and this finding should be taken into consideration in the conservation and management of wolves and their prey.
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Affiliation(s)
- Ashley E. Stanek
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
| | - Nathan Wolf
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
| | - Grant V. Hilderbrand
- Alaska Regional Office, National Park Service, 240 West 5th Avenue, Anchorage, AK 99501, USA
| | - Buck Mangipane
- Lake Clark National Park and Preserve, National Park Service, General Delivery, Port Alsworth, AK 99653, USA
| | - Douglas Causey
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
| | - Jeffrey M. Welker
- Department of Biological Sciences, University of Alaska Anchorage, 3211 Providence Drive, Anchorage, AK 99508, USA
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25
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Maldonado K, Bozinovic F, Newsome SD, Sabat P. Testing the niche variation hypothesis in a community of passerine birds. Ecology 2017; 98:903-908. [DOI: 10.1002/ecy.1769] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 01/27/2017] [Accepted: 02/01/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Karin Maldonado
- Departamento de Ciencias Ecológicas; Universidad de Chile; Santiago Chile
| | - Francisco Bozinovic
- Departamento de Ecología and Center of Applied Ecology & Sustainability (CAPES); Facultad de Ciencias Biológicas; Pontificia Universidad Católica de Chile; Santiago 6513677 Chile
| | - Seth D. Newsome
- Department of Biology; University of New Mexico; Albuquerque New Mexico 87131 USA
| | - Pablo Sabat
- Departamento de Ciencias Ecológicas; Universidad de Chile; Santiago Chile
- Departamento de Ecología and Center of Applied Ecology & Sustainability (CAPES); Facultad de Ciencias Biológicas; Pontificia Universidad Católica de Chile; Santiago 6513677 Chile
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26
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Rader JA, Newsome SD, Sabat P, Chesser RT, Dillon ME, Martínez del Rio C. Isotopic niches support the resource breadth hypothesis. J Anim Ecol 2017; 86:405-413. [DOI: 10.1111/1365-2656.12629] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 12/08/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Jonathan A. Rader
- Department of Zoology and Physiology University of Wyoming Laramie WY 82071 USA
| | - Seth D. Newsome
- Department of Biology University of New Mexico Albuquerque NM 87131 USA
| | - Pablo Sabat
- Departamento de Ciencias Ecologicas Universidad de Chile Santiago Chile
- Center of Applied Ecology and Sustainability (CAPES) Santiago Chile
| | - R. Terry Chesser
- USGS Patuxent Wildlife Research Center National Museum of Natural History Smithsonian Institution Washington DC 20013 USA
| | - Michael E. Dillon
- Department of Zoology and Physiology University of Wyoming Laramie WY 82071 USA
- Program in Ecology University of Wyoming Laramie WY 82071 USA
| | - Carlos Martínez del Rio
- Department of Zoology and Physiology University of Wyoming Laramie WY 82071 USA
- Program in Ecology University of Wyoming Laramie WY 82071 USA
- Biodiversity Institute University of Wyoming Laramie WY 82071 USA
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27
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Temporal variation in isotopic composition of Pygoscelis penguins at Ardley Island, Antarctic: Are foraging habits impacted by environmental change? Polar Biol 2016. [DOI: 10.1007/s00300-016-2017-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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deVries MS, Stock BC, Christy JH, Goldsmith GR, Dawson TE. Specialized morphology corresponds to a generalist diet: linking form and function in smashing mantis shrimp crustaceans. Oecologia 2016; 182:429-42. [PMID: 27312263 DOI: 10.1007/s00442-016-3667-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
Many animals are considered to be specialists because they have feeding structures that are fine-tuned for consuming specific prey. For example, "smasher" mantis shrimp have highly specialized predatory appendages that generate forceful strikes to break apart hard-shelled prey. Anecdotal observations suggest, however, that the diet of smashers may include soft-bodied prey as well. Our goal was to examine the diet breadth of the smasher mantis shrimp, Neogonodactylus bredini, to determine whether it has a narrow diet of hard-shelled prey. We combined studies of prey abundance, feeding behavior, and stable isotope analyses of diet in both seagrass and coral rubble to determine if N. bredini's diet was consistent across different habitat types. The abundances of hard-shelled and soft-bodied prey varied between habitats. In feeding experiments, N. bredini consumed both prey types. N. bredini consumed a range of different prey in the field as well and, unexpectedly, the stable isotope analysis demonstrated that soft-bodied prey comprised a large proportion (29-53 %) of the diet in both habitats. Using a Bayesian mixing model framework (MixSIAR), we found that this result held even when we used uninformative, or generalist, priors and informative priors reflecting a specialist diet on hard-shelled prey and prey abundances in the field. Thus, contrary to expectation, the specialized feeding morphology of N. bredini corresponds to a broad diet of both hard-shelled and soft-bodied prey. Using multiple lines of study to describe the natural diets of other presumed specialists may demonstrate that specialized morphology often broadens rather than narrows diet breadth.
