Region Of South-eastern Australia Research Articles

Sex-differences in reasons for non-participation at recruitment: Geelong Osteoporosis Study

BackgroundUnderstanding reasons for non-participation in health studies can help guide recruitment strategies and inform researchers about potential sources of bias in their study sample. Whilst there is a paucity of literature regarding this issue, it remains highly plausible that men and women may have varied reasons for declining an invitation to participate in research. We aimed to investigate sex-differences in the reasons for non-participation at baseline of the Geelong Osteoporosis Study (GOS).MethodsThe GOS, a prospective cohort study, randomly recruited men and women aged 20 years and over from a region in south-eastern Australia using Commonwealth electoral rolls (2001–06 and 1993–97, respectively). Reasons for non-participation (n=1,200) were documented during the two recruitment periods. We used the Pearson’s chi squared test to explore differences in the reasons for non-participation between men and women.ResultsNon-participation in the male cohort was greater than in the female cohort (32.9% vs. 22.9%; p<0.001). Overall, there were sex-differences in the reasons provided for non-participation (p<0.001); apparent differences related to time constraints (men 26.3% vs. women 10.4%), frailty/inability to cope with or understand the study (men 18.7% vs. women 30.6%), and reluctance over medical testing (men 1.1% vs women 9.9%). No sex-differences were observed for non-participation related to personal reason/disinterest, and language- or travel-related reasons.ConclusionsImproving participation rates in epidemiological studies may require different recruitment strategies for men and women in order to address sex-specific concerns about participating in research.

Are farmers in low-rainfall cropping regions under-fertilising with nitrogen? A risk analysis

Abstract In low-rainfall cropping systems farmers typically apply low rates of nitrogen (N) to their cereal crops. However, farmers might benefit from using higher fertiliser rates on some soil types and adjusting the rate of N fertiliser applied during the growing season, because if seasons are favourable the crop demands more nutrients. Using a combination of crop simulation, probability theory, profit function and finance techniques to quantify the trade-offs between magnitude and variability in net returns, we found that the use of higher N rates (relative to the region’s average) on some soil types can reduce economic risk in a highly variable dryland environment like the Mallee region in south-eastern Australia. On some soil types, typically risk-averse Mallee farmers with low starting N seem likely to benefit from increasing their N rates up to 60 kg N ha−1 from the 15 kg N ha−1 currently applied, with less risk-averse farmers being more likely to benefit from in-season tactical N applications in seasons where there is rainfall within an application window of high crop N demand. On other soil types, commonly found within the same field, farmers are unlikely to benefit from increased N rates. We conclude that variable fertiliser rates based on soil-specific management zones have the potential to not only increase profit but reduce risk, based on a number of risk metrics.

Predicting nitrogen dynamics in a dairy farming catchment using systems synthesis modelling

The intensity of milk production from pasture based dairy farming systems is often related to nitrogen (N) losses. This paper investigates dairy farming systems in the Scotts Creek catchment, an intensive farming region in south-eastern Australia, to assess aspects of productive potential and environmental footprint as a result of nutrient loss. A detailed survey of farming systems was coupled with regional data and a dairy farming systems simulation model (DairyMod) to better understand the N flows in farming systems over a range of different input and production intensities. Simulations of representative farming systems – farming system typologies – were run for 100years to provide information on the consistency and proportion of N loss in various pathways over a range of different weather and soil moisture conditions. The typologies covered a very wide range in intensity of stocking rate, inputs (e.g. concentrates, fertiliser). In general N transformations, plant and animal production and the efficiency of conversion of N into animal and plant products were related to the level of N inputs of the farming systems and milk production, or intensity. The long-term average total predicted N loss (via leaching, denitrification and volatilisation) ranged from 24(±6) to 227(±73)kgN/ha/yr and increased relative to the intensity of milk production (L/ha). Over the long term, annual average N losses by leaching ranged from 4 to 143kgN/ha/yr, volatilisation from 17 to 66kgN/ha/yr and denitrification from 2 to 18kgN/ha/yr. In an average system there were similar amounts of N exported from the farming system by leaching (44% of total N), as lost through volatilisation (47%), whereas losses by denitrification were comparatively minor (9%). The inputs were principally related to a potential milk production capacity of the farming system which was not wholly related to stocking rate. The efficiency of N utilisation for milk synthesis (L milk/kgN-consumed) increased with system intensity, however the relative loss (gN loss/kg milk N) also increased. With the current farming system typologies, improvements in animal efficiency due to intensification appear to be offset by the capacity of the system to retain surplus N. In order to meet regional production targets, there are various potential ways to further intensify the current farming systems. However the implications of achieving such targets on N losses (via leaching, denitrification and volatilisation) are important when considering the environmental implications of further intensification.

