1
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Stephenson T, Hudiburg T, Mathias JM, Jones M, Lynch LM. Do Tasmanian devil declines impact ecosystem function? GLOBAL CHANGE BIOLOGY 2024; 30:e17413. [PMID: 38982678 DOI: 10.1111/gcb.17413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/17/2024] [Accepted: 07/01/2024] [Indexed: 07/11/2024]
Abstract
Tasmanian eucalypt forests are among the most carbon-dense in the world, but projected climate change could destabilize this critical carbon sink. While the impact of abiotic factors on forest ecosystem carbon dynamics have received considerable attention, biotic factors such as the input of animal scat are less understood. Tasmanian devils (Sarcophilus harrisii)-an osteophageous scavenger that can ingest and solubilize nutrients locked in bone material-may subsidize plant and microbial productivity by concentrating bioavailable nutrients (e.g., nitrogen and phosphorus) in scat latrines. However, dramatic declines in devil population densities, driven by the spread of a transmissible cancer, may have underappreciated consequences for soil organic carbon (SOC) storage and forest productivity by altering nutrient cycling. Here, we fuse experimental data and modeling to quantify and predict future changes to forest productivity and SOC under various climate and scat-quality futures. We find that devil scat significantly increases concentrations of nitrogen, ammonium, phosphorus, and phosphate in the soil and shifts soil microbial communities toward those dominated by r-selected (e.g., fast-growing) phyla. Further, under expected increases in temperature and changes in precipitation, devil scat inputs are projected to increase above- and below-ground net primary productivity and microbial biomass carbon through 2100. In contrast, when devil scat is replaced by lower-quality scat (e.g., from non-osteophageous scavengers and herbivores), forest carbon pools are likely to increase more slowly, or in some cases, decline. Together, our results suggest often overlooked biotic factors will interact with climate change to drive current and future carbon pool dynamics in Tasmanian forests.
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Affiliation(s)
- Torrey Stephenson
- Department of Soil and Water Systems, University of Idaho, Moscow, Idaho, USA
| | - Tara Hudiburg
- Department of Forest, Rangeland and Fire Sciences, University of Idaho, Moscow, Idaho, USA
| | - Justin M Mathias
- Department of Biology, West Virginia University, Morgantown, West Virginia, USA
| | - Menna Jones
- School of Natural Sciences, West Virginia University, Hobart, Tasmania, Australia
| | - Laurel M Lynch
- Department of Soil and Water Systems, University of Idaho, Moscow, Idaho, USA
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2
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Webster SC, Hinton JW, Chamberlain MJ, Murphy JJ, Beasley JC. Land cover and space use influence coyote carnivory: evidence from stable-isotope analysis. PeerJ 2024; 12:e17457. [PMID: 38854793 PMCID: PMC11160434 DOI: 10.7717/peerj.17457] [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: 11/06/2023] [Accepted: 05/03/2024] [Indexed: 06/11/2024] Open
Abstract
For many species, the relationship between space use and diet composition is complex, with individuals adopting varying space use strategies such as territoriality to facilitate resource acquisition. Coyotes (Canis latrans) exhibit two disparate types of space use; defending mutually exclusive territories (residents) or moving nomadically across landscapes (transients). Resident coyotes have increased access to familiar food resources, thus improved foraging opportunities to compensate for the energetic costs of defending territories. Conversely, transients do not defend territories and are able to redirect energetic costs of territorial defense towards extensive movements in search of mates and breeding opportunities. These differences in space use attributed to different behavioral strategies likely influence foraging and ultimately diet composition, but these relationships have not been well studied. We investigated diet composition of resident and transient coyotes in the southeastern United States by pairing individual space use patterns with analysis of stable carbon (δ13C) and nitrogen (δ15N) isotope values to assess diet. During 2016-2017, we monitored 41 coyotes (26 residents, 15 transients) with GPS radio-collars along the Savannah River area in the southeastern United States. We observed a canopy effect on δ13C values and little anthropogenic food in coyote diets, suggesting 13C enrichment is likely more influenced by reduced canopy cover than consumption of human foods. We also observed other land cover effects, such as agricultural cover and road density, on δ15N values as well as reduced space used by coyotes, suggesting that cover types and localized, resident-like space use can influence the degree of carnivory in coyotes. Finally, diets and niche space did not differ between resident and transient coyotes despite differences observed in the proportional contribution of potential food sources to their diets. Although our stable isotope mixing models detected differences between the diets of resident and transient coyotes, both relied mostly on mammalian prey (52.8%, SD = 15.9 for residents, 42.0%, SD = 15.6 for transients). Resident coyotes consumed more game birds (21.3%, SD = 11.6 vs 13.7%, SD = 8.8) and less fruit (10.5%, SD = 6.9 vs 21.3%, SD = 10.7) and insects (7.2%, SD = 4.7 vs 14.3%, SD = 8.5) than did transients. Our findings indicate that coyote populations fall on a feeding continuum of omnivory to carnivory in which variability in feeding strategies is influenced by land cover characteristics and space use behaviors.
