Journal article
Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches
Ecology, Vol.96(10), pp.2715-2725
2015
Abstract
Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for non-native carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems. Here we tested whether species turnover results in functional ecological equivalence or complementarity, and whether invasive carnivores on islands significantly alter such ecological function. The model system consisted of vertebrate scavengers (dominated by raptors) foraging on animal carcasses on ocean beaches on two Australian islands, one with and one without invasive red foxes (Vulpes vulpes). Partitioning of scavenging events amongst species, carcass removal rates, and detection speeds were quantified using camera traps baited with fish carcasses at the dune-beach interface. Complete segregation of temporal foraging niches between mammals (nocturnal) and birds (diurnal) reflects complementarity in carrion utilisation. Conversely, functional redundancy exists within the bird guild where several species of raptors dominate carrion removal in a broadly similar way. As predicted, effects of red foxes were large. They substantially changed the nature and rate of the scavenging process in the system: i) foxes consumed over half (55%) of all carrion available at night, compared with negligible mammalian foraging at night on the fox-free island, and ii) significant shifts in the composition of the scavenger assemblages consuming beach-cast carrion are the consequence of fox invasion at one island. Arguably, in the absence of other mammalian apex predators, the addition of red foxes creates a new dimension of functional complementarity in beach food webs. However, this functional complementarity added by foxes is neither benign nor neutral, as marine carrion subsidies to coastal red fox populations are likely to facilitate their persistence as exotic carnivores.
Details
- Title
- Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches
- Authors
- Marion Brown (Author) - University of the Sunshine Coast - Faculty of Science, Health, Education and EngineeringThomas Schlacher (Corresponding Author) - University of the Sunshine Coast - Faculty of Science, Health, Education and EngineeringDavid S Schoeman (Author) - University of the Sunshine Coast - Faculty of Science, Health, Education and EngineeringM A Weston (Author) - Deakin UniversityChantal M Huijbers (Author) - Griffith UniversityAndrew D Olds (Author) - University of the Sunshine Coast - Faculty of Science, Health, Education and EngineeringR M Connolly (Author) - Griffith University
- Publication details
- Ecology, Vol.96(10), pp.2715-2725
- Publisher
- Ecological Society of America
- Date published
- 2015
- DOI
- 10.1890/15-0027.1
- ISSN
- 0012-9658
- Copyright note
- Copyright © 2015 Ecological Society of America. Reproduced here in accordance with the publisher's copyright policy.
- Organisation Unit
- School of Science and Engineering - Legacy; University of the Sunshine Coast, Queensland; GeneCology Research Centre - Legacy; School of Science, Technology and Engineering
- Language
- English
- Record Identifier
- 99449553202621
- Output Type
- Journal article
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