Region Of South-west Western Australia Research Articles

Distribution and Prevalence of Theileria orientalis Genotypes in Adult Lactating Dairy Cows in South West Region of Western Australia

Bovine anaemia caused by Theileria orientalis group (BATOG) causes significant production and economic losses in Australia's cattle industry. The pathogenic T. orientalis genotypes reported in Australian cattle are type 1 (Chitose) and type 2 (Ikeda). The present study aimed to determine the prevalence and distribution of T. orientalis genotypes in adult lactating cows in Western Australia (WA) dairy herds. A total of 100 whole blood samples from lactating cows from 10 farms were obtained and screened for T. orientalis using polymerase chain reaction (PCR). Sanger sequencing was subsequently used to characterise T. orientalis genotypes isolated from positive samples. A total of thirteen cows (13%; 95% CI: 7.1-21.2%) were positive for T. orientalis, and six out of ten farms (60%; 95% CI: 26.2-87.8%) housed at least one T. orientalis-positive cow. The distribution of T. orientalis was found to be wide and dense in the South west region of WA and the southern coast of WA. The predominant T. orientalis genotype identified was Ikeda (n = 11, 11%; 95% CI: 5.6-18.8%), while the Buffeli genotype was identified in WA for the first time, albeit at a low prevalence (n = 1, 1%; 95% CI: 0.0-5.4%). This study has provided useful epidemiological evidence on the prevalence and distribution of T. orientalis in adult lactating dairy cows in WA dairy farms, and on the importance of conducting widespread surveillance programs for the understanding of BATOG in WA.

The Compassionate Communities Connectors programme: experiences of supported families and referring healthcare providers.

Comprehensive evaluations that include the experience of patients and service providers are vital if interventions are to be translated into the standard practice of health services and allow formal networks to work as partners with informal community networks. However, published evaluations are limited in the palliative care volunteering literature. The objective of the study is to explore the experiences and views of both patients and their family carers who received support and their referring healthcare providers concerning their participation in the Compassionate Communities Connectors programme, in the south-west region of Western Australia. Connectors identified and addressed gaps in community and healthcare provision by accessing resources and mobilising social networks of people with life-limiting illnesses. The perspectives of patients, carers and service providers concerning the feasibility and acceptability of the intervention were sought. Semistructured interviews were undertaken with 28 patients/families and 12 healthcare providers, resulting in 47 interviews in total (March 2021-April 2022). An inductive content analysis was used in analysing interview transcripts to identify key themes. Families greatly appreciated the support and enablement received from the Connectors. Healthcare providers were impressed with the high level of resourcefulness exhibited by the Connectors and perceived a great need for the programme, particularly for those socially isolated. Three themes captured the patients'/families' perspectives: connector as an advocate, increasing social connectedness and taking the pressure off families. Healthcare providers' perspectives were captured in three themes: reducing social isolation, filling a gap in service provision and building the capacity of the service. Perspectives of patients/families and healthcare providers demonstrated the mediating role of Connectors. Each group saw the Connectors' contribution through the lens of their particular interests or needs. However, there were indications that the connection was shifting the way each group understood and practised care, encouraging or restoring agency to families and reminding healthcare providers that collaborating beyond the boundaries of their roles actually enhances the whole ecology of care. Using a Compassionate Communities approach to mobilise health and community sectors has the potential to develop a more holistic approach that addresses the social, practical and emotional domains of care.

Prevalence of Mycoplasma bovis Infection in Calves and Dairy Cows in Western Australia.