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Affiliation(s)
- Maya S deVries
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA. .,Scripps Institution of Oceanography, University of California, 9500 Gilman Drive # 0202, La Jolla, San Diego, CA, 92093-0202, USA.
| | - Brian C Stock
- Scripps Institution of Oceanography, University of California, 9500 Gilman Drive # 0202, La Jolla, San Diego, CA, 92093-0202, USA
| | - John H Christy
- Naos Marine Laboratories, Smithsonian Tropical Research Institute, Balboa, Ancón, Panamá, República de Panamá
| | - Gregory R Goldsmith
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA.,Ecosystem Fluxes Group, Laboratory for Atmospheric Chemistry, Paul Scherrer Institut, Villigen, 5232, Switzerland
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
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29
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Voigt CC, Lindecke O, Schönborn S, Kramer-Schadt S, Lehmann D. Habitat use of migratory bats killed during autumn at wind turbines. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2016; 26:771-783. [PMID: 27411249 DOI: 10.1890/15-0671] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The killing of large numbers of migratory bats at wind turbines is a pressing conservation problem. Even though avoidance and mitigation measures could benefit from a better knowledge of the species' migratory habits, we lack basic information about what habitats and corridors bats use during migration. We studied the isotopic niche dimensions of three bat species that are frequently killed at wind turbines in Germany: non-migratory Pipistrellus pipistrellus, mid-distance migratory Nyctalus noctula, and long- distance migratory Pipistrellus nathusii. We measured stable carbon and nitrogen isotope ratios (δ¹³C, δ¹⁵N) in five tissues that differed in isotopic retention time (fur, wing membrane tissue, muscle, liver, blood) to shed light on the species-specific habitat use during the autumn migration period using standard ellipse areas (SEAc). Further, we used stable isotope ratios of non-exchangeable hydrogen (δ²H(K)) in fur keratin to assess the breeding origin of bats. We inferred from isotopic composition (δ¹³C, δ¹⁵N) of fur keratin that isotopic niche dimensions of P. nathusii was distinct from that of N. noctula and P. pipistrellus, probably because P. nathusii was using more aquatic habitats than the other two species. Isoscape origin models supported that traveled distances before dying at wind turbines was largest for P. nathusii, intermediate for N. noctula, and shortest for P. pipistrellus. Isotopic niche dimensions calculated for each sample type separately reflected the species' migratory behavior. Pipistrellus pipistrellus and N. noctula showed similar isotopic niche breadth across all tissue types, whereas SEAc values of P. nathusii increased in tissues with slow turnaround time. Isotopic data suggested that P. nathusii consistently used aquatic habitats throughout the autumn period, whereas N. noctula showed a stronger association with terrestrial habitats during autumn compared to the pre-migration period.
