Functional gene analysis suggests different acetogen populations in the Bovine Rumen and Tammar Wallaby Forestomach

Reductive acetogenesis via the acetyl coenzyme A (acetyl-CoA) pathway is an alternative hydrogen sink to methanogenesis in the rumen. Functional gene-based analysis is the ideal approach for investigating organisms capable of this metabolism (acetogens). However, existing tools targeting the formyltetrahydrofolate synthetase gene (fhs) are compromised by lack of specificity due to the involvement of formyltetrahydrofolate synthetase (FTHFS) in other pathways. Acetyl-CoA synthase (ACS) is unique to the acetyl-CoA pathway and, in the present study, acetyl-CoA synthase genes (acsB) were recovered from a range of acetogens to facilitate the design of acsB-specific PCR primers. fhs and acsB libraries were used to examine acetogen diversity in the bovine rumen and forestomach of the tammar wallaby (Macropus eugenii), a native Australian marsupial demonstrating foregut fermentation analogous to rumen fermentation but resulting in lower methane emissions. Novel, deduced amino acid sequences of acsB and fhs affiliated with the Lachnospiraceae in both ecosystems and the Ruminococcaeae/Blautia group in the rumen. FTHFS sequences that probably originated from nonacetogens were identified by low "homoacetogen similarity" scores based on analysis of FTHFS residues, and comprised a large proportion of FTHFS sequences from the tammar wallaby forestomach. A diversity of FTHFS and ACS sequences in both ecosystems clustered between the Lachnospiraceae and Clostridiaceae acetogens but without close sequences from cultured isolates. These sequences probably originated from novel acetogens. The community structures of the acsB and fhs libraries from the rumen and the tammar wallaby forestomach were different (LIBSHUFF, P < 0.001), and these differences may have significance for overall hydrogenotrophy in both ecosystems

The effects of land use change on native dung beetle diversity and function in Australia’s Wet Tropics

The impacts of land use change on biodiversity and ecosystem functions are variable, particularly in fragmented tropical rainforest systems with high diversity. Dung beetles (Scarabaeinae) are an ideal group to investigate the relationship between land use change, diversity and ecosystem function as they are easily surveyed, sensitive to habitat modification and perform many ecosystem functions. Although this relationship has been investigated for dung beetles in some tropical regions, there has been no study assessing how native dung beetles in Australia's tropical rainforests respond to deforestation, and what the corresponding consequences are for dung removal (a key ecosystem function fulfilled by dung beetles). In this study we investigated the relationship between dung beetle community attributes (determined through trapping) and function (using dung removal experiments that allowed different dung beetle functional groups to access the dung) in rainforest and cleared pasture in a tropical landscape in Australia's Wet Tropics. Species richness, abundance and biomass were higher in rainforest compared to adjacent pasture, and species composition between these land use types differed significantly. However, average body size and evenness in body size were higher in pasture than in rainforest. Dung removal was higher in rainforest than in pasture when both functional groups or tunnelers only could access the dung. Increased dung removal in the rainforest was explained by higher biodiversity and dominance of a small number of species with distinct body sizes, as dung removal was best predicted by the evenness in body size of the community. Our findings suggest that functional traits (including body size and dung relocation behaviour) present in a dung beetle community are key drivers of dung removal. Overall, our results show that deforestation has reduced native dung beetle diversity in Australian tropical landscapes, which negatively impacts on the capacity for dung removal by dung beetles in this region

Mammals of the Upper Henty River Region, Western Tasmania

A mammal survey was conducted in the Upper Henty River Region in western Tasmania. The area had been subject to much disturbance from mining, forestry and frequent fires and was covered by a maze of roads and tracks. Nineteen native species (including bats) were recorded. Four of the species listed in 1983 as occurring in the Lower Gordon Region, 80 km south of the present study area, were not recorded during our survey. It is considered that three of these species would probably have been found in the area with further searching. The fourth species, Mastacomysfuscus, is thought not to be present due to increased fire frequency in the sedgeland areas compared with the Lower Gordon Region. Potorous tridactylus is recorded for the first time from rainforest. Microhabitat selection by Rattus lutreolus and Pseudomys higginsi differed from that previously reported. Disturbance from road construction led to the creation of a new food source for Thylogale billardierii. The abundance of tracks in the area increased ease of movement for carnivorous mammals. Only one introduced species Felis catus, which is also known to occur in the Lower Gordon, was recorded. Disturbance had thus not led to an invasion of exotics

Whole-organism concentration ratios in wildlife inhabiting Australian uranium mining environments

Wildlife concentration ratios for 226Ra, 210Pb, 210Po and isotopes of Th and U from soil, water, and sediments were evaluated for a range of Australian uranium mining environments. Whole-organism concentration ratios (CRwo-media) were developed for 271 radionuclide-organism pairs within the terrestrial and freshwater wildlife groups. Australian wildlife often has distinct physiological attributes, such as the lower metabolic rates of macropod marsupials as compared with placental mammals. In addition, the Australian CRswo-media originate from tropical and semi-arid climates, rather than from the temperate-dominated climates of Europe and North America from which most (>90%) of internationally available CRwo-media values originate. When compared, the Australian and non-Australian CRs are significantly different for some wildlife categories (e.g. grasses, mammals) but not others (e.g. shrubs). Where differences exist, the Australian values were higher, suggesting that site-, or region-specific CRswo-media should be used in detailed Australian assessments. However, in screening studies, use of the international mean values in the Wildlife Transfer Database (WTD) appears to be appropriate, as long as the values used encompass the Australian 95th percentile values. Gaps in the Australian datasets include a lack of marine parameters, and no CR data are available for freshwater phytoplankton, zooplankton, insects, insect larvae or amphibians; for terrestrial environments, there are no data for amphibians, annelids, ferns, fungi or lichens & bryophytes. The new Australian specific parameters will aide in evaluating remediation plans and ongoing operations at mining and waste sites within Australia. They have also substantially bolstered the body of U- and Th-series CRwo-media data for use internationally

Investigating the impact of removing rabbit harbour on animal and vegetation dynamics Cottonvale Project Report 2007-2013

The field study reported here documented differences between sites that were either side of the Darling Downs Moreton Rabbit Board fence: one side had a long history of rabbit exclusion with few rabbits present whereas the other side had higher rabbit numbers over time. There were marked differences in the flora and fauna on either side of the fence, particularly rabbit abundance and pasture biomass. This difference reflected the long period of separation of the two areas by the DDMRB fence with differences in rabbit abundance as well as possible differences in general grazing management. The control of rabbit numbers on the infested side of the fence did not improve pasture condition to a state similar to that in the rabbit free area during the relatively short period of this study. Recent reviews and simulation studies of the pasture response to changes in grazing management (including changing in grazing pressure) have shown that pastures may takes many years to respond to even quite large reductions in grazing pressure (Hunt et al. 2014, Scanlan et al. 2014). Any positive impact of reduced rabbit density on the infested side will require a much longer time frame for any measureable improvement could be recorded and will depend on the general grazing management of the area. Small sample size precluded conclusively comparing rabbit survival on either side of the fence. This needs further investigation, particularly the effects on rabbit survival of those harbouring above ground compared with those living in warren systems. Similarly, reproductive output and recruitment appeared better where warrens were available, but this needs further testing in this environment with more data before more definitive conclusions can be made