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In New South Wales, legislation governing land clearing and development as it relates to koala conservation acts to prevent the destruction of habitat containing key tree species used by koalas. The identification of these key tree species is therefore critical to koala conservation. We aimed to compile a list of tree species used by koalas within the Wollondilly Shire region and investigate tree-use preferences. We radio-collared one female and four male koalas and tracked their movements over a period of 107--195 days. We conducted surveys within each koala's home range to quantify the relative availability of each tree species, which we compared with their relative frequency of use. Koalas used 19 different tree species (17 during day, 12 during night), despite over 32 species being available. Eight species were preferentially used by one or more koalas; these were Eucalyptuts bosistoana, E. longifolia, E. puncata, E. crebra, E. globoidea, E. pilularis, E. tereticornis and Angophora flohbunda. Two species were avoided: Corymbia gummifera and Acacia decurrens. Koalas consistently used larger trees relative to their availability, and we found a general but non-significant trend towards the use of larger trees at night compared with during the day. To achieve koala conservation, it will be necessary to preserve habitat patches comprising a diverse mixture of tree species and sizes, particularly trees >35 cm diameter at breast height (DBH), and to appropriately revegetate land with these criteria in mind. [ABSTRACT FROM AUTHOR]

Movement is often used to indicate host vigour, as it has various ecological and evolutionary implications, and has been shown to be affected by parasites. We investigate the relationship between tick load and movement in the Australian Sleepy Lizard (Tiliqua rugosa (Gray, 1825)) using high resolution GPS tracking. This allowed us to track individuals across the entire activity season. We hypothesized that tick load negatively affects host movement (mean distance moved per day). We used a multivariate statistical model informed by the ecology and biology of the host and parasite, their host--parasite relationship, and known host movement patterns. This allowed us to quantify the effects of ticks on lizard movement above and beyond effects of other factors such as time in the activity season, lizard body condition, and stress. We did not find any support for our hypothesis. Instead, our results provide evidence that lizard movement is strongly driven by internal state (sex and body condition independent of tick load) and by external factors (environmental conditions). We suggest that the Sleepy Lizard has largely adapted to natural levels of tick infection in this system. Our results conform to host--parasite arms race theory, which predicts varying impacts of parasites on hosts in natural systems.Key words: reptile, body-mass index, movement ecology, parasite, GPS tracking, host--parasite interaction, spatial behaviour, Sleepy Lizard, Tiliqua rugosa.Les deplacements sont souvent utilises pour inferer la vigueur des hotes, puisqu'ils temoignent de differentes manieres de l'ecologie et de l'evolution et qu'il a ete demontre qu'ils sont influences par les parasites. Nous examinons la relation entre la charge de tiques et les deplacements chez le scinque rugueux (Tiliqua rugosa (Gray, 1825)) en utilisant le reperage par GPS de haute resolution, qui permet de suivre des individus durant toute la periode d'activite. Nous avons postule que la charge de tiques a une incidence negative sur les deplacements des hotes (distance de deplacement moyenne par jour). Nous utilisons un modele statistique multi-variable integrant de l'information sur l'ecologie et la biologie de l'hote et du parasite, leur relation hote--parasite et les motifs de deplacement connus de l'hote. Cela nous permet de quantifier les effets des tiques sur les deplacements des scinques en excluant les effets d'autres facteurs comme le moment de la periode d'activite, l'embonpoint des scinques et le stress. Les resultats ne supportent aucunement notre hypothese. Ils indiquent plutot que les deplacements des scinques sont fortement modules par l'etat interne (sexe et embonpoint independants de la charge de tiques) et des facteurs externes (conditions ambiantes). Nous proposons que le scinque rugueux s'est en bonne partie adapte aux niveaux naturels d'infection de tiques dans ce systeme. Nos resultats sont conformes a la theorie de la course aux armements entre hote et parasite, qui predit des impacts variables des parasites sur les hotes dans des systemes naturels. [Traduit par la Redaction]Mots-cles: reptile, indice de masse corporelle, ecologie des deplacements, parasite, reperage par GPS, interaction hote-parasite, comportement spatial, scinquea rugueux, Tiliqua rugosa., IntroductionParasites, by definition, gain their energy resources from their hosts, which negatively impacts the host's health and vigour (Beyer and Grossman 1997; Fenner and Bull 2008). Such impacts in host--parasite [...]

Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced as a biological control agent. However, little is known about the rate at which this evolutionary change occurred. We collated data from challenge trials that estimated rabbit resistance to myxomatosis in Australia and expressed resistance on a continuous scale, enabling trends in its development to be assessed over 45 years up to 1995. Resistance initially increased rapidly, followed by a plateau lasting ten years, before a second rapid increase occurred associated with the introduction of European rabbit fleas as myxoma virus vectors. By contrast, in the United Kingdom, where rabbit flea vectors were already present when the myxoma virus initially spread, resistance developed more slowly. No estimates of rabbit resistance to myxomatosis have been made for almost 30 years, despite other highly lethal rabbit pathogens becoming established worldwide. Continued testing of wild-caught rabbits in Australia to determine current levels of resistance to myxomatosis is recommended to assess its current effectiveness for managing pest rabbits. Given the economic and environmental significance of invasive rabbits, it would be remiss to manage such biological resources and ecosystem services poorly. [ABSTRACT FROM AUTHOR]

Rabbit haemorrhagic disease virus (RHDV) is highly pathogenic to European rabbits. Until recently, only one serotype of RHDV was known, GI.1/RHDV. RHDV2/GI.2 is a novel virus that has rapidly spread and become the dominant pathogenic calicivirus in wild rabbits worldwide. It is speculated that RHDV2 has three competitive advantages over RHDV: (a) the ability to partially overcome immunity to other variants; (b) the ability to clinically infect young rabbits; and (c) a wider host range. These differences would be expected to influence virus transmission dynamics. We used markers of recent infection (IgM/IgA antibodies) to investigate virus transmission dynamics pre and post the arrival of RHDV2. Our data set contained over 3,900 rabbits sampled across a 7-year period at 12 Australian sites. Following the arrival of RHDV2, seasonal peaks in IgM and IgA seropositivity shifted forward one season, from winter to autumn and spring to winter, respectively. Contrary to predictions, we found only weak effects of rabbit age, seropositivity to non-pathogenic calicivirus RCV-A1 and population abundance on IgM/IgA seropositivity. Our results demonstrate that RHDV2 enters rabbit populations shortly after the commencement of annual breeding cycles. Upon entering, the population RHDV2 undergoes extensive replication in young rabbits, causing clinical disease, high virus shedding, mortality and the creation of virus-laden carcasses. This results in high virus contamination in the environment, furthering the transmission of RHDV2 and initiating outbreaks, whilst simultaneously removing the susceptible cohort required for the effective transmission of RHDV. Although RHDV may enter the population at the same time point, it is sub-clinical in young rabbits, causing minimal virus shedding and low environmental contamination. Our results demonstrate a major shift in epidemiological patterns in virus transmission, providing the first evidence that RHDV2's ability to clinically infect young rabbits is a key competitive advantage in the field. [ABSTRACT FROM AUTHOR]

Introduced rabbits are a continuing threat to native Australian flora and fauna. Three interventions using biological control agents, myxomatosis, European rabbit fleas, and rabbit hemorrhagic disease, have reduced rabbit abundance and kept numbers low over the last 70 years. We considered the benefits of biological control for native fauna to put the role of rabbits in influencing vegetation cover, food supply, and predation into better perspective. Numerous examples exist demonstrating increases in native vegetation and the expansion and recovery of native animal populations at landscape scales following intense rabbit suppression. Ongoing research on methods for supplementing the impact of biological control agents and managing introduced predators are needed to restore Australia's arid‐zone ecosystems. However, many biologists and rangeland managers first need to reevaluate the misconception that removing rabbits also introduces other serious and insurmountable problems such as prey‐switching by introduced cats and foxes. [ABSTRACT FROM AUTHOR]

We describe our experiences collecting blood from Australian Rattus. We found uniform anatomy of the external jugular vein between Australian and exotic Rattus species. Understanding where the maxillary and linguofacial veins join to form the external jugular vein is critical to venepuncture. After locating this union, we consistently achieved successful venepuncture of the external jugular vein; yielding large blood volumes. All other routes of venepuncture yielded minute blood volumes or were unsuccessful. We provide recommendations for venepuncture in Australian rodents and encourage others to share their experiences; such reports facilitate sampling rarely sampled species and promote animal welfare. The collection of blood from live small rodents is essential to many research endeavours. We describe our experiences and provide recommendations for the collection of blood from Australian rodents. Such reports facilitate sampling rarely sampled species and promote animal welfare. Photograph by Dr Elisa Sparrow. [ABSTRACT FROM AUTHOR]

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