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30
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Davis M, Pineda Munoz S. The temporal scale of diet and dietary proxies. Ecol Evol 2016; 6:1883-97. [PMID: 27087936 PMCID: PMC4801961 DOI: 10.1002/ece3.2054] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/08/2016] [Accepted: 02/12/2016] [Indexed: 11/09/2022] Open
Abstract
Diets estimated from different proxies such as stable isotopes, stomach contents, and dental microwear often disagree, leading to nominally well-supported but greatly differing estimates of diet for both extinct and extant species that complicate our understanding of ecology. We show that these perceived incongruences can be caused by proxies recording diet over vastly different timescales. Field observations reveal a diet averaged over minutes or hours, whereas dental morphology may reflect the diet of a lineage over millions of years of evolution. Failing to explicitly consider the scale of proxies and the potentially large temporal variability in diet can cause erroneous predictions in any downstream analyses such as conservation planning or paleohabitat reconstructions. We propose a cross-scale framework for conceptualizing diet suitable for both modern ecologists and paleontologists and provide recommendations for any studies involving dietary data. Treating diet in this temporally explicit framework and matching the scale of our questions with the scale of our data will lead to a much richer and clearer understanding of ecological and evolutionary processes.
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Affiliation(s)
- Matt Davis
- Department of Geology and Geophysics Yale University New Haven Connecticut 06520; Department of Paleobiology National Museum of Natural History Smithsonian Institution Washington District of Columbia 20004
| | - Silvia Pineda Munoz
- Department of Paleobiology National Museum of Natural History Smithsonian Institution Washington District of Columbia 20004
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31
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Yeakel JD, Bhat U, Elliott Smith EA, Newsome SD. Exploring the Isotopic Niche: Isotopic Variance, Physiological Incorporation, and the Temporal Dynamics of Foraging. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00001] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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32
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Turner TF, Krabbenhoft TJ, Collyer ML, Krabbenhoft CA, Edwards MS, Sharp ZD. Retrospective stable isotope analysis reveals ecosystem responses to river regulation over the last century. Ecology 2015; 96:3213-26. [DOI: 10.1890/14-1666.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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33
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Newsome SD, Sabat P, Wolf N, Rader JA, del Rio CM. Multi-tissue δ2H analysis reveals altitudinal migration and tissue-specific discrimination patterns inCinclodes. Ecosphere 2015. [DOI: 10.1890/es15-00086.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Intraspecific Niche Partitioning and Ecosystem State Drive Carbon Pathways Supporting Lake Food Webs. Ecosystems 2015. [DOI: 10.1007/s10021-015-9910-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kernaléguen L, Dorville N, Ierodiaconou D, Hoskins AJ, Baylis AMM, Hindell MA, Semmens J, Abernathy K, Marshall GJ, Cherel Y, Arnould JPY. From video recordings to whisker stable isotopes: a critical evaluation of timescale in assessing individual foraging specialisation in Australian fur seals. Oecologia 2015; 180:657-70. [DOI: 10.1007/s00442-015-3407-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 07/16/2015] [Indexed: 11/29/2022]
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Cloyed CS, Newsome SD, Eason PK. Trophic Discrimination Factors and Incorporation Rates of Carbon- and Nitrogen-Stable Isotopes in Adult Green Frogs, Lithobates clamitans. Physiol Biochem Zool 2015; 88:576-85. [PMID: 26658253 DOI: 10.1086/682576] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Stable isotope analysis is an increasingly useful ecological tool, but its accuracy depends on quantifying the tissue-specific trophic discrimination factors (TDFs) and isotopic incorporation rates for focal taxa. Despite the technique's ubiquity, most laboratory experiments determining TDFs and incorporation rates have focused on birds, mammals, and fish; we know little about terrestrial ectotherms, and amphibians in particular are understudied. In this study we used two controlled feeding experiments to determine carbon (δ(13)C) and nitrogen (δ(15)N) isotope TDFs for skin, whole blood, and bone collagen and incorporation rates for skin and whole blood in adult green frogs, Lithobates clamitans. The mean (±SD) TDFs for δ(13)C were 0.1‰ (±0.4‰) for skin, 0.5‰ (±0.5‰) for whole blood, and 1.6‰ (0.6‰) for bone collagen. The mean (±SD) TDFs for δ(15)N were 2.3‰ (±0.5‰) for skin, 2.3‰ (±0.4‰) for whole blood, and 3.1‰ (±0.6‰) for bone collagen. A combination of different isotopic incorporation models was best supported by our data. Carbon in skin was the only tissue in which incorporation was best explained by two compartments, which had half-lives of 89 and 8 d. The half-life of carbon in whole blood was 69 d. Half-lives for nitrogen were 75 d for skin and 71 d for whole blood. Our results help fill a taxonomic gap in our knowledge of stable isotope dynamics and provide ecologists with a method to measure anuran diets.