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Affiliation(s)
- Sarah C. Webster
- Warnell School of Forestry and Natural Resources, University of Georgia, Savannah River Ecology Laboratory, Aiken, South Carolina, United States
| | | | - Michael J. Chamberlain
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia, United States
| | | | - James C. Beasley
- Warnell School of Forestry and Natural Resources, University of Georgia, Savannah River Ecology Laboratory, Aiken, South Carolina, United States
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3
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Reid REB, Crowley BE, Haupt RJ. The prospects of poop: a review of past achievements and future possibilities in faecal isotope analysis. Biol Rev Camb Philos Soc 2023; 98:2091-2113. [PMID: 37438959 DOI: 10.1111/brv.12996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023]
Abstract
What can the stable isotope values of human and animal faeces tell us? This often under-appreciated waste product is gaining recognition across a variety of disciplines. Faecal isotopes provide a means of monitoring diet, resource partitioning, landscape use, tracking nutrient inputs and cycling, and reconstructing past climate and environment. Here, we review what faeces are composed of, their temporal resolution, and how these factors may be impacted by digestive physiology and efficiency. As faeces are often used to explore diet, we clarify how isotopic offsets between diet and faeces can be calculated, as well as some differences among commonly used calculations that can lead to confusion. Generally, faecal carbon isotope (δ13 C) values are lower than those of the diet, while faecal nitrogen isotope values (δ15 N) values are higher than in the diet. However, there is considerable variability both within and among species. We explore the role of study design and how limitations stemming from a variety of factors can affect both the reliability and interpretability of faecal isotope data sets. Finally, we summarise the various ways in which faecal isotopes have been applied to date and provide some suggestions for future research. Despite remaining challenges, faecal isotope data are poised to continue to contribute meaningfully to a variety of fields.
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Affiliation(s)
- Rachel E B Reid
- Department of Geosciences, Virginia Tech, 4044 Derring Hall, 926 West Campus Dr, Blacksburg, VA, 24061, USA
| | - Brooke Erin Crowley
- Department of Geosciences, University of Cincinnati, 500 Geology Physics Building, 345 Clifton Court, Cincinnati, OH, 45221-0013, USA
- Department of Anthropology, University of Cincinnati, 481 Braunstein Hall, Cincinnati, OH, 45221-0380, USA
| | - Ryan J Haupt
- National Youth Science Foundation, PO Box 3387, Charleston, WV, 25333-3387, USA
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4
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Canales-Cerro C, Hidalgo-Hermoso E, Cabello J, Sacristán I, Cevidanes A, Di Cataldo S, Napolitano C, Moreira-Arce D, Klarian S, Millán J. Carbon and nitrogen isotopic similarity between the endangered Darwin's fox ( Lycalopex fulvipes) and sympatric free-ranging dogs in Chiloé Island, Chile. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2022; 58:316-326. [PMID: 35968628 DOI: 10.1080/10256016.2022.2106225] [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: 12/22/2021] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Darwin's fox is an opportunistic omnivorous predator native to Chile classified as endangered by the IUCN Red List. Habitat use by Darwin's foxes can be negatively affected by the presence of free-ranging dogs that range freely across native and non-native habitats and can be a source of fox mortality. The objective of this study was to analyze the isotopic similarity of Darwin's fox and sympatric free-ranging dogs in Chiloé Island to determine the impact of anthropogenic environmental alterations on wild predators. We use hair samples to characterise and compare their δ13C and δ15N values and to evaluate isotopic similarity and isotope niches overlap. A generalised linear model was used to associate the isotope value with landscape variables (forest cover and vegetation type) and distance to the nearest house. We found no significant differences in δ13C or δ15N values between foxes and dogs, and a marginally significant isotope niche overlap (59.4 %). None of the selected variables at landscape and site scale were related to isotope values. Although our study is not a probe of direct contact between foxes and free-ranging dogs, the high isotopic similarity highlights the risk of pathogen spillover from free-ranging dogs to Darwin's foxes.
