1
|
Fortuna R, Covas R, D'Amelio PB, Silva LR, Parenteau C, Bliard L, Rybak F, Doutrelant C, Paquet M. Interplay of cooperative breeding and predation risk on egg allocation and reproductive output. Behav Ecol 2024; 35:arae010. [PMID: 38486920 PMCID: PMC10939053 DOI: 10.1093/beheco/arae010] [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: 05/02/2023] [Revised: 01/21/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024] Open
Abstract
Predation risk can influence behavior, reproductive investment, and, ultimately, individuals' fitness. In high-risk environments, females often reduce allocation to reproduction, which can affect offspring phenotype and breeding success. In cooperative breeders, helpers contribute to feed the offspring, and groups often live and forage together. Helpers can, therefore, improve reproductive success, but also influence breeders' condition, stress levels and predation risk. Yet, whether helper presence can buffer the effects of predation risk on maternal reproductive allocation remains unstudied. Here, we used the cooperatively breeding sociable weaver Philetairus socius to test the interactive effects of predation risk and breeding group size on maternal allocation to clutch size, egg mass, yolk mass, and yolk corticosterone. We increased perceived predation risk before egg laying using playbacks of the adults' main predator, gabar goshawk (Micronisus gabar). We also tested the interactive effects of group size and prenatal predator playbacks on offspring hatching and fledging probability. Predator-exposed females laid eggs with 4% lighter yolks, but predator-calls' exposure did not clearly affect clutch size, egg mass, or egg corticosterone levels. Playback-treatment effects on yolk mass were independent of group size, suggesting that helpers' presence did not mitigate predation risk effects on maternal allocation. Although predator-induced reductions in yolk mass may decrease nutrient availability to offspring, potentially affecting their survival, playback-treatment effects on hatching and fledging success were not evident. The interplay between helper presence and predator effects on maternal reproductive investment is still an overlooked area of life history and physiological evolutionary trade-offs that requires further studies.
Collapse
Affiliation(s)
- Rita Fortuna
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4099-002, Porto, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
- Centre for Biodiversity Dynamics, Institutt for Biologi, NTNU, 7491, Trondheim, Norway
| | - Rita Covas
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
- FitzPatrick Institute, DST-NRF Centre of Excellence, University of Cape Town, 7701, Cape Town, South Africa
| | - Pietro B D'Amelio
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293, Montpellier, France
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400, Saclay, France
| | - Liliana R Silva
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Charline Parenteau
- Centre d’Etudes Biologiques de Chizé, CNRS-La Rochelle Université, 79360, Villiers-en-Bois, France
| | - Louis Bliard
- Department of Evolutionary Biology & Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Fanny Rybak
- Université Paris-Saclay, CNRS, Institut des Neurosciences Paris-Saclay, 91400, Saclay, France
| | - Claire Doutrelant
- FitzPatrick Institute, DST-NRF Centre of Excellence, University of Cape Town, 7701, Cape Town, South Africa
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, 34293, Montpellier, France
| | - Matthieu Paquet
- Institute of Mathematics of Bordeaux, University of Bordeaux, CNRS, Bordeaux INP, 33405, Talence, France
- Theoretical and Experimental Ecology Station (SETE), CNRS, 09200, Moulis, France
| |
Collapse
|
2
|
Passoni G, Coulson T, Cagnacci F, Hudson P, Stahler DR, Smith DW, Lachish S. Investigating tritrophic interactions using bioenergetic demographic models. Ecology 2024; 105:e4197. [PMID: 37897692 DOI: 10.1002/ecy.4197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/27/2023] [Accepted: 09/18/2023] [Indexed: 10/30/2023]
Abstract
A central debate in ecology has been the long-running discussion on the role of apex predators in affecting the abundance and dynamics of their prey. In terrestrial systems, research has primarily relied on correlational approaches, due to the challenge of implementing robust experiments with replication and appropriate controls. A consequence of this is that we largely suffer from a lack of mechanistic understanding of the population dynamics of interacting species, which can be surprisingly complex. Mechanistic models offer an opportunity to examine the causes and consequences of some of this complexity. We present a bioenergetic mechanistic model of a tritrophic system where the primary vegetation resource follows a seasonal growth function, and the herbivore and carnivore species are modeled using two integral projection models (IPMs) with body mass as the phenotypic trait. Within each IPM, the demographic functions are structured according to bioenergetic principles, describing how animals acquire and transform resources into body mass, energy reserves, and breeding potential. We parameterize this model to reproduce the population dynamics of grass, elk, and wolves in northern Yellowstone National Park (USA) and investigate the impact of wolf reintroduction on the system. Our model generated predictions that closely matched the observed population sizes of elk and wolf in Yellowstone prior to and following wolf reintroduction. The introduction of wolves into our basal grass-elk bioenergetic model resulted in a population of 99 wolves and a reduction in elk numbers by 61% (from 14,948 to 5823) at equilibrium. In turn, vegetation biomass increased by approximately 25% in the growing season and more than threefold in the nongrowing season. The addition of wolves to the model caused the elk population to switch from being food-limited to being predator-limited and had a stabilizing effect on elk numbers across different years. Wolf predation also led to a shift in the phenotypic composition of the elk population via a small increase in elk average body mass. Our model represents a novel approach to the study of predator-prey interactions, and demonstrates that explicitly considering and linking bioenergetics, population demography and body mass phenotypes can provide novel insights into the mechanisms behind complex ecosystem processes.
Collapse
Affiliation(s)
- Gioele Passoni
- Department of Biology, University of Oxford, Oxford, UK
- Animal Ecology Unit, Research and Innovation Centre (CRI), Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Tim Coulson
- Department of Biology, University of Oxford, Oxford, UK
| | - Francesca Cagnacci
- Animal Ecology Unit, Research and Innovation Centre (CRI), Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Peter Hudson
- The Huck Institutes, Penn State University, State College, Pennsylvania, USA
| | - Daniel R Stahler
- Yellowstone Center for Resources, Yellowstone National Park, Wyoming, USA
| | - Douglas W Smith
- Yellowstone Center for Resources, Yellowstone National Park, Wyoming, USA
| | - Shelly Lachish
- Commonwealth Scientific Industrial Research Organisation (CSIRO) Environment Unit, Dutton Park, Queensland, Australia
| |
Collapse
|
3
|
Ruth KA, Berkeley LI, Strickfaden KM, Dreitz VJ. Density dependence of songbird demographics in grazed sagebrush steppe. PLoS One 2023; 18:e0289605. [PMID: 38134130 PMCID: PMC10745192 DOI: 10.1371/journal.pone.0289605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 07/21/2023] [Indexed: 12/24/2023] Open
Abstract
Sagebrush steppe is one of the most threatened ecosystems in North America. Adult density of songbirds within sagebrush steppe is a metric used to evaluate conservation actions. However, relying on only adult density to guide conservation may be misleading. Information on how conservation actions influence the nest density and nest survival of songbird species, in addition to adult density, are needed. We evaluated the relationships between nest density, nest survival, and adult density of Brewer's sparrow (Spizella breweri) and vesper sparrow (Pooecetes gramineus) over 3 breeding seasons in central Montana. Our findings suggest that adult pairs of both species were often present in higher numbers than nests, and this relationship was most prominent for Brewer's sparrows. However, our results do not support density dependence when considering nest survival. This discrepancy suggests that songbirds may not breed every year and that density dependence may be operating on nest densities within these populations differently than we examined. This study provides information on relationships between population demographics for 2 songbird species in grazed sagebrush steppe that will improve monitoring and management activities of conservation efforts.
Collapse
Affiliation(s)
- Kayla A. Ruth
- Wildlife Biology Program and Avian Science Center, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
- Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, Oregon, United States of America
| | - Lorelle I. Berkeley
- Montana Fish, Wildlife & Parks, Helena, Montana, United States of America
- SWCA Environmental Consultants, Salt Lake City, Utah, United Stated of America
| | - Kaitlyn M. Strickfaden
- Wildlife Biology Program and Avian Science Center, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
| | - Victoria J. Dreitz
- Wildlife Biology Program and Avian Science Center, W.A. Franke College of Forestry and Conservation, University of Montana, Missoula, Montana, United States of America
| |
Collapse
|
4
|
Arévalo-Ayala DJ, Real J, Mañosa S, Aymerich J, Durà C, Hernández-Matías A. Age-Specific Demographic Response of a Long-Lived Scavenger Species to Reduction of Organic Matter in a Landfill. Animals (Basel) 2023; 13:3529. [PMID: 38003146 PMCID: PMC10668657 DOI: 10.3390/ani13223529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/01/2023] [Accepted: 11/11/2023] [Indexed: 11/26/2023] Open
Abstract
Food availability shapes demographic parameters and population dynamics. Certain species have adapted to predictable anthropogenic food resources like landfills. However, abrupt shifts in food availability can negatively impact such populations. While changes in survival are expected, the age-related effects remain poorly understood, particularly in long-lived scavenger species. We investigated the age-specific demographic response of a Griffon vulture (Gyps fulvus) population to a reduction in organic matter in a landfill and analyzed apparent survival and the probability of transience after initial capture using a Bayesian Cormack-Jolly-Seber model on data from 2012-2022. The proportion of transients among newly captured immatures and adults increased after the reduction in food. Juvenile apparent survival declined, increased in immature residents, and decreased in adult residents. These results suggest that there was a greater likelihood of permanent emigration due to intensified intraspecific competition following the reduction in food. Interestingly, resident immatures showed the opposite trend, suggesting the persistence of high-quality individuals despite the food scarcity. Although the reasons behind the reduced apparent survival of resident adults in the final four years of the study remain unclear, non-natural mortality potentially plays a part. In Europe landfill closure regulations are being implemented and pose a threat to avian scavenger populations, which underlines the need for research on food scarcity scenarios and proper conservation measures.
Collapse
Affiliation(s)
- Diego J. Arévalo-Ayala
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain; (J.R.); (S.M.); (A.H.-M.)
| | - Joan Real
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain; (J.R.); (S.M.); (A.H.-M.)
- Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Santi Mañosa
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain; (J.R.); (S.M.); (A.H.-M.)
- Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Joan Aymerich
- Grup d’Anellament de Calldetenes-Osona (GACO), 08506 Calldetenes, Spain; (J.A.); (C.D.)
| | - Carles Durà
- Grup d’Anellament de Calldetenes-Osona (GACO), 08506 Calldetenes, Spain; (J.A.); (C.D.)
- Estació Biològica del Montseny, Institut Català d’Ornitologia (ICO), Edifici Fontmartina, 08081 Fogars de Montclús, Spain
| | - Antonio Hernández-Matías
- Equip de Biologia de la Conservació, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain; (J.R.); (S.M.); (A.H.-M.)
- Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, 08028 Barcelona, Spain
| |
Collapse
|
5
|
Brönmark C, Hellström G, Baktoft H, Hansson LA, McCallum ES, Nilsson PA, Skov C, Brodin T, Hulthén K. Ponds as experimental arenas for studying animal movement: current research and future prospects. MOVEMENT ECOLOGY 2023; 11:68. [PMID: 37880741 PMCID: PMC10601242 DOI: 10.1186/s40462-023-00419-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 09/02/2023] [Indexed: 10/27/2023]
Abstract
Animal movement is a multifaceted process that occurs for multiple reasons with powerful consequences for food web and ecosystem dynamics. New paradigms and technical innovations have recently pervaded the field, providing increasingly powerful means to deliver fine-scale movement data, attracting renewed interest. Specifically in the aquatic environment, tracking with acoustic telemetry now provides integral spatiotemporal information to follow individual movements in the wild. Yet, this technology also holds great promise for experimental studies, enhancing our ability to truly establish cause-and-effect relationships. Here, we argue that ponds with well-defined borders (i.e. "islands in a sea of land") are particularly well suited for this purpose. To support our argument, we also discuss recent experiences from studies conducted in an innovative experimental infrastructure, composed of replicated ponds equipped with modern aquatic telemetry systems that allow for unparalleled insights into the movement patterns of individual animals.