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Affiliation(s)
- Carl S Cloyed
- Department of Biology, University of Louisville, Louisville, Kentucky 40292; 2Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
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Augusto FG, Tassoni Filho M, Ferreira A, Pereira AL, Camargo PBD, Martinelli LA. Land use change in the Atlantic Forest affects carbon and nitrogen sources of streams as revealed by the isotopic composition of terrestrial invertebrates. BIOTA NEOTROPICA 2015. [DOI: 10.1590/1676-06032015018814] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Terrestrial invertebrates link terrestrial systems to aquatic ones, making vegetal material produced in the watershed available to aquatic food webs. In this study, using carbon and nitrogen stable isotopes, we evaluated the importance of introduced C4 grasses as a source of carbon in aquatic food webs of headwater streams of the coastal Atlantic Forest located on the north coast of the State of São Paulo, in the southeastern region of Brazil. Terrestrial invertebrates were collected in two streams: one where the main land cover was pristine montane Atlantic Forest (forest stream) and another where the main land cover was introduced C4 forage grasses for livestock (pasture stream). The average δ13C of terrestrial invertebrates collected in the forest stream (−26.3±2.1‰) was significantly (p<0.01) smaller than the average δ13C of terrestrial invertebrates collected in the pasture stream (−15.7±4.7‰), denoting a larger contribution of C4grasses to terrestrial invertebrates of the pasture stream. The average δ15N of terrestrial invertebrates of the forest stream (4.1±2.4‰) was significantly (p<0.01) lower than the average δ15N of terrestrial invertebrates of the pasture stream (9.5±2.7‰). The relative contribution of C3 and C4 plants to terrestrial invertebrates was estimated using SIAR. In the forest stream, the C3 contribution was on average 0.75 (0.72 minimum to 0.79 maximum), and the C4 contribution was on average 0.25 (0.21 minimum to 0.28 maximum). In the pasture stream, the C3contribution decreased to 0.20 (0.14 minimum to 0.26 maximum), and the C4 contribution increased to 0.80 (0.74 minimum to 0.86 maximum). These results have several implications for the ecosystem functioning as well as for recent changes in environmental policies of Brazil. The lower nutritional value of C4 grasses may not only decrease invertebrate performance, but also alter the stoichiometry of several components of the aquatic food webs with potential consequence for the whole ecosystem functioning. On the public policy side, recent changes in the Brazilian Forest Act, a series of laws that regulate land cover at the property level, reduced the width of the forested riparian area with potentially dangerous consequences for aquatic ecosystems.
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Lehmann D, Mfune JKE, Gewers E, Brain C, Voigt CC. Individual variation of isotopic niches in grazing and browsing desert ungulates. Oecologia 2015; 179:75-88. [PMID: 25953117 DOI: 10.1007/s00442-015-3335-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 04/28/2015] [Indexed: 11/29/2022]
Abstract
Ungulates often adjust their diet when food availability varies over time. However, it is poorly understood when and to what extent individuals change their diet and, if they do so, if all individuals of a population occupy distinct or similar dietary niches. In the arid Namibian Kunene Region, we studied temporal variations of individual niches in grazing gemsbok (Oryx gazella gazella) and predominantly browsing springbok (Antidorcas marsupialis). We used variation in stable C and N isotope ratios of tail hair increments as proxies to estimate individual isotopic dietary niches and their temporal plasticity. Isotopic dietary niches of populations of the two species were mutually exclusive, but similar in breadth. Isotopic niche breadth of gemsbok was better explained by within-individual variation than by between-individual variation of stable isotope ratios, indicating that gemsbok individuals were facultative specialists in using isotopically distinct local food resources. In contrast, inter- and intra-individual variations contributed similarly to the isotopic niche breadth of the springbok population, suggesting a higher degree of individual isotopic segregation in a more generalist ungulate. In both species, between-individual variation was neither explained by changes in plant primary productivity, sex, geographical position nor by group size. Within species, individual dietary niches overlapped partially, suggesting that both populations included individuals with distinct isotopic dietary niches. Our study provides the first evidence for isotopic dietary niche segregation in individuals of two distinct desert ungulates. Similar, yet isotopically distinct dietary niches of individuals may facilitate partitioning of food resources and thus individual survival in desert ecosystems.