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Affiliation(s)
- C Canales-Cerro
- Centro de Investigación Marina Quintay (CIMARQ), Faculty of Life Sciences, Universidad Andres Bello, Viña del Mar, Chile
- Earth Sciences Department, Lemu, Frutillar, Chile
- Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - E Hidalgo-Hermoso
- Conservation and Research Department, Parque Zoologico Buin Zoo, Buin, Chile
| | - J Cabello
- Chiloé Silvestre Center for the Conservation of Biodiversity, Ancud, Chile
| | - I Sacristán
- Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - A Cevidanes
- Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Department of Animal Health, NEIKER-Basque Institute for Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Parque Científico y Tecnológico de Bizkaia, Derio, Spain
| | - S Di Cataldo
- Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
| | - C Napolitano
- Departamento de Ciencias Biológicas y Biodiversidad, Universidad de Los Lagos, Osorno, Chile
- Instituto de Ecología y Biodiversidad (IEB), Santiago-Concepción, Chile
- Centro Internacional Cabo de Hornos (CHIC), Puerto Williams, Chile
| | - D Moreira-Arce
- Instituto de Ecología y Biodiversidad (IEB), Santiago-Concepción, Chile
- Fundación ARAID, Universidad de Santiago de Chile (USACH), Santiago, Chile
| | - S Klarian
- Centro de Investigación Marina Quintay (CIMARQ), Faculty of Life Sciences, Universidad Andres Bello, Viña del Mar, Chile
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - J Millán
- Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Zaragoza, Spain
- Fundación ARAID, Zaragoza, Spain
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5
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Reevaluating trophic discrimination factors (
Δδ
13
C
and
Δδ
15
N
) for diet reconstruction. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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6
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Mychajliw AM, Almonte JN, Martinez PA, Hadly EA. Stable isotopes reveal seasonal dietary responses to agroforestry in a venomous mammal, the Hispaniolan solenodon (
Solenodon paradoxus
). Ecol Evol 2022; 12:e8761. [PMID: 35356572 PMCID: PMC8948124 DOI: 10.1002/ece3.8761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 12/18/2022] Open
Affiliation(s)
- Alexis M. Mychajliw
- Departments of Biology and Environmental Studies Middlebury College Middlebury Vermont USA
- Department of Biology Stanford University Stanford California USA
| | - Juan N. Almonte
- Museo Nacional de Historia Natural “Prof. Eugenio de Jesús Marcano” Santo DomingoDominican Republic
| | - Pedro A. Martinez
- Escuela de Biología Universidad Autónoma de Santo Domingo Santo DomingoDominican Republic
| | - Elizabeth A. Hadly
- Department of Biology Stanford University Stanford California USA
- Woods Institute of the Environment Stanford University Stanford CaliforniaUSA
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7
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Black-backed jackal niche analysis: a stable isotope approach to a generalist mesopredator. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00241-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Page HM, Schamel J, Emery KA, Schooler NK, Dugan JE, Guglielmino A, Schroeder DM, Palmstrom L, Hubbard DM, Miller RJ. Diet of a threatened endemic fox reveals variation in sandy beach resource use on California Channel Islands. PLoS One 2021; 16:e0258919. [PMID: 34710148 PMCID: PMC8553077 DOI: 10.1371/journal.pone.0258919] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/07/2021] [Indexed: 11/29/2022] Open
Abstract
