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von Takach B, Ranjard L, Burridge CP, Cameron SF, Cremona T, Eldridge MDB, Fisher DO, Frankenberg S, Hill BM, Hohnen R, Jolly CJ, Kelly E, MacDonald AJ, Moussalli A, Ottewell K, Phillips BL, Radford IJ, Spencer PBS, Trewella GJ, Umbrello LS, Banks SC. Population genomics of a predatory mammal reveals patterns of decline and impacts of exposure to toxic toads. Mol Ecol 2022; 31:5468-5486. [PMID: 36056907 PMCID: PMC9826391 DOI: 10.1111/mec.16680] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 01/11/2023]
Abstract
Mammal declines across northern Australia are one of the major biodiversity loss events occurring globally. There has been no regional assessment of the implications of these species declines for genomic diversity. To address this, we conducted a species-wide assessment of genomic diversity in the northern quoll (Dasyurus hallucatus), an Endangered marsupial carnivore. We used next generation sequencing methods to genotype 10,191 single nucleotide polymorphisms (SNPs) in 352 individuals from across a 3220-km length of the continent, investigating patterns of population genomic structure and diversity, and identifying loci showing signals of putative selection. We found strong heterogeneity in the distribution of genomic diversity across the continent, characterized by (i) biogeographical barriers driving hierarchical population structure through long-term isolation, and (ii) severe reductions in diversity resulting from population declines, exacerbated by the spread of introduced toxic cane toads (Rhinella marina). These results warn of a large ongoing loss of genomic diversity and associated adaptive capacity as mammals decline across northern Australia. Encouragingly, populations of the northern quoll established on toad-free islands by translocations appear to have maintained most of the initial genomic diversity after 16 years. By mapping patterns of genomic diversity within and among populations, and investigating these patterns in the context of population declines, we can provide conservation managers with data critical to informed decision-making. This includes the identification of populations that are candidates for genetic management, the importance of remnant island and insurance/translocated populations for the conservation of genetic diversity, and the characterization of putative evolutionarily significant units.
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Affiliation(s)
- Brenton von Takach
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityDarwinNorthern TerritoryAustralia,School of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Louis Ranjard
- The Research School of Biology, Faculty of ScienceThe Australian National UniversityActonAustralian Capital TerritoryAustralia,PlantTech Research InstituteTaurangaNew Zealand
| | | | - Skye F. Cameron
- Australian Wildlife ConservancyKimberleyWestern AustraliaAustralia,School of Biological SciencesUniversity of QueenslandSt LuciaQueenslandAustralia
| | - Teigan Cremona
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityDarwinNorthern TerritoryAustralia
| | | | - Diana O. Fisher
- School of Biological SciencesUniversity of QueenslandSt LuciaQueenslandAustralia
| | | | - Brydie M. Hill
- Flora and Fauna Division, Department of Environment, Parks and Water SecurityNorthern Territory GovernmentNorthern TerritoryAustralia
| | - Rosemary Hohnen
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityDarwinNorthern TerritoryAustralia
| | - Chris J. Jolly
- Institute of Land, Water and Society, School of Environmental ScienceCharles Sturt UniversityAlburyNew South WalesAustralia,School of Natural SciencesMacquarie UniversityMacquarie ParkNew South WalesAustralia
| | - Ella Kelly
- School of BioSciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Anna J. MacDonald
- The Research School of Biology, Faculty of ScienceThe Australian National UniversityActonAustralian Capital TerritoryAustralia,Australian Antarctic Division, Department of AgricultureWater and the EnvironmentKingstonTasmaniaAustralia
| | - Adnan Moussalli
- School of BioSciencesUniversity of MelbourneParkvilleVictoriaAustralia,Department of ScienceMuseums VictoriaMelbourneVictoriaAustralia
| | - Kym Ottewell
- Department of Biodiversity, Conservation and AttractionsPerthWestern AustraliaAustralia
