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Bransford TD, Harris SA, Forys EA. Seasonal Variation in Mammalian Mesopredator Spatiotemporal Overlap on a Barrier Island Complex. Animals (Basel) 2024; 14:2431. [PMID: 39199963 PMCID: PMC11350757 DOI: 10.3390/ani14162431] [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: 06/30/2024] [Revised: 08/10/2024] [Accepted: 08/20/2024] [Indexed: 09/01/2024] Open
Abstract
Due to lack of apex predators in human-dominated landscapes, mesopredator relationships are complex and spatiotemporal niche partitioning strategies can vary, especially when seasonal shifts in resource availability occur. Our objective was to understand spatiotemporal niche overlap across seasons among mesopredators inhabiting a barrier island complex. We placed 19 unbaited cameras throughout Fort De Soto County Park, Florida, USA between February 2021 and July 2023. Of six mesopredator species detected, three species had >75 detections during both the wet and dry seasons (coyote, Canis latrans; Virginia opossum, Didelphis virginiana; and raccoon, Procyon lotor). Using general linear mixed models, we determined that during the wet season coyote-raccoon and raccoon-opossum detections were positively associated with each other (p < 0.05). During the dry season, raccoon-opossum detections were positively associated, and opossums were more likely to be detected around mangroves. After calculating coefficients of overlap, we found all three species varied their temporal activity between seasons. During the dry season exclusively, all three mesopredators occupied different temporal niches. The park's isolated but developed nature has potentially led to a destabilized mesopredator community. Understanding seasonal mesopredator dynamics of Fort De Soto is particularly important because this park supports a high number of nesting shorebirds and sea turtles, which are known food sources for mesopredators.
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Affiliation(s)
| | - Spencer A. Harris
- Animal Studies Discipline, Eckerd College, St. Petersburg, FL 33711, USA
- Economics Discipline, Eckerd College, St. Petersburg, FL 33711, USA
- Environmental Studies Discipline, Eckerd College, St. Petersburg, FL 33711, USA
| | - Elizabeth A. Forys
- Environmental Studies Discipline, Eckerd College, St. Petersburg, FL 33711, USA
- Biology Discipline, Eckerd College, St. Petersburg, FL 33711, USA
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Jensen AJ, Muthersbaugh M, Ruth CR, Butfiloski JW, Cantrell J, Adams J, Waits L, Kilgo JC, Jachowski DS. Resource pulses shape seasonal and individual variation in the diet of an omnivorous carnivore. Ecol Evol 2024; 14:e11632. [PMID: 38966241 PMCID: PMC11222735 DOI: 10.1002/ece3.11632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 06/01/2024] [Accepted: 06/06/2024] [Indexed: 07/06/2024] Open
Abstract
Resource pulses are ecologically important phenomenon that occur in most ecosystems globally. Following optimal foraging theory, many consumers switch to pulsatile foods when available, examples of which include fruit mast and vulnerable young prey. Yet how the availability of resource pulses shapes the ecology of predators is still an emerging area of research; and how much individual variation there is in response to pulses is not well understood. We hypothesized that resource pulses would lead to dietary convergence in our population, which we tested by tracking both population-level and individual coyote diets for 3 years in South Carolina, USA. We (1) described seasonal dietary shifts in relation to resource pulses; (2) compared male and female diets across seasons; and (3) tested this dietary convergence hypothesis by quantifying individual dietary variation both across and within periods when resource pulses were available. We found that pulses of white-tailed deer fawns and blackberries composed over half of coyote diet in summer, and persimmon fruits were an important component in fall. Male and female coyotes generally had similar diets, but males consumed more deer in fall, perhaps driven by scavenging more. We found support for our dietary convergence hypothesis, where individuals had more similar diets during resource pulses compared to a non-pulse period. We also found that this convergence happened before peak availability, suggesting a non-symmetric response to pulse availability. We show that nearly all coyotes eat fawns, suggesting that targeted efforts to remove "fawn killers" would be in vain. Instead, given how quickly coyotes collectively converge on resource pulses, our findings show that resource pulses could potentially be used by managers to alter the behavior of apex predators. More broadly, we open a new line of inquiry into how variation in individual foraging decisions scales up to shape the effects of resource pulses on ecological communities.