The coastal zone provides foraging opportunities for insular populations of terrestrial mammals, allowing for expanded habitat use, increased dietary breadth, and locally higher population densities. We examined the use of sandy beach resources by the threatened island fox (Urocyon littoralis) on the California Channel Islands using scat analysis, surveys of potential prey, beach habitat attributes, and stable isotope analysis. Consumption of beach invertebrates, primarily intertidal talitrid amphipods (Megalorchestia spp.) by island fox varied with abundance of these prey across sites. Distance-based linear modeling revealed that abundance of giant kelp (Macrocystis pyrifera) wrack, rather than beach physical attributes, explained the largest amount of variation in talitrid amphipod abundance and biomass across beaches. δ13C and δ15N values of fox whisker (vibrissae) segments suggested individualism in diet, with generally low δ13C and δ15N values of some foxes consistent with specializing on primarily terrestrial foods, contrasting with the higher isotope values of other individuals that suggested a sustained use of sandy beach resources, the importance of which varied over time. Abundant allochthonous marine resources on beaches, including inputs of giant kelp, may expand habitat use and diet breadth of the island fox, increasing population resilience during declines in terrestrial resources associated with climate variability and long-term climate change.
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Affiliation(s)
- Henry M. Page
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
- * E-mail:
| | - Juliann Schamel
- Channel Islands National Park, Ventura, California, United States of America
| | - Kyle A. Emery
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Nicholas K. Schooler
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Jenifer E. Dugan
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Angela Guglielmino
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, United States of America
| | - Donna M. Schroeder
- Bureau of Ocean Energy Management, Camarillo, California, United States of America
| | - Linnea Palmstrom
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - David M. Hubbard
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Robert J. Miller
- Marine Science Institute, University of California, Santa Barbara, California, United States of America
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9
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Hixon SW, Douglass KG, Godfrey LR, Eccles L, Crowley BE, Rakotozafy LMA, Clark G, Haberle S, Anderson A, Wright HT, Kennett DJ. Ecological Consequences of a Millennium of Introduced Dogs on Madagascar. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.689559] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Introduced predators currently threaten endemic animals on Madagascar through predation, facilitation of human-led hunts, competition, and disease transmission, but the antiquity and past consequences of these introductions are poorly known. We use directly radiocarbon dated bones of introduced dogs (Canis familiaris) to test whether dogs could have aided human-led hunts of the island’s extinct megafauna. We compare carbon and nitrogen isotope data from the bone collagen of dogs and endemic “fosa” (Cryptoprocta spp.) in central and southwestern Madagascar to test for competition between introduced and endemic predators. The distinct isotopic niches of dogs and fosa suggest that any past antagonistic relationship between these predators did not follow from predation or competition for shared prey. Radiocarbon dates confirm that dogs have been present on Madagascar for over a millennium and suggest that they at least briefly co-occurred with the island’s extinct megafauna, which included giant lemurs, elephant birds, and pygmy hippopotamuses. Today, dogs share a mutualism with pastoralists who also occasionally hunt endemic vertebrates, and similar behavior is reflected in deposits at several Malagasy paleontological sites that contain dog and livestock bones along with butchered bones of extinct megafauna and extant lemurs. Dogs on Madagascar have had a wide range of diets during the past millennium, but relatively high stable carbon isotope values suggest few individuals relied primarily on forest bushmeat. Our newly generated data suggest that dogs were part of a suite of animal introductions beginning over a millennium ago that coincided with widespread landscape transformation and megafaunal extinction.