Simple SummaryMycoplasma bovis is an emerging pathogen of economic and welfare concern for both adult and young cattle. A study was conducted to determine the prevalence of M. bovis in adult cows and calves in the southwest region of Western Australia. Nasal swabs and blood samples were collected from the animals and bulk tank milk samples were assessed for both seroprevalence and active infections of M. bovis infections in adult cows and calves. The study recorded a high seroprevalence of M. bovis in 699 apparently healthy adult lactating cows and 495 young calves on 29 dairy farms. The herd-level seroprevalence was also detected as being higher in both adult lactating cows and calves. No current active infections were recorded on the farms. The female calves and pure Holstein–Friesian animals were found to be twice as likely to be seropositive for M. bovis compared to male calves and the Holstein–Friesian crossbred calves. The high seroprevalence of M. bovis in both adult and young cattle in the southwest dairy farms of Western Australia warrants more effective farm biosecurity measures and further evaluation of the current prevention and management measures practiced on the farms.Mycoplasma bovis (M. bovis) can cause a multitude of diseases in cattle, with detrimental effects on the farm economy and the welfare of both adult and young cattle. The objective of this study was to determine the prevalence of M. bovis in adult cows and calves in the south-west region of Western Australia. A cross-sectional study was conducted on 29 dairy farms with 699 apparently healthy adult lactating cows and 495 young calves during 2019–2020. Nasal swabs and blood samples collected from the animals and bulk tank milk (BTM) samples were assessed for M. bovis-specific proteins and antibodies by using polymerase chain reaction (PCR) and Mycoplasma immunogenic lipase A- Enzyme-Linked Immune Sorbent Assay (MilA ELISA). A seroprevalence of 42.5% (95% CI: 38.9–46.2) and 61% (95% CI: 56.6–65.2) was found in adult lactating cows and calves, respectively. The herd-level seroprevalence of M. bovis ranged from 4% (95% CI: 07–19.5) to 92% (95% CI: 75.0–97.8) in adult lactating cows and 25% (95% CI: 10.2–49.5) to 87% (95% CI: 67.9–95.5) for calves in these farms. None of the BTM and nasal swab samples were positive for M. bovis, indicating an absence of any current active infections on the farms. The female calves and pure Holstein–Friesian animals are twice as likely to be seropositive for M. bovis compared to male calves (OR 2.4; 95% CI: 1.7–3.5) and Holstein–Friesian crossbred calves (OR 2.4; 95% CI: 1.7–3.5). The high seroprevalence in both adult and young cattle in the southwest dairy farms of Western Australia warrants more effective farm biosecurity measures and further evaluation of the current prevention and management measures practiced on the farms.

A pilot study on bacterial isolates associated with purulent vaginal discharge in dairy cows in the south-west region of Western Australia.

This study aimed to determine the bacterial isolates associated with postpartum endometritis among dairy cows in Western Australia and their antimicrobial susceptibility profiles. A cross‐sectional study was conducted between June–October 2020. Endometritis was defined as evidence of mucopurulent to purulent vaginal discharge 60–100 days postpartum. Vaginal discharge samples were obtained, cultured, identified and tested for antimicrobial susceptibility. A total of 118 bacterial isolates were grown from 46 animals, representing 36 species. The bacteria isolated from both aerobic and anaerobic cultures included Bacillus (60.2%), Streptococcus (12.7%), Trueperella (10.1%), Escherichia (6.7%) and Staphylococcus (5.9%). The remaining genera <5% were Histophilus, Aeroccocus, Enterococcus and Moraxella. Resistance was variable between isolates, but the highest resistance levels were observed in Streptococcal and Bacillus isolates to enrofloxacin, clindamycin and erythromycin, respectively. All Streptococcal isolates exhibited 100% resistance to enrofloxacin, and the greatest resistance levels were found in Streptococcus luteinises to trimethoprim‐sulfamethoxazole 83%, clindamycin 66% and 33% quinupristin‐dalfopristin. There was 84.5% resistance to clindamycin and 35.2% to erythromycin in the Bacillus isolates, with the highest resistance found in Bacillus licheniformis and Bacillus subtilis. Escherichia coli exhibited 12.5% resistance to gentamycin, ceftiofur, whereas amoxicillin‐clavulanic acid exhibited 37.5%. Within the Staphylococcal isolates, 28.5%, 28.5%, 42.8% and 14.2% resistance to ceftiofur, erythromycin, cefoxitin, penicillin and tetracycline were observed, respectively. The presence of resistance to important antimicrobials for human use, such as cephalosporins, macrolides and fluoroquinolones, highlights the need for judicious use of antimicrobials in dairy cattle.