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Affiliation(s)
- D Lehmann
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, 10315, Berlin, Germany,
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Environmental variability drives shifts in the foraging behaviour and reproductive success of an inshore seabird. Oecologia 2015; 178:967-79. [PMID: 25894092 DOI: 10.1007/s00442-015-3294-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/10/2015] [Indexed: 10/23/2022]
Abstract
Marine animals forage in areas that aggregate prey to maximize their energy intake. However, these foraging 'hot spots' experience environmental variability, which can substantially alter prey availability. To survive and reproduce animals need to modify their foraging in response to these prey shifts. By monitoring their inter-annual foraging behaviours, we can understand which environmental variables affect their foraging efficiency, and can assess how they respond to environmental variability. Here, we monitored the foraging behaviour and isotopic niche of little penguins (Eudyptula minor), over 3 years (2008, 2011, and 2012) of climatic and prey variability within Port Phillip Bay, Australia. During drought (2008), penguins foraged in close proximity to the Yarra River outlet on a predominantly anchovy-based diet. In periods of heavy rainfall, when water depth in the largest tributary into the bay (Yarra River) was high, the total distance travelled, maximum distance travelled, distance to core-range, and size of core- and home-ranges of penguins increased significantly. This larger foraging range was associated with broad dietary diversity and high reproductive success. These results suggest the increased foraging range and dietary diversity of penguins were a means to maximize resource acquisition rather than a strategy to overcome local depletions in prey. Our results demonstrate the significance of the Yarra River in structuring predator-prey interactions in this enclosed bay, as well as the flexible foraging strategies of penguins in response to environmental variability. This plasticity is central to the survival of this small-ranging, resident seabird species.
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Vander Zanden HB, Tucker AD, Bolten AB, Reich KJ, Bjorndal KA. Stable isotopic comparison between loggerhead sea turtle tissues. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:2059-2064. [PMID: 25156595 DOI: 10.1002/rcm.6995] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/21/2014] [Accepted: 07/22/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Stable isotope analysis has been used extensively to provide ecological information about diet and foraging location of many species. The difference in isotopic composition between animal tissue and its diet, or the diet-tissue discrimination factor, varies with tissue type. Therefore, direct comparisons between isotopic values of tissues are inaccurate without an appropriate conversion factor. We focus on the loggerhead sea turtle (Caretta caretta), for which a variety of tissues have been used to examine diet, habitat use, and migratory origin through stable isotope analysis. We calculated tissue-to-tissue conversions between two commonly sampled tissues. METHODS Epidermis and scute (the keratin covering on the carapace) were sampled from 33 adult loggerheads nesting at two beaches in Florida (Casey Key and Canaveral National Seashore). Carbon and nitrogen stable isotope ratios were measured in the epidermis and the youngest portion of the scute tissue, which reflect the isotopic composition of the diet and habitat over similar time periods of the order of several months. RESULTS Significant linear relationships were observed between the δ(13)C and δ(15)N values of these two tissues, indicating they can be converted reliably. CONCLUSIONS Whereas both epidermis and scute samples are commonly sampled from nesting sea turtles to study trophic ecology and habitat use, the data from these studies have not been comparable without reliable tissue-to-tissue conversions. The equations provided here allow isotopic datasets using the two tissues to be combined in previously published and subsequent studies of sea turtle foraging ecology and migratory movement. In addition, we recommend that future isotopic comparisons between tissues of any organism utilize linear regressions to calculate tissue-to-tissue conversions.