Time-since-fire and inter-fire interval influence hollow availability for fauna in a fire-prone system

Tree hollows are a critical, yet potentially limiting habitat resource for many animal species. Fire influences hollow availability, and the associated indirect effects on fauna can threaten the persistence of hollow-dependent species in fire-prone systems. We investigated the influence of two temporal aspects of fire regimes (time-since-fire, inter-fire interval) on hollow occurrence in a semi-arid, fire-prone region in south-eastern Australia. Empirical data on the characteristics of hollow-bearing eucalypt stems and fire-history attributes were compiled for 581 study sites. Mixed models were used to examine the relative influence of time-since-fire and inter-fire interval on hollow occurrence. Time-since-fire and inter-fire interval both affected the probability of hollow occurrence, but in different ways. Time-since-fire influenced the occurrence of hollows in live and dead stems. As time-since-fire increased, so too did the probability of live and dead stems containing hollows. Live stems did not provide hollows before 40years post-fire, while the probability of dead stems containing hollows peaked at 50–60years. Inter-fire interval influenced the availability of hollows in dead stems. Longer inter-fire intervals resulted in an increased density of dead hollow-bearing stems. In this region, hollow-dependent fauna will benefit from increased fire-free periods, both in terms of individual fire events and the intervals between repeated fires. These results highlight the complex way in which fire affects the availability of faunal habitat resources, and the extended time periods over which such influences operate. Understanding the effects of fire regimes on slow-developing habitat resources over long time-frames is imperative for sound ecological fire management.

Using trait‐based filtering as a predictive framework for conservation: a case study of bats on farms in southeastern Australia

Summary1. With world‐wide changes in human land use, an important challenge for conservation biologists is to develop frameworks to predict how species will respond to landscape change. Environmental filtering, where different environments favour different species’ traits, has the potential to be a useful predictive framework. Therefore, it is important to advance our understanding of how species with different traits respond to environmental variables.2. We investigated the distribution of microbats in a 1 000 000 ha agricultural region in southeastern Australia, with specific emphasis on the effects of tree density on bat species characterized by different sizes, wing shapes and echolocation frequencies. The study area is substantially cleared, and trees are continuing to decline because grazing inhibits tree regeneration. We monitored bat activity acoustically at 80 sites spanning a wide range of tree densities. We used regression modelling to quantify the response of bats to tree density and other ecological covariates, and RLQ analysis to assess how different traits correlated with various environmental gradients.3. Total bat activity and species richness peaked at intermediate tree densities. Species composition was explained by tree density and the traits of individual species. Sites with low tree cover were dominated by large, fast‐flying species, whereas sites with dense tree cover were dominated by smaller, highly manoeuvrable species. These findings are consistent with recent findings from other locations around the world.4. Synthesis and applications. Trait‐based predictive frameworks enable landscape managers to assess how different management strategies and landscape modifications are likely to affect different species. Here, we propose a framework to derive general predictions of how bats respond to landscape modification, based on tree density and species traits. We apply this framework to a current conservation issue of tree decline in our study area and derive management priorities including: (i) maintaining a range of tree densities throughout the region; (ii) ensuring the persistence of locations with intermediate tree densities; and (iii) using environmentally sensitive grazing practices, for example, by incorporating long rest periods.

