101
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VAN DER MERWE JORISTA, MARSHAL JASONP. Hierarchical resource selection by impala in a savanna environment. AUSTRAL ECOL 2011. [DOI: 10.1111/j.1442-9993.2011.02297.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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102
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Lima SL, Bednekoff PA. On the perception of targeting by predators during attacks on socially feeding birds. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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103
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Hopcraft JGC, Anderson TM, Pérez-Vila S, Mayemba E, Olff H. Body size and the division of niche space: food and predation differentially shape the distribution of Serengeti grazers. J Anim Ecol 2011; 81:201-13. [PMID: 21801174 DOI: 10.1111/j.1365-2656.2011.01885.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J Grant C Hopcraft
- Community and Conservation Ecology Group, University of Groningen, PO Box 11103, 9700 CC, Groningen, The Netherlands.
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104
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Hossie TJ, Murray DL. Effects of Structural Refuge and Density on Foraging Behaviour and Mortality of Hungry Tadpoles Subject to Predation Risk. Ethology 2011. [DOI: 10.1111/j.1439-0310.2011.01927.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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105
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Morris G, Conner LM, Oli MK. Effects of mammalian predator exclusion and supplemental feeding on space use by hispid cotton rats. J Mammal 2011. [DOI: 10.1644/10-mamm-a-309.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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106
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GORINI L, LINNELL JDC, MAY R, PANZACCHI M, BOITANI L, ODDEN M, NILSEN EB. Habitat heterogeneity and mammalian predator-prey interactions. Mamm Rev 2011. [DOI: 10.1111/j.1365-2907.2011.00189.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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107
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Marealle WN, Fossøy F, Holmern T, Stokke BG, Røskaft E. Does illegal hunting skew Serengeti wildlife sex ratios? WILDLIFE BIOLOGY 2010. [DOI: 10.2981/10-035] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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108
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de Boer WF, Vis MJP, de Knegt HJ, Rowles C, Kohi EM, van Langevelde F, Peel M, Pretorius Y, Skidmore AK, Slotow R, van Wieren SE, Prins HHT. Spatial distribution of lion kills determined by the water dependency of prey species. J Mammal 2010. [DOI: 10.1644/09-mamm-a-392.1] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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109
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Prugh L, Brashares J. Basking in the moonlight? Effect of illumination on capture success of the endangered giant kangaroo rat. J Mammal 2010. [DOI: 10.1644/10-mamm-a-011.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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110
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Ward D. A parsimonious optimal foraging model explaining mortality patterns in Serengeti wildebeest. Ecol Modell 2010. [DOI: 10.1016/j.ecolmodel.2010.06.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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111
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Owen-Smith N, Fryxell JM, Merrill EH. Foraging theory upscaled: the behavioural ecology of herbivore movement. Philos Trans R Soc Lond B Biol Sci 2010; 365:2267-78. [PMID: 20566503 PMCID: PMC2894968 DOI: 10.1098/rstb.2010.0095] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We outline how principles of optimal foraging developed for diet and food patch selection might be applied to movement behaviour expressed over larger spatial and temporal scales. Our focus is on large mammalian herbivores, capable of carrying global positioning system (GPS) collars operating through the seasonal cycle and dependent on vegetation resources that are fixed in space but seasonally variable in availability and nutritional value. The concept of intermittent movement leads to the recognition of distinct movement modes over a hierarchy of spatio-temporal scales. Over larger scales, periods with relatively low displacement may indicate settlement within foraging areas, habitat units or seasonal ranges. Directed movements connect these patches or places used for other activities. Selection is expressed by switches in movement mode and the intensity of utilization by the settlement period relative to the area covered. The type of benefit obtained during settlement periods may be inferred from movement patterns, local environmental features, or the diel activity schedule. Rates of movement indicate changing costs in time and energy over the seasonal cycle, between years and among regions. GPS telemetry potentially enables large-scale movement responses to changing environmental conditions to be linked to population performance.
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Affiliation(s)
- N Owen-Smith
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Wits 2050, South Africa.