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Affiliation(s)
- Alex J. Jensen
- Department of Forestry and Environmental ConservationClemson UniversityClemsonSouth CarolinaUSA
- North Carolina Museum of Natural SciencesRaleighNorth CarolinaUSA
| | - Michael Muthersbaugh
- Department of Forestry and Environmental ConservationClemson UniversityClemsonSouth CarolinaUSA
| | - Charles R. Ruth
- South Carolina Department of Natural ResourcesColumbiaSouth CarolinaUSA
| | | | - Jay Cantrell
- South Carolina Department of Natural ResourcesColumbiaSouth CarolinaUSA
| | - Jennifer Adams
- Department of Fish and Wildlife SciencesUniversity of IdahoMoscowIdahoUSA
| | - Lisette Waits
- Department of Fish and Wildlife SciencesUniversity of IdahoMoscowIdahoUSA
| | - John C. Kilgo
- United States Forest Service Southern Research StationNew EllentonSouth CarolinaUSA
| | - David S. Jachowski
- Department of Forestry and Environmental ConservationClemson UniversityClemsonSouth CarolinaUSA
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Ganz TR, Bassing SB, DeVivo MT, Gardner B, Kertson BN, Satterfield LC, Shipley LA, Turnock BY, Walker SL, Abrahamson D, Wirsing AJ, Prugh LR. White-tailed deer population dynamics in a multipredator landscape shaped by humans. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e3003. [PMID: 38890813 DOI: 10.1002/eap.3003] [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: 09/01/2023] [Revised: 02/23/2024] [Accepted: 04/22/2024] [Indexed: 06/20/2024]
Abstract
Large terrestrial mammals increasingly rely on human-modified landscapes as anthropogenic footprints expand. Land management activities such as timber harvest, agriculture, and roads can influence prey population dynamics by altering forage resources and predation risk via changes in habitat, but these effects are not well understood in regions with diverse and changing predator guilds. In northeastern Washington state, USA, white-tailed deer (Odocoileus virginianus) are vulnerable to multiple carnivores, including recently returned gray wolves (Canis lupus), within a highly human-modified landscape. To understand the factors governing predator-prey dynamics in a human context, we radio-collared 280 white-tailed deer, 33 bobcats (Lynx rufus), 50 cougars (Puma concolor), 28 coyotes (C. latrans), and 14 wolves between 2016 and 2021. We first estimated deer vital rates and used a stage-structured matrix model to estimate their population growth rate. During the study, we observed a stable to declining deer population (lambda = 0.97, 95% confidence interval: 0.88, 1.05), with 74% of Monte Carlo simulations indicating population decrease and 26% of simulations indicating population increase. We then fit Cox proportional hazard models to evaluate how predator exposure, use of human-modified landscapes, and winter severity influenced deer survival and used these relationships to evaluate impacts on overall population growth. We found that the population growth rate was dually influenced by a negative direct effect of apex predators and a positive effect of timber harvest and agricultural areas. Cougars had a stronger effect on deer population dynamics than wolves, and mesopredators had little influence on the deer population growth rate. Areas of recent timber harvest had 55% more forage biomass than older forests, but horizontal visibility did not differ, suggesting that timber harvest did not influence predation risk. Although proximity to roads did not affect the overall population growth rate, vehicle collisions caused a substantial proportion of deer mortalities, and reducing these collisions could be a win-win for deer and humans. The influence of apex predators and forage indicates a dual limitation by top-down and bottom-up factors in this highly human-modified system, suggesting that a reduction in apex predators would intensify density-dependent regulation of the deer population owing to limited forage availability.
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Affiliation(s)
- Taylor R Ganz
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Sarah B Bassing
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Melia T DeVivo
- Washington Department of Fish and Wildlife, Spokane Valley, Washington, USA
| | - Beth Gardner
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Brian N Kertson
- Washington Department of Fish and Wildlife, Snoqualmie, Washington, USA
| | - Lauren C Satterfield
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Lisa A Shipley
- School of the Environment, Washington State University, Pullman, Washington, USA
| | | | | | | | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
| | - Laura R Prugh
- School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA
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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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Hayward MW, Mitchell CD, Kamler JF, Rippon P, Heit DR, Nams V, Montgomery RA. Diet selection in the Coyote Canis latrans. J Mammal 2023; 104:1338-1352. [PMID: 38059008 PMCID: PMC10697429 DOI: 10.1093/jmammal/gyad094] [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: 09/07/2022] [Accepted: 09/06/2023] [Indexed: 12/08/2023] Open
Abstract
The Coyote (Canis latrans) is one of the most studied species in North America with at least 445 papers on its diet alone. While this research has yielded excellent reviews of what coyotes eat, it has been inadequate to draw deeper conclusions because no synthesis to date has considered prey availability. We accounted for prey availability by investigating the prey selection of coyotes across its distribution using the traditional Jacobs' index method, as well as the new iterative preference averaging (IPA) method on scats and biomass. We found that coyotes selected for Dall's Sheep (Ovis dalli), White-tailed Deer (Odocoileus virginianus), Eastern Cottontail Rabbit (Sylvilagus floridanus), and California Vole (Microtus californicus), which yielded a predator-to-preferred prey mass ratio of 1:2. We also found that coyotes avoided preying on other small mammals, including carnivorans and arboreal species. There was strong concordance between the traditional and IPA method on scats, but this pattern was weakened when biomass was considered. General linear models revealed that coyotes preferred to prey upon larger species that were riskier to hunt, reflecting their ability to hunt in groups, and were least likely to hunt solitary species. Coyotes increasingly selected Mule Deer (O. hemionus) and Snowshoe Hare (Lepus americanus) at higher latitudes, whereas Black-tailed Jackrabbit (L. californicus) were increasingly selected toward the tropics. Mule Deer were increasingly selected at higher coyote densities, while Black-tailed Jackrabbit were increasingly avoided at higher coyote densities. Coyote predation could constrain the realized niche of prey species at the distributional limits of the predator through their increased efficiency of predation reflected in increased prey selection values. These results are integral to improved understandings of Coyote ecology and can inform predictive analyses allowing for spatial variation, which ultimately will lead to better understandings about the ecological role of the coyote across different ecosystems.