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10
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Tsukada H, Nishikawa Y, Shimada H, Hijikata K, Minami M. A refined method for estimating the number of earthworm chaetae in carnivore feces. Ecol Res 2021. [DOI: 10.1111/1440-1703.12223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hideharu Tsukada
- Laboratory of Wildlife Ecology and Conservation, Department of Animal Science and Biotechnology, School of Veterinary Medicine Azabu University Sagamihara Japan
| | - Yuka Nishikawa
- Laboratory of Wildlife Ecology and Conservation, Department of Animal Science and Biotechnology, School of Veterinary Medicine Azabu University Sagamihara Japan
| | - Haruka Shimada
- Laboratory of Wildlife Ecology and Conservation, Department of Animal Science and Biotechnology, School of Veterinary Medicine Azabu University Sagamihara Japan
| | - Koji Hijikata
- Laboratory of Wildlife Ecology and Conservation, Department of Animal Science and Biotechnology, School of Veterinary Medicine Azabu University Sagamihara Japan
| | - Masato Minami
- Laboratory of Wildlife Ecology and Conservation, Department of Animal Science and Biotechnology, School of Veterinary Medicine Azabu University Sagamihara Japan
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11
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Colborn AS, Kuntze CC, Gadsden GI, Harris NC. Spatial variation in diet-microbe associations across populations of a generalist North American carnivore. J Anim Ecol 2020; 89:1952-1960. [PMID: 32445202 DOI: 10.1111/1365-2656.13266] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 05/05/2020] [Indexed: 11/28/2022]
Abstract
Generalist species, by definition, exhibit variation in niche attributes that promote survival in changing environments. Increasingly, phenotypes previously associated with a species, particularly those with wide or expanding ranges, are dissolving and compelling greater emphasis on population-level characteristics. In the present study, we assessed spatial variation in diet characteristics, gut microbiome and associations between these two ecological traits across populations of coyotes Canis latrans. We highlight the influence of the carnivore community in shaping these relationships, as the coyote varied from being an apex predator to a subordinate, mesopredator across sampled populations. We implemented a scat survey across three distinct coyote populations in Michigan, USA. We used carbon (δ13 C) and nitrogen (δ15 N) isotopic values to reflect consumption patterns and trophic level, respectively. Corresponding samples were also paired with 16S rRNA sequencing to describe the microbial community and correlate with isotopic values. Although consumption patterns were comparable, we found spatial variation in trophic level among coyote populations. Specifically, δ15 N was highest where coyotes were the apex predator and lowest where coyotes co-occurred with grey wolves Canis lupus. The gut microbial community exhibited marked spatial variation across populations with the lowest operational taxonomic units diversity found where coyotes occurred at their lowest trophic level. Bacteriodes and Fusobacterium dominated the microbiome and were positively correlated across all populations. We found no correlation between δ13 C and microbial community attributes. However, positive associations between δ15 N and specific microbial genera increased as coyotes ascended trophic levels. Coyotes provide a model for exploring implications of niche plasticity because they are a highly adaptable, wide-ranging omnivore. As coyotes continue to vary in trophic position and expand their geographic range, we might expect increased divergence within their microbial community, changes in physiology and alterations in behaviour.