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112
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Anderson TM, Hopcraft JGC, Eby S, Ritchie M, Grace JB, Olff H. Landscape-scale analyses suggest both nutrient and antipredator advantages to Serengeti herbivore hotspots. Ecology 2010; 91:1519-29. [DOI: 10.1890/09-0739.1] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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113
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Ndibalema VG. A comparison of sex ratio, birth periods and calf survival among Serengeti wildebeest sub-populations, Tanzania. Afr J Ecol 2009. [DOI: 10.1111/j.1365-2028.2008.00994.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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114
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Tozetti AM, Oliveira RBD, Pontes GMF. Defensive repertoire of Xenodon dorbignyi (Serpentes, Dipsadidae). BIOTA NEOTROPICA 2009. [DOI: 10.1590/s1676-06032009000300016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ability of a species to defend itself against a predator is directly correlated with its survivorship. Thus, prey/predator interaction mechanisms are important elements of the natural history of species. In this study, we examined the defensive repertoire of the South-American hognose snake (Xenodon dorbignyi) through simulations of predator attacks in the field. Nine defensive displays were observed. The most frequently observed displays were erratic movements, body flattening, head triangulation and tail display. No differences were detected in the defensive strategies shown by males and females, regardless of their reproductive state. Our findings suggest that X. dorbignyi has the ability to evaluate the level of threat imposed by the aggressor, with cryptic behavior, body flattening and locomotor escape as the primary defensive strategies, with other displays used as secondary responses to a predator attack. Our results support the hypothesis that X. dorbignyi is a mimic of both Micrurus and Bothrops.
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115
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McLoughlin PD, Morris DW, Fortin D, Vander Wal E, Contasti AL. Considering ecological dynamics in resource selection functions. J Anim Ecol 2009; 79:4-12. [PMID: 19732211 DOI: 10.1111/j.1365-2656.2009.01613.x] [Citation(s) in RCA: 173] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Describing distribution and abundance is requisite to exploring interactions between organisms and their environment. Recently, the resource selection function (RSF) has emerged to replace many of the statistical procedures used to quantify resource selection by animals. 2. A RSF is defined by characteristics measured on resource units such that its value for a unit is proportional to the probability of that unit being used by an organism. It is solved using a variety of techniques, particularly the binomial generalized linear model. 3. Observing dynamics in a RSF - obtaining substantially different functions at different times or places for the same species - alerts us to the varying ecological processes that underlie resource selection. 4. We believe that there is a need for us to reacquaint ourselves with ecological theory when interpreting RSF models. We outline a suite of factors likely to govern ecologically based variation in a RSF. In particular, we draw attention to competition and density-dependent habitat selection, the role of predation, longitudinal changes in resource availability and functional responses in resource use. 5. How best to incorporate governing factors in a RSF is currently in a state of development; however, we see promise in the inclusion of random as well as fixed effects in resource selection models, and matched case-control logistic regression. 6. Investigating the basis of ecological dynamics in a RSF will allow us to develop more robust models when applied to forecasting the spatial distribution of animals. It may also further our understanding of the relative importance of ecological interactions on the distribution and abundance of species.
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Affiliation(s)
- Philip D McLoughlin
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada.
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116
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Glucocorticoid stress hormones and the effect of predation risk on elk reproduction. Proc Natl Acad Sci U S A 2009; 106:12388-93. [PMID: 19617549 DOI: 10.1073/pnas.0902235106] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Predators affect prey demography through direct predation and through the costs of antipredator behavioral responses, or risk effects. Experiments have shown that risk effects can comprise a substantial proportion of a predator's total effect on prey dynamics, but we know little about their strength in wild populations, or the physiological mechanisms that mediate them. When wolves are present, elk alter their grouping patterns, vigilance, foraging behavior, habitat selection, and diet. These responses are associated with decreased progesterone levels, decreased calf production, and reduced population size [Creel S, Christianson D, Liley S, Winnie JA (2007) Science 315:960]. Two general mechanisms for the effect of predation risk on reproduction have been proposed: the predation stress hypothesis and the predator-sensitive-food hypothesis. Here, we used enzyme immunoassay to measure fecal glucocorticoid metabolite concentrations for 1,205 samples collected from 4 elk populations over 4 winters to test the hypothesis that the effect of predation risk on elk reproduction is mediated by chronic stress. Across populations and years, fecal glucocorticoid concentrations were not related to predator-prey ratios, progesterone concentrations or calf-cow ratios. Overall, the effect of wolf presence on elk reproduction is better explained by changes in foraging patterns that carry nutritional costs than by changes in glucocorticoid concentrations.
