Predation on seabird eggs by Keen's mice (Peromyscus keeni): using stable isotopes to decipher the diet of a terrestrial omnivore on a remote offshore island

2000 ◽  
Vol 78 (11) ◽  
pp. 2010-2018 ◽  
Author(s):  
M C Drever ◽  
L K Blight ◽  
K A Hobson ◽  
D F Bertram
Keyword(s):  
Isotope Analysis ◽  
Terrestrial Plants ◽  
General Phenomenon ◽  
Mouse Population ◽  
Terrestrial Invertebrates ◽  
Seabird Colony ◽  
Muscle Tissues ◽  
Terrestrial Biomes ◽  
Microtus Townsendii ◽  
Prey Items

We used stable isotope techniques to analyze tissues of Keen's mice (Peromyscus keeni) and Townsend's voles (Microtus townsendii cowani) and a subset of prey items at Triangle Island, British Columbia, western Canada's largest seabird colony. Isotope analysis allowed us to investigate the importance of seabird prey in rodent diets in a system where seabirds and non-introduced rodents occur sympatrically. The δ15N values for terrestrial plants and terrestrial invertebrates on Triangle Island exceeded levels found in many terrestrial biomes and are typical of localities with high inputs of marine-derived N. We used multiple-source mixing models to estimate the relative inputs of potential prey items to vole and mouse diets. The δ13C and δ15N values of liver and muscle tissues of voles indicate that voles on Triangle Island derived their protein primarily from terrestrial plants, with some contribution by terrestrial invertebrates. In contrast, isotopic values of liver and muscle tissues of mice on Triangle Island indicated that mice prey primarily on seabird eggs and terrestrial invertebrates. Our results show that egg predation on Triangle Island is a general phenomenon in the mouse population, rather than occurring in only a few specialist feeders. Mice appear to feed on eggs once they become available and continue to utilize seabird prey, likely in the form of abandoned eggs or carcasses of chicks and adults, throughout the breeding season.

scholarly journals Comparing the diet of Great Horned Owls (Bubo virginianus) in rural and urban areas of southwestern British Columbia

2015 ◽  
Vol 128 (4) ◽  
pp. 393 ◽  
Author(s):  
Sofi Hindmarch ◽  
John E. Elliott
Keyword(s):  
British Columbia ◽  
Rural Areas ◽  
Urban Areas ◽  
Bubo Virginianus ◽  
Rural And Urban Areas ◽  
Rural And Urban ◽  
Commensal Rodents ◽  
Urban And Rural Areas ◽  
Microtus Townsendii ◽  
Prey Items

We investigated the diet of Great Horned Owls (Bubo virginianus) in southwestern British Columbia. Our objective was to compare the diets of owls in urban and rural areas and determine whether urban owls consume a higher proportion of commensal rodents to understand possible pathways of secondary rodenticide poisoning of Great Horned Owls. Among 546 prey items identified at seven sites, Townsend’s Vole (Microtus townsendii [Bachman, 1839]) and rats (Rattus G. Fischer, 1803) were the two main prey items, making up 65.9% and 13.1% of the diet, respectively. The proportion of rats in the diet was positively correlated with the degree of urban development in the owls’ home range (rp = 0.83, P < 0.05, df = 5).

scholarly journals Aquatic Macrophytes are Seasonally Important Dietary Resources for Moose

Diversity ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 209
Author(s):  
Tischler ◽  
Severud ◽  
Peterson ◽  
Bump
Keyword(s):  
Stable Isotope ◽  
Aquatic Macrophytes ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Food Sources ◽  
Mixing Models ◽  
Terrestrial Plants ◽  
Growth Variability ◽  
Isle Royale National Park ◽  
Aquatic Food

Moose (Alces alces) are generalist herbivores, but are important aquatic-terrestrial ecotone specialists. Aquatic macrophytes are a high-quality food source for moose during summer, but the importance of aquatic food sources to the moose diet is difficult to study. We used stable isotope analysis of carbon and nitrogen from moose hooves and forage (terrestrial plants, aquatic macrophytes, and arboreal lichen) to assess the diet of moose at Isle Royale National Park, Michigan, USA, using Bayesian mixing models. We also evaluated the isotopic variability along chronologies of serially sampled hooves. Overall, our mixing models indicate that 13%–27% of the summer moose diet was aquatic in origin. Among moose that died during winter, body condition was impaired and hoof 15N was higher where aquatic habitats were sparse. Although isotope chronologies preserved in hooves could significantly enhance our understanding of ungulate foraging ecology, interpretation of such chronologies is presently limited by our lack of knowledge pertaining to hoof growth rate and seasonal growth variability related to age and health. Distinct isotopic values among terrestrial plants, aquatic macrophytes, and arboreal lichens indicate that continued methodological advances in stable isotope ecology will lead to more precise estimates of the contribution of aquatic feeding to moose population dynamics and other ungulates.

