Predators

@misc{arnold1972species1,
    author = "Arnold, S. J",
    title = "Species densities of predators and their prey",
    year = "1972",
    howpublished = "American Naturalist, v. 106, p. 220-236",
    note = "talkorigins\_source = {true}; raw\_reference = {Arnold, S. J., 1972, Species densities of predators and their prey: American Naturalist, v. 106, p. 220-236.}"
}

@book{kruuk1972the3,
    author = "Kruuk, H",
    title = "The Spotted Hyena",
    year = "1972",
    publisher = "A Study of Predation and Social Behavior: Chicago, University of Chicago Press",
    note = "talkorigins\_source = {true}; raw\_reference = {Kruuk, H., 1972, The Spotted Hyena: A Study of Predation and Social Behavior: Chicago, University of Chicago Press.}"
}

@misc{paulson1973predator4,
    author = "Paulson, D. R",
    title = "Predator polymorphism and stochastic selection",
    year = "1973",
    howpublished = "Evolution, v. 27, p. 269-277",
    note = "talkorigins\_source = {true}; raw\_reference = {Paulson, D. R., 1973, Predator polymorphism and stochastic selection: Evolution, v. 27, p. 269-277.}"
}

@book{bartram1979serengeti2,
    author = "Bartram, B. C. R",
    title = "Serengeti Predators and Their Social Systems, in Sinclair, A. R. E., and Norton-Griffiths, M., eds., Serengeti",
    year = "1979",
    publisher = "Dynamics of an Ecosystem: Chicago, University of Chicago Press, p. 221-248",
    note = "talkorigins\_source = {true}; raw\_reference = {Bartram, B. C. R., 1979, Serengeti Predators and Their Social Systems, in Sinclair, A. R. E., and Norton-Griffiths, M., eds., Serengeti: Dynamics of an Ecosystem: Chicago, University of Chicago Press, p. 221-248.}"
}

@article{thompson1982predatorprey,
    author = "Thompson, Robert W. and DiBiasio, David and Mendes, Charles",
    title = "Predator-prey interactions: egg-eating predators",
    year = "1982",
    journal = "Mathematical Biosciences",
    url = "https://doi.org/10.1016/0025-5564(82)90034-7",
    doi = "10.1016/0025-5564(82)90034-7",
    number = "1",
    pages = "109-120",
    volume = "60"
}

@article{saleem1983predatorprey,
    author = "Saleem, M.",
    title = "Predator-prey relationships: egg-eating predators",
    year = "1983",
    journal = "Mathematical Biosciences",
    url = "https://doi.org/10.1016/0025-5564(83)90060-3",
    doi = "10.1016/0025-5564(83)90060-3",
    number = "2",
    pages = "187-197",
    volume = "65"
}

@article{thrush1994the,
    author = "Thrush, SF and Pridmore, RD and Hewitt, JE and Cummings, VJ",
    title = "The importance of predators on a sandflat: interplay between seasonal changes in prey densities and predator effects",
    year = "1994",
    journal = "Marine Ecology Progress Series",
    url = "https://doi.org/10.3354/meps107211",
    doi = "10.3354/meps107211",
    pages = "211-222",
    volume = "107"
}

Although invasive species can have substantial impacts on animal communities, cases of invasive species facilitating native species by removing their predators have rarely been demonstrated across vertebrate trophic linkages. The predictable spread of the invasive cane toad (Rhinella marina), however, offered a unique opportunity to quantify cascading effects. In northern Australia, three species of predatory monitor lizards suffered severe population declines due to toad‐induced lethal toxic ingestion (yellow‐spotted monitor [Varanus panoptes], Mertens' water monitor [V. mertensi], Mitchell's water monitor [V. mitchelli]). We, thus, predicted subsequent increases in the abundance and recruitment of prey species due to the reduction of those predators. Toad‐induced population‐level declines in the water monitor species approached 50% over a five‐year period spanning the toad invasion, apparently causing fledging success of the Crimson Finch (Neochmia phaeton) to increase from 55% to 81%. The consensus of our original and published long‐term data is that invasive cane toads are causing predators to lose a foothold on top‐down regulation of their prey, triggering shifts in the relative densities of predator and prey in the Australian tropical savannah ecosystem.