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117
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Thomson JA, Burkholder D, Heithaus MR, Dill LM. Validation of a Rapid Visual-Assessment Technique for Categorizing the Body Condition of Green Turtles (Chelonia mydas) in the Field. COPEIA 2009. [DOI: 10.1643/ce-07-227] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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118
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Ale SB, Brown JS. Prey Behavior Leads to Predator: A Case Study of the Himalayan Tahr and the Snow Leopard in Sagarmatha (Mt. Everest) National Park, Nepal. Isr J Ecol Evol 2009. [DOI: 10.1560/ijee.55.4.315] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Rare, elusive predators offer few sightings, hindering research with small sample sizes and lack of experimentation. While predators may be elusive, their prey are more readily observed. Prey respond to the presence of a predator, and these fear responses may have population- and community-level consequences. Anti-predator behaviors, such as vigilance, allow us to sidestep the difficulty of direct field studies of large predators by studying them indirectly. Here we used a behavioral indicator, the vigilance behavior of the Himalayan tahr, the snow leopard's main local prey, to reveal the distribution and habitat use of snow leopards in the Mt. Everest region of Nepal. We combined techniques of conventional field biology with concepts of foraging theory to study prey behavior in order to obtain insights into the predator's ecology. The Himalayan tahr's vigilance behavior correlates with the distribution of snow leopard signs. Tahr actually led us to six sightings of snow leopards. We conclude that behavioral indicators provided by prey offer a valuable tool for studying and monitoring stealthy and rare carnivores.
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Affiliation(s)
- Som B. Ale
- Department of Biological Sciences, University of Illinois—Chicago
- Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota
| | - Joel S. Brown
- Department of Biological Sciences, University of Illinois—Chicago
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119
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Marshal JP, Cain JW, Bleich VC, Rosenstock SS. Intrinsic and extrinsic sources of variation in the dynamics of large herbivore populations. CAN J ZOOL 2009. [DOI: 10.1139/z08-142] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We evaluated the relative importance of intrinsic (density-dependent) and extrinsic (density-independent) sources of resource variability in the dynamics of bighorn sheep ( Ovis canadensis Shaw, 1804) populations in southwestern USA. We tested the hypothesis that populations experiencing greater variation in forage availability are less likely to be at equilibrium density with forage supplies, and thus, would demonstrate weaker evidence of intraspecific competition. We used regression to relate population growth rate to rainfall (forage conditions) and to abundance (intraspecific competition) for 20 sheep populations, and we estimated the strength of the effects of density and rainfall for each population. Then we compared among populations to look for relationships between the strengths of rainfall and density effects and the variability in rainfall experienced by each population. Populations demonstrating a density effect were associated with environments having lower variability than those that did not. Populations showing a rainfall effect were associated with environments having a variability higher than those that lacked a rainfall effect. These findings are consistent with the hypothesis that populations experiencing higher variation in forage resources are less likely to achieve an equilibrium density with forage supplies where intraspecific competition would be a large determinant to the dynamics of that population.
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Affiliation(s)
- J. P. Marshal
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
- California Department of Fish and Game, 407 West Line Street, Bishop, CA 93514, USA
- Arizona Game and Fish Department, 5000 West Carefree Highway, Phoenix, AZ 85086, USA
- School of Natural Resources, University of Arizona, Tucson, AZ 85721, USA
| | - J. W. Cain
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
- California Department of Fish and Game, 407 West Line Street, Bishop, CA 93514, USA
- Arizona Game and Fish Department, 5000 West Carefree Highway, Phoenix, AZ 85086, USA
- School of Natural Resources, University of Arizona, Tucson, AZ 85721, USA
| | - V. C. Bleich
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
- California Department of Fish and Game, 407 West Line Street, Bishop, CA 93514, USA
- Arizona Game and Fish Department, 5000 West Carefree Highway, Phoenix, AZ 85086, USA
- School of Natural Resources, University of Arizona, Tucson, AZ 85721, USA
| | - S. S. Rosenstock
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
- California Department of Fish and Game, 407 West Line Street, Bishop, CA 93514, USA
- Arizona Game and Fish Department, 5000 West Carefree Highway, Phoenix, AZ 85086, USA
- School of Natural Resources, University of Arizona, Tucson, AZ 85721, USA
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120
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121
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McLoughlin PD, Coulson T, Clutton-Brock T. CROSS-GENERATIONAL EFFECTS OF HABITAT AND DENSITY ON LIFE HISTORY IN RED DEER. Ecology 2008; 89:3317-26. [DOI: 10.1890/07-1044.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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122
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Salo P, Nordström M, Thomson RL, Korpimäki E. Risk induced by a native top predator reduces alien mink movements. J Anim Ecol 2008; 77:1092-8. [DOI: 10.1111/j.1365-2656.2008.01430.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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123