Collapse
Affiliation(s)
- Christer Brönmark
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden.
| | - Gustav Hellström
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, 90183, Sweden
| | - Henrik Baktoft
- National Institute of Aquatic Resources, Technical University of Denmark (DTU), Silkeborg, Denmark
| | - Lars-Anders Hansson
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden
| | - Erin S McCallum
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, 90183, Sweden
| | - P Anders Nilsson
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden
| | - Christian Skov
- National Institute of Aquatic Resources, Technical University of Denmark (DTU), Silkeborg, Denmark
| | - Tomas Brodin
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Umeå, 90183, Sweden
| | - Kaj Hulthén
- Department of Biology-Aquatic Ecology, Lund University, Ecology building, Sölvegatan 37 223 62, Lund, Sweden.
| |
Collapse
|
6
|
Oli MK, Kenney AJ, Boonstra R, Boutin S, Murray DL, Peers MJL, Gilbert BS, Jung TS, Chaudhary V, Hines JE, Krebs CJ. Does coat colour influence survival? A test in a cyclic population of snowshoe hares. Proc Biol Sci 2023; 290:20221421. [PMID: 37015272 PMCID: PMC10072933 DOI: 10.1098/rspb.2022.1421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023] Open
Abstract
Some mammal species inhabiting high-latitude biomes have evolved a seasonal moulting pattern that improves camouflage via white coats in winter and brown coats in summer. In many high-latitude and high-altitude areas, the duration and depth of snow cover has been substantially reduced in the last five decades. This reduction in depth and duration of snow cover may create a mismatch between coat colour and colour of the background environment, and potentially reduce the survival rate of species that depend on crypsis. We used long-term (1977-2020) field data and capture-mark-recapture models to test the hypothesis that whiteness of the coat influences winter apparent survival in a cyclic population of snowshoe hares (Lepus americanus) at Kluane, Yukon, Canada. Whiteness of the snowshoe hare coat in autumn declined during this study, and snowshoe hares with a greater proportion of whiteness in their coats in autumn survived better during winter. However, whiteness of the coat in spring did not affect subsequent summer survival. These results are consistent with the hypothesis that the timing of coat colour change in autumn can reduce overwinter survival. Because declines in cyclic snowshoe hare populations are strongly affected by low winter survival, the timing of coat colour change may adversely affect snowshoe hare population dynamics as climate change continues.
Collapse
Affiliation(s)
- Madan K Oli
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA
- School of Biological Sciences, Zoology Building, Tillydrone Avenue, University of Aberdeen, AB24 2TZ, UK
| | - Alice J Kenney
- Department of Zoology, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada M1C 1A4
| | | | - Dennis L Murray
- Department of Biology, Trent University, Peterborough, ON, Canada K9L 1Z8
| | | | - B Scott Gilbert
- Renewable Resources Management Program, Yukon University, Whitehorse, Yukon, Canada Y1A 5K4
| | - Thomas S Jung
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
- Department of Environment, Government of Yukon, Whitehorse, Yukon, Canada Y1A 2C6
| | - Vratika Chaudhary
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA
| | - James E Hines
- U.S. Geological Survey Eastern Ecological Science Center, Laurel, MD 20708, USA
| | - Charles J Krebs
- Department of Zoology, University of British Columbia, Vancouver, Canada V6T 1Z4
| |
Collapse
|
7
|
Kennah JL, Peers MJL, Vander Wal E, Majchrzak YN, Menzies AK, Studd EK, Boonstra R, Humphries MM, Jung TS, Kenney AJ, Krebs CJ, Boutin S. Coat color mismatch improves survival of a keystone boreal herbivore: Energetic advantages exceed lost camouflage. Ecology 2023; 104:e3882. [PMID: 36208219 DOI: 10.1002/ecy.3882] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 07/25/2022] [Indexed: 02/03/2023]
Abstract
Climate warming is causing asynchronies between animal phenology and environments. Mismatched traits, such as coat color change mismatched with snow, can decrease survival. However, coat change does not serve a singular adaptive benefit of camouflage, and alternate coat change functions may confer advantages that supersede mismatch costs. We found that mismatch reduced, rather than increased, autumn mortality risk of snowshoe hares in Yukon by 86.5% when mismatch occurred. We suggest that the increased coat insulation and lower metabolic rates of winter-acclimatized hares confer energetic advantages to white mismatched hares that reduce their mortality risk. We found that white mismatched hares forage 17-77 min less per day than matched brown hares between 0°C and -10°C, thus lowering their predation risk and increasing survival. We found no effect of mismatch on spring mortality risk, during which mismatch occurred at warmer temperatures, suggesting a potential temperature limit at which the costs of conspicuousness outweigh energetic benefits.
Collapse
Affiliation(s)
- Joanie L Kennah
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Michael J L Peers
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Eric Vander Wal
- Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Yasmine N Majchrzak
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Allyson K Menzies
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Emily K Studd
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Murray M Humphries
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Thomas S Jung
- Department of Environment, Government of Yukon, Whitehorse, Yukon, Canada.,Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Alice J Kenney
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Charles J Krebs
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
8
|
Hunting behavior of a solitary sailfish Istiophorus platypterus and estimated energy gain after prey capture. Sci Rep 2023; 13:1484. [PMID: 36707627 PMCID: PMC9883507 DOI: 10.1038/s41598-023-28748-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/24/2023] [Indexed: 01/29/2023] Open
Abstract
Foraging behavior and interaction with prey is an integral component of the ecological niche of predators but is inherently difficult to observe for highly mobile animals in the marine environment. Billfishes have been described as energy speculators, expending a large amount of energy foraging, expecting to offset high costs with periodic high energetic gain. Surface-based group feeding of sailfish, Istiophorus platypterus, is commonly observed, yet sailfish are believed to be largely solitary roaming predators with high metabolic requirements, suggesting that individual foraging also represents a major component of predator-prey interactions. Here, we use biologging data and video to examine daily activity levels and foraging behavior, estimate metabolic costs, and document a solitary predation event for a 40 kg sailfish. We estimate a median active metabolic rate of 218.9 ± 70.5 mgO2 kg-1 h-1 which increased to 518.8 ± 586.3 mgO2 kg-1 h-1 during prey pursuit. Assuming a successful predation, we estimate a daily net energy gain of 2.4 MJ (5.1 MJ acquired, 2.7 MJ expended), supporting the energy speculator model. While group hunting may be a common activity used by sailfish to acquire energy, our calculations indicate that opportunistic individual foraging events offer a net energy return that contributes to the fitness of these highly mobile predators.
Collapse
|
9
|
Medeiros LP, Allesina S, Dakos V, Sugihara G, Saavedra S. Ranking species based on sensitivity to perturbations under non-equilibrium community dynamics. Ecol Lett 2023; 26:170-183. [PMID: 36318189 PMCID: PMC10092288 DOI: 10.1111/ele.14131] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 09/20/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
Managing ecological communities requires fast detection of species that are sensitive to perturbations. Yet, the focus on recovery to equilibrium has prevented us from assessing species responses to perturbations when abundances fluctuate over time. Here, we introduce two data-driven approaches (expected sensitivity and eigenvector rankings) based on the time-varying Jacobian matrix to rank species over time according to their sensitivity to perturbations on abundances. Using several population dynamics models, we demonstrate that we can infer these rankings from time-series data to predict the order of species sensitivities. We find that the most sensitive species are not always the ones with the most rapidly changing or lowest abundance, which are typical criteria used to monitor populations. Finally, using two empirical time series, we show that sensitive species tend to be harder to forecast. Our results suggest that incorporating information on species interactions can improve how we manage communities out of equilibrium.
Collapse
Affiliation(s)
- Lucas P Medeiros
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Massachusetts, Cambridge, USA.,Institute of Marine Sciences, University of California Santa Cruz, California, Santa Cruz, USA
| | - Stefano Allesina
- Department of Ecology & Evolution, University of Chicago, Illinois, Chicago, USA.,Northwestern Institute on Complex Systems, Northwestern University, Illinois, Evanston, USA
| | - Vasilis Dakos
- Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier, Montpellier, France
| | - George Sugihara
- Scripps Institution of Oceanography, University of California San Diego, California, La Jolla, USA
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Massachusetts, Cambridge, USA
| |
Collapse
|
10
|
Season and prey identity mediate the effect of predators on parasites in rodents: a test of the healthy herds hypothesis. Oecologia 2023; 201:107-118. [PMID: 36414861 DOI: 10.1007/s00442-022-05284-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 11/06/2022] [Indexed: 11/24/2022]
Abstract
The healthy herds hypothesis (HHH) suggests that predators decrease parasitism in their prey. Repeated tests of this hypothesis across a range of taxa and ecosystems have revealed significant variation in the effect of predators on parasites in prey. Differences in the response to predators (1) between prey taxa, (2) between seasons, and (3) before and after catastrophic disturbance are common in natural systems, but typically ignored in empirical tests of the HHH. We used a predator exclusion experiment to measure the effect of these heterogeneities on the tri-trophic interaction among predators, parasites and prey. We experimentally excluded mammalian predators from the habitats of hispid cotton rats (Sigmodon hispidus) and cotton mice (Peromyscus gossypinus) and measured the effect of exclusion on gastrointestinal parasites in these rodents. Our experiment spanned multiple seasons and before and after a prescribed burn. We found that the exclusion of the same predators had opposite effects on the parasites of small mammal prey species. Additionally, we found that the effect of mammal exclusion on parasitism differed before versus after fire disturbance. Finally, we saw that the effect of predator exclusion was highly dependent on prey capture season. Significant effects of exclusion emerged primarily in the fall and winter months. The presence of so many different effects in one relatively simple system suggests that predator effects on parasites in prey are highly context dependent.
Collapse
|
11
|
Hodge JR, Price SA. Biotic Interactions and the Future of Fishes on Coral Reefs: The Importance of Trait-Based Approaches. Integr Comp Biol 2022; 62:1734-1747. [PMID: 36138511 DOI: 10.1093/icb/icac147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/24/2022] [Accepted: 09/06/2022] [Indexed: 01/05/2023] Open
Abstract
Biotic interactions govern the structure and function of coral reef ecosystems. As environmental conditions change, reef-associated fish populations can persist by tracking their preferred niche or adapting to new conditions. Biotic interactions will affect how these responses proceed and whether they are successful. Yet, our understanding of these effects is currently limited. Ecological and evolutionary theories make explicit predictions about the effects of biotic interactions, but many remain untested. Here, we argue that large-scale functional trait datasets enable us to investigate how biotic interactions have shaped the assembly of contemporary reef fish communities and the evolution of species within them, thus improving our ability to predict future changes. Importantly, the effects of biotic interactions on these processes have occurred simultaneously within dynamic environments. Functional traits provide a means to integrate the effects of both ecological and evolutionary processes, as well as a way to overcome some of the challenges of studying biotic interactions. Moreover, functional trait data can enhance predictive modeling of future reef fish distributions and evolvability. We hope that our vision for an integrative approach, focused on quantifying functionally relevant traits and how they mediate biotic interactions in different environmental contexts, will catalyze new research on the future of reef fishes in a changing environment.
