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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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2
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Johnson MTJ, Arif I, Marchetti F, Munshi-South J, Ness RW, Szulkin M, Verrelli BC, Yauk CL, Anstett DN, Booth W, Caizergues AE, Carlen EJ, Dant A, González J, Lagos CG, Oman M, Phifer-Rixey M, Rennison DJ, Rosenberg MS, Winchell KM. Effects of urban-induced mutations on ecology, evolution and health. Nat Ecol Evol 2024; 8:1074-1086. [PMID: 38641700 DOI: 10.1038/s41559-024-02401-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/13/2024] [Indexed: 04/21/2024]
Abstract
Increasing evidence suggests that urbanization is associated with higher mutation rates, which can affect the health and evolution of organisms that inhabit cities. Elevated pollution levels in urban areas can induce DNA damage, leading to de novo mutations. Studies on mutations induced by urban pollution are most prevalent in humans and microorganisms, whereas studies of non-human eukaryotes are rare, even though increased mutation rates have the potential to affect organisms and their populations in contemporary time. Our Perspective explores how higher mutation rates in urban environments could impact the fitness, ecology and evolution of populations. Most mutations will be neutral or deleterious, and higher mutation rates associated with elevated pollution in urban populations can increase the risk of cancer in humans and potentially other species. We highlight the potential for urban-driven increased deleterious mutational loads in some organisms, which could lead to a decline in population growth of a wide diversity of organisms. Although beneficial mutations are expected to be rare, we argue that higher mutation rates in urban areas could influence adaptive evolution, especially in organisms with short generation times. Finally, we explore avenues for future research to better understand the effects of urban-induced mutations on the fitness, ecology and evolution of city-dwelling organisms.
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Affiliation(s)
- Marc T J Johnson
- Centre for Urban Environments, University of Toronto Mississauga, Mississauga, Ontario, Canada.
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada.
| | - Irtaqa Arif
- Centre for Urban Environments, University of Toronto Mississauga, Mississauga, Ontario, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Jason Munshi-South
- Department of Biology and Louis Calder Center, Fordham University, Armonk, NY, USA
| | - Rob W Ness
- Centre for Urban Environments, University of Toronto Mississauga, Mississauga, Ontario, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Marta Szulkin
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Brian C Verrelli
- Center for Biological Data Science, Virginia Commonwealth University, Richmond, VA, USA
| | - Carole L Yauk
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Daniel N Anstett
- Department of Plant Biology, Department of Entomology, Plant Resilience Institute, Michigan State University, East Lansing, MI, USA
| | - Warren Booth
- Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Aude E Caizergues
- Centre for Urban Environments, University of Toronto Mississauga, Mississauga, Ontario, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Elizabeth J Carlen
- Living Earth Collaborative, Washington University in St. Louis, St. Louis, MO, USA
| | - Anthony Dant
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Josefa González
- Institute of Evolutionary Biology, CSIC, UPF, Barcelona, Spain
| | - César González Lagos
- Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Santiago, Chile
- Center of Applied Ecology and Sustainability (CAPES), Santiago, Chile
| | - Madeleine Oman
- Centre for Urban Environments, University of Toronto Mississauga, Mississauga, Ontario, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | | | - Diana J Rennison
- School of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Michael S Rosenberg
- Center for Biological Data Science, Virginia Commonwealth University, Richmond, VA, USA
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3
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Leighton GRM, Froneman W, Serieys LEK, Bishop JM. Trophic downgrading of an adaptable carnivore in an urbanising landscape. Sci Rep 2023; 13:21582. [PMID: 38062237 PMCID: PMC10703923 DOI: 10.1038/s41598-023-48868-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Urbanisation critically alters wildlife habitat and resource distribution, leading to shifts in trophic dynamics. The loss of apex predators in human-transformed landscapes can result in changes in the ecological roles of the remaining mesocarnivores. Decreased top-down control together with increased bottom-up forcing through greater availability of anthropogenic foods can result in a predation paradox. Understanding these changes is important for conserving ecological function and biodiversity in rapidly urbanising systems. Here, we use stable isotope analysis to provide insight into longer term changes in trophic position, niche width and overlap of an elusive, medium-sized urban adapter, the caracal (Caracal caracal) in and around the city of Cape Town, South Africa. Using fur samples (n = 168) from individuals along a gradient of urbanisation we find that overall caracals have a broad isotopic dietary niche that reflects their large variation in resource use. When accounting for underlying environmental differences, the intensity of anthropogenic pressure, measured using the Human Footprint Index (HFI), explained variation in both food subsidy use (δ13C values) and trophic status (δ15N values). The significantly higher δ13C values (P < 0.01) and lower δ15N values (P < 0.001) of caracals in more urbanised areas suggest that predator subsidy consumption occurs via predictable, anthropogenic resource subsidies to synanthropic prey. These prey species are predominantly primary consumers, resulting in shifts in diet composition towards lower trophic levels. Further, caracals using areas with higher HFI had narrower isotope niches than those in less impacted areas, likely due to their hyperfocus on a few lower trophic level prey species. This pattern of niche contraction in urban areas is retained when accounting for caracal demographics, including sex and age. The removal of apex predators in human-transformed landscapes together with reliable resource availability, including abundant prey, may paradoxically limit the ecological influence of the remaining predators, and bring about a degree of predator trophic downgrading. The dampening of top-down control, and thus ecosystem regulation, likely points to widespread disruption of trophic dynamics in rapidly developing areas globally.