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124
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Predicting synergistic effects of resources and predators on foraging decisions by juvenile Steller sea lions. Oecologia 2008; 158:775-86. [DOI: 10.1007/s00442-008-1189-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 10/01/2008] [Indexed: 10/21/2022]
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125
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Frank DA. Evidence for top predator control of a grazing ecosystem. OIKOS 2008. [DOI: 10.1111/j.0030-1299.2008.16846.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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126
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Winnie JA, Cross P, Getz W. Habitat quality and heterogeneity influence distribution and behavior in African buffalo (Syncerus caffer). Ecology 2008; 89:1457-68. [PMID: 18543637 DOI: 10.1890/07-0772.1] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Top-down effects of predators on prey behavior and population dynamics have been extensively studied. However, some populations of very large herbivores appear to be regulated primarily from the bottom up. Given the importance of food resources to these large herbivores, it is reasonable to expect that forage heterogeneity (variation in quality and quantity) affects individual and group behaviors as well as distribution on the landscape. Forage heterogeneity is often strongly driven by underlying soils, so substrate characteristics may indirectly drive herbivore behavior and distribution. Forage heterogeneity may further interact with predation risk to influence prey behavior and distribution. Here we examine differences in spatial distribution, home range size, and grouping behaviors of African buffalo as they relate to geologic substrate (granite and basalt) and variation in food quality and quantity. In this study, we use satellite imagery, forage quantity data, and three years of radio-tracking data to assess how forage quality, quantity, and heterogeneity affect the distribution and individual and herd behavior of African buffalo. We found that buffalo in an overall poorer foraging environment keyed-in on exceptionally high-quality areas, whereas those foraging in a more uniform, higher-quality area used areas of below-average quality. Buffalo foraging in the poorer-quality environment had smaller home range sizes, were in smaller groups, and tended to be farther from water sources than those foraging in the higher-quality environment. These differences may be due to buffalo creating or maintaining nutrient hotspots (small, high-quality foraging areas) in otherwise low-quality foraging areas, and the location of these hotspots may in part be determined by patterns of predation risk.
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Affiliation(s)
- John A Winnie
- Ecology Department, Montana State University, Bozeman, Montana 59717, USA.
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127
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Madsen T, Shine R. Silver spoons and snake body sizes: prey availability early in life influences long-term growth rates of free-ranging pythons. J Anim Ecol 2008. [DOI: 10.1111/j.1365-2656.2000.00477.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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128
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Munson L, Terio KA, Kock R, Mlengeya T, Roelke ME, Dubovi E, Summers B, Sinclair ARE, Packer C. Climate extremes promote fatal co-infections during canine distemper epidemics in African lions. PLoS One 2008; 3:e2545. [PMID: 18575601 PMCID: PMC2435602 DOI: 10.1371/journal.pone.0002545] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2008] [Accepted: 05/21/2008] [Indexed: 11/22/2022] Open
Abstract
Extreme climatic conditions may alter historic host-pathogen relationships and synchronize the temporal and spatial convergence of multiple infectious agents, triggering epidemics with far greater mortality than those due to single pathogens. Here we present the first data to clearly illustrate how climate extremes can promote a complex interplay between epidemic and endemic pathogens that are normally tolerated in isolation, but with co-infection, result in catastrophic mortality. A 1994 canine distemper virus (CDV) epidemic in Serengeti lions (Panthera leo) coincided with the death of a third of the population, and a second high-mortality CDV epidemic struck the nearby Ngorongoro Crater lion population in 2001. The extent of adult mortalities was unusual for CDV and prompted an investigation into contributing factors. Serological analyses indicated that at least five “silent” CDV epidemics swept through the same two lion populations between 1976 and 2006 without clinical signs or measurable mortality, indicating that CDV was not necessarily fatal. Clinical and pathology findings suggested that hemoparsitism was a major contributing factor during fatal epidemics. Using quantitative real-time PCR, we measured the magnitude of hemoparasite infections in these populations over 22 years and demonstrated significantly higher levels of Babesia during the 1994 and 2001 epidemics. Babesia levels correlated with mortalities and extent of CDV exposure within prides. The common event preceding the two high mortality CDV outbreaks was extreme drought conditions with wide-spread herbivore die-offs, most notably of Cape buffalo (Syncerus caffer). As a consequence of high tick numbers after the resumption of rains and heavy tick infestations of starving buffalo, the lions were infected by unusually high numbers of Babesia, infections that were magnified by the immunosuppressive effects of coincident CDV, leading to unprecedented mortality. Such mass mortality events may become increasingly common if climate extremes disrupt historic stable relationships between co-existing pathogens and their susceptible hosts.