A survey of calf rearing practices in the south-west region of Western Australia

ABSTRACT Aims To gather data on the calf management and rearing practices of a subset of dairy farmers in the south-west region of Western Australia. Methods A 30-minute face-to-face survey was conducted with dairy cattle producers in the south-west region of Western Australia from April–June 2019 to determine pre-weaning calf rearing practices. Participation was voluntary, using a self-selected subset of dairy farmers registered with a regional extension group. The questionnaire assessed three broad categories: farm demographics, colostrum harvesting and management and calf rearing practices. Results The study response rate was 34/140 (24%). The following key areas were identified where there were deviations from recognised best practice: Precalving: no transition diet was fed pre-calving on 4/34 (12%) of farms, and on a further 5/34 (15%) it was fed for less than 3 weeks; mixing of heifers and adult cows in the calving paddocks occurred in 24/34 (70%) of the farms, with 15% (5/34) of the farms using calving induction. During calving 14/34 (41%) of the farms did not disinfect navels of new-born calves; although 23/34 farmers stated that they collected calves within 6 hours of birth, data on frequency of calf pick-up (2/34 did not separate calves and dams and 19/34 picked up only once per day) indicated that on 21/34 farms (62%) the reality was that calves were picked up >12 hours after birth. Colostrum quality was not assessed appropriately on 18/34 (53%) farms and farmers overestimated how soon after birth it was administered: 23/34 (68%) reported feeding it within 6 hours of calving, despite 62% picking up calves >12 hours after calving. Regarding calf rearing practices, no pain relief before or after dehorning was used on 20/34 (59%) farms, calf bedding was removed infrequently (<weekly) on 26/35 (76%) farms and appropriate isolation of sick calves was only reported by 14/34 (41%) farmers. Conclusion and clinical relevance Although limited by the low response rate, this is the first survey of dairy calf rearing practices in the south-western region of Western Australia. We found evidence of at least one process inconsistent with industry best-practice on 34/140 (24%) of responding farms and all farms had more than one sub-optimal calf rearing practice. This highlights the need to improve calf rearing in this region and identifies key areas of deficiency for further study and extension to producers.

Bacterial pathogens associated with clinical and subclinical mastitis in a Mediterranean pasture-based dairy production system of Australia

Mastitis is an economically important production disease in the dairy industry worldwide. There is limited information on the aetiology of clinical mastitis (CM) and subclinical mastitis (SCM) in Australia's Mediterranean pasture-based production system. A prospective study was conducted in the south-west region of Western Australia to characterise the bacterial pathogens associated with CM and SCM cases and their associated antimicrobial susceptibility profiles. A total of 102 CM and 132 SCM milk samples were collected in twelve dairy farms between April 2020 and September 2020 recovering a total of 310 bacterial isolates. The isolates were evaluated for their antimicrobial susceptibility to twelve antibiotics using the agar disk diffusion (ADD) method. The most common pathogens associated with CM was Bacillus spp. (35.29%), followed by coagulase-negative staphylococci (CNS) (22.55%), Pseudomonas spp. (19.61%), Staphylococcus aureus (10.78%), Escherichia coli (5.88%) and Streptococcus uberis (2.94%). The most common pathogens associated with SCM was CNS (44.70%), followed by Bacillus spp. (30.30%), S. aureus (20.45%), Strep. uberis (15.91%), coliforms (Citrobacter spp., Cronobacter spp., Enterobacter spp., Klebsiella spp., Kosakonia spp., Morganella spp., Serratia spp.) (9.86%), environmental Streptococci (6.06%) and E. coli (6.06%). Beta-lactams resistance was the most common resistance observed in the Staphylococcal isolates and a high proportion of Streptococcal isolates exhibited resistance to enrofloxacin. Overall, the proportion of bacterial pathogens isolated in this study was comparable to the figures reported in other studies in Australia. Future research should focus on risk factors and the determination of resistant genetic components among the common isolates.

Responding to rural adversity: a qualitative study of alcohol and other drug service users' experiences of service response to COVID-19 in Western Australia's Southwest.

ObjectiveThis study reports on the impact of the COVID-19 pandemic on the lived experiences of people with substance use problems in accessing services in the Southwest region of Western Australia, and its implications for preparedness in a context of rural adversity.MethodThis was a qualitative study informed by the principles of phenomenology. Data were collected through semi-structured interviews and subjected to thematic analysis.ResultsTwenty-two participants were interviewed. Two main themes were identified: disruption to supportive connections; and bridging the connection gap: local service response to the COVID-19 pandemic.ConclusionsThe COVID-19 pandemic restrictions exacerbated social isolation and mental health issues, and disrupted services and treatment in the Southwest. Our results demonstrate that local alcohol and other drug services in rural areas can successfully respond to crises by assertively and flexibly adapting their service provision.