@article{doody2015invasive,
    author = "Doody, J. Sean and Soanes, Rebekah and Castellano, Christina M. and Rhind, David and Green, Brian and McHenry, Colin R. and Clulow, Simon",
    title = "Invasive toads shift predator–prey densities in animal communities by removing top predators",
    year = "2015",
    journal = "Ecology",
    abstract = "Although invasive species can have substantial impacts on animal communities, cases of invasive species facilitating native species by removing their predators have rarely been demonstrated across vertebrate trophic linkages. The predictable spread of the invasive cane toad (Rhinella marina), however, offered a unique opportunity to quantify cascading effects. In northern Australia, three species of predatory monitor lizards suffered severe population declines due to toad‐induced lethal toxic ingestion (yellow‐spotted monitor [Varanus panoptes], Mertens' water monitor [V. mertensi], Mitchell's water monitor [V. mitchelli]). We, thus, predicted subsequent increases in the abundance and recruitment of prey species due to the reduction of those predators. Toad‐induced population‐level declines in the water monitor species approached 50\% over a five‐year period spanning the toad invasion, apparently causing fledging success of the Crimson Finch (Neochmia phaeton) to increase from 55\% to 81\%. The consensus of our original and published long‐term data is that invasive cane toads are causing predators to lose a foothold on top‐down regulation of their prey, triggering shifts in the relative densities of predator and prey in the Australian tropical savannah ecosystem.",
    url = "https://doi.org/10.1890/14-1332.1",
    doi = "10.1890/14-1332.1",
    number = "9",
    pages = "2544-2554",
    volume = "96"
}

@misc{crossref2017nortongriffiths,
    title = "Norton-Griffiths, Sir Michael, (born 11 Jan. 1941)",
    year = "2017",
    booktitle = "Who's Who",
    url = "https://doi.org/10.1093/ww/9780199540884.013.u288810",
    doi = "10.1093/ww/9780199540884.013.u288810"
}

@misc{crossref2018nortongriffiths,
    title = "Norton-Griffiths, Sir John, first baronet (1871–1930)",
    year = "2018",
    booktitle = "Oxford Dictionary of National Biography",
    url = "https://doi.org/10.1093/odnb/9780192683120.013.35260",
    doi = "10.1093/odnb/9780192683120.013.35260"
}

The high failure rate of threatened species translocations has prompted many managers to fence areas to protect wildlife from introduced predators. However, conservation fencing is expensive, restrictive and exacerbates prey naïveté reducing the chance of future co‐existence between native prey and introduced predators. Here, we ask whether two globally threatened mammal species protected in fenced reserves, with a history of predation‐driven decline and reintroduction failure, could co‐exist with introduced predators. We defined co‐existence as population persistence for at least 3 years and successful recruitment. We manipulated the density of feral cats within a large fenced paddock and measured the impact on abundance and reproduction of 353 reintroduced burrowing bettongs and 47 greater bilbies over 3 years. We increased cat densities from 0.038 to 0.46 per square km and both threatened species survived, reproduced and increased their population size. However, a previous reintroduction trial of 66 bettongs into the same paddock found one red fox (Vulpes vulpes), at a density of 0.027 per square km, drove the bettong population extinct within 12 months. Our results show that different predator species vary in their impact and that despite a history of reintroduction failure, threatened mammal species can co‐exist with low densities of feral cats. There may be a threshold density below which it is possible to maintain unfenced populations of reintroduced marsupials. Understanding the numerical relationships between population densities of introduced predators and threatened species is urgently needed if these species are to be re‐established at landscape scales. Such knowledge will enable a priori assessment of the risk of reintroduction failure thereby increasing the likelihood of reintroduction success and reducing the financial and ethical cost of failed translocations.