| | - Ben L. Phillips
- School of BioSciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Ian J. Radford
- Department of Biodiversity, Conservation and AttractionsPerthWestern AustraliaAustralia
| | - Peter B. S. Spencer
- Environmental and Conservation Sciences, Murdoch UniversityPerthWestern AustraliaAustralia
| | - Gavin J. Trewella
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityDarwinNorthern TerritoryAustralia
| | - Linette S. Umbrello
- Department of Biodiversity, Conservation and AttractionsPerthWestern AustraliaAustralia,Collections and Research CentreWestern Australian MuseumWelshpoolWestern AustraliaAustralia
| | - Sam C. Banks
- Research Institute for the Environment and LivelihoodsCharles Darwin UniversityDarwinNorthern TerritoryAustralia
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Collett SJ, Crewe TL, Radford IJ, Garnett ST, Campbell HA. Sympatric finches increase trophic and spatiotemporal partitioning to enable coexistence through periods of low resource availability. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sydney J. Collett
- Research Institute for the Environment and Livelihoods Charles Darwin University Darwin NT Australia
| | - Tara L. Crewe
- Research Institute for the Environment and Livelihoods Charles Darwin University Darwin NT Australia
- Department of Lands and Forestry Government of Nova Scotia Kentville NS Canada
| | - Ian J. Radford
- Department of Biodiversity, Conservation and Attractions Biodiversity and Conservation Science WA Australia
| | - Stephen T. Garnett
- Research Institute for the Environment and Livelihoods Charles Darwin University Darwin NT Australia
| | - Hamish A. Campbell
- Research Institute for the Environment and Livelihoods Charles Darwin University Darwin NT Australia
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Radford IJ, Corey B, Carnes K, Shedley E, McCaw L, Woolley LA. Landscape-Scale Effects of Fire, Cats, and Feral Livestock on Threatened Savanna Mammals: Unburnt Habitat Matters More Than Pyrodiversity. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.739817] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Northern Australia has undergone significant declines among threatened small and medium-sized mammals in recent decades. Conceptual models postulate that predation by feral cats is the primary driver, with changed disturbance regimes from fire and feral livestock in recent decades reducing habitat cover and exacerbating declines. However, there is little guidance on what scale habitat and disturbance attributes are most important for threatened mammals, and what elements and scale of fire mosaics actually support mammals. In this study, we test a series of hypotheses regarding the influence of site-scale (50 × 50 m) habitat and disturbance attributes, as well as local-scale (1 km radius), meta-local scale (3 km), landscape-scale (5 km) and meta-landscape scale (10 km) fire mosaic attributes on mammal abundance and richness. We found that habitat cover (rock, perennial grass, and shrub cover) at the site-scale had a positive effect, and disturbance factors (feral cats, fire, feral livestock) had a negative influence on mammal abundance and richness. Models supported site-scale habitat and disturbance factors as more important for mammals than broader-scale (local up to meta-landscape scale) fire mosaic attributes. Finally, we found that increasing the extent of ≥ 4 year unburnt habitat, and having an intermediate percentage (ca. 25%) of recently burnt (1-year burnt) habitat within the mosaic, were the most important functional elements of the fire mosaic at broad scales for mammals. Contrary to expectations, diversity of post-fire ages (‘pyrodiversity’) was negatively associated with mammal abundance and richness. These results highlight the need for management to promote retention of longer unburnt vegetation in sufficient patches across savanna landscapes (particularly of shrub and fruiting trees), maintain low-intensity patchy fire regimes, reduce the extent of intense late dry season wildfires, and to reduce the impact of feral livestock. This study provides further evidence for the role of feral cats in northern Australian mammal declines, and highlights the need for increased research into the efficacy of cat control methodologies in reducing biodiversity impacts in these extensive landscapes.