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Affiliation(s)
- Matt W Hayward
- Conservation Science Research Group, College of Engineering, Science and the Environment, University of Newcastle, Callaghan, New South Wales 2207, Australia
- Mammal Research Institute, University of Pretoria, Tshwane X001, South Africa
- Centre for African Conservation Ecology, Nelson Mandela University, Port Elizabeth 6213, South Africa
| | | | - Jan F Kamler
- Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Biology, University of Oxford, Oxford OX13 5QL, United Kingdom
| | - Paul Rippon
- School of Information and Physical Sciences, University of Newcastle, Callaghan, New South Wales 2207, Australia
| | - David R Heit
- University of New Hampshire, Department of Natural Resources and the Environment, Durham, New Hampshire 03824, USA
| | - Vilis Nams
- Department of Plant, Food and Environmental Sciences, Agricultural Campus, Dalhousie University, Truro, Nova Scotia B2N 5E3, Canada
| | - Robert A Montgomery
- Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Biology, University of Oxford, Oxford OX13 5QL, United Kingdom
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Wisniewski AL, Nations JA, Slater GJ. Bayesian Prediction of Multivariate Ecology from Phenotypic Data Yields New Insights into the Diets of Extant and Extinct Taxa. Am Nat 2023; 202:192-215. [PMID: 37531278 DOI: 10.1086/725055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
AbstractMorphology often reflects ecology, enabling the prediction of ecological roles for taxa that lack direct observations, such as fossils. In comparative analyses, ecological traits, like diet, are often treated as categorical, which may aid prediction and simplify analyses but ignores the multivariate nature of ecological niches. Furthermore, methods for quantifying and predicting multivariate ecology remain rare. Here, we ranked the relative importance of 13 food items for a sample of 88 extant carnivoran mammals and then used Bayesian multilevel modeling to assess whether those rankings could be predicted from dental morphology and body size. Traditional diet categories fail to capture the true multivariate nature of carnivoran diets, but Bayesian regression models derived from living taxa have good predictive accuracy for importance ranks. Using our models to predict the importance of individual food items, the multivariate dietary niche, and the nearest extant analogs for a set of data-deficient extant and extinct carnivoran species confirms long-standing ideas for some taxa but yields new insights into the fundamental dietary niches of others. Our approach provides a promising alternative to traditional dietary classifications. Importantly, this approach need not be limited to diet but serves as a general framework for predicting multivariate ecology from phenotypic traits.
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Marneweck CJ, Allen BL, Butler AR, Do Linh San E, Harris SN, Jensen AJ, Saldo EA, Somers MJ, Titus K, Muthersbaugh M, Vanak A, Jachowski DS. Middle‐out ecology: small carnivores as sentinels of global change. Mamm Rev 2022. [DOI: 10.1111/mam.12300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Courtney J. Marneweck
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Benjamin L. Allen
- Institute for Life Sciences and the Environment University of Southern Queensland Toowoomba QLD 4350 Australia
- Centre for African Conservation Ecology Nelson Mandela University Port Elizabeth 6034 South Africa
| | - Andrew R. Butler
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Emmanuel Do Linh San
- Department of Zoology and Entomology University of Fort Hare Alice 5700 South Africa
| | - Stephen N. Harris
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Alex J. Jensen
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Elizabeth A. Saldo
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Michael J. Somers
- Mammal Research Institute, Centre for Invasion Biology, Department of Zoology and Entomology University of Pretoria Pretoria 0002 South Africa
| | - Keifer Titus
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Michael Muthersbaugh
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
| | - Abi Vanak
- Ashoka Trust for Research in Ecology and the Environment Bengaluru 560064 India
- School of Life Sciences University of KwaZulu‐Natal 3629 South Africa
| | - David S. Jachowski
- Department of Forestry and Environmental Conservation Clemson University Clemson SC 29634 USA
- School of Life Sciences University of KwaZulu‐Natal 3629 South Africa
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