scholarly journals Using Stable Carbon and Nitrogen Isotopes to Evaluate Parrotfish Diet

2013 ◽  
pp. 108-123
Author(s):  
Maria Elisa Gerona ◽  
Florence Evacitas
Keyword(s):  
Stable Isotope ◽  
Nitrogen Isotopes ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Carbon Sources ◽  
Δ13c And Δ15n ◽  
Δ13c Values ◽  
Dual Isotope ◽  
Muscle Tissues ◽  
Carbon Intake

With limited inconclusive data provided by gut content analysis, stable isotope analysis has recently emerged to validate trophic position and dietary intake. In this study, a dual isotope approach was used to reveal parrotfish feeding. Comparisons of δ13C and δ15N values of muscle and liver among yellow barred (Scarus dimidiatus), rosy cheek (S. psittacus), and blue-barred (S. ghobban) parrotfishes from Canigao Island, Matalom, Leyte were made to track dietary shifting and to compare dietary carbon intake. Trophic assignment was based on the assumption that consumers are enriched by a factor of 3-4‰ for δ15N, relative to their diet. The δ13C values of muscle tissues of the three species of parrotfish were significantly higher (p=0.001) than those of their liver suggesting dietary shifting. The δ13C values of both muscle and liver tissues of S. dimidiatus were significantly (p<0.001) higher than those of S. psittacus and S. ghobban, but δ13C values of muscle and liver of S. psittacus and S. ghobban did not vary significantly. These mean that S. dimidiatus have different long term and recent dietary carbon intake compared to the other two species, while S. psittacus and S. ghobban have relatively the same dietary carbon intake. Considering the 1‰ δ13C trophic enrichment of consumers relative to their diet, possible dietary carbon sources of the sampled parrotfish include Dendronephthya spp., Ulva reticulata, Sargassum oligocystum, Dictyota sp., Digenea sp., Chlorodesmis sp., and Sargassum muticum suggesting that parrotfishes are generalist consumers. Mean stable isotope nitrogen ratios of S. dimidiatus (5.9‰), S. psittacus (6.9‰) and S. ghobban (6.7‰) together with their carbon isotope ratios confirmed that all sampled parrotfish species are generalist primary consumers.

Diet and recruitment of green turtles in Fiji, South Pacific, inferred from in-water capture and stable isotope analysis

2020 ◽  
Vol 640 ◽  
pp. 201-213 ◽  
Author(s):  
S Piovano ◽  
GE Lemons ◽  
A Ciriyawa ◽  
A Batibasaga ◽  
JA Seminoff
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Green Turtle ◽  
Isotope Analysis ◽  
South Pacific ◽  
Chelonia Mydas ◽  
Iucn Red List ◽  
Mixing Model ◽  
Green Turtles ◽  
Prey Items

Green turtles Chelonia mydas are listed as Endangered on the IUCN Red List, yet in the South Pacific few conservation-relevant data are available for the species, especially relating to foraging and habitat use. Here, in situ observations and stable isotope analysis (δ13C and δ15N) were used to evaluate green turtle diet and recruitment patterns at Yadua Island and Makogai Island, Fiji. Juvenile green turtles (N = 110) were hand-captured, measured, and sampled. Stable isotope analysis was performed on skin samples and on putative prey items. ‘Resident’ turtles versus ‘recent recruits’ were classified based on their bulk skin tissue isotope values, which were compared with stable isotope values of local prey items and analyzed via cluster analysis. Green turtle diet composition was estimated using MixSIAR, a Bayesian mixing model. Recent recruits were characterized by ‘low δ13C/high δ15N’ values and ranged in curved carapace length (CCL) from 25.5 to 60.0 cm (mean ± SD = 48.5 ± 5.7 cm). Recruitment mostly occurred in summer. Green turtles identified as ‘residents’ had CCLs ranging from 43.5 to 89.0 cm (mean ± SD = 57.4 ± 9.0 cm) and were characterized by ‘high δ13C/low δ15N’ values; mixing model results indicate they fed primarily on invertebrates (40%), fishes (31%), and marine plants (29%). This study confirms the value of seagrass pastures as both an essential habitat and a primary food source for green turtles, and can serve as a baseline for evaluations of natural and anthropogenic changes in local green turtle aggregations.

scholarly journals The Green Deer: Chaya as a Potential Source of Protein for the Ancient Maya