Phytoplankton assemblages of two intermittently open and closed coastal lakes in SE Australia

Species composition and biomass of phytoplankton assemblages of a heavily impacted lake (Lake Illawarra) and a less impacted lake (Burrill Lake) in the South-Eastern region of Australia were compared based on bimonthly samples from three sites in each lake collected between April 2005 and April 2007. Lake Illawarra was generally characterized by higher nutrient concentrations and lower salinity than Burrill Lake. Phytoplankton assemblages displayed significant differences between the two lakes in terms of the dominant species composition and patterns of seasonal change rather than biomass. Diatoms were the dominant species in Lake Illawarra on most sampling occasions. In contrast, dinoflagellates (including toxic species) dominated in Burrill Lake during most seasons. Seasonal succession of phytoplankton in the two lakes did not follow the strict spring maximum that is generally observed in temperate waters. In Burrill Lake, maximum phytoplankton biomass often occurred in winter, while the maximum biomasses in Lake Illawarra occurred in autumn, winter and spring. The significant difference of nutrient structure between two lakes and warm temperate regime was regarded as important factors to affect these results. The results suggested care should be taken when relying on estuary health “indicators”, such as chlorophyll a, rather than more detailed investigations of phytoplankton species compositions.

Modelling the potential impact of climate variability and change on species regeneration potential in the temperate forests of South‐Eastern Australia

AbstractThe sensitivity of early plant regeneration to environmental change makes regeneration a critical stage for understanding species response to climate change. We investigated the spatial and temporal response of eucalypt trees in the Central Highland region of south eastern Australia to high and low climate change scenarios. We developed a novel mechanistic model incorporating germination processes, TACA‐GEM, to evaluate establishment probabilities of five key eucalypt species, Eucalyptus pauciflora, Eucalyptus delegatensis, Eucalyptus regnans, Eucalyptus nitens and Eucalyptus obliqua. Changes to regeneration potential at landscape and site levels were calculated to determine climate thresholds. Model results demonstrated that climate change is likely to impact plant regeneration. We observed increases and decreases in regeneration potential depending on the ecosystem, indicating that some species will increase in abundance in some forest types, whilst other forest types will become inhabitable. In general, the dry forest ecosystems were most impacted, whilst the wet forests were least impacted. We also observed that species with seed dormancy mechanisms, like E. pauciflora and E. delegatensis, are likely to be at higher risk than those without. Landscape‐ and site‐level analysis revealed heterogeneity in species response at different scales. On a landscape scale, a 4.3 °C mean temperature increase and 22% decline in precipitation (predicted for 2080) is predicted to be a threshold for large spatial shifts in species regeneration niches across the study region, while a 2.6 °C increase and 15% decline in precipitation (predicted for 2050) will likely result in local site‐level shifts. Site‐level analysis showed that considerable declines in regeneration potential for E. delegatensis, E. pauciflora and E. nitens were modelled to occur in some ecosystems by 2050. While overall model performance and accuracy was good, better understanding of effects from extreme events and other underlying processes on regeneration will improve modelling and development of species conservation strategies.

Mycobacterium ulcerans DNA Not Detected in Faecal Samples from Buruli Ulcer Patients: Results of a Pilot Study

It has recently been shown that in a Buruli ulcer (BU) endemic region of southeastern Australia, significant numbers of possums (native tree-dwelling marsupials) have clinical BU disease. Furthermore, based on quantitative PCR (qPCR) analysis, animals with BU lesions (and some without) shed M. ulcerans DNA in their faeces, indicative of bacterial loads of up to 108 organisms/gram. These findings led us to propose that humans might also harbour M. ulcerans in their gastrointestinal tract and shed the bacterium in their faeces. We conducted a pilot study and collected faecal swabs from 26 patients with confirmed BU and 31 healthy household controls. Faecal samples were also collected from 10 healthy controls from non-endemic regions in Ghana. All 67 specimens were negative when tested by IS2404 PCR. The detection sensitivity of this method was ≥104 bacteria per gram (wet-weight) of human faecal material. We conclude that the human gastrointestinal tract is unlikely to be a significant reservoir of M. ulcerans.

