Home ranges of introduced rats on <scp>C</scp>hristmas <scp>I</scp>sland: A pilot study

Low, Bing Wen; Mills, Harriet; Algar, Dave; Hamilton, Neil

doi:10.1111/emr.12024

Cited by 9 publications

(30 citation statements)

References 21 publications

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“…Different rat tracking methods provide distinctive information on rat space use scales. The HR 95 values from SECR modelling used as estimators for total area ranged by rats (pooled over individuals) are consistent with previous home range studies on tropical islands using radio-tracking and other live-trapping methods (Low et al 2013). Basic statistics on maximum range extent (MMDM) derived from trapping distances confirmed a habitat effect on distances moved by rats although they clearly underestimate total rat home range and could not supply useful information on true range boundaries.…”

Section: Range Scalessupporting

confidence: 77%

“…Previous studies have shown that rat home range size may vary due to a large number of factors including sex of individuals, population density, food availability and population breeding cycle (Innes & Skipworth 1983;Hooker & Innes 1995;Low, Mills, Algar, & Hamilton 2013). On tropical islands rat dynamics are primarily driven by bottom-up effects with summer high densities associated with seasonal pulses of rainfall (Harris & Macdonald 2007;Russell et al 2011).…”

Section: Space Use Dynamicsmentioning

confidence: 99%

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Invasive rat space use on tropical islands: Implications for bait broadcast

Ringler

Russell

Jaeger

et al. 2014

Basic and Applied Ecology

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Invasive rats on oceanic islands impact a large number of native species. Control programmes, and in many cases complete eradication, are used to alleviate these impacts. Basic data on rodent biology facilitate the design of control or eradication programmes, and is particularly required for programmes on tropical islands where such data are missing. Here we test for interactive effects of habitat and season that may alter black rat (Rattus rattus) space use dynamics and inform rodent management on two tropical islands. Five years of summer and winter trapping data were analysed using spatially explicit capture-recapture to calculate rat space-use and overlap, coupled with spool and line experiments ground-truthing microhabitat use. Variation in individual rat space use is primarily driven by sex and bottom-up trophic effects of seasonal rainfall on food resources, but is altered by island-specific contexts. In the absence of other introduced mammals, rats tend to have stable range overlap throughout the year but home range sizes fluctuate seasonally with rat density. The presence of other introduced mammals causes predictable greater seasonal fluctuations in rat space-use, putatively a behavioural adjustment to feral cats (Felis catus) diet-switching to rats from seasonal influxes of their alternative seabird prey. We identify winter as the recommended treatment period on both islands and discuss bait broadcast strategies. ZusammenfassungInvasive Ratten beeinträchtigen auf ozeanischen Inseln eine große Anzahl von einheimischen Arten. Kontrollprogramme und in vielen Fällen die vollständige Ausrottung werden genutzt, um diese Beeinträchtigungen zu mildern. Grundlegende Daten zur Kleinsäugerbiologie erleichtern die Planung von Kontroll-und Ausrottungsprogrammen. Sie werden besonders für Programme auf tropischen Inseln benötigt, wo solche Daten fehlen. Hier untersuchen wir die Interaktionen zwischen Habitat und Jahreszeit, die die Raumnutzung von Hausratten (Rattus rattus) verändern und dem Kleinsäugermanagement zugrunde gelegt werden können. Sommer-und Winterfallenfänge aus fünf Jahren mit räumlich explizitem Fang/Wiederfang wurden analysiert, um Raumnutzung und Überlappung der Ratten zu berechnen. Mit der Fadenspulen-Methode wurden Vergleichsmessungen zur Mikrohabitatnutzung durchgeführt. Die Variation der Raumnutzung durch Rattenindividuen wird in erster Linie vom Geschlecht und den durch saisonale Regenfälle bedingten Nahrungsressourcen bestimmt; sie wird aber durch inselspezifische Zusammenhänge modifiziert. (D. Ringler).Wenn keine anderen eingeführten Säuger vorhanden sind, ist die Überlappung der Territorien über das Jahr hinweg tendenziell stabil, aber die Größe der Aktionsräume schwankt saisonal mit der Rattendichte. Die Anwesenheit anderer eingeführter Säuger ist mit vorhersagbaren, größeren saisonalen Schwankungen der Raumnutzung durch die Ratten verbunden-vermutlich eine verhaltensbedingte Anpassung an den saisonal bedingten Nahrungswechsel verwilderter Hauskatzen (Felis catus)v on Seevögeln, ihrer alter...