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Affiliation(s)
- Hannah B Vander Zanden
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, Gainesville, FL, 32611, USA; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, 84112, USA
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Voigt CC, Thalwitzer S, Melzheimer J, Blanc AS, Jago M, Wachter B. The conflict between cheetahs and humans on Namibian farmland elucidated by stable isotope diet analysis. PLoS One 2014; 9:e101917. [PMID: 25162403 PMCID: PMC4146470 DOI: 10.1371/journal.pone.0101917] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/12/2014] [Indexed: 11/18/2022] Open
Abstract
Large areas of Namibia are covered by farmland, which is also used by game and predator species. Because it can cause conflicts with farmers when predators, such as cheetahs (Acinonyx jubatus), hunt livestock, we assessed whether livestock constitutes a significant part of the cheetah diet by analysing the stable isotope composition of blood and tissue samples of cheetahs and their potential prey species. According to isotopic similarities, we defined three isotopic categories of potential prey: members of a C4 food web with high δ15N values (gemsbok, cattle, springhare and guinea fowl) and those with low δ15N values (hartebeest, warthog), and members of a C3 food web, namely browsers (eland, kudu, springbok, steenbok and scrub hare). We quantified the trophic discrimination of heavy isotopes in cheetah muscle in 9 captive individuals and measured an enrichment for 15N (3.2‰) but not for 13C in relation to food. We captured 53 free-ranging cheetahs of which 23 were members of groups. Cheetahs of the same group were isotopically distinct from members of other groups, indicating that group members shared their prey. Solitary males (n = 21) and males in a bachelor groups (n = 11) fed mostly on hartebeest and warthogs, followed by browsers in case of solitary males, and by grazers with high δ15N values in case of bachelor groups. Female cheetahs (n = 9) predominantly fed on browsers and used also hartebeest and warthogs. Mixing models suggested that the isotopic prey category that included cattle was only important, if at all, for males living in bachelor groups. Stable isotope analysis of fur, muscle, red blood cells and blood plasma in 9 free-ranging cheetahs identified most individuals as isotopic specialists, focussing on isotopically distinct prey categories as their food.
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Affiliation(s)
- Christian C. Voigt
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Susanne Thalwitzer
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Jörg Melzheimer
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Anne-Sophie Blanc
- Institute of Zoology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Mark Jago
- The AfriCat Foundation, Farm Okonjima, Otjiwarongo, Otjozondjupa, Namibia
| | - Bettina Wachter
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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Caron-Beaudoin É, Gentes ML, Patenaude-Monette M, Hélie JF, Giroux JF, Verreault J. Combined usage of stable isotopes and GPS-based telemetry to understand the feeding ecology of an omnivorous bird, the Ring-billed Gull (Larus delawarensis). CAN J ZOOL 2013. [DOI: 10.1139/cjz-2013-0008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to investigate the feeding ecology of an omnivorous bird, the Ring-billed Gull (Larus delawarensis Ord, 1815), breeding in a highly urbanized and heterogeneous landscape (Montréal area, Quebec, Canada). We used gastrointestinal (G.I.) tract content analysis, GPS-based tracking information, and stable isotope profiles of carbon (δ13C) and nitrogen (δ15N) in selected tissues and major food items. Based on GPS tracking data (1–3 days), Ring-billed Gulls were categorized according to their use of three main foraging habitats: agricultural, St. Lawrence River, and anthropogenic (comprising urban areas, landfills, and wastewater treatment plant basins). Ring-billed Gulls that foraged predominantly in anthropogenic habitats exhibited significantly lower δ15N in blood cells and higher total C to N ratios (C:N) in liver. These lower δ15N and higher C:N ratios were characteristic of profiles determined in food items consumed by Ring-billed Gulls at these urbanized sites (e.g., processed foods). The strong positive correlations between δ13C and δ15N in Ring-billed Gull tissues (plasma, blood cells, and liver) that differed in isotopic turnover times, as well as the strong positive correlations in both δ13C and δ15N between tissue pairs, indicated that Ring-billed Gulls exhibited conserved dietary habits throughout the nesting period. This study demonstrates that combining conventional dietary examination, tissue stable isotope analysis, and fine-scale GPS tracking information may improve our understanding of the large intrapopulation variations in foraging behaviour (and isotopic profiles) commonly observed in omnivorous birds.