Impacts of future climate scenarios on the balance between productivity and total greenhouse gas emissions from pasture based dairy systems in south-eastern Australia

The challenge for agriculture is to increase production in warmer climates in order to meet the demands of an increasing global population, while also meeting targets for reduced greenhouse gas (GHG) emissions. Our aim was to quantify the net effect of future climate scenarios on the productivity and total GHG emissions from pasture based dairy systems in 4 regions of south-eastern Australia using the biophysical model DairyMod. In each region, a single paddock in the grazing rotation of a dairy farm was simulated. This paddock was grazed at a stocking density of 50 lactating dairy cows/ha for a period of one day each time the pasture biomass reached 2.2t dry matter (DM)/ha. In this way, the annual stocking rate (i.e., cows/ha) reflected the number of times that the paddock was grazed annually. No supplementary feed was offered to the animals. Model estimates of annual pasture intake, stocking rate, milk production, CH4 and N2O emissions were compared at each site in a baseline climate (1971–2000) and 3 future climate scenarios representing increasingly warm and dry conditions, termed the ‘2030’, ‘2070 mid’ and ‘2070 high’ scenarios. At Kyabram (northern Victoria) summer irrigated perennial pastures were modelled in the baseline scenario, with supplementary irrigated annual pasture systems simulated in the baseline scenario for comparison, and in the future scenarios. At Terang (south-western Victoria), Ellinbank (south-eastern Victoria) and Elliott (north-western Tasmania) dryland perennial pastures were modelled. In dryland systems, increased pasture intake, stocking rate and milk production was modelled in all future scenarios for the cool temperate climate at Elliott, with reduced production in the ‘2070 mid’ and ‘2070 high’ scenarios at Ellinbank and Terang. At Kyabram, productivity of the annual system was lower than the perennial system in the baseline scenario, but increased in future climates, assuming adequate irrigation water availability. Among sites and climate scenarios, annual per cow GHG emissions were 3.4–5.5t CO2 equivalents (CO2e), with CH4 making 0.63–0.89 of total emissions. Annual emissions per unit area ranged from 2.6 to 13.1t CO2e/ha among sites and climate scenarios, and generally reflected stocking rates. However, in the future scenarios, there were changes in N2O emissions at dryland sites due to increased direct N2O losses and lower indirect N2O through volatilisation and leaching. Annual emission intensities ranged from 7.5 to 10.9t CO2e/t milk protein plus fat among sites and climate scenarios. The lowest emissions intensity was at Elliott, which also had little change in future climates. At Terang and Ellinbank, the emission intensity was 8.8t CO2e/t MS in the baseline climate, but this increased by more than 20% in the 2070 high scenario. Results suggest that pasture based production systems can continue as the basis of the dairy industry in north-western Tasmania, but lower production and higher emission intensity at Terang and Ellinbank suggest that systems adaptations are required to meet future GHG emissions reduction goals.This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

Modeling of bore hydrographs to determine the impact of climate and land-use change in a temperate subhumid region of southeastern Australia

To determine the relative impact of climate and human intervention on groundwater elevations in western Victoria, southeast Australia, bore hydrograph fluctuations in three aquifers were modelled using a transfer function noise model (PIRFICT) and an auto-regressive model (HARTT), which give generally comparable results. Most of the groundwater-level fluctuations (>90%) are explained by climatic variation, particularly rainfall. The overall non-climate-related trend in groundwater level is downward and small but statistically significant (−0.04 to −0.066 m/yr), and is probably due to the widespread replacement of grazing land by wheat and canola cultivation, as these crops use more water than pasture. A large non-climate-related trend (−0.30 m/yr) for bores in an irrigation area is mainly related to groundwater extraction. The response time of the system is rapid (only 4.85 years on average), much faster than previously estimated. Rates of groundwater flow are much slower; groundwater ages are up to ~35,000 years. Response times effectively represent the time for the system to move to a new state of hydrologic equilibrium; this prediction of the time scale of the impacts of land-use change on groundwater resources will allow the development of better strategies for groundwater management.