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Section: Range Scalessupporting

confidence: 77%

Section: Space Use Dynamicsmentioning

confidence: 99%

Invasive rat space use on tropical islands: Implications for bait broadcast

Ringler

Russell

Jaeger

et al. 2014

Basic and Applied Ecology

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“…For both Norway and black rats (hereafter termed "rats" when referencing both species), the home range size and shape is determined by access to feeding and harborage sites (Davis et al, 1948;Recht, 1982;Low et al, 2013) as well as access to mates (Low et al, 2013;Glass et al, 2016). These associations lead to irregularly shaped home ranges with individuals often moving along narrow pathways connecting harborage and food sources (Davis et al, 1948;Recht, 1982;Recht et al, 1983).…”

Section: Home Rangementioning

confidence: 99%

“…rats (Low et al, 2013;Oyedele et al, 2015). Beyond the value of regular access to resources, an intimate familiarity with the features of the home range may serve as a protective measure for rats.…”

Section: Home Rangementioning

confidence: 99%

Rats About Town: A Systematic Review of Rat Movement in Urban Ecosystems

et al. 2019

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Norway and black rats (Rattus norvegicus and Rattus rattus) are ubiquitous urban pests, inhabiting cities worldwide. Despite their close association with people, urban rats remain difficult to control. This can be partly attributed to a general lack of information on basic rat ecology to inform management efforts. In this systematic review and narrative synthesis, we collate the published literature to provide a comprehensive description of what is known about urban rat movement, including information on home range, site fidelity, dispersal, movement patterns, barriers to, and factors impacting, movement. We also discuss the methodologies used to track and infer rat movement, as well as the advantages and limitations of employing these techniques. Our review suggests that the distances traveled by urban rats are location-specific, determined by both local resource availability and barriers to movement such as roadways. Although roads may impede rat movement, genetic techniques suggest that rats traverse roadways more often than revealed by capture-based tools, while long-distance dispersal events by either natural migration or facilitated by humans (i.e., as stowaways in transport vehicles) can maintain connectivity among distant populations. Because rat movement patterns are related to the transmission of rat-associated pathogens and the success of rodent control programs, these results have implications for city planners, pest control efforts, and public health. Therefore, we emphasize the importance of understanding local rat movement patterns in order to devise and deploy efficient and effective rat mitigation initiatives in urban centers.

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“…These authors record several island reptile declines (lizards, tuatara) induced by the introduction of R. rattus, R. exulans or R. norvegicus. The blue-tailed skink (Cryptoblepharus egeriae) is assumed to have declined because of rodent predation on Christmas Island (Low et al 2013), which is also the case for the endemic Belize leaf-toed gecko (Phyllodactylus insularis) on Half Moon Caye (Meerman 1996) and the whiptail lizard (Cnemidophorus vanzoi) on St Lucia (John 1999). On Rodrigues Island, large gecko species (Phelsuma edwardnewtoni and P. gigas) were devastated after rat introductions (Vinson & Vinson 1969).…”

Section: Introductionmentioning

confidence: 99%

Invasive rodents, an overlooked threat for skinks in a tropical island hotspot of biodiversity

Thibault¹,

Brescia²,

Jourdan³

et al. 2017

NZ J Ecol

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Squamata are one of the most threatened groups among island vertebrates, facing high pressure from exotic species. However, the contribution of small terrestrial reptiles in invasive rodents' diet remains poorly investigated, partly because of the lack of tools for accurately identifying chewed prey fragments in gut contents. The New Caledonia archipelago (South Pacific) hosts an exceptional terrestrial squamata fauna (105 species, 91.6% endemic) that are faced with many invasive species (rodents, feral cats, feral pigs, ants) and strong human pressures. Our study aimed to evaluate the frequency of occurrence of endemic skink remains by gut content analysis of two species of invasive rodents. Four rodent trapping sessions were implemented at two ultramafic sites and for two distinct habitats (closed canopy forest and open shrubland habitat). A total of 284 rats were trapped from two species (the ship rat Rattus rattus and the Pacific rat R. exulans) over 1200 trap nights. Combined analysis of stomach and caecum contents provided far more information than traditional stomach analysis alone. Analyses showed that 15.9% of rat samples included remains of at least 12 different skink species out of the 23 present. Six species are classified as threatened by the IUCN, the most endangered being Marmorosphax taom (CR) and Kanakysaurus viviparus (EN). This study provides new prospects for the assessment of invasive rodent impacts and new insights into the respective impacts of two sympatric invasive rodent species on native skinks.

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Home ranges of introduced rats on Christmas Island: A pilot study

Cited by 9 publications

References 21 publications

Invasive rat space use on tropical islands: Implications for bait broadcast

Invasive rat space use on tropical islands: Implications for bait broadcast

Rats About Town: A Systematic Review of Rat Movement in Urban Ecosystems

Invasive rodents, an overlooked threat for skinks in a tropical island hotspot of biodiversity

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