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Affiliation(s)
- A Shawn Colborn
- Applied Wildlife Ecology Lab, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Corbin C Kuntze
- Applied Wildlife Ecology Lab, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Gabriel I Gadsden
- Applied Wildlife Ecology Lab, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Nyeema C Harris
- Applied Wildlife Ecology Lab, Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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12
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13
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Crowley BE, Wultsch C, Kelly MJ. Does faecal matter reflect location? An initial assessment of isotopic variability between consumed prey remains and faecal matter for wild jaguars . ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2019; 55:478-498. [PMID: 31402710 DOI: 10.1080/10256016.2019.1648263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 07/01/2019] [Indexed: 06/10/2023]
Abstract
Faecal isotopic analysis may complement other non-invasive wildlife survey tools for monitoring landscape use by carnivores, such as motion-detecting cameras and non-invasive genetic sampling. We analysed carbon, nitrogen, and strontium isotopes in faecal matter produced by jaguars (Panthera onca) as well as bones from consumed prey at the Mountain Pine Ridge Forest Reserve (MPR) in Belize, Central America. The MPR is ideally suited for a spatial isotope study as vegetation and geology both vary considerably. The isotopic composition of faecal matter should reflect the habitat and geology where consumed prey lived. We used bone from consumed prey recovered from jaguar scats as a proxy for diet. Faecal matter and bone showed comparable spatial isotopic trends, suggesting that the isotopic composition of jaguar faeces can be used to detect foraging in different habitats (pine forest versus broadleaf forest) or on different geologies (Mesozoic carbonates; Palaeozoic granite, contact metamorphics, and metasediments). This result is reassuring as bones are not always present in carnivore scats. Studying landscape use by cryptic and wide-ranging carnivore species like jaguars remains challenging. Isotopic analysis of faecal matter complements the existing array of non-invasive spatial monitoring tools.
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Affiliation(s)
- Brooke E Crowley
- Department of Geology, University of Cincinnati , Cincinnati , OH , USA
- Department of Anthropology, University of Cincinnati , Cincinnati , OH , USA
| | - Claudia Wultsch
- Bioinformatics and Computational Genomics Laboratory, Hunter College, City University of New York , New York , NY , USA
- Sackler Institute for Comparative Genomics, American Museum of Natural History , New York , NY , USA
- Department of Fish and Wildlife Conservation, Virginia Tech , Blacksburg , VA , USA
| | - Marcella J Kelly
- Department of Fish and Wildlife Conservation, Virginia Tech , Blacksburg , VA , USA
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14
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Keenan SW, DeBruyn JM. Changes to vertebrate tissue stable isotope (δ 15N) composition during decomposition. Sci Rep 2019; 9:9929. [PMID: 31289347 PMCID: PMC6617491 DOI: 10.1038/s41598-019-46368-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/26/2019] [Indexed: 01/10/2023] Open
Abstract
During carcass decomposition, tissues undergo biochemical changes: Cells autolyze, enteric microbes ferment cellular products, and tissues degrade. Ultimately, decomposition fluids are released as an ephemeral nitrogen (N) and carbon source to the surrounding environment. However, decomposition fluids are δ15N-enriched relative to body tissues, leading to a disconnect between starting tissue composition and ending fluid composition. It remains largely unknown when or if tissues exhibit δ15N enrichment postmortem despite the importance of tissue stable isotopes to ecologists. To test our hypothesis that tissues would become progressively δ15N-enriched during decay, soft tissues and bone were collected from beaver carcasses at five time points. All soft tissues, including muscle, were significantly δ15N-enriched compared to fresh tissues, but were not as enriched as decomposition fluids. Tissue breakdown is initially dominated by anaerobic autolysis and later by microbe and insect infiltration, and partly explains decay fluid isotopic enrichment. We speculate that after rupture, preferential volatilization of δ15N-depleted compounds (especially ammonia) contributes to further enrichment. These results constrain the timing, rate, and potential mechanisms driving carcass isotopic enrichment during decay, and suggest that found carcasses (e.g., road kill) should be used with caution for inferring trophic ecology as decay can result in significant postmortem δ15N enrichment.
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Affiliation(s)
- Sarah W Keenan
- University of Tennessee, Department of Biosystems Engineering and Soil Science, 2506 E.J. Chapman Drive, Knoxville, TN, 37996, USA. .,South Dakota School of Mines & Technology, Department of Geology and Geological Engineering, 501 East St. Joseph Street, Rapid City, SD, 57701, USA.