2021 ◽  
pp. 1-12
Author(s):  
Henry P. Schwarcz ◽  
Anabel Ford ◽  
Martin Knyf ◽  
Anil Kumar
Keyword(s):  
Isotope Analysis ◽  
Bone Collagen ◽  
Cultivated Plants ◽  
Ancient Maya ◽  
Terrestrial Plants ◽  
Spanish Conquest ◽  
Protein Requirements ◽  
Human Bones ◽  
Cnidoscolus Aconitifolius ◽  
Stable Isotopic

Archaeologists have used isotope analysis (δ13C, δ15N) of the collagen of human bones, as well as knowledge of available nutrients, to infer that the diet of the ancient Maya was drawn from the resources of the Maya forest landscape. The interpretations have focused on plant carbohydrates from maize and protein dominated by white-tail deer. The δ15N values of bone collagen suggest that most of the protein requirements of the Maya could have been satisfied with a mixture of wild animal flesh and wild and cultivated plants including beans. Chaya, Cnidoscolus aconitifolius, domesticated before the Spanish conquest, has a high-protein content and the potential to have been a significant contributor to the ancient Maya diet. Chaya is easily propagated, is grown in home gardens by the Maya today, and is a significant part of the local traditional diet. Chaya's stable isotopic composition of carbon (δ13C) resembles that of other terrestrial plants, but its values for nitrogen (δ15N) are significantly higher. Consumption of chaya would result in slightly higher δ15N values in humans than expected from the consumption of terrestrial animals. Thus, chaya is situated well as a component of the complex, diverse, and varied diets of ancient Mesoamericans.

scholarly journals Aquatic Macrophytes are Seasonally Important Dietary Resources for Moose

2019 ◽  
Author(s):  
Keren B. Tischler ◽  
William J. Severud ◽  
Rolf O. Peterson ◽  
Joseph K. Bump
Keyword(s):  
Stable Isotope ◽  
Body Condition ◽  
Aquatic Macrophytes ◽  
Aquatic Macrophyte ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Aquatic Habitats ◽  
Terrestrial Plants ◽  
Marrow Fat ◽  
Isle Royale National Park

Moose (Alces alces) are generalist herbivores but are important aquatic-terrestrial ecotone specialists. Aquatic macrophytes are a high-quality food source for moose during the summer, however their relative importance to moose diet is difficult to study. We used stable isotope analysis of carbon and nitrogen from moose hooves and forage (terrestrial plants, aquatic macrophytes, and arboreal lichen) to estimate the diet of moose at Isle Royale National Park, Michigan, USA, and to evaluate the isotopic variability along chronologies of serially sampled hooves. We hypothesized that aquatic macrophyte consumption and winter body condition (as measured by bone marrow fat content) would be greater at the eastern end of the island where aquatic habitats were most abundant. We were unable to evaluate spatial differences in aquatic macrophyte consumption, but overall, our mixing model results suggest that between 13% and 27% of summer moose diet was from aquatic sources. Among moose that died during winter, body condition was impaired and hoof &delta;15N (measured at the hairline) was higher at the western end of the island, where aquatic habitats are sparse. Although isotope chronologies preserved in hooves could significantly enhance our understanding of ungulate foraging ecology, interpretation of such chronologies is presently limited by our lack of knowledge pertaining to hoof growth rate and seasonal dynamics in relation to age and health. Significant isotope distinction among terrestrial plants, aquatic macrophytes, and arboreal lichens indicate that continued methodological advances in stable isotope ecology will lead to more precise estimates of the contribution of aquatic feeding to moose population dynamics.

scholarly journals Carbon sources in the Beaufort Sea revealed by molecular lipid biomarkers and compound specific isotope analysis

2012 ◽  
Vol 9 (10) ◽  
pp. 13925-13985 ◽  
Author(s):  
I. Tolosa ◽  
S. Fiorini ◽  
B. Gasser ◽  
J. Martín ◽  
J. C. Miquel
Keyword(s):  
Organic Matter ◽  
Isotope Analysis ◽  
River Mouth ◽  
Beaufort Sea ◽  
Lipid Biomarkers ◽  
Total Carbon ◽  
Terrestrial Plants ◽  
Compound Specific Isotope Analysis ◽  
Amundsen Gulf ◽  
Algal Material

Abstract. Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (Southeast Beaufort Sea, Arctic Ocean), were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the sedimentary organic matter (OM). Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and < 1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (> 80%) with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%) whereas those from the slope contained the highest proportion of fossil (40%) and C3 terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments.

scholarly journals The early development of tetrapod herbivory

1992 ◽  
Vol 6 ◽  
pp. 21-21
Author(s):  
Richard Beerbower ◽  
Everett C. Olson ◽  
Nicholas Hotton
Keyword(s):  
Terrestrial Ecosystems ◽  
Late Carboniferous ◽  
Upper Permian ◽  
Plant Tissues ◽  
Early Permian ◽  
Terrestrial Plants ◽  
Dry Land ◽  
Terrestrial Invertebrates ◽  
High Fiber ◽  
Juvenile Mortality

