Role of Native Fish in Integrated Aquatic Weed and Water Quality Management within the Burdekin Irrigation Area

This report summarises work conducted by the QDPI, in partnership with the South Burdekin Water Board (SBWB) and the Burdekin Shire Council (BSC) between 2001 and 2003. The broad aim of the research was to assess the potential of native fish as biocontrol agents for noxious weeds, as part of an integrated program for managing water quality in the Burdekin Irrigation Area. A series of trials were conducted at, or using water derived from, the Sandy Creek Diversion near Groper Creek (lower Burdekin delta). Trials demonstrated that aquatic weeds play a positive role in trapping transient nutrients, until such time that weed growth becomes self-shading and weed dieback occurs, which releases stored nutrients and adversely affects water quality. Transient nutrient levels (av. TN<0.5mg/L; av. TP<0.1mg/L) found in the irrigation channel during the course of this research were substantially lower than expected, especially considering the intensive agriculture and sewage effluent discharge upstream from the study site. This confirms the need to consider the control of weeds rather than complete weed extermination when formulating management plans. However, even when low nutrient levels are available, there is competitive exploitation of habitat variables in the irrigation area leading to succession and eventual domination by certain weed species. During these trials, we have seen filamentous algae, phytoplankton, hyacinth and curled pondweed each hold competitive advantage at certain points. However without intervention, floating weeds, especially hyacinth, ultimately predominate in the Burdekin delta due to their fast propagation rate and their ability to out-shade submerged plants. We have highlighted the complexity of interactions in these highly disturbed ecosystems in that even if the more prevalent noxious weeds are contained, other weed species will exploit the vacant niche. This complexity places stringent requirements on the type of native fish that can be used as biocontrol agents. Of the seven fish species identified with herbivorous trophic niches, most target plankton or algae and do not have the physical capacity to directly eat the larger macrophytes of the delta. We do find however that following mechanical weed harvesting, inoculative releases of fish can slow the rate of hyacinth recolonisation. This occurs by mechanisms in addition to direct weed consumption, such as disturbing growth surfaces by grazing on attached biofilms. Predation by birds and water rats presents another impediment to the efficacy of large-scale releases of fish. However, alternative uses of fish in water quality management in the Burdekin irrigation area are discussed.

Influence of Measured Characteristics on Price Received for Merino Wool from the Traprock Area of Southern Queensland

In this study of a commercial wool clip sold in the years 1991/92-1996/97, the effect of wool characteristics, (staple length, staple strength, fibre diameter, position of break, vegetable matter, hauteur, yield and coefficient of variation of staple length) on price was explored together with their effect on the ratio of price received per lot to the average weekly price (1994/95 basis) for clean wool of the same fibre diameter. Fibre diameter and where the point of break occurred had the most effect on price. As hauteur, staple length and yield increased, so did the price ratio but it decreased as the percentage of vegetable matter and the coefficient of variation of the staple length increased. The ratio of proceeds if all wool had been sold at average weekly market price, to proceeds if all wool had been 21µm or less, indicated little financial advantage over the six-year period as most sale lots were under 22µm. To raise the proceeds of sale above the proceeds estimated using average market price for each lot, the analyses suggested that hauteur, staple length and its coefficient of variation, could be considered, in addition to fibre diameter, when sourcing wethers for purchase. Animal production for a consuming world : proceedings of 9th Congress of the Asian-Australasian Association of Animal Production Societies [AAAP] and 23rd Biennial Conference of the Australian Society of Animal Production [ASAP] and 17th Annual Symposium of the University of Sydney, Dairy Research Foundation, [DRF]. 2-7 July 2000, Sydney, Australia.