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Affiliation(s)
- Gabriella R M Leighton
- SARChI Chair in Marine Ecology, Department of Zoology and Entomology, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa.
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa.
| | - William Froneman
- SARChI Chair in Marine Ecology, Department of Zoology and Entomology, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
| | - Laurel E K Serieys
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- Panthera, 8 W 40th St, New York, NY, 10018, USA
- Cape Leopard Trust, Cape Town, South Africa
| | - Jacqueline M Bishop
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
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Rosenblatt AE, Greco R, Beal E, Colbert J, Moore Y, Baglin V, Nifong JC. Golf course living leads to a diet shift for American alligators. Ecol Evol 2023; 13:e10495. [PMID: 37664492 PMCID: PMC10468965 DOI: 10.1002/ece3.10495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/31/2023] [Accepted: 08/11/2023] [Indexed: 09/05/2023] Open
Abstract
Human-driven land use change can fundamentally alter ecological communities, especially the diversity and abundance of large-bodied predators. Yet, despite the important roles large-bodied predators play in structuring communities through feeding, there have been only a few investigations of how the feeding patterns of large-bodied predators change in human-dominated landscapes. One group of large-bodied predators that has been largely overlooked in the context of land use change is the crocodilians. To help fill these gaps, we studied the feeding patterns of juvenile American alligators (Alligator mississippiensis) on neighboring barrier islands on the southeast coast of Georgia, USA. Jekyll Island has multiple golf courses and substantial amounts of human activity, while Sapelo Island does not have any golf courses and a much smaller amount of human activity. We found that juvenile alligator populations on both islands ate the same types of prey but in vastly different quantities. Sapelo Island alligators primarily consumed crustaceans while alligators that lived on Jekyll Island's golf courses ate mostly insects/arachnids. Furthermore, the Jekyll Island alligators exhibited a much more generalist feeding pattern (individuals mostly ate the same types of prey in the same quantities) than the more specialized Sapelo Island alligators (diets were more varied across individuals). The most likely explanation for our results is that alligators living on golf courses have different habitat use patterns and have access to different prey communities relative to alligators in more natural habitats. Thus, land use change can strongly alter the feeding patterns of large-bodied predators and, as a result, may affect their body condition, exposure to human-made chemicals, and role within ecological communities.
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Affiliation(s)
| | - Robert Greco
- University of North FloridaJacksonvilleFloridaUSA
| | - Eli Beal
- University of North FloridaJacksonvilleFloridaUSA
| | | | - Yank Moore
- Jekyll Island AuthorityJekyll IslandGeorgiaUSA
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Brown N, Escobar LE. A review of the diet of the common vampire bat ( Desmodus rotundus) in the context of anthropogenic change. Mamm Biol 2023; 103:1-21. [PMID: 37363038 PMCID: PMC10258787 DOI: 10.1007/s42991-023-00358-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 03/30/2023] [Indexed: 06/28/2023]
Abstract
The common vampire bat (Desmodus rotundus) maintains a diverse, sanguivorous diet, utilizing a broad range of prey taxa. As anthropogenic change alters the distribution of this species, shifts in predator-prey interactions are expected. Understanding prey richness and patterns of prey selection is, thus, increasingly informative from ecological, epidemiological, and economic perspectives. We reviewed D. rotundus diet and assessed the geographical, taxonomical, and behavioral features to find 63 vertebrate species within 21 orders and 45 families constitute prey, including suitable host species in regions of invasion outside D. rotundus' range. Rodentia contained the largest number of species utilized by D. rotundus, though cattle were the most commonly reported prey source, likely linked to the high availability of livestock and visibility of bite wounds compared to wildlife. Additionally, there was tendency to predate upon species with diurnal activity and social behavior, potentially facilitating convenient and nocturnal predation. Our review highlights the dietary heterogeneity of D. rotundus across its distribution. We define D. rotundus as a generalist predator, or parasite, depending on the ecological definition of its symbiont roles in an ecosystem (i.e., lethal vs. non-lethal blood consumption). In view of the eminent role of D. rotundus in rabies virus transmission and its range expansion, an understanding of its ecology would benefit public health, wildlife management, and agriculture. Supplementary Information The online version contains supplementary material available at 10.1007/s42991-023-00358-3.