Prevalence of failure of passive transfer of immunity in dairy calves in a Mediterranean pasture-based production system of the south-west region of Western Australia

The objective of this study was to estimate the prevalence of failure of passive transfer of immunity (FPTI) in dairy calves in the south-west region of Western Australia herds. A cross-sectional study was conducted in 26/140 dairy farms and serum samples were collected from 495 healthy 2–7 day-old calves. A radial immunodiffusion (RID) test was used to determine the concentration of serum IgG and calves were classified as having FPTI if the IgG concentration was less than 10 mg/mL. Estimation of FPTI was also assessed using two indirect methods using serum total protein (STP) and a brix refractometer. The estimated prevalence of FPTI was found to be 8.7% (43 calves out of 495) by RID with the concentration of IgG ranging between 0 and 6.2 mg/ml. The STP was found to vary from 46 to 96 mg/mL and using a cut-off point of 55 mg/mL the calf level prevalence was estimated as 7.1% (33 calves). Using the brix refractometer, the prevalence was found to be 13.1% (65 calves) with the refractometer reading ranging 6–14% of IgG. In the present study there was no association between calf-level factors (age, sex and breed) and FPTI. There was a higher correlation of the RID test results and the STP results compared to the RID and brix refractometer results. It is concluded that the prevalence of FPTI in dairy calves in the south-west region of Western Australia is low (8.7%) and the brix refractometer is not a reliable indirect method for determining passive transfer of immunity to calves.

Food community: Understanding community needs for a food security website to support rural and remote Western Australians.

The South West Food Community (SWFC) project (2018) was implemented to identify initiatives working to enhance healthy food availability, access and use in the South West region of Western Australia (SWWA); and enhance how they functioned as a system. The SWFC project participants included government and community members. This study aimed to understand how a tailored food security website could be developed as a support mechanism to increase understanding of food security, connect participants and enhance the effectiveness of SWFC initiatives. Initiative leaders from the SWFC project (n=46) were invited to participate in semi-structured telephone interviews which sought to understand needs for a food security website. Fifteen stakeholders completed the interviews (32% response rate). Data relating to desirable and undesirable website components were analysed thematically using QSR NVivo 12. Participants requested the website to include concise content, food security resources, inviting/useful images and information about initiatives. Undesirable features included academic literature, difficult-to-use functions, discussion boards and hard-to-view images. A tailored, co-designed website that is monitored, user-friendly and functional were key stakeholder requirements. A tailored, co-designed food security website that promotes partnership development, builds networks, increases understanding and communication about food security and implementation strategies is needed.

A simple hourly wind power simulation for the South-West region of Western Australia using MERRA data

A simple simulator capable of generating synthetic hourly values of wind power was developed for the South West region of Western Australia. The global Modern Era Retrospective Analysis for Research and Applications (MERRA) atmospheric database was used to calibrate the simulation with wind speeds 50 m above ground level. Analysis of the MERRA data indicated that the normalised residual of hourly wind speed had a double exponential distribution. A translated square-root transformation function yn=((1.96+ye)−1.4)/0.302 was used to convert this to a normal-like distribution so that autoregressive (AR) time series analysis could be used. There was a significant dependency in this time series on the last 3 h m so a third order AR model was used to generate hourly 50 m wind speed residuals. The MERRA daily average 50 m wind speed was found to have a Weibull-like distribution, so a square root conversion was used on the data to obtain a normal distribution. The time series for this distribution was found to have a significant dependency on the values for the last two days, so a second order AR model was also used in the simulation to generate synthetic time series values for the square root of the daily average wind speed. Seasonal, daily, diurnal, and hourly components were added to generate synthetic time series values of total 50 m wind speed. To scale this wind speed to turbine hub height, a time varying wind shear factor model was created and calibrated using measured data at a coastal and an inland site. Standard wind turbine power curves were modified to produce an estimate of wind farm power output from the hub-height wind speed. Comparison with measured grid supervisory control and data acquisition (SCADA) data indicated that the simulation generated conservative power output values. The simulation was compared to two other models: a Weibull distribution model, and an AR model with normally distributed residuals. The statistical fit with the SCADA data was found to be closer than these two models. Spatial correlation using only the MERRA data was found to be higher than the SCADA data, indicating that there is still a further source of variability to be accounted for. Hence the simulation spatial correlation was calibrated to previously reported findings, which were similar to the SCADA data.