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Affiliation(s)
- Linda Munson
- Department of Pathology, Microbiology and Immunology, University of California Davis, Davis, California, United States of America
| | - Karen A. Terio
- University of Illinois Zoological Pathology Program, Maywood, Illinois, United States of America
| | - Richard Kock
- African Union International Bureau for Animal Resources, Nairobi, Kenya
| | | | - Melody E. Roelke
- Tanzania National Parks, Arusha, Tanzania
- Laboratory of Genomic Diversity, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States of America
| | - Edward Dubovi
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, United States of America
| | - Brian Summers
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | | | - Craig Packer
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
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129
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Owen-Smith N, Mills MGL. SHIFTING PREY SELECTION GENERATES CONTRASTING HERBIVORE DYNAMICS WITHIN A LARGE-MAMMAL PREDATOR–PREY WEB. Ecology 2008; 89:1120-33. [DOI: 10.1890/07-0970.1] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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130
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Owen-Smith N. Changing vulnerability to predation related to season and sex in an African ungulate assemblage. OIKOS 2008. [DOI: 10.1111/j.0030-1299.2008.16309.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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131
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Kauffman MJ, Varley N, Smith DW, Stahler DR, MacNulty DR, Boyce MS. Landscape heterogeneity shapes predation in a newly restored predator-prey system. Ecol Lett 2008; 10:690-700. [PMID: 17594424 DOI: 10.1111/j.1461-0248.2007.01059.x] [Citation(s) in RCA: 201] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Because some native ungulates have lived without top predators for generations, it has been uncertain whether runaway predation would occur when predators are newly restored to these systems. We show that landscape features and vegetation, which influence predator detection and capture of prey, shape large-scale patterns of predation in a newly restored predator-prey system. We analysed the spatial distribution of wolf (Canis lupus) predation on elk (Cervus elaphus) on the Northern Range of Yellowstone National Park over 10 consecutive winters. The influence of wolf distribution on kill sites diminished over the course of this study, a result that was likely caused by territorial constraints on wolf distribution. In contrast, landscape factors strongly influenced kill sites, creating distinct hunting grounds and prey refugia. Elk in this newly restored predator-prey system should be able to mediate their risk of predation by movement and habitat selection across a heterogeneous risk landscape.
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Affiliation(s)
- Matthew J Kauffman
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA.
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132
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Chapter 16 Wolf Prey Selection in an Elk-Bison System. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1936-7961(08)00216-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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133
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Owen-Smith N. The Comparative Population Dynamics of Browsing and Grazing Ungulates. ECOLOGICAL STUDIES 2008. [DOI: 10.1007/978-3-540-72422-3_6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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134
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Heithaus MR, Frid A, Wirsing AJ, Dill LM, Fourqurean JW, Burkholder D, Thomson J, Bejder L. State-dependent risk-taking by green sea turtles mediates top-down effects of tiger shark intimidation in a marine ecosystem. J Anim Ecol 2007; 76:837-44. [PMID: 17714261 DOI: 10.1111/j.1365-2656.2007.01260.x] [Citation(s) in RCA: 229] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. A predictive framework of community and ecosystem dynamics that applies across systems has remained elusive, in part because non-consumptive predator effects are often ignored. Further, it is unclear how much individual-level detail community models must include. 2. Previous studies of short-lived species suggest that state-dependent decisions add little to our understanding of community dynamics. Body condition-dependent decisions made by long-lived herbivores under risk of predation, however, might have greater community-level effects. This possibility remains largely unexplored, especially in marine environments. 3. In the relatively pristine seagrass community of Shark Bay, Australia, we found that herbivorous green sea turtles (Chelonia mydas Linnaeus, 1758) threatened by tiger sharks (Galeocerdo cuvier Peron and LeSueur, 1822) select microhabitats in a condition-dependent manner. Turtles in poor body condition selected profitable, high-risk microhabitats, while turtles in good body condition, which are more abundant, selected safer, less profitable microhabitats. When predation risk was low, however, turtles in good condition moved into more profitable microhabitats. 4. Condition-dependent use of space by turtles shows that tiger sharks modify the spatio-temporal pattern of turtle grazing and their impacts on ecosystem dynamics (a trait-mediated indirect interaction). Therefore, state-dependent decisions by individuals can have important implications for community dynamics in some situations. 5. Our study suggests that declines in large-bodied sharks may affect ecosystems more substantially than assumed when non-lethal effects of these top predators on mesoconsumers are not considered explicitly.