Herbivorous tetrapods make their first appearance in Upper Carboniferous fossil assemblages but only become abundant and diverse in Upper Permian ones. During the Late Carboniferous-Early Permian interval, herbivory appeared independently at least five times: in diadectids, bolosaurids, captorhinids, edaphosaurids and caseids. These animals ranged from small forms with aptitudes for collection and processing of low-fiber plant tissues (as well as terrestrial invertebrates) to giants particularly apt for utilization of high-fiber tissues. Our report focuses on the latter group since the development of high-fiber herbivory has had a critical impact on evolution of terrestrial plants and animals as well as on the organization of terrestrial ecosystems.The low abundance and diversity of early, high-fiber herbivores reflect on one hand, sampling biases toward habitats suboptimal for herbivory, and on the other, the limited ecological capabilities of the animals themselves. Most of the Permo-Carboniferous assemblages derive from wet-land swamp and forest ecosystems where plant tissues would have been relatively rare and/or inaccessible and predation relatively intense. The likely herbivores appear apt for life in wet-land ecosystems; there they probably utilized localized patchs of productive shrub and herb along rivers and around lakes as refuges from disturbance (desiccation, temperature extremes and predation) as well as sources of food. Their low metabolic levels and growth rates minimized nutritional requirements but along with large size provided adequately for adult maintenance and for reproduction. High adult survivorship and production of a large number of eggs through a long adult lifespan would have offset high egg and juvenile mortality.Only a few Late Carboniferous and Early Permian assemblages sample drier woodland and shrub habitats where conditions would have been more favorable for high-fiber herbivory, but by Late Permian such assemblages occur in much greater numbers and diversity. The high-fiber herbivores in these dry-land ecosystems had ecological aptitudes comparable to wet-land forms but were relatively more abundant and diverse, reflecting both a greater abundance and extent of shrubby vegetation and a lower incidence of predation.

scholarly journals Recovery of aquatic and terrestrial populations in the context of European pesticide risk assessment

2015 ◽  
Vol 23 (4) ◽  
pp. 382-394 ◽  
Author(s):  
Mira Kattwinkel ◽  
Matthias Liess ◽  
Maria Arena ◽  
Stephanie Bopp ◽  
Franz Streissl ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Aquatic Invertebrates ◽  
Experimental Studies ◽  
Ecological Modelling ◽  
Ecological Knowledge ◽  
Ecological Context ◽  
Long Term Effects ◽  
Terrestrial Plants ◽  
Terrestrial Invertebrates ◽  
Terrestrial Arthropods

In the present review, we compiled and evaluated the available information supporting the assessment of population and community recovery after pesticide application. This information is crucial for the environmental risk assessment of pesticides. We reviewed more than 3900 manuscripts on those organism groups relevant or likely to become relevant for the risk assessment procedures in Europe, that is, aquatic invertebrates, algae, aquatic plants, fish, aquatic microbes, amphibians, as well as birds and mammals, non-target terrestrial arthropods including honeybees, non-arthropod invertebrates, terrestrial microbes, non-target terrestrial plants, nematodes, and reptiles. Finally, 106 aquatic and 76 terrestrial studies met our selection criteria and were evaluated in detail. We extracted the following general conclusions. (i) Internal recovery depends strongly on reproduction capacity. For aquatic invertebrates, recovery was generally observed within a maximum of five generation times. (ii) In cases where recovery occurred within one generation, migration from uncontaminated areas was identified as the main pathway for aquatic and terrestrial invertebrates, in particular, for insect species with the ability for aerial recolonization. (iii) Community composition in general did not recover within the study duration in the majority of cases. (iv) The ecological context, including factors such as food resources, habitat quality, and recolonization potential, is a crucial factor for recovery from pesticide effects. (v) Indirect effects acting through food chain processes, including predation and competition, are highly relevant for increasing the magnitude of effect and for prolonging recovery time. Based on our findings, we recommend defining realistic scenarios for risk assessment regarding exposure, taxa considered, environmental conditions, and ecological context. In addition to experimental studies, field monitoring was shown to yield valuable information to identify relevant taxa, long-term effects, and the conditions for recovery, and should therefore be considered to validate approaches of risk assessment. Likewise, ecological modelling was found to be a valuable tool for assessing recovery. Finally, both study design and interpretation of results still often suffer from missing ecological information or from neglect of the available knowledge. Hence, a more rigorous utilization of existing knowledge (e.g., from general disturbance ecology) and the generation of systematic ecological knowledge on the various factors influencing recovery are needed.

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