Assessing the relationship between patch type and soil mites: A molecular approach

An urgent need exists for indicators of soil health and patch functionality in extensive rangelands that can be measured efficiently and at low cost. Soil mites are candidate indicators, but their identification and handling is so specialised and time-consuming that their inclusion in routine monitoring is unlikely. The aim of this study was to measure the relationship between patch type and mite assemblages using a conventional approach. An additional aim was to determine if a molecular approach traditionally used for soil microbes could be adapted for soil mites to overcome some of the bottlenecks associated with soil fauna diversity assessment. Soil mite species abundance and diversity were measured using conventional ecological methods in soil from patches with perennial grass and litter cover (PGL), and compared to soil from bare patches with annual grasses and/or litter cover (BAL). Soil mite assemblages were also assessed using a molecular method called terminal-restriction fragment length polymorphism (T-RFLP) analysis. The conventional data showed a relationship between patch type and mite assemblage. The Prostigmata and Oribatida were well represented in the PGL sites, particularly the Aphelacaridae (Oribatida). For T-RFLP analysis, the mite community was represented by a series of DNA fragment lengths that reflected mite sequence diversity. The T-RFLP data showed a distinct difference in the mite assemblage between the patch types. Where possible, T-RFLP peaks were matched to mite families using a reference 18S rDNA database, and the Aphelacaridae prevalent in the conventional samples at PGL sites were identified, as were prostigmatids and oribatids. We identified limits to the T-RFLP approach and this included an inability to distinguish some species whose DNA sequences were similar. Despite these limitations, the data still showed a clear difference between sites, and the molecular taxonomic inferences also compared well with the conventional ecological data. The results from this study indicated that the T-RFLP approach was effective in measuring mite assemblages in this system. The power of this technique lies in the fact that species diversity and abundance data can be obtained quickly because of the time taken to process hundreds of samples, from soil DNA extraction to data output on the gene analyser, can be as little as 4 days.

Detection of equine herpesvirus type 1 using a real-time polymerase chain reaction.

Equid herpesvirus 1 (EHV1) is a major disease of equids worldwide causing considerable losses to the horse industry. A variety of techniques, including PCR have been used to diagnose EHV1. Some of these PCRs were used in combination with other techniques such as restriction enzyme analysis (REA) or hybridisation, making them cumbersome for routine diagnostic testing and increasing the chances of cross-contamination. Furthermore, they involve the use of suspected carcinogens such as ethidium bromide and ultraviolet light. In this paper, we describe a real-time PCR, which uses minor groove-binding probe (MGB) technology for the diagnosis of EHV1. This technique does not require post-PCR manipulations thereby reducing the risk of cross-contamination. Most importantly, the technique is specific; it was able to differentiate EHV1 from the closely related member of the Alphaherpesvirinae, equid herpesvirus 4 (EHV4). It was not reactive with common opportunistic pathogens such as Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa and Enterobacter agglomerans often involved in abortion. Similarly, it did not react with equine pathogens such as Streptococcus equi, Streptococcus equisimilis, Streptococcus zooepidemicus, Taylorella equigenitalis and Rhodococcus equi, which also cause abortion. The results obtained with this technique agreed with results from published PCR methods. The assay was sensitive enough to detect EHV1 sequences in paraffin-embedded tissues and clinical samples. When compared to virus isolation, the test was more sensitive. This test will be useful for the routine diagnosis of EHV1 based on its specificity, sensitivity, ease of performance and rapidity.

Completion of the genome sequence of Lettuce necrotic yellows virus, type species of the genus Cytorhabdovirus