Mytilus mitochondrial DNA haplotypes in southeastern Australia

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 12:47-53 (2011) - DOI: https://doi.org/10.3354/ab00323 Mytilus mitochondrial DNA haplotypes in southeastern Australia Donald J. Colgan*, Peter Middelfart Research Branch, The Australian Museum, 6 College Street, Sydney 2010, Australia *Email: don.colgan@austmus.gov.au ABSTRACT: Mitochondrial DNA (mtDNA) analyses suggest that Southern Hemisphere mussels of the Mytilus edulis species complex include an endemic lineage and invasive genetic elements derived from the Northern Hemisphere species M. galloprovincialis and M. edulis. Haplotypes from these species have been reported in substantial frequencies from South America, South Africa, Western Australia and New Zealand, but only at very low frequencies in Tasmania and the coast near Melbourne in Victoria, the only regions studied in southeastern Australia. Here we investigate cytochrome c oxidase sequences from a wider region in southeastern Australia. Substantial frequencies of Northern Hemisphere Mytilus haplotypes of the female form of the mtDNA were observed, particularly in southern New South Wales. These haplotypes represented a broad range of divergent lineages among the Northern Hemisphere clades. All 3 haplotypes of the male form of mtDNA belonged to the lineage previously identified as the ‘European’ clade of M. edulis. KEY WORDS: Mytilus · Invasive species · Introgression · Mitochondrial DNA Full text in pdf format PreviousNextCite this article as: Colgan DJ, Middelfart P (2011) Mytilus mitochondrial DNA haplotypes in southeastern Australia. Aquat Biol 12:47-53. https://doi.org/10.3354/ab00323 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 12, No. 1. Online publication date: March 17, 2011 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2011 Inter-Research.

Managing Grapevines through Severe Heat: A Survey of Growers after the 2009 Summer Heatwave in South-eastern Australia

A survey of 92 vineyards, representing 10 winegrowing regions in south-eastern Australia, soon after exposure to a severe heatwave, revealed variation in the reported heat-related impact. This variation was observed between regions, within regions and within vineyards. Notably the estimates of losses were not always related to the amount of heat above a certain threshold but to the management practices employed in the lead-up and through the event. Applicable and achievable recommendations for managing severe heat events have resulted from this assessment. We believe this method of capturing information from the diverse knowledge-base of managers is a very effective way to reveal potential adaptive capacity to a changing climate.

The effect of EGM2008-based normal, normal-orthometric and Helmert orthometric height systems on the Australian levelling network

This paper investigates the normal-orthometric correction used in the definition of the Australian Height Datum, and also computes and evaluates normal and Helmert orthometric corrections for the Australian National Levelling Network (ANLN). Testing these corrections in Australia is important to establish which height system is most appropriate for any new Australian vertical datum. An approximate approach to assigning gravity values to ANLN benchmarks (BMs) is used, where the EGM2008-modelled gravity field is used to ‘re-construct’ observed gravity at the BMs. Network loop closures (for first- and second-order levelling) indicate reduced misclosures for all height corrections considered, particularly in the mountainous regions of south eastern Australia. Differences between Helmert orthometric and normal-orthometric heights reach 44 cm in the Australian Alps, and differences between Helmert orthometric and normal heights are about 26 cm in the same region. Normal-orthometric heights differ from normal heights by up to 18 cm in mountainous regions >2,000 m. This indicates that the quasigeoid is not compatible with normal-orthometric heights in Australia.

