Effects of an invasive species on refuge-site selection by native fauna : the impact of cane toads on native frogs in the Australian tropics

Invasive species can induce shifts in habitat use by native taxa: either by modifying habitat availability, or by repelling or attracting native species to the vicinity of the invader. The ongoing invasion of cane toads (Rhinella marina) through tropical Australia might affect native frogs by affecting refuge-site availability, because both frogs and toads frequently shelter by day in burrows. Our laboratory and field studies in the wet-dry tropics show that native frogs of at least three species (Litoria tornieri, Litoria nasuta and Litoria dahlii) preferentially aggregate with conspecifics, and with (some) other species of native frogs. However, the frogs rarely aggregated with cane toads either in outdoor arenas or in standardized experimental burrows that we monitored in the field. The native frogs that we tested either avoided burrows containing cane toads (or cane toad scent) or else ignored the stimulus (i.e. treated such a burrow in the same way as they did an empty burrow). Native frogs selected a highly non-random suite of burrows as diurnal retreat sites, whereas cane toads were less selective. Hence, even in the absence of toads, frogs do not use many of the burrows that are suitable for toads. The invasion of cane toads through tropical Australia is unlikely to have had a major impact on retreat-site availability for native frogs.

Comparison of genetic diversities in native and alien populations of hoary mustard (Hirschfeldia incana [L.] Lagreze-Fossat)

Increased selfing and inbreeding and, consequently, depauperate genetic diversities are commonly expected for alien colonies. We compared RAPDs data for native (southern Europe) and alien (British Isles) populations of hoary mustard (Hirschfeldia incana). This species is normally out-breeding, but it is capable of self- fertilization. Contrary to the common expectations, genetic diversities in native and alien populations were similar, without any strong evidence of decreased levels of genetic diversities in alien populations. A variety of factors may have contributed to this observation, including high variation in founding groups, founders originating from multiple H. incana source populations, and high rates of past and/or current gene flow. A review of other studies showed that this pattern of similar genetic diversities in native and alien populations was not unusual but has been regularly observed in other invasive plant species.

Networks of Meaning: Learning How Native Speakers Think and Use Language

This article discusses the way in whic language learners master meaning, particularly of on-literal language. This issue is discussed in the context of the learner's cognitive framework with specific reference to Indonesian and English.

How do native English academic writers and Chinese native speakers writing in English promote their research

This paper reports on an investigation of a rhetorical organization of Applied Linguistics abstracts produced in Anglophone and Chinese academic discourse communities and written by native English and native Chinese speaking scholars. The study utilises the Framework for the Analysis of the Rhetorical Structure of Texts (FARS), proposed by Golebiowski (2009, 2011). FARS provides a functional account of the relational structure of texts in terms of strategies employed by writers to achieve their communicative purposes. I show how the two groups of abstracts utilize different relational schemata in order to indicate the functional prominence of textual propositions. It is proposed that relational choices, which result in differences in the accentuation of communicative messages in the two groups of abstracts, are dictated by cultural traditions and conventions underlying the discourse community into which the authors have been socialized.

Genome sequence of Ensifer sp. TW10, a Tephrosia wallichii (Biyani) microsymbiont native to the Indian Thar Desert

Ensifer sp. TW10 is novel N2-fixingbacterium isolated from a root nodule of the perennial legume Tephrosia wallichii Graham (known locally as Biyani) found in the Great Indian (or Thar) desert, a large arid regionin the northwestern part of the Indian subcontinent. Strain TW10 is a Gram-negative, rod shaped,aerobic, motile, non-spore forming, species of root nodule bacteria (RNB) that promiscuously nodulates legumes in Thar Desert alkaline soil. It is fast growing, acid-producing, and tolerates up to 2% NaCl and capable of growth at 40C. In this report we describe for the first time the primary features of this Thar Desert soil saprophyte together with genome sequence informationand annotation. The 6,802,256 bp genome has a GC content of 62% and is arranged into 57 scaffolds containing 6,470 protein-coding genes, 73 RNA genes and asingle rRNA operon. This genome is one of 100 RNB genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.