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Affiliation(s)
- Michael R Heithaus
- Department of Biological Sciences, Marine Biology Program, Florida International University, Biscayne Bay Campus ACI 371, 3000 NE 151 St, North Miami, FL 33181, USA.
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Bolger DT, Newmark WD, Morrison TA, Doak DF. The need for integrative approaches to understand and conserve migratory ungulates. Ecol Lett 2007; 11:63-77. [PMID: 17897327 DOI: 10.1111/j.1461-0248.2007.01109.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Over the last two centuries overhunting, anthropogenic barriers and habitat loss have disrupted many ungulate migrations. We review the literature on ungulate migration disruptions and find that for many species the disruption of migratory routes causes a rapid population collapse. Previous research has focused on the proximal ecological factors that might favour migration, particularly spatiotemporal variation in resources and predation. However, this does not provide an adequate basis for understanding and mitigating anthropogenic effects on migratory populations. Migration is a complex behaviour and we advocate an integrative approach that incorporates population dynamics, evolution, genetics, behaviour and physiology, and that borrows insights and approaches from research on other taxa. We draw upon research on avian migration to illustrate research approaches that might also be fruitful in ungulates. In particular, we suggest that the migratory cycle should be evaluated in the context of seasonal population limitation, an approach we highlight with a preliminary demographic perturbation analysis of the Serengeti wildebeest (Connochaetes taurinus) population. We provide suggestions for avenues of future research and highlight areas where we believe rapid progress can be made by applying recent advances in theory, technology and analytical approaches.
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Affiliation(s)
- Douglas T Bolger
- Environmental Studies Program, HB6182, Dartmouth College, Hanover, NH 03755, USA.
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Abstract
1. Ecosystems have higher-order emerging properties that can affect the conservation of species. We identify some of these properties in order to facilitate a better understanding of them. 2. Nonlinear, indirect effects of food web interactions among species can produce counterintuitive changes in populations. 3. Species differ in their roles and linkages with other species in the system. These roles are a property of the system. Such differences in roles influence how we conserve individual species. 4. Ecosystems operate at a multitude of interacting spatial and temporal scales, which together structure the system and affect the dynamics of individual populations. 5. Disturbance also structures an ecosystem, producing both long-term slow changes and sudden shifts in ecosystem dynamics. 6. Ecosystems therefore can have multiple states, determined both by disturbance regimes and biotic interactions. Conservation should recognize a possible multiplicity of natural states while avoiding aberrant (human-induced) states. 7. Ecosystem processes are influenced by the composition of the biota they contain. Disturbances to the biota can distort processes and functions, which in turn can endanger individual species. 8. The goal of ecosystem conservation is the long-term persistence of the biota in the system. There are two paradigms: community-based conservation (CBC) and protected area conservation. Both have their advantages but neither is sufficient to protect the biota on its own. 9. CBC is required to conserve the majority of the world's biota not included in protected areas. However, current CBC methods favour a few idiosyncratic species, distort the species complex, and ignore the majority. More comprehensive methods are required for this approach to meet the goal of ecosystem conservation. 10. Protected areas are essential to conserve species unable to coexist with humans. They also function as ecological baselines to monitor the effects of humans on their own ecosystems. 11. However, protected areas suffer from loss of habitat through attrition of critical areas. Thus, renewal (addition) of habitat is required in order to achieve the long-term persistence of biota in functioning ecosystems. Identification of minimum habitat areas and restoration of ecosystems become two major priorities for future research.
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Affiliation(s)
- A R E Sinclair
- Centre for Biodiversity Research, 6270 University Boulevard, University of British Columbia, Vancouver, V6T 1Z4, Canada.