Influence of sustained deficit irrigation on colour parameters of Cabernet Sauvignon and Shiraz microscale wine fermentations

Background and Aims: This study aimed to explore the influence of sustained deficit irrigation (SDI) on the grape and wine colour parameters of two premium red wine grape varieties grown in the Sunraysia region of South Eastern Australia. Methods and Results: The SDI experiments were conducted during three vintages from 2003 to 2004, 2004 to 2005 and 2005 to 2006 on the Vitis vinfera cultivars Cabernet Sauvignon and Shiraz grafted to 140 Ruggeri (V. berlandieri × V. rupestris) rootstock. The grapevines were drip irrigated providing 100% of estimated ETc (control) and three graded sustained water deficits (Cabernet Sauvignon 70, 52 and 43% of the control; Shiraz 65, 45 and 34% of the control). Microscale wine fermentations were conducted on grapes from the 2006 harvest to assess wine colour density, wine hue, red pigments, anthocyanins, phenolics and copigmentation products in the wine. Wine anthocyanin and phenolic concentrations for both varieties showed significant increases with increasing intensity of SDI. Conclusion: Increases in wine colour with SDI may result from changes in flavonoid biosynthesis as a result of grapevine responses to water deficit. Alternatively, increases in red wine colour could be caused by changes in chemical properties of the anthocyanins to copigmented or polymeric forms during the winemaking or ageing process. Significance of the Study: The Australian wine industry is currently affected by drought and reduced water allocations resulting in production of wine from grapes exposed to water deficit. Findings from this study provide knowledge to the wine industry as to how sustained deficit irrigation may modify wine colour.

Patterns of demography for rocky-shore, intertidal invertebrates approaching their geographical range limits: tests of the abundant-centre hypothesis in south-eastern Australia

The abundant-centre hypothesis predicts that species' abundances peak at the centre of their geographical ranges and decline gradually towards their range limits. We tested predictions of this hypothesis for three rocky-shore, intertidal invertebrates with planktonic larvae (the whelk, Morula marginalba, the snail, Afrolittorina pyramidalis, and the barnacle, Tesseropora rosea) by quantifying their patterns of abundance and size, and inferring pulses of recruitment from size-frequency distributions, at multiple spatial scales spanning a 600-km region in south-eastern Australia and encompassing roughly the southern third of their geographical ranges. At the regional scale, abundances for all species were, as predicted, dramatically lower at their range limits. This decline was not gradual, however, because there were large variations in abundance at smaller spatial scales, and abrupt declines at the south-eastern corner of Australia. Size did not change towards the range limit for any species, but size-frequency distributions suggested a decline in the frequency of recruitment events at the range limit for T. rosea. We conclude that the abundant-centre hypothesis is not an appropriate model for abundance distributions of benthic marine invertebrates with planktonic larvae, because of the vagaries of dispersal and recruitment interacting with complex current patterns along non-uniform coastlines.

Associations between salinity and use of non-riverine wetland habitats by diurnal birds

The secondary salinisation of wetlands is a global problem that poses a profound threat to freshwater biodiversity. We examined wetland use by diurnal birds in relation to wetland salinity in the Wimmera region of southeastern Australia to better understand the threat posed to biodiversity by secondary salinisation. Forty species of birds were detected in 66 non-riverine wetlands that spanned the broad range of salinities encountered among wetlands in the study region. Use of wetlands by birds was related to conductivity of water using a statistical model that accounted for imperfect detection of bird species during the surveys. Of the 40 species encountered during the study, it was estimated that 20 (95% credible interval 17–24) would respond positively to increasing salinity, and 20 (95% credible interval 16–23) would respond negatively to increased salinity. Expected species numbers are highest in wetlands of intermediate salinity. Our results accord well with our existing understanding of wetland use and salinity for most bird species we encountered, and show that expected future increases in wetland salinity are likely to dramatically alter patterns of wetland use by birds.

Evolution and maintenance of divergent lineages in an endangered freshwater fish, Macquaria australasica