Collapse
Affiliation(s)
- Jennifer R Hodge
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Samantha A Price
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| |
Collapse
|
12
|
Lennox RJ, Dahlmo LS, Ford AT, Sortland LK, Vogel EF, Vollset KW. Predation research with electronic tagging. WILDLIFE BIOLOGY 2022. [DOI: 10.1002/wlb3.01045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Robert J. Lennox
- Norwegian Inst. for Nature Research Trondheim Norway
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
| | - Lotte S. Dahlmo
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
- Dept of Biological Sciences, Univ. of Bergen Bergen Norway
| | - Adam T. Ford
- Univ. of British Columbia Okanagan Kelowna BC Canada
| | - Lene K. Sortland
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
- Dept of Biological Sciences, Univ. of Bergen Bergen Norway
| | - Emma F. Vogel
- UiT − The Arctic Univ. of Norway, Faculty of Biosciences, Fisheries and Economics Tromsø Norway
| | - Knut Wiik Vollset
- NORCE Norwegian Research Centre, Laboratory for Freshwater Ecology and Inland Fisheries Bergen Norway
| |
Collapse
|
13
|
Morozov NS. The Role of Predators in Shaping Urban Bird Populations: 1. Who Succeeds in Urban Landscapes? BIOL BULL+ 2022. [DOI: 10.1134/s1062359022080118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
14
|
Driessen MMG, Versteegh MA, Gerritsma YH, Tieleman BI, Pen IR, Verhulst S. Effects of manipulated food availability and seasonality on innate immune function in a passerine. J Anim Ecol 2022; 91:2400-2411. [PMID: 36268692 PMCID: PMC10092825 DOI: 10.1111/1365-2656.13822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 09/05/2022] [Indexed: 12/14/2022]
Abstract
The innate immune system is essential for survival, yet many immune traits are highly variable between and within individuals. In recent years, attention has shifted to the role of environmental factors in modulating this variation. A key environmental factor is food availability, which plays a major role in shaping life histories, and may affect resource allocation to immune function through its effect on nutritional state. We developed a technique to permanently increase foraging costs in seed-eating birds, and leveraged this technique to study the effects of food availability on the innate immune system over a 3-year period in 230 zebra finches housed in outdoor aviaries. The immune components we studied were haptoglobin, ovotransferrin, nitric oxide, natural antibodies through agglutination, complement-mediated lysis, and killing capacity of Escherichia coli and Candida albicans, covering a broad spectrum of the innate immune system. We explored the effects of food availability in conjunction with other potentially important variables: season, age, sex and manipulated natal brood size. Increased foraging costs affected multiple components of the immune system, albeit in a variable way. Nitric oxide and agglutination levels were lower under harsh foraging conditions, while Escherichia coli killing capacity was increased. Agglutination levels also varied seasonally, but only at low foraging costs. C. albicans killing capacity was lower in winter, and even more so for animals in harsh foraging conditions that were raised in large broods. Effects of food availability on ovotransferrin were also seasonal, and only apparent in males. Haptoglobin levels were independent of foraging costs and season. Males had higher levels of immune function than females for three of the measured immune traits. Innate immune function was independent of age and manipulated natal brood size. Our finding that food availability affects innate immune function suggests that fitness effects of food availability may at least partially be mediated by effects on the immune system. However, food availability effects on innate immunity varied in direction between traits, illustrating the complexity of the immune system and precluding conclusions on the level of disease resistance.
Collapse
Affiliation(s)
| | | | | | | | - Ido R Pen
- University of Groningen, Groningen, the Netherlands
| | | |
Collapse
|
15
|
Morozov NS. The Role of Predators in Shaping Urban Bird Populations. 4. The Urban Predation Paradox and Its Probable Causes. BIOL BULL+ 2022. [DOI: 10.1134/s1062359022090242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
16
|
Petrullo L, Delaney D, Boutin S, McAdam AG, Lane JE, Boonstra R, Palme R, Dantzer B. The glucocorticoid response to environmental change is not specific to agents of natural selection in wild red squirrels. Horm Behav 2022; 146:105262. [PMID: 36191397 DOI: 10.1016/j.yhbeh.2022.105262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/04/2022]
Abstract
Evolutionary endocrinology aims to understand how natural selection shapes endocrine systems and the degree to which endocrine systems themselves can induce phenotypic responses to environmental changes. Such responses may be specialized in that they reflect past selection for responsiveness only to those ecological factors that ultimately influence natural selection. Alternatively, endocrine responses may be broad and generalized, allowing organisms to cope with a variety of environmental changes simultaneously. Here, we empirically tested whether the endocrine response of female North American red squirrels (Tamiasciurus hudsonicus) was specialized or generalized. We first quantified the direction and magnitude of natural selection acting on three female life history traits (parturition date, litter size, offspring postnatal growth rate) during 32 years of fluctuations in four potential ecological agents of selection (food availability, conspecific density, predator abundance, and temperature). Only three of the four variables (food, density, and predators) affected patterns of natural selection on female life history traits. We then quantified fecal glucocorticoid metabolites (FGMs) across 7 years and found that all four environmental variables, regardless of their effects on patterns of selection, were associated with glucocorticoid production. Our results provide support for a generalized, rather than specific, glucocorticoid response to environmental change that can integrate across multiple co-occurring environmental stressors.
Collapse
Affiliation(s)
- Lauren Petrullo
- Department of Psychology, University of Michigan, Ann Arbor, MI 48108, USA.
| | - David Delaney
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Andrew G McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, Centre for the Neurobiology of Stress, University of Toronto Scarborough, Toronto, ON M1C 1A6, Canada
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterina ̈rplatz 1, Vienna 1210, Austria
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI 48108, USA; Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48108, USA
| |
Collapse
|
17
|
Fragoso JMV, Antunes AP, Silvius KM, Constantino PAL, Zapata-Ríos G, Bizri HRE, Bodmer RE, Camino M, de Thoisy B, Wallace RB, Morcatty TQ, Mayor P, Richard-Hansen C, Hallett MT, Reyna-Hurtado RA, Beck HH, de Bustos S, Keuroghlian A, Nava A, Montenegro OL, Painkow Neto E, Altrichter M. Large-scale population disappearances and cycling in the white-lipped peccary, a tropical forest mammal. PLoS One 2022; 17:e0276297. [PMID: 36264921 PMCID: PMC9584423 DOI: 10.1371/journal.pone.0276297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/04/2022] [Indexed: 11/19/2022] Open
Abstract
Many vertebrate species undergo population fluctuations that may be random or regularly cyclic in nature. Vertebrate population cycles in northern latitudes are driven by both endogenous and exogenous factors. Suggested causes of mysterious disappearances documented for populations of the Neotropical, herd-forming, white-lipped peccary (Tayassu pecari, henceforth “WLP”) include large-scale movements, overhunting, extreme floods, or disease outbreaks. By analyzing 43 disappearance events across the Neotropics and 88 years of commercial and subsistence harvest data for the Amazon, we show that WLP disappearances are widespread and occur regularly and at large spatiotemporal scales throughout the species’ range. We present evidence that the disappearances represent 7–12-year troughs in 20–30-year WLP population cycles occurring synchronously at regional and perhaps continent-wide spatial scales as large as 10,000–5 million km2. This may represent the first documented case of natural population cyclicity in a Neotropical mammal. Because WLP populations often increase dramatically prior to a disappearance, we posit that their population cycles result from over-compensatory, density-dependent mortality. Our data also suggest that the increase phase of a WLP cycle is partly dependent on recolonization from proximal, unfragmented and undisturbed forests. This highlights the importance of very large, continuous natural areas that enable source-sink population dynamics and ensure re-colonization and local population persistence in time and space.
Collapse
Affiliation(s)
- José M. V. Fragoso
- Departamento de Zoologia, Universidade de Brasília, Brasília, DF, Brazil
- Instituto Nacional de Pesquisas da Amazônia (INPA/MCTIC), Manaus, Brazil
- California Academy of Sciences, San Francisco, California, United States of America
- * E-mail: ,
| | - André P. Antunes
- Instituto Nacional de Pesquisas da Amazônia (INPA/MCTIC), Manaus, Brazil
- RedeFauna–Rede de Pesquisa em Diversidade, Conservação e Uso da Fauna da Amazônia, Tefé, Amazonas, Brazil
| | - Kirsten M. Silvius
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Pedro A. L. Constantino
- RedeFauna–Rede de Pesquisa em Diversidade, Conservação e Uso da Fauna da Amazônia, Tefé, Amazonas, Brazil
| | | | - Hani R. El Bizri
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, United Kingdom
- Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, Amazonas, Brazil
| | - Richard E. Bodmer
- Museum of Amazonian Cultures-Fundamazonia, Iquitos, Loreto, Perú
- DICE, School of Anthropology & Conservation, University of Kent, Canterbury, United Kingdom
| | - Micaela Camino
- Proyecto Quimilero, Roosevelt 4344, CABA, Resistencia, Argentina
- EDGE of Existence—Zoological Society of London, Regent’s Park, London, England, United Kingdom
| | | | - Robert B. Wallace
- Wildlife Conservation Society, Bronx, New York, United States of America
| | - Thais Q. Morcatty
- Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, Amazonas, Brazil
- Department of Social Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Pedro Mayor
- Departament de Sanitat i d’Anatomia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra, Spain
- Museo de Culturas Indígenas Amazónicas, Loreto, Iquitos, Peru
| | | | - Mathew T. Hallett
- Department of Wildlife Ecology & Conservation, University of Florida, Gainesville, Florida, United States of America
- Institute for the Environment & Sustainability, Miami University, Oxford, Ohio, United States of America
- Center for International Forestry Research (CIFOR), Bogor, Indonesia
| | | | - H. Harald Beck
- Department of Biological Sciences, Towson University, Towson, Baltimore, Maryland, United States of America
| | - Soledad de Bustos
- Secretaría de Ambiente y Desarrollo Sustentable de Salta, Santiago del Estero, Salta, Argentina
- Fundación Biodiversidad Argentina, Suipacha, Argentina
| | | | | | - Olga L. Montenegro
- Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia
| | | | - Mariana Altrichter
- Faculty Environmental Studies, Prescott College, Prescott, Arizona, United States of America
| |
Collapse
|
18
|
Erazo D, Pedersen AB, Fenton A. The predicted impact of resource provisioning on the epidemiological responses of different parasites. J Anim Ecol 2022; 91:1719-1730. [PMID: 35643978 PMCID: PMC9546467 DOI: 10.1111/1365-2656.13751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/07/2022] [Indexed: 11/27/2022]
Abstract
Anthropogenic activities and natural events such as periodic tree masting can alter resource provisioning in the environment, directly affecting animals, and potentially impacting the spread of infectious diseases in wildlife. The impact of these additional resources on infectious diseases can manifest through different pathways, affecting host susceptibility, contact rate and host demography. To date however, empirical research has tended to examine these different pathways in isolation, for example by quantifying the effects of provisioning on host behaviour in the wild or changes in immune responses in controlled laboratory studies. Furthermore, while theory has investigated the interactions between these pathways, this work has focussed on a narrow subset of pathogen types, typically directly transmitted microparasites. Given the diverse ways that provisioning can affect host susceptibility, contact patterns or host demography, we may expect the epidemiological consequences of provisioning to vary among different parasite types, dependent on key aspects of parasite life history, such as the duration of infection and transmission mode. Focusing on an exemplar empirical system, the wood mouse Apodemus sylvaticus, and its diverse parasite community, we developed a suite of epidemiological models to compare how resource provisioning alters responses for a range of these parasites that vary in their biology (microparasite and macroparasite), transmission mode (direct, environmental and vector transmitted) and duration of infection (acute, latent and chronic) within the same host population. We show there are common epidemiological responses to host resource provisioning across all parasite types examined. In particular, the epidemiological impact of provisioning could be driven in opposite directions, depending on which host pathways (contact rate, susceptibility or host demography) are most altered by the addition of resources to the environment. Broadly, these responses were qualitatively consistent across all parasite types, emphasising the importance of identifying general trade-offs between provisioning-altered parameters. Despite the qualitative consistency in responses to provisioning across parasite types, we predicted notable quantitative differences between parasites, with directly transmitted parasites (those conforming to SIR and SIS frameworks) predicted to show the strongest responses to provisioning among those examined, whereas the vector-borne parasites showed negligible responses to provisioning. As such, these analyses suggest that different parasites may show different scales of response to the same provisioning scenario, even within the same host population. This highlights the importance of knowing key aspects of host-parasite biology, to understand and predict epidemiological responses to provisioning for any specific host-parasite system.
