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Jameson TJM, Johnston GR, Barr M, Sandow D, Head JJ, Turner EC. Squamate scavenging services: Heath goannas ( Varanus rosenbergi) support carcass removal and may suppress agriculturally damaging blowflies. Ecol Evol 2024; 14:e11535. [PMID: 38919645 PMCID: PMC11197000 DOI: 10.1002/ece3.11535] [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: 02/11/2024] [Revised: 05/15/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024] Open
Abstract
Human-induced environmental change has caused widespread loss of species that support important functions for ecosystems and society. For example, vertebrate scavengers contribute to the functional health of ecosystems and provide services to agricultural landscapes by removing carcasses and associated pests. Widespread extirpation of native Australian mammals since the arrival of Europeans in Australia has removed many scavenging species from landscapes, while scavenging mammals such as European red foxes (Vulpes vulpes) have been introduced. In much of Australia, squamate reptiles are the largest native terrestrial scavengers remaining, where large native mammals are extinct and conservation management is being undertaken to remove invasive mammals. The contribution of reptiles to scavenging functions is not well understood. In this study, we investigated the ecosystem functions provided by large reptiles as scavengers to better understand how populations can be managed to support ecosystem services. We investigated the ecosystem services provided by vertebrate scavengers in Australian coastal mallee ecosystems, focusing on the heath goanna (Varanus rosenbergi), the only extant native terrestrial scavenger in the region. We carried out exclosure experiments, isolating the scavenging activity of different taxonomic groups to quantify the contribution of different taxa to scavenging services, specifically the removal of rat carcasses, and its impact on the occurrence of agriculturally damaging blowflies. We compared areas with different native and invasive scavenger communities to investigate the impact of invasive species removal and native species abundance on scavenging services. Our results indicated that vertebrate scavenging significantly contributes to carcass removal and limitation of necrophagous fly breeding in carcasses and that levels of removal are higher in areas associated with high densities of heath goannas and low densities of invasive mammals. Therefore, augmentation of heath goanna populations represents a promising management strategy to restore and maximize scavenging ecosystem services.
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Affiliation(s)
- Tom J. M. Jameson
- Department of Zoology and University Museum of ZoologyUniversity of CambridgeCambridgeUK
| | - Gregory R. Johnston
- College of Science & EngineeringFlinders UniversityAdelaideSouth AustraliaAustralia
- South Australian MuseumAdelaideSouth AustraliaAustralia
| | - Max Barr
- Northern and Yorke Landscape BoardMinlatonSouth AustraliaAustralia
| | - Derek Sandow
- Northern and Yorke Landscape BoardClareSouth AustraliaAustralia
| | - Jason J. Head
- Department of Zoology and University Museum of ZoologyUniversity of CambridgeCambridgeUK
| | - Edgar C. Turner
- Department of Zoology and University Museum of ZoologyUniversity of CambridgeCambridgeUK
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Newsome T, Cairncross R, Cunningham CX, Spencer EE, Barton PS, Ripple WJ, Wirsing AJ. Scavenging with invasive species. Biol Rev Camb Philos Soc 2024; 99:562-581. [PMID: 38148253 DOI: 10.1111/brv.13035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 11/19/2023] [Accepted: 11/22/2023] [Indexed: 12/28/2023]
Abstract
Carrion acts as a hotspot of animal activity within many ecosystems globally, attracting scavengers that rely on this food source. However, many scavengers are invasive species whose impacts on scavenging food webs and ecosystem processes linked to decomposition are poorly understood. Here, we use Australia as a case study to review the extent of scavenging by invasive species that have colonised the continent since European settlement, identify the factors that influence their use of carcasses, and highlight the lesser-known ecological effects of invasive scavengers. From 44 published studies we identified six invasive species from 48 vertebrates and four main groups of arthropods (beetles, flies, ants and wasps) that scavenge. Invasive red foxes (Vulpes vulpes), domestic dogs (Canis familiaris), feral pigs (Sus scrofa), black rats (Rattus rattus) and feral cats (Felis catus) were ranked as highly common vertebrate scavengers. Invasive European wasps (Vespula germanica) are also common scavengers where they occur. We found that the diversity of native vertebrate scavengers is lower when the proportion of invasive scavengers is higher. We highlight that the presence of large (apex) native vertebrate scavengers can decrease rates of scavenging by invasive species, but that invasive scavengers can monopolise carcass resources, outcompete native scavengers, predate other species around carcass resources and even facilitate invasion meltdowns that affect other species and ecological processes including altered decomposition rates and nutrient cycling. Such effects are likely to be widespread where invasive scavengers occur and suggest a need to determine whether excessive or readily available carcass loads are facilitating or exacerbating the impacts of invasive species on ecosystems globally.
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Affiliation(s)
- Thomas Newsome
- School of Life and Environmental Science, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Rhys Cairncross
- School of Life and Environmental Science, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Calum X Cunningham
- School of Environmental and Forest Sciences, University of Washington, College of the Environment, Box 352100, Seattle, WA, 98195-2100, USA
| | - Emma E Spencer
- School of Life and Environmental Science, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Philip S Barton
- School of Life and Environmental Science, Deakin University, Geelong, Victoria, 3216, Australia
| | - William J Ripple
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, College of the Environment, Box 352100, Seattle, WA, 98195-2100, USA
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Newsome TM, Spencer EE. Megafires attract avian scavenging but carcasses still persist. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Thomas M. Newsome
- Global Ecology Lab School of Life and Environmental Sciences The University of Sydney Sydney NSW Australia
| | - Emma E. Spencer
- Global Ecology Lab School of Life and Environmental Sciences The University of Sydney Sydney NSW Australia
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