Variable hydrological regimes and habitat availability are factors that affect the distribution of freshwater dependent species and are expected to influence their levels of genetic diversity. Although geologically relatively stable, the south eastern region of Australia has experienced significant changes in hydrological conditions during the Quaternary. This area has also been recently affected by anthropogenic activities, resulting in dramatic population declines of Macquarie Perch (Macquaria australasica). We conducted a range-wide phylogeographic study of this endangered fish to assess the relationship between landscape and freshwater fish evolution in south eastern Australia and infer levels of genetic diversity and population structure. Surprisingly, we detected high genetic diversity, with 46 mtDNA control region haplotypes found across 37 sampling locations. Some lineages were remarkably divergent; one represents a putative undescribed species that probably went extinct during the period of this study. Our reconstruction of population history using a combination of coalescent and phylogenetic methods indicates that the species originated on the coast, east of the Great Dividing Range (GDR), with subsequent colonisation of the Murray-Darling basin, west of the GDR. Nested clade and IM analyses inferred a series of range expansions and fragmentations across the species range consistent with the history of climatic oscillations in south eastern Australia during the Pleistocene. We conclude that the unexpected high levels of diversity and divergence observed in M. australasica may be due to specific habitat requirements, localised recruitment, and Pleistocene climate fluctuations. Under expectations of a drier climate and increased sea levels due to global warming, populations of this and other freshwater species may be expected to experience increased habitat fragmentation and loss of genetic diversity. Conservation management should focus on habitat protection, the maintenance of genetic diversity and taxonomic review.

Heat increases germination of water-permeable seeds of obligate-seeding Darwinia species (Myrtaceae)

We examined the response of seeds to heat in four geographically restricted and one widespread species of shrubby Darwinia from the fire-prone region of southeastern Australia. These shrubs are killed by fire and rely on seed germination after a fire to maintain populations. We replicated the germination trials across several sites and several fruiting seasons for most species. Seeds had a high level of viability and were largely dispersed in a dormant state, except in D. glaucophylla, where seed dormancy varied significantly across fruiting seasons. The indehiscent fruit of all species readily imbibes moisture when wet and seeds are not considered to be ‘hard-seeded’. All species had increased seed germination in response to a limited range of heating temperatures (generally 80–100°C). Higher temperatures killed increasing proportions of seeds. This pattern was broadly consistent across species, population and seasons, although the proportion of seeds whose germination was promoted by heat varied from high (D. diminuta, D. fascicularis, D. glaucophylla) to moderate (D. biflora, D. procera). Our work highlights the importance of heat as a mechanism for influencing germination in species that are not hard-seeded. Consequently, soil temperatures during a fire should strongly influence post-fire germination levels in Darwinia. The roles of other cues that promote germination, i.e. smoke, seasonal temperatures and their interactions with heat, remain to be investigated.

When will integrated pest management strategies be adopted? Example of the development and implementation of integrated pest management strategies in cropping systems in Victoria

This paper discusses the development and implementation of integrated pest management (IPM) strategies for broadacre cropping in Victoria, Australia, with reference to other crops and also the levels of adoption of IPM in Australia and overseas. Levels and rates of adoption are mostly low but with some exceptions. The reasons for differing levels of adoption include the failure of strategies to successfully deal with all pests, the lack of motivation to change to using IPM given current successful pesticide-based controls, and the poor availability of IPM advisors in the field. This paper outlines how IPM strategies for wheat, barley and canola crops were developed and implemented using a collaborative approach between farmers, agronomists and entomologists. It was found that although there were no existing specific IPM strategies for the crops grown in the region of south-eastern Australia, there was sufficient information for farmers to start using an IPM approach. This paper gives a case study of implementing change to IPM from conventional pesticide spraying, including the development of a course in IPM for growers and agronomists. It focuses on the process of changing practices and information transfer rather than on entomological details.

Functional Richness and Relative Resilience of Bird Communities in Regions with Different Land Use Intensities

Empirical estimates of the function and resilience of communities under different management regimes can provide valuable information for sustainable natural resource management, but such estimates are scarce to date. We quantified the functional richness and relative resilience of bird communities inhabiting five regions in southeastern Australia that represented different management regimes. First, we show that functional richness and relative resilience were reduced at species-poor sites in all regions. Second, we show that bird communities in agricultural regions had fewer body mass groups and fewer functional groups than expected by chance. This suggests that both the function and the resilience of bird communities in agricultural regions were reduced. The likely mechanisms for the observed loss of function and relative resilience are: (1) the simplification of landscape texture resulting in selective extinction of certain body mass groups; and (2) the selective extinction of certain functional groups that are particularly sensitive to intensive land use.