Collapse
Affiliation(s)
- Diana Erazo
- Spatial Epidemiology Lab (SpELL)Université Libre de BruxellesBruxellesBelgium
- Institute of Infection, Veterinary & Ecological SciencesUniversity of LiverpoolLiverpoolUK
| | - Amy B. Pedersen
- Institute of Evolutionary BiologySchool of Biological SciencesUniversity of EdinburghEdinburghUK
| | - Andy Fenton
- Institute of Infection, Veterinary & Ecological SciencesUniversity of LiverpoolLiverpoolUK
| |
Collapse
|
19
|
Kvalnes T, Sæther BE, Engen S, Roulin A. Density-dependent selection and the maintenance of colour polymorphism in barn owls. Proc Biol Sci 2022; 289:20220296. [PMID: 35642371 PMCID: PMC9156910 DOI: 10.1098/rspb.2022.0296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The capacity of natural selection to generate adaptive changes is (according to the fundamental theorem of natural selection) proportional to the additive genetic variance in fitness. In spite of its importance for development of new adaptations to a changing environment, processes affecting the magnitude of the genetic variance in fitness-related traits are poorly understood. Here, we show that the red-white colour polymorphism in female barn owls is subject to density-dependent selection at the phenotypic and genotypic level. The diallelic melanocortin-1 receptor gene explained a large amount of the phenotypic variance in reddish coloration in the females ([Formula: see text]). Red individuals (RR genotype) were selected for at low densities, while white individuals (WW genotype) were favoured at high densities and were less sensitive to changes in density. We show that this density-dependent selection favours white individuals and predicts fixation of the white allele in this population at longer time scales without immigration or other selective forces. Still, fluctuating population density will cause selection to fluctuate and periodically favour red individuals. These results suggest how balancing selection caused by fluctuations in population density can be a general mechanism affecting the level of additive genetic variance in natural populations.
Collapse
Affiliation(s)
- Thomas Kvalnes
- Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Bernt-Erik Sæther
- Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Steinar Engen
- Department of Mathematical Sciences, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Alexandre Roulin
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, Lausanne CH-1015, Switzerland
| |
Collapse
|
20
|
Abstract
Most natural ecosystems contain animals feeding on many different types of food, but it is difficult to predict what will be eaten when food availabilities change. We present a method that estimates food preference over many study sites, even when number of food types vary widely from site to site. Sampling variation is estimated using bootstrapping. We test the precision and accuracy of this method using computer simulations that show the effects of overall number of food types, number of sites, and proportion of missing prey items per site. Accuracy is greater with fewer missing prey types, more prey types and more sites, and is affected by the number of sites more than the number of prey types. We present a case study using lion (Panthera leo) feeding data and show that preference vs prey size follows a bell-curve. Using just two estimated parameters, this curve can be used as a general way to describe predator feeding patterns. Our method can be used to: test hypotheses about what factors affect prey selection, predict preferences in new sites, and estimate overall prey consumed in new sites.
Collapse
Affiliation(s)
- Vilis O. Nams
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, Canada
- * E-mail:
| | - Matt W. Hayward
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
- Mammal Research Institute, University of Pretoria, Hatfield, Pretoria, South Africa
| |
Collapse
|
21
|
Gerritsma YH, Driessen MMG, Tangili M, de Boer SF, Verhulst S. Experimentally manipulated food availability affects offspring quality but not quantity in zebra finch meso-populations. Oecologia 2022; 199:769-783. [PMID: 35614323 PMCID: PMC9465982 DOI: 10.1007/s00442-022-05183-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/03/2022] [Indexed: 11/29/2022]
Abstract
Food availability modulates survival, reproduction and thereby population size. In addition to direct effects, food availability has indirect effects through density of conspecifics and predators. We tested the prediction that food availability in isolation affects reproductive success by experimentally manipulating food availability continuously for 3 years in zebra finches (Taeniopygia guttata) housed in outdoor aviaries. To this end, we applied a technique that mimics natural variation in food availability: increasing the effort required per food reward without affecting diet. Lower food availability resulted in a slight delay of start of laying and fewer clutches per season, but did not affect clutch size or number of offspring reared per annum. However, increasing foraging costs substantially reduced offspring growth. Thus, food availability in isolation did not impact the quantity of offspring reared, at the expense of offspring quality. Growth declined strongly with brood size, and we interpret the lack of response with respect to offspring number as an adaptation to environments with low predictability, at the time of egg laying, of food availability during the period of peak food demand, typically weeks later. Manipulated natal brood size of the parents did not affect reproductive success. Individuals that were more successful reproducers were more likely to survive to the next breeding season, as frequently found in natural populations. We conclude that the causal mechanisms underlying associations between food availability and reproductive success in natural conditions may be more complex than usually assumed. Experiments in semi-natural meso-populations can contribute to further unravelling these mechanisms.
Collapse
|
22
|
Suraci JP, Smith JA, Chamaillé‐Jammes S, Gaynor KM, Jones M, Luttbeg B, Ritchie EG, Sheriff MJ, Sih A. Beyond spatial overlap: harnessing new technologies to resolve the complexities of predator–prey interactions. OIKOS 2022. [DOI: 10.1111/oik.09004] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | - Justine A. Smith
- Dept of Wildlife, Fish and Conservation Biology, Univ. of California Davis CA USA
| | - Simon Chamaillé‐Jammes
- CEFE, Univ. Montpellier, CNRS, EPHE, IRD Montpellier France
- Mammal Research Inst., Dept of Zoology&Entomology, Univ. of Pretoria Pretoria South Africa
| | - Kaitlyn M. Gaynor
- National Center for Ecological Analysis and Synthesis, Univ. of California Santa Barbara CA USA
| | - Menna Jones
- School of Natural Sciences, Univ. of Tasmania Tasmania Australia
| | - Barney Luttbeg
- Dept of Integrative Biology, Oklahoma State Univ. Stillwater OK USA
| | - Euan G. Ritchie
- School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin Univ. Burwood VIC Australia
| | | | - Andrew Sih
- Dept of Environmental Science and Policy, Univ. of California Davis CA USA
| |
Collapse
|
23
|
Majchrzak YN, Peers MJL, Studd EK, Menzies AK, Walker PD, Shiratsuru S, McCaw LK, Boonstra R, Humphries M, Jung TS, Kenney AJ, Krebs CJ, Murray DL, Boutin S. Balancing food acquisition and predation risk drives demographic changes in snowshoe hare population cycles. Ecol Lett 2022; 25:981-991. [PMID: 35148018 DOI: 10.1111/ele.13975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 12/08/2021] [Accepted: 01/04/2022] [Indexed: 11/28/2022]
Abstract
Snowshoe hare cycles are one of the most prominent phenomena in ecology. Experimental studies point to predation as the dominant driving factor, but previous experiments combining food supplementation and predator removal produced unexplained multiplicative effects on density. We examined the potential interactive effects of food limitation and predation in causing hare cycles using an individual-based food-supplementation experiment over-winter across three cycle phases that naturally varied in predation risk. Supplementation doubled over-winter survival with the largest effects occurring in the late increase phase. Although the proximate cause of mortality was predation, supplemented hares significantly decreased foraging time and selected for conifer habitat, potentially reducing their predation risk. Supplemented hares also lost less body mass which resulted in the production of larger leverets. Our results establish a mechanistic link between how foraging time, mass loss and predation risk affect survival and reproduction, potentially driving demographic changes associated with hare cycles.
Collapse
Affiliation(s)
- Yasmine N Majchrzak
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Michael J L Peers
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Emily K Studd
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Allyson K Menzies
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Philip D Walker
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Shotaro Shiratsuru
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Laura K McCaw
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Murray Humphries
- Department of Natural Resource Sciences, McGill University, Montreal, Quebec, Canada
| | - Thomas S Jung
- Department of Environment, Government of Yukon, Whitehorse, Yukon, Canada.,Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Alice J Kenney
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Charles J Krebs
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dennis L Murray
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
24
|
Wilson EC, Zuckerberg B, Peery MZ, Pauli JN. Experimental repatriation of snowshoe hares along a southern range boundary reveals historical community interactions. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Evan C. Wilson
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | - Benjamin Zuckerberg
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | - M. Zachariah Peery
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| | - Jonathan N. Pauli
- Department of Forest and Wildlife Ecology University of Wisconsin Madison Wisconsin USA
| |
Collapse
|
25
|
LaBarge LR, Evans MJ, Miller JRB, Cannataro G, Hunt C, Elbroch LM. Pumas
Puma concolor
as ecological brokers: a review of their biotic relationships. Mamm Rev 2022. [DOI: 10.1111/mam.12281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Laura R. LaBarge
- Program in Evolution, Ecology and Behavior, Department of Environment and Sustainability, The State University of New York University at Buffalo Amherst NY14260USA
- Center for Conservation Innovation Defenders of Wildlife Washington DC20036USA
- Max Planck Institute of Animal Behavior Bücklestraße 5 Konstanz DE78467Germany
| | - Michael J. Evans
- Center for Conservation Innovation Defenders of Wildlife Washington DC20036USA
- Department of Environmental Science and Policy George Mason University 4400 University Dr Fairfax VA22030USA
| | - Jennifer R. B. Miller
- Center for Conservation Innovation Defenders of Wildlife Washington DC20036USA
- Department of Environmental Science and Policy George Mason University 4400 University Dr Fairfax VA22030USA
| | - Gillian Cannataro
- Center for Conservation Innovation Defenders of Wildlife Washington DC20036USA
- Conservation, Management and Welfare Sciences Association of Zoos and Aquariums 8403 Colesville Rd., Suite 710 Silver Spring MD20910‐3314USA
| | - Christian Hunt
- Field Conservation Defenders of Wildlife Washington DC20036USA
| | | |
Collapse
|
26
|
Oli MK, Kenney AJ, Boonstra R, Boutin S, Chaudhary V, Hines JE, Krebs CJ. Estimating abundance, temporary emigration, and the pattern of density dependence in a cyclic snowshoe hare (Lepus americanus) population in Yukon, Canada. CAN J ZOOL 2022. [DOI: 10.1139/cjz-2021-0139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Estimates of demographic parameters based on capture–mark–recapture (CMR) methods may be biased when some individuals in the population are temporarily unavailable for capture (temporary emigration). We estimated snowshoe hare abundance, apparent survival, and probability of temporary emigration in a population of snowshoe hares (Lepus americanus Erxleben, 1777) in the Yukon (Canada) using Pollock’s robust design CMR model, and population density using spatially explicit CMR models. Survival rates strongly varied among cyclic phases, seasons, and across five population cycles. We found strong evidence that temporary emigration was Markovian (i.e., nonrandom), suggesting that it varied among individuals that were temporary emigrant in the previous sampling period and those that were present in the sampled area. The probability of temporary emigration for individuals that were in the study area during the previous sampling occasion (γ″) varied among cycles. Probability that individuals that were temporarily absent from the sampled area would remain temporary emigrants (γ′) showed strongly seasonal pattern, low in winter and high during summers. Snowshoe hare population density ranged from 0.017 (0.015–0.05) hares/ha to 4.43 (3.90–5.00) hares/ha and showed large-scale cyclical fluctuations. Autocorrelation functions and autoregressive analyses revealed that our study population exhibited statistically significant cyclic fluctuations, with a periodicity of 9–10 years.