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Penton CE, Davies HF, Radford IJ, Woolley LA, Rangers TL, Murphy BP. A Hollow Argument: Understory Vegetation and Disturbance Determine Abundance of Hollow-Dependent Mammals in an Australian Tropical Savanna. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.739550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Native mammals are suffering widespread and ongoing population declines across northern Australia. These declines are likely driven by multiple, interacting factors including altered fire regimes, predation by feral cats, and grazing by feral herbivores. In addition, the loss of tree hollows due to frequent, intense fires may also be contributing to the decline of hollow-dependent mammals. We currently have little understanding of how the availability of tree hollows influences populations of hollow-dependent mammals in northern Australian savannas. Here, we test the hypothesis that the abundance of hollow-dependent mammals is higher in areas with a greater availability of tree hollows. We used camera-trap data from 82 sites across the savannas of Melville Island, the largest island in monsoonal northern Australia. Royle–Nichols abundance-induced heterogeneity models were used to investigate the biophysical correlates of the abundance of three threatened mammals: northern brushtail possum (Trichosurus vulpecula arnhemensis), black-footed tree-rat (Mesembriomys gouldii), and brush-tailed rabbit-rat (Conilurus penicillatus). Our analyses included two variables that reflect the availability of tree hollows: the density of tree hollows, estimated from the ground, and the density of large eucalypt trees (Eucalyptus and Corymbia spp.). We found no evidence that the abundance of the three hollow-dependent mammals is positively associated with the availability of tree hollows on Melville Island. Despite their reliance on hollow-bearing trees for denning, the abundance of these mammals appears to be more strongly associated with other factors, such as the characteristics of the understory (i.e., shrub density), which affords protection from predators (including feral cats) and access to food resources. Future conservation management should aim to maintain a dense, diverse understory by managing fire and feral herbivores to facilitate the persistence of hollow-dependent mammals across northern Australia.
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von Takach B, Penton CE, Murphy BP, Radford IJ, Davies HF, Hill BM, Banks SC. Population genomics and conservation management of a declining tropical rodent. Heredity (Edinb) 2021; 126:763-775. [PMID: 33664461 PMCID: PMC8102610 DOI: 10.1038/s41437-021-00418-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 01/31/2023] Open
Abstract
Conservation management is improved by incorporating information about the spatial distribution of population genetic diversity into planning strategies. Northern Australia is the location of some of the world's most severe ongoing declines of endemic mammal species, yet we have little genetic information from this regional mammal assemblage to inform a genetic perspective on conservation assessment and planning. We used next-generation sequencing data from remnant populations of the threatened brush-tailed rabbit-rat (Conilurus penicillatus) to compare patterns of genomic diversity and differentiation across the landscape and investigate standardised hierarchical genomic diversity metrics to better understand brush-tailed rabbit-rat population genomic structure. We found strong population structuring, with high levels of differentiation between populations (FST = 0.21-0.78). Two distinct genomic lineages between the Tiwi Islands and mainland are also present. Prioritisation analysis showed that one population in both lineages would need to be conserved to retain at least ~80% of alleles for the species. Analysis of standardised genomic diversity metrics showed that approximately half of the total diversity occurs among lineages (δ = 0.091 from grand total γ = 0.184). We suggest that a focus on conserving remnant island populations may not be appropriate for the preservation of species-level genomic diversity and adaptive potential, as these populations represent a small component of the total diversity and a narrow subset of the environmental conditions in which the species occurs. We also highlight the importance of considering both genomic and ecological differentiation between source and receiving populations when considering translocations for conservation purposes.
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Affiliation(s)
- Brenton von Takach
- grid.1043.60000 0001 2157 559XResearch Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia
| | - Cara E. Penton
- grid.1043.60000 0001 2157 559XResearch Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia
| | - Brett P. Murphy
- grid.1043.60000 0001 2157 559XResearch Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia ,grid.1043.60000 0001 2157 559XNESP Threatened Species Recovery Hub, Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia
| | - Ian J. Radford
- grid.452589.70000 0004 1799 3491Department of Biodiversity, Conservation and Attractions, Kununurra, WA Australia
| | - Hugh F. Davies
- grid.1043.60000 0001 2157 559XResearch Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia ,grid.1043.60000 0001 2157 559XNESP Threatened Species Recovery Hub, Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia
| | - Brydie M. Hill
- grid.483876.60000 0004 0394 3004Flora and Fauna Division, Department of Environment, Parks and Water Security, Northern Territory Government, Darwin, Northern Territory Australia
| | - Sam C. Banks
- grid.1043.60000 0001 2157 559XResearch Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory Australia
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Tuft K, Legge S, Frank ASK, James AI, May T, Page E, Radford IJ, Woinarski JCZ, Fisher A, Lawes MJ, Gordon IJ, Johnson CN. Cats are a key threatening factor to the survival of local populations of native small mammals in Australia’s tropical savannas: evidence from translocation trials with Rattus tunneyi. Wildl Res 2021. [DOI: 10.1071/wr20193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
ContextInvasive predators are a key threat to biodiversity worldwide. In Australia, feral cats are likely to be responsible for many extinctions of native mammal species in the south and centre of the continent.