| | - Jennifer M DeBruyn
- University of Tennessee, Department of Biosystems Engineering and Soil Science, 2506 E.J. Chapman Drive, Knoxville, TN, 37996, USA
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15
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Cullen TM, Longstaffe FJ, Wortmann UG, Goodwin MB, Huang L, Evans DC. Stable isotopic characterization of a coastal floodplain forest community: a case study for isotopic reconstruction of Mesozoic vertebrate assemblages. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181210. [PMID: 30891263 PMCID: PMC6408390 DOI: 10.1098/rsos.181210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 01/04/2019] [Indexed: 06/09/2023]
Abstract
Stable isotopes are powerful tools for elucidating ecological trends in extant vertebrate communities, though their application to Mesozoic ecosystems is complicated by a lack of extant isotope data from comparable environments/ecosystems (e.g. coastal floodplain forest environments, lacking significant C4 plant components). We sampled 20 taxa across a broad phylogenetic, body size, and physiological scope from the Atchafalaya River Basin of Louisiana as an environmental analogue to the Late Cretaceous coastal floodplains of North America. Samples were analysed for stable carbon, oxygen and nitrogen isotope compositions from bioapatite and keratin tissues to test the degree of ecological resolution that can be determined in a system with similar environmental conditions, and using similar constraints, as those in many Mesozoic assemblages. Isotopic results suggest a broad overlap in resource use among taxa and considerable terrestrial-aquatic interchange, highlighting the challenges of ecological interpretation in C3 systems, particularly when lacking observational data for comparison. We also propose a modified oxygen isotope-temperature equation that uses mean endotherm and mean ectotherm isotope data to more precisely predict temperature when compared with measured Atchafalaya River water data. These results provide a critical isotopic baseline for coastal floodplain forests, and act as a framework for future studies of Mesozoic palaeoecology.
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Affiliation(s)
- T M Cullen
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
- Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6
| | - F J Longstaffe
- Department of Earth Sciences, The University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 5B7
| | - U G Wortmann
- Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, Ontario, Canada M5S 3B1
| | - M B Goodwin
- University of California Museum of Paleontology, 1101 Valley Life Sciences, Berkeley, CA 94720-4780, USA
| | - L Huang
- Department of Earth Sciences, The University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 5B7
| | - D C Evans
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
- Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6
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Lynggaard C, Woolsey ID, Al-Sabi MNS, Bertram N, Jensen PM. Parasites in Myodes glareolus and their association with diet assessed by stable isotope analysis. Int J Parasitol Parasites Wildl 2018; 7:180-186. [PMID: 29988840 PMCID: PMC6032500 DOI: 10.1016/j.ijppaw.2018.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/10/2018] [Accepted: 04/25/2018] [Indexed: 11/26/2022]
Abstract
Vertebrates are hosts to numerous parasites, belonging to many different taxa. These parasites differ in transmission, being through either direct contact, a faecal-oral route, ingestion of particular food items, vertical or sexual transmission, or by a vector. Assessing the impact of diet on parasitism can be difficult because analysis of faecal and stomach content are uncertain and labourious; and as with molecular methods, do not provide diet information over a longer period of time. We here explored whether the analysis of stable isotopes in hair provides insight into the impact of diet and the presence of parasites in the rodent Myodes glareolus. Twenty-one animals were examined for parasites and their hair analysed for stable isotopes (C and N). A positive correlation between δ15N and one species of intestinal parasite was observed in females. Furthermore, several ectoparasites were negatively correlated with δ15N, indicating that infections are further associated with foraging habits (size and layout of the home range, length and timing of foraging, interaction with other rodents, etc.) that set the rodents in direct contact with infected hosts. Although a limited number of animals were included, it seemed that the isotope values allowed for identification of the association between diet and parasite occurrence in this rodent. We therefore propose that this method is useful in providing further insight into host biology, feeding preferences and potential exposure to parasites species, contributing to the understanding of the complex relationship between hosts and parasites.
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Affiliation(s)
- Christina Lynggaard
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Ian David Woolsey
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Mohammad Nafi Solaiman Al-Sabi
- Section of Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg C, Denmark
| | - Nicolas Bertram
- The National Research Centre for the Working Environment, 2100 Copenhagen, Denmark
| | - Per Moestrup Jensen
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
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