Collapse
Affiliation(s)
- Madan K. Oli
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA
| | - Alice J. Kenney
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Vratika Chaudhary
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA
| | - James E. Hines
- Eastern Ecological Science Center, U.S. Geological Survey, Laurel, MD 20708, USA
| | - Charles J. Krebs
- Department of Zoology, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| |
Collapse
|
27
|
Richmond IC, Balluffi-Fry J, Vander Wal E, Leroux SJ, Rizzuto M, Heckford TR, Kennah JL, Riefesel GR, Wiersma YF. Individual snowshoe hares manage risk differently: integrating stoichiometric distribution models and foraging ecology. J Mammal 2021. [DOI: 10.1093/jmammal/gyab130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Herbivores making space use decisions must consider the trade-off between perceived predation risk and forage quality. Herbivores, specifically snowshoe hares (Lepus americanus), must constantly navigate landscapes that vary in predation risk and food quality, providing researchers with the opportunity to explore the factors that govern their foraging decisions. Herein, we tested predictions that intersect the risk allocation hypothesis (RAH) and optimal foraging theory (OFT) in a spatially explicit ecological stoichiometry framework to assess the trade-off between predation risk and forage quality. We used individual and population estimates of snowshoe hare (n = 29) space use derived from biotelemetry across three summers. We evaluated resource forage quality for lowbush blueberry (Vaccinium angustifolium), a common and readily available forage species within our system, using carbon:nitrogen and carbon:phosphorus ratios. We used habitat complexity to proxy perceived predation risk. We analyzed how forage quality of blueberry, perceived predation risk, and their interaction impact the intensity of herbivore space use. We used generalized mixed effects models, structured to enable us to make inferences at the population and individual home range level. We did not find support for RAH and OFT. However, variation in the individual-level reactions norms in our models showed that individual hares have unique responses to forage quality and perceived predation risk. Our finding of individual-level responses indicates that there is fine-scale decision-making by hares, although we did not identify the mechanism. Our approach illustrates spatially explicit empirical support for individual behavioral responses to the food quality–predation risk trade-off.
Collapse
Affiliation(s)
- Isabella C Richmond
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Juliana Balluffi-Fry
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Eric Vander Wal
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Shawn J Leroux
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Matteo Rizzuto
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Travis R Heckford
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Joanie L Kennah
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Gabrielle R Riefesel
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Yolanda F Wiersma
- Department of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada
| |
Collapse
|
28
|
Richards RL, Drake JM, Ezenwa VO. Do predators keep prey healthy or make them sicker? A meta-analysis. Ecol Lett 2021; 25:278-294. [PMID: 34738700 DOI: 10.1111/ele.13919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/17/2021] [Accepted: 10/14/2021] [Indexed: 11/27/2022]
Abstract
Ecological theory suggests that predators can either keep prey populations healthy by reducing parasite burdens or alternatively, increase parasitism in prey. To quantify the overall magnitude and direction of the effect of predation on parasitism in prey observed in practice, we conducted a meta-analysis of 47 empirical studies. We also examined how study attributes, including parasite type and life cycle, habitat type, study design, and whether predators were able to directly consume prey contributed to variation in the predator-prey-parasite interaction. We found that the overall effect of predation on parasitism differed between parasites and parasitoids and that whether consumptive effects were present, and whether a predator was a non-host spreader of parasites, were the most important traits predicting the parasite response. Our results suggest that the mechanistic basis of predator-prey interactions strongly influences the effects of predators on parasites and that these effects, although context dependent, are predictable.
Collapse
Affiliation(s)
- Robert L Richards
- Odum School of Ecology, University of Georgia, Athens, Georgia, USA.,Center for the Ecology of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - John M Drake
- Odum School of Ecology, University of Georgia, Athens, Georgia, USA.,Center for the Ecology of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Vanessa O Ezenwa
- Odum School of Ecology, University of Georgia, Athens, Georgia, USA.,Center for the Ecology of Infectious Diseases, University of Georgia, Athens, Georgia, USA.,Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| |
Collapse
|
29
|
Luttbeg B, Beaty LE, Ambardar M, Grindstaff JL. Mathematical modeling reveals how the speed of endocrine regulation should affect baseline and stress-induced glucocorticoid levels. Horm Behav 2021; 136:105059. [PMID: 34508875 PMCID: PMC8629843 DOI: 10.1016/j.yhbeh.2021.105059] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/10/2021] [Accepted: 08/23/2021] [Indexed: 10/20/2022]
Abstract
Unpredictable environmental changes displace individuals from homeostasis and elicit a stress response. In vertebrates, the stress response is mediated mainly by glucocorticoids (GCs) which initiate physiological changes while minimizing allostatic overload. Individuals and species vary consistently in baseline and stress-induced GC levels and the speed with which GC levels can be upregulated or downregulated, but the extent to which variation in hormone regulation influences baseline and stress-induced GC levels is unclear. Using mathematical modeling, we tested how GC regulation rate, frequencies and durations of acute stressors, fitness functions, and allostatic overload affect GC levels during control and acute stress periods. As GC regulation rate slows, baseline and acute stress-induced GC levels become more similar. When the speed of up- and downregulation decreased, hormone levels became more linked to anticipated future conditions to avoid fitness costs of mismatching a new environmental state. More frequent acute stressors caused baseline and acute stress-induced GC levels to converge. When fitness was more tightly linked to hormone levels during acute stress periods than during control states, the speed of upregulation influenced optimal hormone levels more than the downregulation rate. With allostatic overload costs included, predicted GC levels were lower and more dependent on the frequency of past acute stressors. Our results show the value of optimality modeling to study the hormonal response to stressors and suggest GC levels depend on past and anticipated future environmental states as well as individual differences in hormone regulation.
Collapse
Affiliation(s)
- Barney Luttbeg
- Department of Integrative Biology, Oklahoma State University, OK 74078, United States.
| | - Lynne E Beaty
- School of Science, Penn State Erie, The Behrend College, Erie, PA 16563, United States
| | - Medhavi Ambardar
- Department of Biological Sciences, Fort Hays State University, Hays, KS 67601, United States
| | - Jennifer L Grindstaff
- Department of Integrative Biology, Oklahoma State University, OK 74078, United States
| |
Collapse
|
30
|
Timing outweighs magnitude of rainfall in shaping population dynamics of a small mammal species in steppe grassland. Proc Natl Acad Sci U S A 2021; 118:2023691118. [PMID: 34649988 PMCID: PMC8545474 DOI: 10.1073/pnas.2023691118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2021] [Indexed: 12/04/2022] Open
Abstract
Disentangling the effects of rainfall timing and magnitude on animal and plant populations is essential to reveal the biological consequence of diverse climate change scenarios around the world. We conducted a 10-y, large-scale, manipulative experiment to examine the bottom-up effects of changes in rainfall regime on the population dynamics of Brandt’s voles in the steppe grassland of Inner Mongolia, China. We found that a moderate rainfall increase during the early growing season could produce marked increases in vole population size by increasing the biomass of preferred plant species, whereas large increases in rainfall produced no additional increase in vole population growth. Our study highlights the importance of rainfall magnitude and timing on the nonlinear population dynamics of herbivores. Climate change–induced shifts in species phenology differ widely across trophic levels, which may lead to consumer–resource mismatches with cascading population and ecosystem consequences. Here, we examined the effects of different rainfall patterns (i.e., timing and amount) on the phenological asynchrony of population of a generalist herbivore and their food sources in semiarid steppe grassland in Inner Mongolia. We conducted a 10-y (2010 to 2019) rainfall manipulation experiment in 12 0.48-ha field enclosures and found that moderate rainfall increases during the early rather than late growing season advanced the timing of peak reproduction and drove marked increases in population size through increasing the biomass of preferred plant species. By contrast, greatly increased rainfall produced no further increases in vole population growth due to the potential negative effect of the flooding of burrows. The increases in vole population size were more coupled with increased reproduction of overwintered voles and increased body mass of young-of-year than with better survival. Our results provide experimental evidence for the fitness consequences of phenological mismatches at the population level and highlight the importance of rainfall timing on the population dynamics of small herbivores in the steppe grassland environment.
Collapse
|
31
|
Lavergne SG, Krebs CJ, Kenney AJ, Boutin S, Murray D, Palme R, Boonstra R. The impact of variable predation risk on stress in snowshoe hares over the cycle in North America's boreal forest: adjusting to change. Oecologia 2021; 197:71-88. [PMID: 34435235 DOI: 10.1007/s00442-021-05019-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/16/2021] [Indexed: 11/26/2022]
Abstract
The boreal forest is one of the world's ecosystems most affected by global climate warming. The snowshoe hare, its predators, and their population dynamics dominate the mammalian component of the North American boreal forest. Our past research has shown the 9-11-year hare cycle to be predator driven, both directly as virtually all hares that die are killed by their predators, and indirectly through sublethal risk effects on hare stress physiology, behavior, and reproduction. We replicated this research over the entire cycle by measuring changes in predation risk expected to drive changes in chronic stress. We examined changes in hare condition and stress axis function using a hormonal challenge protocol in the late winter of 7 years-spanning all phases of the cycle from the increase through to the low (2014-2020). We simultaneously monitored changes in hare abundance as well as those of their primary predators, lynx and coyotes. Despite observing the expected changes in hare-predator numbers over the cycle, we did not see the predicted changes in chronic stress metrics in the peak and decline phases. Thus, the comprehensive physiological signature indicative of chronic predator-induced stress seen from our previous work was not present in this current cycle. We postulate that hares may now be increasingly showing behavior-mediated rather than stress-mediated responses to their predators. We present evidence that increases in primary productivity have affected boreal community structure and function. We speculate that climate change has caused this major shift in the indirect effects of predation on hares.