AimsHere we examine the effect of feral cats on native rodent populations in the second of two translocation experiments.
MethodsIn a wild-to-wild translocation, we introduced pale field rats, Rattus tunneyi, whose populations are declining in the wild, into two pairs of enclosures where accessibility by feral cats was manipulated.
Key resultsIndividual rats translocated into enclosures accessible to cats were rapidly extirpated after cats were first detected visiting the enclosures. Rats in the enclosure not exposed to cats were 6.2 times more likely to survive than those exposed to cats. Two individual cats were responsible for the deaths of all but 1 of 18 cat-accessible rats. Rats in the site with denser ground cover persisted better than in the site with more open cover.
ConclusionsThese results are consistent with our previous study of a different native rat species in the same experimental setup, and provide further evidence that, even at low densities, feral cats can drive local populations of small mammals to extinction.
ImplicationsEffective feral cat control may be necessary to enable recovery of small mammals.
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Penton CE, Woolley LA, Radford IJ, Murphy BP. Overlapping den tree selection by three declining arboreal mammal species in an Australian tropical savanna. J Mammal 2020; 101:1165-1176. [PMID: 33033470 PMCID: PMC7528645 DOI: 10.1093/jmammal/gyaa074] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 06/15/2020] [Indexed: 11/25/2022] Open
Abstract
Tree cavities are important denning sites for many arboreal mammals. Knowledge of cavity requirements of individual species, as well as potential den overlap among species, is integral to their conservation. In Australia’s tropical savannas, development of tree cavities is enhanced by high termite activity, and, conversely, reduced by frequent fires. However, it is poorly understood how the availability of tree cavities in the tropical savannas impacts tree cavity use and selection by cavity-dependent fauna. There has been a severe decline among arboreal mammal species in northern Australia over recent decades. Investigation of their cavity requirements may illuminate why these species have declined drastically in some areas but are persisting in others. Here we examined this issue in three species of arboreal mammals (Trichosurus vulpecula, Mesembriomys gouldii, Conilurus penicillatus) on Melville Island, northern Australia. We radiotracked individuals to their den sites to evaluate whether the species differ in their den tree and tree-cavity selection. The strongest influence on den tree selection was the presence of large cavities (> 10 cm entrance diameter), with all three species using larger cavities most frequently. Conilurus penicillatus, the smallest species, differed the most from the other species: it frequently was found in smaller, dead trees and its den sites were closer to the ground, including in hollow logs. The two larger species had broader den tree use, using larger live trees and dens higher up in the canopy. Dens of C. penicillatus are likely to be more susceptible to predation and destruction by high-intensity savanna fires. This may have contributed to this species’ rapid decline, both on Melville Island and on the mainland. However, the apparent preference for larger tree cavities by all three arboreal species is concerning due to the limited availability of large trees across Australian savannas, which are subject to frequent, high-intensity fires.
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Affiliation(s)
- Cara E Penton
- Research Institute for Environment and Livelihoods, Charles Darwin University, Casuarina, NT, Australia
| | - Leigh-Ann Woolley
- NESP Threatened Species Recovery Hub, Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, NT, Australia.,WWF-Australia, Broome, WA, Australia
| | - Ian J Radford
- Department of Biodiversity, Conservation and Attractions, Kununurra, WA, Australia
| | - Brett P Murphy
- NESP Threatened Species Recovery Hub, Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, NT, Australia
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Radford IJ, Woolley LA, Dickman CR, Corey B, Trembath D, Fairman R. Invasive anuran driven trophic cascade: An alternative hypothesis for recent critical weight range mammal collapses across northern Australia. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02226-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Corey B, Andersen AN, Legge S, Woinarski JCZ, Radford IJ, Perry JJ. Better biodiversity accounting is needed to prevent bioperversity and maximize co‐benefits from savanna burning. Conserv Lett 2019. [DOI: 10.1111/conl.12685] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Ben Corey
- Department of Biodiversity, Conservation and Attractions Kununurra Western Australia Australia
| | - Alan N. Andersen
- Research Institute for the Environment and LivelihoodsCharles Darwin University Darwin Northern Territory Australia
| | - Sarah Legge
- School of Conservation and Biodiversity ScienceUniversity of Queensland St. Lucia Queensland Australia