@article{moseby2019understanding,
    author = "Moseby, Katherine E. and Letnic, Michael and Blumstein, Daniel T. and West, Rebecca",
    title = "Understanding predator densities for successful co‐existence of alien predators and threatened prey",
    year = "2019",
    journal = "Austral Ecology",
    abstract = "The high failure rate of threatened species translocations has prompted many managers to fence areas to protect wildlife from introduced predators. However, conservation fencing is expensive, restrictive and exacerbates prey naïveté reducing the chance of future co‐existence between native prey and introduced predators. Here, we ask whether two globally threatened mammal species protected in fenced reserves, with a history of predation‐driven decline and reintroduction failure, could co‐exist with introduced predators. We defined co‐existence as population persistence for at least 3 years and successful recruitment. We manipulated the density of feral cats within a large fenced paddock and measured the impact on abundance and reproduction of 353 reintroduced burrowing bettongs and 47 greater bilbies over 3 years. We increased cat densities from 0.038 to 0.46 per square km and both threatened species survived, reproduced and increased their population size. However, a previous reintroduction trial of 66 bettongs into the same paddock found one red fox (Vulpes vulpes), at a density of 0.027 per square km, drove the bettong population extinct within 12 months. Our results show that different predator species vary in their impact and that despite a history of reintroduction failure, threatened mammal species can co‐exist with low densities of feral cats. There may be a threshold density below which it is possible to maintain unfenced populations of reintroduced marsupials. Understanding the numerical relationships between population densities of introduced predators and threatened species is urgently needed if these species are to be re‐established at landscape scales. Such knowledge will enable a priori assessment of the risk of reintroduction failure thereby increasing the likelihood of reintroduction success and reducing the financial and ethical cost of failed translocations.",
    url = "https://doi.org/10.1111/aec.12697",
    doi = "10.1111/aec.12697",
    number = "3",
    pages = "409-419",
    volume = "44"
}

Large carnivore populations are declining worldwide due to anthropogenic causes such as habitat loss and human expansion into wild areas. Competition between large carnivores can exacerbate this decline. While brown hyena Parahyaena brunnea and spotted hyena Crocuta crocuta belong to the same family, they are rarely found in the same area or co‐occur at low densities as spotted hyena are known to exclude brown hyena. In Central Tuli, Botswana, however, brown hyena and spotted hyena are both found at high densities. We undertook a camera trap survey in this area to estimate the densities of both species, and to examine temporal overlap and co‐detection patterns of brown and spotted hyena. Estimated population densities based on spatial capture–recapture models were 10.5 ± 1.9/100 km 2 for brown hyena and 14.9 ± 2.2/100 km 2 for spotted hyena. These population densities are among the highest reported estimates in southern Africa. Strong temporal overlap was found between brown and spotted hyena, while there was no decrease in detection rate of brown hyena at camera sites where spotted hyena were also detected, which indicates that both hyena species did not tend to avoid encounters. Although both species compete for the same prey, we suggest as possible explanations that prey densities are high and that competition does not significantly negatively impact brown hyena, because brown hyena is a scavenger whereas spotted hyena scavenge and kill prey. With the found high densities of both carnivores, this study adds to the known variation in composition of existing large carnivore communities and suggests testable explanations for these densities.

@article{vissia2021cooccurrence,
    author = "Vissia, S. and Wadhwa, R. and van Langevelde, F.",
    title = "Co‐occurrence of high densities of brown hyena and spotted hyena in central Tuli, Botswana",
    year = "2021",
    journal = "Journal of Zoology",
    abstract = "Large carnivore populations are declining worldwide due to anthropogenic causes such as habitat loss and human expansion into wild areas. Competition between large carnivores can exacerbate this decline. While brown hyena Parahyaena brunnea and spotted hyena Crocuta crocuta belong to the same family, they are rarely found in the same area or co‐occur at low densities as spotted hyena are known to exclude brown hyena. In Central Tuli, Botswana, however, brown hyena and spotted hyena are both found at high densities. We undertook a camera trap survey in this area to estimate the densities of both species, and to examine temporal overlap and co‐detection patterns of brown and spotted hyena. Estimated population densities based on spatial capture–recapture models were 10.5 ± 1.9/100 km 2 for brown hyena and 14.9 ± 2.2/100 km 2 for spotted hyena. These population densities are among the highest reported estimates in southern Africa. Strong temporal overlap was found between brown and spotted hyena, while there was no decrease in detection rate of brown hyena at camera sites where spotted hyena were also detected, which indicates that both hyena species did not tend to avoid encounters. Although both species compete for the same prey, we suggest as possible explanations that prey densities are high and that competition does not significantly negatively impact brown hyena, because brown hyena is a scavenger whereas spotted hyena scavenge and kill prey. With the found high densities of both carnivores, this study adds to the known variation in composition of existing large carnivore communities and suggests testable explanations for these densities.",
    url = "https://doi.org/10.1111/jzo.12873",
    doi = "10.1111/jzo.12873",
    number = "2",
    pages = "143-150",
    volume = "314"
}

@misc{crossrefNonetable,
    title = "Table 6: Spotted hyena densities recorded in the literature.",
    year = "None",
    url = "https://doi.org/10.7717/peerj.12307/table-6",
    doi = "10.7717/peerj.12307/table-6"
}