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Huitu O, Jokinen I, Korpimäki E, Koskela E, Mappes T. Phase dependence in winter physiological condition of cyclic voles. OIKOS 2007. [DOI: 10.1111/j.0030-1299.2007.15488.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Teixeira CP, de Azevedo CS, Mendl M, Cipreste CF, Young RJ. Revisiting translocation and reintroduction programmes: the importance of considering stress. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.06.002] [Citation(s) in RCA: 302] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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141
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Sex-specific behavioural responses of elk to spatial and temporal variation in the threat of wolf predation. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.07.007] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Minderman J, Lind J, Cresswell W. Behaviourally mediated indirect effects: interference competition increases predation mortality in foraging redshanks. J Anim Ecol 2006; 75:713-23. [PMID: 16689954 DOI: 10.1111/j.1365-2656.2006.01092.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. The effect of competition for a limiting resource on the population dynamics of competitors is usually assumed to operate directly through starvation, yet may also affect survival indirectly through behaviourally mediated effects that affect risk of predation. Thus, competition can affect more than two trophic levels, and we aim here to provide an example of this. 2. We show that the foraging success of redshanks Tringa totanus (L.) foraging on active prey was highest in the front of flocks, whereas this was not the case for redshanks foraging on inactive prey. Also, when foraging on active prey, foraging success in a flock decreased as more birds passed through a patch, while overall foraging success was not lower on subsequent visits to the same patch. Thus, redshanks foraging on active prey suffered from interference competition, whereas this was not the case for redshanks foraging on inactive prey. 3. This interference competition led to differences in activity: redshanks attaining a lower foraging success had a higher walking rate. Greater activity was associated with wider flock spacing and shorter distances to cover, which has previously been shown to increase predation risk and mortality from sparrowhawks Accipiter nisus (L.). 4. We conclude that behavioural adaptations of prey species can lead to interference competition in foraging redshanks, and thus can affect their predation risk and mortality through increased activity. This study is one of the first to show how interference competition can be a mechanism for behaviourally mediated indirect effects, and provides further evidence for the suggestion that a single species occupying an intermediate trophic level may be simultaneously top-down controlled by a predator and bottom-up controlled by a behavioural response of its prey.
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Affiliation(s)
- Jeroen Minderman
- Centre for Ecological and Evolutionary Studies, Animal Ecology Group, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
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Bertilsson-Friedman P. Distribution and frequencies of shark-inflicted injuries to the endangered Hawaiian monk seal (Monachus schauinslandi). J Zool (1987) 2006. [DOI: 10.1111/j.1469-7998.2006.00066.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Owen-Smith N, Mills MGL. MANIFOLD INTERACTIVE INFLUENCES ON THE POPULATION DYNAMICS OF A MULTISPECIES UNGULATE ASSEMBLAGE. ECOL MONOGR 2006. [DOI: 10.1890/04-1101] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Owen-Smith N. DEMOGRAPHIC DETERMINATION OF THE SHAPE OF DENSITY DEPENDENCE FOR THREE AFRICAN UNGULATE POPULATIONS. ECOL MONOGR 2006. [DOI: 10.1890/05-0765] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Loehr J, Kovanen M, Carey J, Högmander H, Jurasz C, Kärkkäinen S, Suhonen J, Ylönen H. Gender- and age-class-specific reactions to human disturbance in a sexually dimorphic ungulate. CAN J ZOOL 2005. [DOI: 10.1139/z05-162] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
According to optimality theory, an individual's characteristics should play a major part in determining antipredator strategies. We studied behavioural reactions to human presence of gender and age classes of 35 thinhorn sheep (Ovis dalli Nelson, 1884) in late winter 2001 in Faro, Yukon Territory, Canada. The behaviour of undisturbed sheep was observed from distances of 400–1200 m and compared with the behaviour recorded when one or two people were in close proximity to the sheep. Ewes decreased bedding and increased foraging when humans were present, but there were no changes in these behaviours in rams. Disturbance caused an increase in vigilance and a trend was found for adults to react more strongly to disturbance than juveniles. We demonstrate the importance for disturbance research of gaining detailed information about all different kinds of population members and using applicable statistical tests in the data analyses.
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Creel S, Winnie J, Maxwell B, Hamlin K, Creel M. ELK ALTER HABITAT SELECTION AS AN ANTIPREDATOR RESPONSE TO WOLVES. Ecology 2005. [DOI: 10.1890/05-0032] [Citation(s) in RCA: 490] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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