- Fenner School of Environment and SocietyThe Australian National University Canberra Australian Capital Territory Australia
| | - John C. Z. Woinarski
- Research Institute for the Environment and LivelihoodsCharles Darwin University Darwin Northern Territory Australia
| | - Ian J. Radford
- Department of Biodiversity, Conservation and Attractions Kununurra Western Australia Australia
| | - Justin J. Perry
- Department of Land and WaterCSIRO Townsville Queensland Australia
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Weier A, Radford IJ, Bellairs SM, Lawes MJ. Seed set inSorghum stipoideum, and not fire, determines the timing of breeding by Gouldian finches (Erythrura gouldiae). AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12662] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anna Weier
- Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin Northern Territory Australia
| | - Ian J. Radford
- Department of Biodiversity, Conservation and Attractions; Science and Conservation; PO Box 942 Lot 248 Ivanhoe Rd Kununurra Western Australia 6743 Australia
| | - Sean M. Bellairs
- Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin Northern Territory Australia
| | - Michael J. Lawes
- Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin Northern Territory Australia
- School of Life Sciences; University of KwaZulu-Natal; Scottsville South Africa
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Weier A, Radford IJ, Manson A, Durrans LJ, Lawes MJ. Frequent fires reduce the nutritional quality of Sorghum stipoideum seed, a keystone food resource for the Gouldian finch (Erythrura gouldiae). Rangel J 2017. [DOI: 10.1071/rj16124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fire is a pervasive feature of the tropical savannas of northern Australia. Increasingly extensive and intensive fires have had an adverse effect on grass layer diversity. Reduced grass species diversity and abundance are important correlates of the decline of granivores in these tropical savannas. The Gouldian finch (Erythrura gouldiae), an endangered species that is endemic to northern Australia, is particularly vulnerable to changes to the grass layer as its diet comprises only grass seed, and it relies mostly on Sorghum stipoideum during the breeding season. Although this annual grass species is abundant at breeding sites, the finches do not always choose to breed at these sites, raising the possibility that seed quality may vary from year to year. This study examines the effect of fire (time since last fire; fire frequency) on soil fertility and seed nutritional quality. We hypothesise that recently burnt sites produce a flush of soil nutrients and Sorghum stipoideum seed at these sites is of higher nutritional quality. Furthermore, we posit that frequently burnt sites become depleted of soil nutrients and their seeds are of lower nutritional quality. There was a significant increase in inorganic nitrogen in soils following a fire, but no notable change in other soil nutrients. Contingent on this increase in soil inorganic nitrogen, seed nutrient levels, particularly essential proteins, were greater at sites that were recently, but infrequently burnt. Fires appear to affect soil nitrogen and in turn seed nutrition, providing a plausible explanation for why Gouldian finches choose recently, but infrequently burnt breeding sites.
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Hohnen R, Tuft K, Legge S, Walters N, Johanson L, Carver S, Radford IJ, Johnson CN. The significance of topographic complexity in habitat selection and persistence of a declining marsupial in the Kimberley region of Western Australia. AUST J ZOOL 2016. [DOI: 10.1071/zo16015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mammalian species in northern Australia are declining. The resources that many species from this region require to persist in the landscape remain poorly understood. We examined habitat selection and diet of the scaly-tailed possum (Wyulda squamicaudata, hereafter called Wyulda) in the north-west Kimberley, Western Australia, in relation to variation in complexity of rocky habitat, habitat heterogeneity, and recent fire history. We fitted GPS tags to 23 Wyulda between January 2013 and February 2014 and analysed step selection between GPS fixes to describe habitat choice. We assessed diet by microscopic analysis of plant fragments from 47 faecal samples. Individual Wyulda preferentially foraged in locations with high rock complexity and high habitat heterogeneity in a wide variety of habitats, but denned exclusively in complex rock piles. They used savannas of a range of post-fire ages, including recently burnt (1–2 months after fire) and long unburnt (>24 months after fire). They were highly frugivorous with, on average, 77% of plant fragments per scat sample identified as fruit epidermal layers. Overall, rock complexity appears to be an important landscape attribute for Wyulda, as it may provide den sites and protect fire-sensitive landscape features such as fruiting trees and habitat heterogeneity.