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Affiliation(s)
- É. Caron-Beaudoin
- Centre de recherche en toxicologie de l’environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
| | - M.-L. Gentes
- Centre de recherche en toxicologie de l’environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
| | - M. Patenaude-Monette
- Groupe de recherche en écologie comportementale et animale (GRECA), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
| | - J.-F. Hélie
- Centre de recherche en géochimie et géodynamique (GEOTOP), Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
| | - J.-F. Giroux
- Groupe de recherche en écologie comportementale et animale (GRECA), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
| | - J. Verreault
- Centre de recherche en toxicologie de l’environnement (TOXEN), Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC H3C 3P8, Canada
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Strong migratory connectivity and seasonally shifting isotopic niches in geographically separated populations of a long-distance migrating songbird. Oecologia 2013; 173:1217-25. [PMID: 23839267 DOI: 10.1007/s00442-013-2726-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 06/26/2013] [Indexed: 10/26/2022]
Abstract
Whether migratory animals use similar resources during continental-scale movements that characterize their annual cycles is highly relevant to both individual performances and population dynamics. Direct knowledge of the locations and resources used by migrants during non-breeding is generally scarce. Our goal was to estimate migratory connectivity of a small Palaearctic long-distance migrant, the common nightingale Luscinia megarhynchos, and to compare resources used in non-breeding areas with resources used at the breeding grounds. We tracked individuals of three geographically separated populations and characterised their stable isotope niches during breeding and non-breeding over 2 years. Individuals spent the non-breeding period in population-specific clusters from west to central Africa, indicating strong migratory connectivity at the population level. Irrespective of origin, their isotopic niches were surprisingly similar within a particular period, although sites of residence were distant. However, niche characteristics differed markedly between breeding and non-breeding periods, indicating a consistent seasonal isotopic niche shift in the sampled populations. Although nightingales of distinct breeding populations migrated to different non-breeding areas, they chose similar foraging conditions within specific periods. However, nightingales clearly changed resource use between breeding and non-breeding periods, indicating adaptations to changes in food availability.
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Temporal consistency and individual specialization in resource use by green turtles in successive life stages. Oecologia 2013; 173:767-77. [DOI: 10.1007/s00442-013-2655-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 04/05/2013] [Indexed: 11/30/2022]
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Osmoregulatory and metabolic costs of salt excretion in the Rufous-collared sparrow Zonotrichia capensis. Comp Biochem Physiol A Mol Integr Physiol 2013; 164:314-8. [DOI: 10.1016/j.cbpa.2012.10.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 10/20/2012] [Accepted: 10/20/2012] [Indexed: 11/17/2022]
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Vander Zanden HB, Bjorndal KA, Mustin W, Ponciano JM, Bolten AB. Inherent variation in stable isotope values and discrimination factors in two life stages of green turtles. Physiol Biochem Zool 2012; 85:431-41. [PMID: 22902371 DOI: 10.1086/666902] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We examine inherent variation in carbon and nitrogen stable isotope values of multiple soft tissues from a population of captive green turtles Chelonia mydas to determine the extent of isotopic variation due to individual differences in physiology. We compare the measured inherent variation in the captive population with the isotopic variation observed in a wild population of juvenile green turtles. Additionally, we measure diet-tissue discrimination factors to determine the offset that occurs between isotope values of the food source and four green turtle tissues. Tissue samples (epidermis, dermis, serum, and red blood cells) were collected from captive green turtles in two life stages (40 large juveniles and 30 adults) at the Cayman Turtle Farm, Grand Cayman, and analyzed for carbon and nitrogen stable isotopes. Multivariate normal models were fit to the isotope data, and the Bayesian Information Criterion was used for model selection. Inherent variation and discrimination factors differed among tissues and life stages. Inherent variation was found to make up a small portion of the isotopic variation measured in a wild population. Discrimination factors not only are tissue and life stage dependent but also appear to vary with diet and sea turtle species, thus highlighting the need for appropriate discrimination factors in dietary reconstructions and trophic-level estimations. Our measures of inherent variation will also be informative in field studies employing stable isotope analysis so that differences in diet or habitat are more accurately identified.