Collapse
Affiliation(s)
- Sophia G Lavergne
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
| | - Charles J Krebs
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Alice J Kenney
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Dennis Murray
- Department of Biology, Trent University, Peterborough, ON, Canada
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.
| |
Collapse
|
32
|
Cowards or clever guys: an alternative nest defence strategy employed by shrikes against magpies. Anim Cogn 2021; 25:307-317. [PMID: 34427802 DOI: 10.1007/s10071-021-01552-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/05/2021] [Accepted: 08/16/2021] [Indexed: 10/20/2022]
Abstract
Red-backed shrikes (Lanius collurio) show a substantial variability in their nest defence behaviour, which usually follows the rules of optimal parental behaviour, vigorously attacking egg and chick predators and only passively guarding against harmless animals. Nevertheless, shrikes hesitate to attack the Eurasian magpie (Pica pica), which specializes in plundering passerine nests. Our previous studies have suggested that this behaviour may be the result of an alternative defence strategy, relying on nest crypsis. To test this hypothesis, at the shrike nests, we presented a magpie dummy associated with playbacks drawing the predators' attention to the presence of the nest. We predicted that the presentation of a magpie dummy associated with shrike alarm calls moves the parents to action, causing them to chase the magpie away from the nest. We showed that the presence of a magpie dummy associated with shrike alarm calls elicits a significantly more active response in shrike parents compared to a magpie dummy associated with neutral song. Parents actively moved around the dummy and produced alarm calls; nevertheless, most of the tested pairs hesitated to attack the dummy. We may conclude that the low nest defence activity of shrike parents towards magpie dummy was partly the result of an alternative strategy, which may be cancelled out by alerting the predator to the location of the nest; nevertheless, shrikes seem to be afraid of the magpie and hesitate to attack it physically.
Collapse
|
33
|
Occhiuto F, Mohallal E, Gilfillan GD, Lowe A, Reader T. Seasonal patterns in habitat use by the harvest mouse ( Micromys minutus) and other small mammals. MAMMALIA 2021. [DOI: 10.1515/mammalia-2020-0095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The ecology of the harvest mouse (Micromys minutus) is poorly understood, partly because it is a difficult species to monitor. It is commonly associated with reedbeds, where evidence suggests that it experiences strong seasonal fluctuations in abundance. However, it is unknown whether these fluctuations are caused by real changes in population size, or by movement between habitats. This study investigated seasonal changes in population size and habitat use by harvest mice, and other small mammal species, by trapping the reedbed and three associated habitat types: woodland, pasture and arable land. A sampling effort of 9887 trap bouts across nine months, resulted in 70 captures of harvest mice, as well as wood mice (N = 1022), bank voles (N = 252), field voles (N = 9), common shrews (N = 86) and pygmy shrews (N = 7). The reedbed was the habitat with the most captures and highest diversity. Harvest mice were caught exclusively in the reedbed at the beginning of autumn. Wood mice and bank voles experienced fluctuations in population numbers and wood mice also showed seasonal variation in habitat use. Our study supports the idea that harvest mice undergo extreme seasonal fluctuations in abundance in reedbeds, but these do not appear to be related to changes in habitat use.
Collapse
Affiliation(s)
- Francesca Occhiuto
- School of Life Sciences, University of Nottingham , Nottingham , NG7 2RD , UK
| | - Eman Mohallal
- Desert Research Center , 1 Mathaf El Matarya St., P.O. Box 11753, El 5 Matareya , Cairo , Egypt
| | | | - Andrew Lowe
- 159 Sherwood Street, Market Warsop , Nottinghamshire , NG20 0JX , UK
| | - Tom Reader
- School of Life Sciences, University of Nottingham , Nottingham , NG7 2RD , UK
| |
Collapse
|
34
|
Shiratsuru S, Majchrzak YN, Peers MJL, Studd EK, Menzies AK, Derbyshire R, Humphries MM, Krebs CJ, Murray DL, Boutin S. Food availability and long-term predation risk interactively affect antipredator response. Ecology 2021; 102:e03456. [PMID: 34165786 DOI: 10.1002/ecy.3456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 04/01/2021] [Accepted: 05/13/2021] [Indexed: 11/07/2022]
Abstract
Food availability and temporal variation in predation risk are both important determinants of the magnitude of antipredator responses, but their effects have rarely been examined simultaneously, particularly in wild prey. Here, we determine how food availability and long-term predation risk affect antipredator responses to acute predation risk by monitoring the foraging response of free-ranging snowshoe hares (Lepus americanus) to an encounter with a Canada lynx (Lynx canadensis) in Yukon, Canada, over four winters (2015-2016 to 2018-2019). We examined how this response was influenced by natural variation in long-term predation risk (2-month mortality rate of hares) while providing some individuals with supplemental food. On average, snowshoe hares reduced foraging time up to 10 h after coming into close proximity (≤75 m) with lynx, and reduced foraging time an average of 15.28 ± 7.08 min per lynx encounter. Hares tended to respond more strongly when the distance to lynx was shorter. More importantly, the magnitude of hares' antipredator response to a lynx encounter was affected by the interaction between food-supplementation and long-term predation risk. Food-supplemented hares reduced foraging time more than control hares after a lynx encounter under low long-term risk, but decreased the magnitude of the response as long-term risk increased. In contrast, control hares increased the magnitude of their response as long-term risk increased. Our findings show that food availability and long-term predation risk interactively drive the magnitude of reactive antipredator response to acute predation risk. Determining the factors driving the magnitude of antipredator responses would contribute to a better understanding of the indirect effects of predators on prey populations.
Collapse
Affiliation(s)
- Shotaro Shiratsuru
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2R3, Canada
| | - Yasmine N Majchrzak
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2R3, Canada
| | - Michael J L Peers
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2R3, Canada
| | - Emily K Studd
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2R3, Canada.,Department of Natural Resource Sciences, McGill University, St-Anne-de-Bellevue, Québec, H9X 3V9, Canada
| | - Allyson K Menzies
- Department of Natural Resource Sciences, McGill University, St-Anne-de-Bellevue, Québec, H9X 3V9, Canada
| | | | - Murray M Humphries
- Department of Natural Resource Sciences, McGill University, St-Anne-de-Bellevue, Québec, H9X 3V9, Canada
| | - Charles J Krebs
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Dennis L Murray
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2R3, Canada
| |
Collapse
|
35
|
Marrotte RR, Bowman J. Seven decades of southern range dynamics of Canada lynx. Ecol Evol 2021; 11:4644-4655. [PMID: 33976837 PMCID: PMC8093747 DOI: 10.1002/ece3.7364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 02/11/2021] [Accepted: 02/18/2021] [Indexed: 11/21/2022] Open
Abstract
The range of the Canada lynx (Lynx canadensis) has contracted substantially from its historical range. Using harvest records, we found that the southern range of the lynx in Ontario in the late 1940s collapsed and then, in a short period of time, increased to its largest extent in the mid-1960s when the lynx range spread south of the boreal forest for a decade. After this expansion, the southern range contracted northwards beginning in the 1970s. Most recently, there has been a slight expansion between 2010 and 2017. We have attributed these dynamics on the southern range periphery to the fluctuation of the boreal lynx population in the core of the species' range. In addition, connectivity to boreal lynx populations and snow depth seemed to condition whether the lynx expanded into an area. However, we did not find any evidence to suggest that these changes were due to anthropogenic landscape disturbances or competition. The boreal lynx population does not reach the peak abundance it once did, without which we would not expect to see large expansions of the southern lynx range as in the mid-1960s. Our results suggest that the southern lynx range in Ontario has been driven by the magnitude of the boreal lynx population cycle, connectivity to the boreal forest, and snow conditions. Future persistence of lynx in the southern range periphery will likely depend on dynamics in the range core.
Collapse
Affiliation(s)
- Robby R. Marrotte
- Environmental & Life Sciences Graduate ProgramTrent UniversityPeterboroughONCanada
| | - Jeff Bowman
- Environmental & Life Sciences Graduate ProgramTrent UniversityPeterboroughONCanada
- Ontario Ministry of Natural Resources & ForestryWildlife Research & Monitoring SectionTrent UniversityPeterboroughONCanada
| |
Collapse
|
36
|
Huang RK, Webber QM, Laforge MP, Robitaille AL, Bonar M, Balluffi-Fry J, Zabihi-Seissan S, Vander Wal E. Coyote (Canis latrans) diet and spatial co-occurrence with woodland caribou (Rangifer tarandus caribou). CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interplay of predator encounters and antipredator responses is an integral part of understanding predator–prey interactions and spatial co-occurrence and avoidance can elucidate these interactions. We conducted hard-part dietary analysis of coyotes (Canis latrans Say, 1823) and space use of coyotes and woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) to test two competing hypotheses about coyote and caribou predator–prey spatial dynamics using resource selection functions. The high encounter hypothesis predicts that coyotes would maximize encounters with caribou via high spatial co-occurrence, whereas the predator stealth hypothesis predicts that through low spatial co-occurrence with caribou, coyotes act as stealth predators by avoiding habitats that caribou typically select. Our dietary analysis revealed that ∼46% of sampled coyote diet is composed of caribou. We found that coyote share space with caribou in lichen-barren habitat in both summer and winter and that coyotes co-occur with caribou in forested habitat during summer, but not during winter. Our findings support predictions associated with the high encounter predator hypothesis whereby coyotes and caribou have high spatial co-occurrence promoting caribou in coyote diet.
Collapse
Affiliation(s)
- Richard K.K. Huang
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Quinn M.R. Webber
- Cognitive and Behavioural Ecology Interdisciplinary Program, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Michel P. Laforge
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Alec L. Robitaille
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Maegwin Bonar
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Juliana Balluffi-Fry
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Sana Zabihi-Seissan
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| | - Eric Vander Wal
- Department of Biology, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
- Cognitive and Behavioural Ecology Interdisciplinary Program, Memorial University of Newfoundland, 232 Elizabeth Avenue, St. John’s, NL A1B 3X9, Canada
| |
Collapse
|
37
|
Heard DC, Zimmerman KL. Fall supplemental feeding increases population growth rate of an endangered caribou herd. PeerJ 2021; 9:e10708. [PMID: 33854825 PMCID: PMC7953878 DOI: 10.7717/peerj.10708] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/14/2020] [Indexed: 12/02/2022] Open
Abstract
Most woodland caribou (Rangifer tarandus caribou) populations are declining primarily because of unsustainable predation resulting from habitat-mediated apparent competition. Wolf (Canis lupus) reduction is an effective recovery option because it addresses the direct effect of predation. We considered the possibility that the indirect effects of predation might also affect caribou population dynamics by adversely affecting summer foraging behaviour. If spring and/or summer nutrition was inadequate, then supplemental feeding in fall might compensate for that limitation and contribute to population growth. Improved nutrition and therefore body condition going into winter could increase adult survival and lead to improved reproductive success the next spring. To test that hypothesis, we fed high-quality food pellets to free-ranging caribou in the Kennedy Siding caribou herd each fall for six years, starting in 2014, to see if population growth rate increased. Beginning in winter 2015–16, the Province of British Columbia began a concurrent annual program to promote caribou population increase by attempting to remove most wolves within the Kennedy Siding and the adjacent caribou herds’ ranges. To evaluate the impact of feeding, we compared lambdas before and after feeding began, and to the population trend in the adjacent Quintette herd over the subsequent four years. Supplemental feeding appeared to have an incremental effect on population growth. Population growth of the Kennedy Siding herd was higher in the year after feeding began (λ = 1.06) compared to previous years (λ = 0.91) and to the untreated Quintette herd (λ = 0.95). Average annual growth rate of the Kennedy Siding herd over the subsequent four years, where both feeding and wolf reduction occurred concurrently, was higher than in the Quintette herd where the only management action in those years was wolf reduction (λ = 1.16 vs. λ = 1.08). The higher growth rate of the Kennedy Siding herd was due to higher female survival (96.2%/yr vs. 88.9%/yr). Many caribou were in relatively poor condition in the fall. Consumption of supplemental food probably improved their nutritional status which ultimately led to population growth. Further feeding experiments on other caribou herds using an adaptive management approach would verify the effect of feeding as a population recovery tool. Our results support the recommendation that multiple management actions should be implemented to improve recovery prospects for caribou.