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Hohnen R, Tuft KD, Legge S, Radford IJ, Carver S, Johnson CN. Post-fire habitat use of the golden-backed tree-rat (Mesembriomys macrurus) in the northwest Kimberley, Western Australia. AUSTRAL ECOL 2015. [DOI: 10.1111/aec.12278] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rosemary Hohnen
- School of Biological Sciences; University of Tasmania; Private Bag 55 Hobart Tasmania 7000 Australia
- Australian Wildlife Conservancy; Mornington Wildlife Sanctuary; Derby Western Australia Australia
| | - Katherine D. Tuft
- Australian Wildlife Conservancy; Mornington Wildlife Sanctuary; Derby Western Australia Australia
| | - Sarah Legge
- Australian Wildlife Conservancy; Mornington Wildlife Sanctuary; Derby Western Australia Australia
| | - Ian J. Radford
- Department of Parks and Wildlife; Kununurra Western Australia Australia
| | - Scott Carver
- School of Biological Sciences; University of Tasmania; Private Bag 55 Hobart Tasmania 7000 Australia
| | - Christopher N. Johnson
- School of Biological Sciences; University of Tasmania; Private Bag 55 Hobart Tasmania 7000 Australia
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Radford IJ, Gibson LA, Corey B, Carnes K, Fairman R. Influence of Fire Mosaics, Habitat Characteristics and Cattle Disturbance on Mammals in Fire-Prone Savanna Landscapes of the Northern Kimberley. PLoS One 2015; 10:e0130721. [PMID: 26121581 PMCID: PMC4488076 DOI: 10.1371/journal.pone.0130721] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 05/22/2015] [Indexed: 11/19/2022] Open
Abstract
Patch mosaic burning, in which fire is used to produce a mosaic of habitat patches representative of a range of fire histories (‘pyrodiversity’), has been widely advocated to promote greater biodiversity. However, the details of desired fire mosaics for prescribed burning programs are often unspecified. Threatened small to medium-sized mammals (35 g to 5.5 kg) in the fire-prone tropical savannas of Australia appear to be particularly fire-sensitive. Consequently, a clear understanding of which properties of fire mosaics are most instrumental in influencing savanna mammal populations is critical. Here we use mammal capture data, remotely sensed fire information (i.e. time since last fire, fire frequency, frequency of late dry season fires, diversity of post-fire ages in 3 km radius, and spatial extent of recently burnt, intermediate and long unburnt habitat) and structural habitat attributes (including an index of cattle disturbance) to examine which characteristics of fire mosaics most influence mammals in the north-west Kimberley. We used general linear models to examine the relationship between fire mosaic and habitat attributes on total mammal abundance and richness, and the abundance of the most commonly detected species. Strong negative associations of mammal abundance and richness with frequency of late dry season fires, the spatial extent of recently burnt habitat (post-fire age <1 year within 3 km radius) and level of cattle disturbance were observed. Shrub cover was positively related to both mammal abundance and richness, and availability of rock crevices, ground vegetation cover and spatial extent of ≥4 years unburnt habitat were all positively associated with at least some of the mammal species modelled. We found little support for diversity of post-fire age classes in the models. Our results indicate that both a high frequency of intense late dry season fires and extensive, recently burnt vegetation are likely to be detrimental to mammals in the north Kimberley. A managed fire mosaic that reduces large scale and intense fires, including the retention of ≥4 years unburnt patches, will clearly benefit savanna mammals. We also highlighted the importance of fire mosaics that retain sufficient shelter for mammals. Along with fire, it is clear that grazing by introduced herbivores also needs to be reduced so that habitat quality is maintained.