We completed the genome sequence of Lettuce necrotic yellows virus (LNYV) by determining the nucleotide sequences of the 4a (putative phosphoprotein), 4b, M (matrix protein), G (glycoprotein) and L (polymerase) genes. The genome consists of 12,807 nucleotides and encodes six genes in the order 3′ leader-N-4a(P)-4b-M-G-L-5′ trailer. Sequences were derived from clones of a cDNA library from LNYV genomic RNA and from fragments amplified using reverse transcription-polymerase chain reaction. The 4a protein has a low isoelectric point characteristic for rhabdovirus phosphoproteins. The 4b protein has significant sequence similarities with the movement proteins of capillo- and trichoviruses and may be involved in cell-to-cell movement. The putative G protein sequence contains a predicted 25 amino acids signal peptide and endopeptidase cleavage site, three predicted glycosylation sites and a putative transmembrane domain. The deduced L protein sequence shows similarities with the L proteins of other plant rhabdoviruses and contains polymerase module motifs characteristic for RNA-dependent RNA polymerases of negative-strand RNA viruses. Phylogenetic analysis of this motif among rhabdoviruses placed LNYV in a group with other sequenced cytorhabdoviruses, most closely related to Strawberry crinkle virus.

Incorporating dugong habitats into the marine protected area design for the Great Barrier Reef Marine Park, Queensland, Australia.

Dugong habitats were considered in the design for the new zoning network for the Great Barrier Reef Marine Park as part of the Representative Areas Program. One of the specific design guidelines developed as part of the biophysical operational principles recommended that 50% of all high priority dugong habitats should be incorporated in the network of no-take areas. The high priority dugong habitat incorporated in no-take protection increased from 1396 to 3476 km2 (or 16.9-42.0% of all identified sites). Although this increase in protection fell short of the recommended 50%, overall the level of protection afforded by the Great Barrier Reef Marine Park Zoning Plan 2003 increased for all the locations identified.

GIS-based tools for management of pine plantations, Queensland, Australia

Two examples of GIS-based multiple-criteria evaluations of plantation forests are presented. These desktop assessments use available topographical, geological and pedological information to establish the risk of occurrence of certain environmentally detrimental processes. The first case study is concerned with the risk that chemical additives (i.e. simazine) applied within the forestry landscape may reach the drainage system. The second case study assesses the vulnerability of forested areas to landslides. The subject of the first multiple-criteria evaluation (MCE) was a 4 km2 logging area, which had been recently site-prepared for a Pinus plantation. The criteria considered relevant to the assessment were proximity to creeks, slope, soil depth to the restrictive layer (i.e. potential depth to a perched water table) and soil erodability (based on clay content). The output of the MCE was in accordance with field observations, showing that this approach has the potential to provide management support by highlighting areas vulnerable to waterlogging, which in turn can trigger overland flow and export of pollutants to the local stream network. The subject of the second evaluation was an Araucaria plantation which is prone to landslips during heavy rain. The parameters included in the assessment were drainage system, the slope of the terrain and geological features such as rocks and structures. A good correlation between the MCE results and field observations was found, suggesting that this GIS approach is useful for the assessment of natural hazards. Multiple-criteria evaluations are highly flexible as they can be designed in either vector or raster format, depending on the type of available data. Although tested on specific areas, the MCEs presented here can be easily used elsewhere and assist both management intervention and the protection of the adjacent environment by assessing the vulnerability of the forest landscape to either introduced chemicals or natural hazards.

Notes on the type, synonyms, and other specimens of the balansioid fungus, Nigrocornus scleroticus

The type, and other specimens of the balansioid fungus, Nigrocornus scleroticus, its synonyms, and similar fungi studied during extensive research on the taxonomy and biology of the fungus, are described. Two hypocrealean fungi found parasitising the ascostromata of N. scleroticus are also discussed.

Spatial patterns of sub-tidal seagrasses and their tissue nutrients in the Torres Strait, northern Australia: Implications for management

The distribution and nutritional profiles of sub-tidal seagrasses from the Torres Strait were surveyed and mapped across an area of 31,000 km2. Benthic sediment composition, water depth, seagrass species type and nutrients were sampled at 168 points selected in a stratified representative pattern. Eleven species of seagrass were present at 56 (33.3%) of the sample points. Halophila spinulosa, Halophila ovalis, Cymodocea serrulata and Syringodium isoetifolium were the most common species and these were nutrient profiled. Sub-tidal seagrass distribution (and associated seagrass nutrient concentrations) was generally confined to northern-central and south-western regions of the survey area (