Collapse
Affiliation(s)
- Douglas C Heard
- Tithonus Wildlife Research, Prince George, British Columbia, Canada
| | - Kathryn L Zimmerman
- Ministry of Environment and Climate Change Strategy, Province of British Columbia, Kamloops, British Columbia, Canada
| |
Collapse
|
38
|
Contribution of late-litter juveniles to the population dynamics of snowshoe hares. Oecologia 2021; 195:949-957. [PMID: 33743069 DOI: 10.1007/s00442-021-04895-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 03/10/2021] [Indexed: 10/21/2022]
Abstract
Determining the factors driving cyclic dynamics in species has been a primary focus of ecology. For snowshoe hares (Lepus americanus), explanations of their 10-year population cycles most commonly feature direct predation during the peak and decline, in combination with their curtailment in reproduction. Hares are thought to stop producing third and fourth litters during the cyclic decline and do not recover reproductive output for several years. The demographic effects of these reproductive changes depend on the consistency of this pattern across cycles, and the relative contribution to population change of late-litter versus early litter juveniles. We used monitoring data on snowshoe hares in Yukon, Canada, to examine the contribution of late-litter juveniles to the demography of their cycles, by assigning litter group for individuals caught in autumn based on body size and capture date. We found that fourth-litter juveniles occur consistently during the increase phase of each cycle, but are rare and have low over-winter survival (0.05) suggesting that population increase is unlikely to be caused by their occurrence. The proportion of third-litter juveniles captured in the autumn remains relatively constant across cycle phases, while over-winter survival rates varies particularly for earlier-litter juveniles (0.14-0.39). Juvenile survival from all litters is higher during the population increase and peak, relative to the low and decline. Overall, these results suggest that the transition from low phase to population growth may stem in large part from changes in juvenile survival as opposed to increased reproductive output through the presence of a 4th litter.
Collapse
|
39
|
Serrouya R, Dickie M, Lamb C, van Oort H, Kelly AP, DeMars C, McLoughlin PD, Larter NC, Hervieux D, Ford AT, Boutin S. Trophic consequences of terrestrial eutrophication for a threatened ungulate. Proc Biol Sci 2021; 288:20202811. [PMID: 33468013 PMCID: PMC7893279 DOI: 10.1098/rspb.2020.2811] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/15/2020] [Indexed: 11/12/2022] Open
Abstract
Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others. Understanding the environmental context and species traits that give rise to these divergent outcomes is a major challenge to the generality of both theoretical and applied ecology. In aquatic systems, nutrient-mediated eutrophication has led to major declines in species diversity, motivating us to seek terrestrial analogues using a large-mammal system across 598 000 km2 of the Canadian boreal forest. These forests are undergoing some of the most rapid rates of land-use change on Earth and are home to declining caribou (Rangifer tarandus caribou) populations. Using satellite-derived estimates of primary productivity, coupled with estimates of moose (Alces alces) and wolf (Canis lupus) abundance, we used path analyses to discriminate among hypotheses explaining how habitat alteration can affect caribou population growth. Hypotheses included food limitation, resource dominance by moose over caribou, and apparent competition with predators shared between moose and caribou. Results support apparent competition and yield estimates of wolf densities (1.8 individuals 1000 km-2) above which caribou populations decline. Our multi-trophic analysis provides insight into the cascading effects of habitat alteration from forest cutting that destabilize terrestrial predator-prey dynamics. Finally, the path analysis highlights why conservation actions directed at the proximate cause of caribou decline have been more successful in the near term than those directed further along the trophic chain.
Collapse
Affiliation(s)
- Robert Serrouya
- Alberta Biodiversity Monitoring Institute, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Melanie Dickie
- Alberta Biodiversity Monitoring Institute, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Clayton Lamb
- Department of Biology, University of British Columbia, Kelowna, British Columbia, Canada V1V 1V7
| | - Harry van Oort
- Environment, BC Hydro, Revelstoke, British Columbia, Canada V0E 2S0
| | - Allicia P. Kelly
- Department of Environment and Natural Resources, Government of the Northwest Territories, Fort Smith, Northwest Territories, Canada X0E 0P0
| | - Craig DeMars
- Alberta Biodiversity Monitoring Institute, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Philip D. McLoughlin
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2
| | - Nicholas C. Larter
- Department of Environment and Natural Resources, Government of the Northwest Territories, Fort Simpson, Northwest Territories, Canada X0E 0N0
| | - Dave Hervieux
- Alberta Environment and Parks, Box 23 Provincial Building, Grande Prairie, Alberta, Canada T8V 6J4
| | - Adam T. Ford
- Department of Biology, University of British Columbia, Kelowna, British Columbia, Canada V1V 1V7
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| |
Collapse
|
40
|
Cheeseman AE, Cohen JB, Ryan SJ, Whipps CM. Is conservation based on best available science creating an ecological trap for an imperiled lagomorph? Ecol Evol 2021; 11:912-930. [PMID: 33520175 PMCID: PMC7820145 DOI: 10.1002/ece3.7104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/02/2020] [Accepted: 11/13/2020] [Indexed: 11/11/2022] Open
Abstract
Habitat quality regulates fitness and population density, making it a key driver of population size. Hence, increasing habitat quality is often a primary goal of species conservation. Yet, assessments of fitness and density are difficult and costly to obtain. Therefore, species conservation often uses "best available science," extending inferences across taxa, space, or time, and inferring habitat quality from studies of habitat selection. However, there are scenarios where habitat selection is not reflective of habitat quality, and this can lead to maladaptive management strategies. The New England cottontail (Sylvilagus transitionalis) is an imperiled shrubland obligate lagomorph whose successful recovery hinges on creation of suitable habitat. Recovery of this species is also negatively impacted by the non-native eastern cottontail (Sylvilagus floridanus), which can competitively exclude New England cottontails from preferred habitat. Herein, we evaluate habitat quality for adult and juvenile New England and eastern cottontails using survival and density as indicators. Our findings did not support selection following an ideal free distribution by New England cottontails. Instead, selected resources, which are a target of habitat management, were associated with low survival and density and pointed to a complex trade-off between density, survival, habitat, and the presence of eastern cottontails. Further, movement distance was inversely correlated with survival in both species, suggesting that habitat fragmentation limits the ability of cottontails to freely distribute based on habitat quality. While habitat did not directly regulate survival of juvenile cottontails, tick burden had a strong negative impact on juvenile cottontails in poor body condition. Given the complex interactions among New England cottontails, eastern cottontails, and habitat, directly assessing and accounting for factors that limit New England cottontail habitat quality in management plans is vital to their recovery. Our study demonstrates an example of management for possible ecological trap conditions via the application of incomplete knowledge.
Collapse
Affiliation(s)
- Amanda E. Cheeseman
- Department of Environmental and Forest BiologySUNY College of Environmental Science and ForestrySyracuseNYUSA
| | - Jonathan B. Cohen
- Department of Environmental and Forest BiologySUNY College of Environmental Science and ForestrySyracuseNYUSA
| | - Sadie J. Ryan
- Quantitative Disease Ecology and Conservation (QDEC) LabDepartment of GeographyUniversity of FloridaGainesvilleFLUSA
- Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- School of Life SciencesUniversity of KwaZulu‐NatalDurbanSouth Africa
| | - Christopher M. Whipps
- Department of Environmental and Forest BiologySUNY College of Environmental Science and ForestrySyracuseNYUSA
| |
Collapse
|
41
|
Geffroy B, Alfonso S, Sadoul B, Blumstein DT. A World for Reactive Phenotypes. FRONTIERS IN CONSERVATION SCIENCE 2020. [DOI: 10.3389/fcosc.2020.611919] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Humans currently occupy all continents and by doing so, modify the environment and create novel threats to many species; a phenomenon known as human-induced rapid environmental changes (HIREC). These growing anthropogenic disturbances represent major and relatively new environmental challenges for many animals, and invariably alter selection on traits adapted to previous environments. Those species that survive often have moved from their original habitat or modified their phenotype through plasticity or genetic evolution. Based on the most recent advances in this research area, we predict that wild individuals with highly plastic capacities, relatively high basal stress level, and that are generally shy—in other words, individuals displaying a reactive phenotype—should better cope with sudden and widespread HIREC than their counterparts' proactive phenotypes. If true, this selective response would have profound ecological and evolutionary consequences and can therefore impact conservation strategies, specifically with respect to managing the distribution and abundance of individuals and maintaining evolutionary potential. These insights may help design adaptive management strategies to maintain genetic variation in the context of HIREC.
Collapse
|
42
|
Wilson ML, Lonsdorf EV, Mjungu DC, Kamenya S, Kimaro EW, Collins DA, Gillespie TR, Travis DA, Lipende I, Mwacha D, Ndimuligo SA, Pintea L, Raphael J, Mtiti ER, Hahn BH, Pusey AE, Goodall J. Research and Conservation in the Greater Gombe Ecosystem: Challenges and Opportunities. BIOLOGICAL CONSERVATION 2020; 252:108853. [PMID: 33343005 DOI: 10.1016/j.biocon.2020.108731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The study of chimpanzees in Gombe National Park, Tanzania, started by Jane Goodall in 1960, provided pioneering accounts of chimpanzee behavior and ecology. With funding from multiple sources, including the Jane Goodall Institute (JGI) and grants from private foundations and federal programs, the project has continued for sixty years, providing a wealth of information about our evolutionary cousins. These chimpanzees face two main challenges to their survival: infectious disease - including simian immunodeficiency virus (SIVcpz), which can cause Acquired Immune Deficiency Syndrome (AIDS) in chimpanzees - and the deforestation of land outside the park. A health monitoring program has increased understanding of the pathogens affecting chimpanzees and has promoted measures to characterize and reduce disease risk. Deforestation reduces connections between Gombe and other chimpanzee populations, which can cause loss of genetic diversity. To promote habitat restoration, JGI facilitated participatory village land use planning, in which communities voluntarily allocated land to a network of Village Land Forest Reserves. Expected benefits to people include stabilizing watersheds, improving water supplies, and ensuring a supply of forest resources. Surveys and genetic analyses confirm that chimpanzees persist on village lands and remain connected to the Gombe population. Many challenges remain, but the regeneration of natural forest on previously degraded lands provides hope that conservation solutions can be found that benefit both people and wildlife. Conservation work in the Greater Gombe Ecosystem has helped promote broader efforts to plan and work for conservation elsewhere in Tanzania and across Africa.