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Affiliation(s)
- Ian J. Radford
- Department of Parks and Wildlife, Lot 248 Ivanhoe Rd (PO Box 942), Kununurra WA 6743, Australia
- * E-mail:
| | - Lesley A. Gibson
- Department of Parks and Wildlife, Locked Bag 104, Bentley Delivery Centre, WA 6983, Australia
| | - Ben Corey
- Department of Parks and Wildlife, Lot 248 Ivanhoe Rd (PO Box 942), Kununurra WA 6743, Australia
| | - Karin Carnes
- Department of Parks and Wildlife, Lot 248 Ivanhoe Rd (PO Box 942), Kununurra WA 6743, Australia
| | - Richard Fairman
- Department of Parks and Wildlife, Lot 248 Ivanhoe Rd (PO Box 942), Kununurra WA 6743, Australia
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Ziembicki MR, Woinarski JCZ, Webb JK, Vanderduys E, Tuft K, Smith J, Ritchie EG, Reardon TB, Radford IJ, Preece N, Perry J, Murphy BP, McGregor H, Legge S, Leahy L, Lawes MJ, Kanowski J, Johnson CN, James A, Griffiths AD, Gillespie G, Frank AS, Fisher A, Burbidge AA. Stemming the tide: progress towards resolving the causes of decline and implementing management responses for the disappearing mammal fauna of northern Australia. Therya 2015. [DOI: 10.12933/therya-15-236] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Radford IJ, Fairman R. Fauna and vegetation responses to fire and invasion by toxic cane toads (Rhinella marina) in an obligate seeder-dominated tropical savanna in the Kimberley, northern Australia. Wildl Res 2015. [DOI: 10.1071/wr14259] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context Changed fire regimes are an important threatening process to savanna biodiversity. Fire-sensitive vegetation such as pindan and its fauna may be particularly susceptible to fire impacts. Invasion by alien species is an additional threatening process. The toxic anuran Rhinella marina is a well publicised invader of savannas. Little is known of impacts in many habitats. Aims To test the hypotheses (1) that fire responses among pindan fauna are greater than general savanna responses, and (2) that cane toad-invasion impacts will be reduced relative to riparian habitats. Methods Reptiles, frogs, invertebrates and mammals were surveyed seven times from 2008 to 2012, four times before and three times following R. marina invasion. Time since last fire was recorded during each survey. Vegetation change was measured. Key results Pindan vegetation structural recovery took 4–5 years, whereas fauna recovery took only 1 year. Ground active agamids, combined Scincidae, fossorial skinks and ground-layer invertebrates responded positively to recent fire. Skinks of Ctenotus spp. declined in size after fire. Short-term fauna responses reflect rapid re-establishment of herbaceous cover. Fauna responses were detected following R. marina invasion, including increases in frogs of Uperoleia spp. and skinks of Carlia spp., and decreases in Lerista griffini and ground-layer invertebrates. Insufficient data were available to test for responses among large predators; however, >50% lower Varanus spp. trap success occurred post-invasion. No invasion response was detected among small mammals. Conclusions Pindan fauna fire responses were similar to those of savannas. Fauna responses to Rhinella marina invasion were relatively minor compared with those previously reported in riparian habitats and this may be related to the lower abundance of the invader here than in previous studies in riparian or more fertile habitats. Implications The dominant obligate seeding tree in pindan woodland, A. tumida, requires >4 years with no high-intensity fires for re-establishment of the dominant tree. Fire management should aim to minimise extensive fires to reduce impacts on fire-sensitive fauna. Persistence of large predators after cane-toad invasion suggests possible refuge value of low-productivity pindan savannas.
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Frank ASK, Johnson CN, Potts JM, Fisher A, Lawes MJ, Woinarski JCZ, Tuft K, Radford IJ, Gordon IJ, Collis MA, Legge S. Experimental evidence that feral cats cause local extirpation of small mammals in Australia's tropical savannas. J Appl Ecol 2014. [DOI: 10.1111/1365-2664.12323] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anke S. K. Frank
- School of Biological Sciences; University of Tasmania; Private Bag 55 Hobart TAS 7001 Australia
- Australian Wildlife Conservancy; Mornington Sanctuary; Derby WA 6728 Australia
| | - Chris N. Johnson
- School of Biological Sciences; University of Tasmania; Private Bag 55 Hobart TAS 7001 Australia
| | - Joanne M. Potts
- The Analytical Edge Pty. Ltd.; PO Box 47 Blackmans Bay TAS 7052 Australia
| | - Alaric Fisher
- Department of Land Resource Management; Northern Territory Government; PO Box 496 Palmerston NT 0831 Australia
| | - Michael J. Lawes
- Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin NT 0909 Australia