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Affiliation(s)
- Natalie Brown
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA USA
| | - Luis E. Escobar
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA USA
- Global Change Center, Virginia Tech, Blacksburg, VA USA
- Center for Emerging Zoonotic and Arthropod-Borne Pathogens, Virginia Tech, Blacksburg, VA USA
- Doctorado en Agrociencias, Facultad de Ciencias Agropecuarias, Universidad de La Salle, Carrera 7 No. 179-03, Bogotá, Colombia
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Malhotra R, Lima S, Harris NC. Temporal refuges of a subordinate carnivore vary across rural–urban gradient. Ecol Evol 2022; 12:e9310. [PMID: 36188497 PMCID: PMC9492470 DOI: 10.1002/ece3.9310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rumaan Malhotra
- Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan USA
| | - Samantha Lima
- Forestry and Natural Resources Purdue University West Lafayette Indiana USA
| | - Nyeema C. Harris
- Applied Wildlife Ecology Lab School of the Environment, Yale University New Haven Connecticut USA
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7
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Gámez S, Potts A, Mills KL, Allen AA, Holman A, Randon PM, Linson O, Harris NC. Downtown diet: a global meta-analysis of increased urbanization on the diets of vertebrate predators. Proc Biol Sci 2022; 289:20212487. [PMID: 35232241 PMCID: PMC8889190 DOI: 10.1098/rspb.2021.2487] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Predation is a fundamental ecological process that shapes communities and drives evolutionary dynamics. As the world rapidly urbanizes, it is critical to understand how human perturbations alter predation and meat consumption across taxa. We conducted a meta-analysis to quantify the effects of urban environments on three components of trophic ecology in predators: dietary species richness, dietary evenness and stable isotopic ratios (IRs) (δ13C and δ15N IR). We evaluated whether the intensity of anthropogenic pressure, using the human footprint index (HFI), explained variation in effect sizes of dietary attributes using a meta-regression. We calculated Hedges' g effect sizes from 44 studies including 11 986 samples across 40 predatory species in 39 cities globally. The direction and magnitude of effect sizes varied among predator taxa with reptilian diets exhibiting the most sensitivity to urbanization. Effect sizes revealed that predators in cities had comparable diet richness, evenness and nitrogen ratios, though carbon IRs were more enriched in cities. We found that neither the 1993 nor 2009 HFI editions explained effect size variation. Our study provides, to our knowledge, the first assessment of how urbanization has perturbed predator-prey interactions for multiple taxa at a global scale. We conclude that the functional role of predators is conserved in cities and urbanization does not inherently relax predation, despite diets broadening to include anthropogenic food sources such as sugar, wheat and corn.
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Affiliation(s)
- Siria Gámez
- Applied Wildlife Ecology Laboratory, School of the Environment, Yale University, 195 Prospect Street, New Haven, CT 06511, USA
| | - Abigail Potts
- Ecology and Evolutionary Biology, University of Michigan, 500 S State Street #2005, Ann Arbor, MI 48109, USA
| | - Kirby L Mills
- Ecology and Evolutionary Biology, University of Michigan, 500 S State Street #2005, Ann Arbor, MI 48109, USA
| | - Aurelia A Allen
- Ecology and Evolutionary Biology, University of Michigan, 500 S State Street #2005, Ann Arbor, MI 48109, USA
| | - Allyson Holman
- School for Environment and Sustainability, University of Michigan, 500 S State Street #2005, Ann Arbor, MI 48109, USA
| | - Peggy M Randon
- Ecology and Evolutionary Biology, University of Michigan, 500 S State Street #2005, Ann Arbor, MI 48109, USA
| | - Olivia Linson
- College of Literature, Science and the Arts, University of Michigan, 500 S State Street #2005, Ann Arbor, MI 48109, USA
| | - Nyeema C Harris
- Applied Wildlife Ecology Laboratory, School of the Environment, Yale University, 195 Prospect Street, New Haven, CT 06511, USA
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