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Affiliation(s)
- Hannah B Vander Zanden
- Archie Carr Center for Sea Turtle Research and Department of Biology, University of Florida, P.O. Box 118525, Gainesville, FL 32611, USA.
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Graves GR, Newsome SD, Willard DE, Grosshuesch DA, Wurzel WW, Fogel ML. Nutritional stress and body condition in the Great Gray Owl (Strix nebulosa) during winter irruptive migrations. CAN J ZOOL 2012. [DOI: 10.1139/z2012-047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The largest irruptive migration of the Great Gray Owl ( Strix nebulosa Forster, 1772) recorded since 1831 occurred in Minnesota, USA, during the winter of 2004–2005. We tested the hypothesis that morphometric indicators of nutritional stress covary with stable isotope signatures in a sample of 265 owls killed by vehicle collisions. The ratio of carbon to nitrogen in muscle (C/Nmuscle) was shown to be a reliable proxy of nutritional stress. δ13C values for liver and muscle were significantly higher in owls in poor condition, reflecting the depletion of lipid reserves in fasting individuals. On the other hand, δ15N values for liver and muscle were marginally lower or unchanged in owls in poor condition. Stomachs of emaciated owls were less likely to contain prey, implying that many nutritionally stressed individuals were too weak to hunt and were near the tipping point of irreversible fasts. In a broader context, sexual differences in the correlative relationships between stable isotope signatures, C/N, and body condition suggest that the consequences of reversed sexual size dimorphism extend to physiological processes during the nonbreeding season.
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Affiliation(s)
- Gary R. Graves
- Department of Vertebrate Zoology, MRC-116, National Museum of Natural History, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013-7012, USA; Center for Macroecology, Evolution and Climate, University of Copenhagen, DK-2100, Copenhagen Ø, Denmark
| | - Seth D. Newsome
- Carnegie Institution of Washington, Geophysical Laboratory, 5251 Broad Branch Road Northwest, Washington, DC 20015, USA; Department of Zoology and Physiology, University of Wyoming, 1000 East University Avenue, Department 3166, Laramie, WY 82071, USA
| | - David E. Willard
- Zoology Department, Field Museum, 1400 South Lake Shore Drive, Chicago, IL 60605-2496, USA
| | | | - William W. Wurzel
- Carnegie Institution of Washington, Geophysical Laboratory, 5251 Broad Branch Road Northwest, Washington, DC 20015, USA; State University of New York College of Environmental Science and Forestry, SUNY-ESF, 1 Forestry Drive, Syracuse, NY 13210, USA
| | - Marilyn L. Fogel
- Carnegie Institution of Washington, Geophysical Laboratory, 5251 Broad Branch Road Northwest, Washington, DC 20015, USA
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Newsome SD, Yeakel JD, Wheatley PV, Tinker MT. Tools for quantifying isotopic niche space and dietary variation at the individual and population level. J Mammal 2012. [DOI: 10.1644/11-mamm-s-187.1] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Martínez del Rio C, Carleton SA. How fast and how faithful: the dynamics of isotopic incorporation into animal tissues: Fig. 1. J Mammal 2012. [DOI: 10.1644/11-mamm-s-165.1] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Fink P, Reichwaldt ES, Harrod C, Rossberg AG. Determining trophic niche width: an experimental test of the stable isotope approach. OIKOS 2012. [DOI: 10.1111/j.1600-0706.2012.20185.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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