| | - John C. Z. Woinarski
- North Australian Hub; National Environmental Research Program; Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin NT 0909 Australia
| | - Katherine Tuft
- Australian Wildlife Conservancy; Mornington Sanctuary; Derby WA 6728 Australia
| | - Ian J. Radford
- Science and Conservation Division; Department of Parks and Wildlife; PO Box 942 Kununurra WA 6743 Australia
| | - Iain J. Gordon
- CSIRO Australian Tropical Sciences and Innovation Precinct; ATSIP; James Cook Drive; James Cook University; Building 145 Douglas Campus Townsville QLD 4811 Australia
- James Hutton Institute; Invergowrie Dundee DD2 5DA UK
| | - Mary-Anne Collis
- Department of Biology; University of Winnipeg; 515 Portage Ave Winnipeg MB R3B 2E9 Canada
| | - Sarah Legge
- Australian Wildlife Conservancy; Mornington Sanctuary; Derby WA 6728 Australia
- North Australian Hub; National Environmental Research Program; Research Institute for the Environment and Livelihoods; Charles Darwin University; Darwin NT 0909 Australia
- Research School of Biology; Australian National University; Canberra ACT 0200 Australia
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Prentis PJ, White EM, Radford IJ, Lowe AJ, Clarke AR. Can hybridization cause local extinction: a case for demographic swamping of the Australian native Senecio pinnatifolius by the invasive Senecio madagascariensis? New Phytol 2007; 176:902-912. [PMID: 17850249 DOI: 10.1111/j.1469-8137.2007.02217.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Hybridization between native and invasive species can have several outcomes, including enhanced weediness in hybrid progeny, evolution of new hybrid lineages and decline of hybridizing species. Whether there is a decline of hybridizing species largely depends on the relative frequencies of parental taxa and the viability of hybrid progeny. Here, the individual- and population-level consequences of hybridization between the Australian native Senecio pinnatifolius and the exotic Senecio madagascariensis were investigated with amplified fragment length polymorphism (AFLP) markers, and this information was used to estimate the annual loss of viable seeds to hybridization. A high frequency (range 8.3-75.6%) of hybrids was detected in open pollinated seeds of both species, but mature hybrids were absent from sympatric populations. A hybridization advantage was observed for S. madagascariensis, where significantly more progeny than expected were sired based on proportional representation of the two species in sympatric populations. Calculations indicated that S. pinnatifolius would produce less viable seed than S. madagascariensis, if hybridization was frequency dependent and S. madagascariensis reached a frequency of between 10 and 60%. For this native-exotic species pair, prezygotic isolating barriers are weak, but low hybrid viability maintains a strong postzygotic barrier to introgression. As a result of asymmetric hybridization, S. pinnatifolius would appear to be under threat if S. madagascariensis increases numerically in areas of contact.
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Affiliation(s)
- P J Prentis
- School of Natural Resource Sciences, QUT, GPO Box 2434, Brisbane 4001, Qld, Australia
- School of Environmental and Earth Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - E M White
- School of Natural Resource Sciences, QUT, GPO Box 2434, Brisbane 4001, Qld, Australia
- Alan Fletcher Research Station, Department of Natural Resources, Mines and Water and CRC for Australian Weed Management, PO Box 36, Sherwood 4075, Qld, Australia
| | - I J Radford
- Department of Environment and Conservation, PO Box 942, Kununurra, WA 6743, Australia
| | - A J Lowe
- School of Environmental and Earth Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - A R Clarke
- School of Natural Resource Sciences, QUT, GPO Box 2434, Brisbane 4001, Qld, Australia
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Radford IJ, Dickinson KJ, Lord JM. Nutrient stress and performance of invasive Hieracium lepidulum and co-occurring species in New Zealand. Basic Appl Ecol 2006. [DOI: 10.1016/j.baae.2005.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Radford IJ, Nicholas M, Tiver F, Brown J, Kriticos D. Seedling establishment, mortality, tree growth rates and vigour of Acacia nilotica in different Astrebla grassland habitats: Implications for invasion. AUSTRAL ECOL 2002. [DOI: 10.1046/j.1442-9993.2002.01176.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Radford IJ, Nicholas DM, Brown JR, Kriticos DJ. Paddock-scale patterns of seed production and dispersal in the invasive shrub Acacia nilotica (Mimosaceae) in northern Australian rangelands. AUSTRAL ECOL 2001. [DOI: 10.1046/j.1442-9993.2001.01119.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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