Demographics, pollination syndrome and conservation status of Macrozamia platyrhachis (Zamiaceae), a geographically restricted Queensland cycad

To assess the International Union for Conservation of Nature (IUCN) status of Macrozamia platyrhachis F.M.Bailey, we surveyed this central Queensland cycad for its population abundance and health and its pollinator type and pollination syndrome (thermogenesis and volatile emissions). Plants are locally abundant within the 11 discrete populations surveyed, with an estimated population of 611 315 adult plants. Plants are highly restricted to a small area of occupancy, seed dispersal is nearly non-existent and extreme fires appear to have destroyed almost all seeds and seedlings and decimated the pollinators. Of known Macrozamia pollinators, only the thrips, Cycadothrips chadwicki Mound, were found on cones, and these were found in very low numbers. The pollination syndrome for this cycad appears to be unique, based on two cone traits. For one, thermogenesis peaks in early evening, a contrast with daytime peaks of other Cycadothrips-pollinated Macrozamia, but matches that of the Tranes weevil-pollinated Macrozamia machinii. In addition, cone volatiles include both previously unreported compounds as well as those reported exclusively on either Cycadothrips- or Tranes-pollinated species. Based on its small, fragmented area of occupancy, projected population declines and the unique pollination syndrome, we recommend that M. platyrhachis retain its current status as 'Endangered'. Habitat management plans should stipulate that controlled burns be avoided during cycad coning season and that wildfires be controlled to minimise damage to seedlings and pollinators.

Recruitment dynamics of invasive species in rainforest habitats following Cyclone Larry

In tropical forests, natural disturbance creates opportunities for species to claim previously utilized space and resources and is considered an important mechanism in the maintenance of species diversity. However, ecologists have long recognized that disturbance also promotes exotic plant invasions. Cyclones cause extensive defoliation, loss of major branches and multiple tree falls, resulting in a significantly more open canopy and increased light and heat levels in the understorey. The widespread and massive disturbance caused by cyclones provides ideal conditions for rapid recruitment and spread of invasive species. The ecological roles of invasive species in rainforest habitats following such a severe disturbance are poorly understood. Severe category 4 Cyclone Larry crossed the North Queensland coast in March 2006 causing massive disturbance to rainforest habitats from Tully to Cairns and west to the Atherton Tablelands. We established 10 plots in an area extensively damaged by this cyclone near El Arish in North Queensland. On each plot nine 2 × 2 m quadrats were established with three quadrats per plot in each of the following treatments: (i) complete debris removal down to the soil layer, (ii) removal of coarse woody debris only, and (iii) uncleared. We monitored recruitment, growth and mortality of all native and invasive species in the 90 quadrats every 3 months since the cyclone. Here we present the recruitment dynamics of invasive species across the study area in relation to the level of disturbance, the type of quadrat treatment, and the diversity and abundance of the native recruiting flora over the first 12 months post-cyclone. Our results suggest that invasive species will mostly comprise a transient component of the flora in the early stages of the successional response. However, some species may have longer-term effects on the successional trajectory of the rainforest and future forest composition and structure.

Crop and environmental attributes underpinning genotype by environment interaction in synthetic-derived bread wheat evaluated in Mexico and Australia