Collapse
Affiliation(s)
- Michael L Wilson
- Department of Anthropology, University of Minnesota, Minneapolis, MN 55455 USA
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108 USA
- Institute on the Environment, University of Minnesota, St. Paul, MN 55108 USA
| | - Elizabeth V Lonsdorf
- Department of Psychology, Franklin and Marshall College, Lancaster, PA 17604 USA
| | - Deus C Mjungu
- Gombe Stream Research Centre, the Jane Goodall Institute - Tanzania, Kigoma, Tanzania
| | - Shadrack Kamenya
- Gombe Stream Research Centre, the Jane Goodall Institute - Tanzania, Kigoma, Tanzania
| | - Elihuruma Wilson Kimaro
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108 USA
- Gombe National Park, Kigoma, Tanzania
| | - D Anthony Collins
- Gombe Stream Research Centre, the Jane Goodall Institute - Tanzania, Kigoma, Tanzania
| | - Thomas R Gillespie
- Department of Environmental Sciences, Emory University, Atlanta, Georgia 30322 USA
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322 USA
- Program in Population, Biology, Ecology and Evolution, Emory University, Atlanta, Georgia 30322 USA
| | - Dominic A Travis
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN, 55108 USA
| | - Iddi Lipende
- Tanzania Wildlife Research Institute (TAWIRI), Arusha, Tanzania
| | - Dismas Mwacha
- Gombe Stream Research Centre, the Jane Goodall Institute - Tanzania, Kigoma, Tanzania
| | - Sood A Ndimuligo
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Norway
| | | | | | | | - Beatrice H Hahn
- Department of Medicine, University of Pennsylvania, Philadelphia, 19104, USA
- Department of Microbiology, University of Pennsylvania, Philadelphia, 19104, USA
| | - Anne E Pusey
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708 USA
| | - Jane Goodall
- The Jane Goodall Institute, Vienna, VA, 22182 USA
| |
Collapse
|
43
|
Zanette LY, Clinchy M. Ecology and Neurobiology of Fear in Free-Living Wildlife. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-011720-124613] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The ecology of fear concerns the population-, community-, and ecosystem-level consequences of the behavioral interactions between predators and prey, i.e., the aggregate impacts of individual responses to life-threatening events. We review new experiments demonstrating that fear itself is powerful enough to affect the population growth rate in free-living wild birds and mammals, and fear of large carnivores—or the human super predator—can cause trophic cascades affecting plant and invertebrate abundance. Life-threatening events like escaping a predator can have enduring, even lifelong, effects on the brain, and new interdisciplinary research on the neurobiology of fear in wild animals is both providing insights into post-traumatic stress (PTSD) and reinforcing the likely commonality of population- and community-level effects of fear in nature. Failing to consider fear thus risks dramatically underestimating the total impact predators can have on prey populations and the critical role predator-prey interactions can play in shaping ecosystems.
Collapse
Affiliation(s)
- Liana Y. Zanette
- Department of Biology, Western University, London, Ontario N6A 5B7, Canada;,
| | - Michael Clinchy
- Department of Biology, Western University, London, Ontario N6A 5B7, Canada;,
| |
Collapse
|
44
|
Abstract
Predation is ubiquitous in nature and can be an important component of both ecological and evolutionary interactions. One of the most striking features of predators is how often they cause evolutionary diversification in natural systems. Here, we review several ways that this can occur, exploring empirical evidence and suggesting promising areas for future work. We also introduce several papers recently accepted in Diversity that demonstrate just how important and varied predation can be as an agent of natural selection. We conclude that there is still much to be done in this field, especially in areas where multiple predator species prey upon common prey, in certain taxonomic groups where we still know very little, and in an overall effort to actually quantify mortality rates and the strength of natural selection in the wild.
Collapse
|
45
|
Dantzer B, McAdam AG, Humphries MM, Lane JE, Boutin S. Decoupling the effects of food and density on life-history plasticity of wild animals using field experiments: Insights from the steward who sits in the shadow of its tail, the North American red squirrel. J Anim Ecol 2020; 89:2397-2414. [PMID: 32929740 DOI: 10.1111/1365-2656.13341] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 08/07/2020] [Indexed: 01/05/2023]
Abstract
Long-term studies of wild animals provide the opportunity to investigate how phenotypic plasticity is used to cope with environmental fluctuations and how the relationships between phenotypes and fitness can be dependent upon the ecological context. Many previous studies have only investigated life-history plasticity in response to changes in temperature, yet wild animals often experience multiple environmental fluctuations simultaneously. This requires field experiments to decouple which ecological factor induces plasticity in fitness-relevant traits to better understand their population-level responses to those environmental fluctuations. For the past 32 years, we have conducted a long-term integrative study of individually marked North American red squirrels Tamiasciurus hudsonicus Erxleben in the Yukon, Canada. We have used multi-year field experiments to examine the physiological and life-history responses of individual red squirrels to fluctuations in food abundance and conspecific density. Our long-term observational study and field experiments show that squirrels can anticipate increases in food availability and density, thereby decoupling the usual pattern where animals respond to, rather than anticipate, an ecological change. As in many other study systems, ecological factors that can induce plasticity (such as food and density) covary. However, our field experiments that manipulate food availability and social cues of density (frequency of territorial vocalizations) indicate that increases in social (acoustic) cues of density in the absence of additional food can induce similar life-history plasticity, as does experimental food supplementation. Changes in the levels of metabolic hormones (glucocorticoids) in response to variation in food and density are one mechanism that seems to induce this adaptive life-history plasticity. Although we have not yet investigated the energetic response of squirrels to elevated density or its association with life-history plasticity, energetics research in red squirrels has overturned several standard pillars of knowledge in physiological ecology. We show how a tractable model species combined with integrative studies can reveal how animals cope with resource fluctuations through life-history plasticity.
Collapse
Affiliation(s)
- Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Andrew G McAdam
- Department for Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Murray M Humphries
- Natural Resource Sciences Department, McGill University, Ste-Anne-de-Bellevue, QC, Canada
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
46
|
Affiliation(s)
- Matthew E. Dyson
- University of Waterloo 200 University Avenue W Waterloo ON N2B 3A5 Canada
| | - Stuart M. Slattery
- Institute for Wetlands and Waterfowl Research, Ducks Unlimited Canada Stonewall MB R0C 2Z0 Canada
| | - Bradley C. Fedy
- University of Waterloo 200 University Avenue W Waterloo ON N2B 3A5 Canada
| |
Collapse
|
47
|
Shang G, Yang Y, Zhu Y, Wu X, Cao Y, Wu Y, Bian J. A complex regulating pattern induced by the effects of predation and parasites on root vole ( Microtus oeconomus) populations during the breeding season. J Mammal 2020. [DOI: 10.1093/jmammal/gyaa084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Predators and parasites have synergistic effects on the phenotype of the species they share as prey and host. Experimental studies that incorporate the interactions between predation and parasitism are, however, scarce in small-mammal populations. Our previous work has shown that the combined effects of predation and coccidian infection reduce overwinter survival and population density in root voles (Microtus oeconomus). Here, we examined the separate and combined effects of these two drivers on the population growth of root voles during the breeding season. We carried out a two-level factorial experiment, in which we manipulated predator exclusion and the removal of parasites in enclosures and measured survival, fecal corticosterone metabolite (FCM) concentration, recruitment, and population density. An expected synergistic effect of predators and parasites on vole population was not found, due to no effect of parasites on FCM level and recruitment rate during the period of the experiment. Instead, we found phase-related effects of predation on demography. Predation reduced the survival rate of voles in spring, which was intensified by parasite infection. Predation risk reduced recruitment rate in early summer by elevating FCM levels. Consequently, both direct and indirect effects of predation lowered population density during the experimental period. In addition, for populations free of predators, the peak density that occurred in early autumn elevated FCM level of adult voles, which reduced recruitment rates and halted population growth. Moreover, predation, parasites, and density affected the quality of the offspring. Our study suggests that multiple regulation processes influence population fluctuations during the breeding season. We conclude that a population experiencing stress acts as a common interface through which interactions between intrinsic and extrinsic factors can be important determinants of fluctuations. We propose a new hypothesis of integrative stress effects to explain small-mammal population fluctuations.
Collapse
Affiliation(s)
- Guozhen Shang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Yuangang Yang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Yahui Zhu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Xueqing Wu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Yifan Cao
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
- Key Laboratory of Restoration Ecology of Cold Area, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
| | - Yan Wu
- School of Life and Environment Sciences, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Jianghui Bian
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
- Qinghai Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Science, Xining, Qinghai, China
| |
Collapse
|
48
|
Song S, Chang Y, Wang D, Jiang T, Feng J, Lin A. Chronic traffic noise increases food intake and alters gene expression associated with metabolism and disease in bats. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Shengjing Song
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory for Vegetation Ecology Ministry of Education Northeast Normal University Changchun China
| | - Yang Chang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Daiping Wang
- Department of Behavioural Ecology and Evolutionary Genetics Max Planck Institute for Ornithology Seewiesen Germany
| | - Tinglei Jiang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory for Vegetation Ecology Ministry of Education Northeast Normal University Changchun China
- College of Life Science Jilin Agricultural University Changchun China
| | - Aiqing Lin
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| |
Collapse
|
49
|
Abstract
The 'ecology of fear' refers to the total impact of predators on prey populations and communities. The traditional view in ecology is that predators directly kill prey, thereby reducing prey survival and prey numbers - and that this is the limit of their ecological role. The ecology of fear posits that the behavioural, physiological and neurobiological costs of avoiding predation ('fear' for short) may additionally reduce prey fecundity and survival, and the total reduction in prey numbers resulting from exposure to predators may thus far exceed that due to direct killing alone. If this is the case, then failing to consider fear as a factor risks profoundly underestimating the ecological role predators play.
Collapse
|
50
|
Sheriff MJ, Peacor SD, Hawlena D, Thaker M. Non-consumptive predator effects on prey population size: A dearth of evidence. J Anim Ecol 2020; 89:1302-1316. [PMID: 32215909 DOI: 10.1111/1365-2656.13213] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/24/2020] [Indexed: 11/30/2022]
Abstract
There is a large and growing interest in non-consumptive effects (NCEs) of predators. Diverse and extensive evidence shows that predation risk directly influences prey traits, such as behaviour, morphology and physiology, which in turn, may cause a reduction in prey fitness components (i.e. growth rate, survival and reproduction). An intuitive expectation is that NCEs that reduce prey fitness will extend to alter population growth rate and therefore population size. However, our intensive literature search yielded only 10 studies that examined how predator-induced changes in prey traits translate to changes in prey population size. Further, the scant evidence for risk-induced changes on prey population size have been generated from studies that were performed in very controlled systems (mesocosm and laboratory), which do not have the complexity and feedbacks of natural settings. Thus, although likely that predation risk alone can alter prey population size, there is little direct empirical evidence that demonstrates that it does. There are also clear reasons that risk effects on population size may be much smaller than the responses on phenotype and fitness components that are typically measured, magnifying the need to show, rather than infer, effects on population size. Herein we break down the process of how predation risk influences prey population size into a chain of events (predation risk affects prey traits, which affect prey fitness components and population growth rate, which affect prey population size), and highlight the complexity of each transition. We illustrate how the outcomes of these transitions are not straightforward, and how environmental context strongly dictates the direction and magnitude of effects. Indeed, the high variance in prey responses is reflected in the variance of results reported in the few studies that have empirically quantified risk effects on population size. It is therefore a major challenge to predict population effects given the complexity of how environmental context interacts with predation risk and prey responses. We highlight the critical need to appreciate risk effects at each level in the chain of events, and that changes at one level cannot be assumed to translate into changes in the next because of the interplay between risk, prey responses, and the environment. The gaps in knowledge we illuminate underscore the need for more evidence to substantiate the claim that predation risk effects extend to prey population size. The lacunae we identify should inspire future studies on the impact of predation risk on population-level responses in free-living animals.
Collapse
Affiliation(s)
- Michael J Sheriff
- Biology Department, University of Massachusetts Dartmouth, Dartmouth, MA, USA
| | - Scott D Peacor
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, USA
| | - Dror Hawlena
- Risk Management Ecology Laboratory, Department of Ecology, Evolution and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Maria Thaker
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
| |
Collapse
|