A case of Kingella kingae endocarditis complicated by native mitral valve rupture

We report a case of Kingella kingae endocarditis in a patient with a history of recent respiratory tract infection and dental extraction. This case is remarkable for embolic and vasculitic phenomena in association with a large valve vegetation and valve perforation. Kingella kingae is an organism known to cause endocarditis, however early major complications are uncommon. Our case of Kingella endocarditis behaved in a virulent fashion necessitating a combined approach of intravenous antibiotic therapy and a valve replacement. It highlights the importance of expedited investigation for endocarditis in patients with Kingella bacteraemia.

Detecting the impact of invasive species on native fauna: Cane toads (Bufo marinus), frillneck lizards (Chlamydosaurus kingii) and the importance of spatial replication

An understanding of which native species are severely impacted by an anthropogenic change (such as the arrival of an invasive species) and which are not is critical to prioritizing conservation efforts. However, it is difficult to detect such impacts if the native taxa exhibit strong stochastic variations in abundance; a ‘natural’ population decline might be wrongly interpreted as an impact of the invader. Frillneck lizards (Chlamydosaurus kingii) are large iconic Australian agamids, and have been reported to decline following the invasion of toxic cane toads. We monitored three populations of the species in the savanna woodland of tropical Australia over a 7-year period bracketing toad arrival. One population crashed, one remained stable and one increased. Hence, studies on any single population might have inferred that cane toads have negative, negligible or positive effects on frillneck lizards. With the benefit of spatial replication, and in combination with observations of prey choice by captive lizards, our data suggest that invasive cane toads have had little or no effect on frillneck abundance.

Increased mortality of naive varanid lizards after the invasion of non-native can toads (bufo marinus)

Exotic animal and plant species introduced into the Australian continent often imparted catastrophic effects on the indigenous fauna and flora. Proponents of biological control introduced the South American Cane Toad (Bufo marinus) into the sugar cane fields of Queensland in 1935. The Cane Toad is one of the most toxic bufonids and when seized by naive Australian predators, the toxin usually kills the attacker. One group of Australian squamate reptiles that are very susceptible to Cane Toad toxins is varanid lizards. Prior to Cane Toad invasion of our study area, the Adelaide River floodplain of the Northern Territory of Australia, annual mortality of adult male radio-tagged yellow-spotted Goannas (Varanus panoptes) was very low. After the arrival of toads in October 2005, all radio-tracked goannas were found dead in August 2006, most likely attempting to feed on the toads. Our results suggest that invasive Cane Toads place naive adult male Yellow-spotted Goannas at risk of possibly >90% mortality. This increase in mortality could reduce the genetic diversity and hamper long-term survival of these large carnivorous lizards.

Nativity, duration of residence and chronic health conditions in Australia: Do trends converge towards the native-born population?

Using data from waves 3, 7 and 9 of the Household, Income and Labour Dynamics in Australia (HILDA) survey, a group-mean-centred multilevel mixed model and self-reported chronic conditions, this study contributes to the limited longitudinal evidence on the nativity health gap in Australia. We investigated whether differences exist in the reporting of any chronic condition (including cancer, cardiovascular disease (CVD), arthritis, diabetes and respiratory disease), and in the total number of chronic conditions, between foreign-born (FB) from English speaking (ES) and non-English speaking (NES) countries and native-born (NB) Australians. We also investigated differences between these groups in the reporting of any chronic condition, and the total number of chronic conditions, by duration of residence. After adjusting for time varying and time invariant covariates, we found a significant difference by nativity status in the reporting of chronic condition, with immigrants from both ES and NES countries less likely to report a chronic condition and having fewer chronic conditions compared with the NB. Immigrants from both ES and NES countries living in Australia for less than 20 years were significantly less likely to report a chronic condition compared with the NB. However, the health of both these groups converged to that of the NB population in terms of reporting a chronic condition after 20 years of stay in Australia.