Synthetic backcrossed-derived bread wheats (SBWs) from CIMMYT were grown in the north-west of Mexico (CIANO) and sites across Australia during 3 seasons. A different set of lines was evaluated each season, as new materials became available from the CIMMYT crop enhancement program. Previously, we have evaluated both the performance of genotypes across environments and the genotype x environment interaction (G x E). The objective of this study was to interpret the G x E for yield in terms of crop attributes measured at individual sites and to identify the potential environmental drivers of this interaction. Groups of SBWs with consistent yield performance were identified, often comprising closely related lines. However, contrasting performance was also relatively common among sister lines or between a recurrent parent and its SBWs. Early flowering was a common feature among lines with broad adaptation and/or high yield in the northern Australian wheatbelt, while yields in the southern region did not show any association with the maturity type. Lines with high yields in the southern and northern regions had cooler canopies during flowering and early grain filling. Among the SBWs with Australian genetic backgrounds, lines best adapted to CIANO were tall (>100 cm), with a slightly higher ground cover. These lines also displayed a higher concentration of water-soluble carbohydrates in the stem at flowering, which was negatively correlated with stem number per unit area when evaluated in southern Australia (Horsham). Possible reasons for these patterns are discussed. Selection for yield at CIANO did not specifically identify the lines best adapted to northern Australia, although they were not the most poorly adapted either. In addition, groups of lines with specific adaptation to the south would not have been selected by choosing the highest yielding lines at CIANO. These findings suggest that selection at CIMMYT for Australian environments may be improved by either trait based selection or yield data combined with trait information. Flowering date, canopy temperature around flowering, tiller density, and water-soluble carbohydrate concentration in the stem at flowering seem likely candidates.

Characterization of disease resistance gene candidates of the nucleotide binding site (NBS) type from banana and correlation of a transcriptional polymorphism with resistance to Fusarium oxysporum f.sp. cubense race 4

Most plant disease resistance (R) genes encode proteins with a nucleotide binding site and leucine-rich repeat structure (NBS-LRR). In this study, degenerate primers were used to amplify genomic NBS-type sequences from wild banana (Musa acuminata ssp. malaccensis) plants resistant to the fungal pathogen Fusarium oxysporum formae specialis (f. sp.) cubense (FOC) race 4. Five different classes of NBS-type sequences were identified and designated as resistance gene candidates (RGCs). The deduced amino acid sequences of the RGCs revealed the presence of motifs characteristic of the majority of known plant NBS-LRR resistance genes. Structural and phylogenetic analyses grouped the banana RGCs within the non-TIR (homology to Toll/interleukin-1 receptors) subclass of NBS sequences. Southern hybridization showed that each banana RGC is present in low copy number. The expression of the RGCs was assessed by RT-PCR in leaf and root tissues of plants resistant or susceptible to FOC race 4. RGC1, 3 and 5 showed a constitutive expression profile in both resistant and susceptible plants whereas no expression was detected for RGC4. Interestingly, RGC2 expression was found to be associated only to FOC race 4 resistant lines. This finding could assist in the identification of a FOC race 4 resistance gene.

Identification of two distinct bovine parainfluenza virus type 3 genotypes

The partial gene sequencing of the matrix (M) protein from seven clinical isolates of bovine parainfluenza virus type 3 (BPIV-3), and the complete sequencing of a representative isolate (Q5592) was completed in this study. Nucleotide sequence analysis was initiated because of the failure of in-house BPIV-3 RT-PCR methods to yield expected products for four of the isolates. Phylogenetic reconstructions based on the nucleotide sequences for the M-protein and the entire genome, using all of the available BPIV-3 nucleotide sequences, demonstrated that there were two distinct BPIV-3 genotypes (BPIV-3a and BPIV-3b). These newly identified genotypes have implications for the development of BPIV-3 molecular detection methods and may also impact on BPIV-3 vaccine formulations.

Determination of specific leaf area of some commercially useful sub-tropical hardwood species

Variability of specific leaf area (SLA) across taxa, sites and crown zones was determined for four sub-tropical hardwood species, Eucalyptus grandis, E. cloeziana, E. argophloia and Corymbia citriodora ssp. variegata, growing in south-eastern Queensland. Mean SLA values were stable amongst those taxa sampled on dry sites but varied markedly between provenances of E. grandis on a moist site. Mean SLA did not vary significantly with crown zone in any of these four sub-tropical eucalypts, which is in contrast to that observed in temperate species, both in Australia and overseas. A provenance of E. cloeziana from a moist coastal site exhibited the largest SLA of all taxa studied.