A case study in the evaluation of geotourism potential through geographic information systems: application in a geology-rich island tourism hotspot

The significant growth in geotourism across all continents over the past two decades has created a strong demand for more creative, robust and systematic approaches to assessing the geotourism potential of natural areas, for identifying suitable sites of geological interest and providing comprehensive frameworks for management. We investigate a range of spatial data-sets using remote sensing analysis tools as well as geographic information systems (GIS) to complement field-derived data and allow for comprehensive analysis of combined data-sets. Such an approach allowed the creation of a spatial geological data base which can be assessed against access and management criteria, including environmental factors and risks. We used the relatively data-rich example of Rottnest Island in the south-west region of Western Australia to demonstrate the opportunities for future geotourism project development.

Production and persistence of subtropical grasses in environments with Mediterranean climates

The agricultural region of south-west Western Australia (WA) has a Mediterranean climate, characterised by a winter-dominant rainfall pattern. Perennial subtropical grasses are increasingly being grown to increase productivity and reduce erosion on infertile sandy soils in the northern agricultural region (NAR) of WA, an area with mild winters and dry, hot summers. However, little information exists on the persistence of different species or their expected seasonal production and feed quality. On the south coast of WA, an area with dry, warm summers and a maritime influence, kikuyu (Pennisetum clandestinum) has been widely sown, but there is little information on the potential of other subtropical grasses. To address these issues, five trials were established across the agricultural area of south-west WA to measure the seasonal production, feed quality and persistence of the main, commercially available subtropical grasses over 3–4 years. This study demonstrates that subtropical grasses have a long-term role in the NAR in areas with mild winters and/or where the rainfall is &gt;400 mm. The best performing subtropical grasses across a range of sites were panic grass (Megathyrsus maximus) and Rhodes grass (Chloris gayana). These species can be expected to have a water-use efficiency of ~10 kg ha–1 mm–1 over a 12-month period, provided there is a good perennial grass density. On the south coast, panic grass, Rhodes grass and setaria (Setaria sphacelata) persisted well and produced significantly more biomass than kikuyu. These grasses could complement kikuyu by increasing out-of-season production. At Kojonup, a more inland site, most of the subtropical grasses died over winter from a combination of occasional frosts and cold, wet soils. However, kikuyu re-grew from rhizomes in spring and maintained &gt;90% ground cover 4 years after sowing. The results from these experiments are likely to be applicable to other regions across the globe with Mediterranean climates and similar soil types.

Is the reptile community affected by Eucalyptus wandoo tree condition?

Context Large portions of the world’s forests and woodlands are currently affected by declines in canopy condition of dominant tree species; however, the effects of these declines on faunal communities are largely unknown. Eucalyptus wandoo woodlands in the south-west region of Western Australia have demonstrated declines in condition since the early 1990s. Such declines in tree condition can result in reduced understorey vegetation, increased leaf-litter cover and coarse woody debris, potentially altering the habitat and resource available to reptiles. Prescribed fire events, another mechanism of habitat change for reptiles, are a common occurrence in these woodlands. Aims The present research investigated whether reptile communities were influenced by E. wandoo tree condition, and the changes in the habitat associated with E. wandoo decline. Methods Reptile trapping was conducted at 24 E. wandoo-dominated sites (of varying condition) in Dryandra State Forest and Wandoo Conservation Park, Western Australia. Overall, reptile abundance, species richness and individual reptile species abundances (only those species captured in sufficient numbers for analysis) were compared with a range of habitat characteristics that are likely to be altered by changes in E. wandoo tree condition. Key results Overall, higher reptile abundance and species richness were observed at sites with longer time since fire and more site litter cover. There was also a greater abundance and diversity of reptiles at sites where E. wandoo trees exhibited fewer symptoms of tree decline. Similar analyses for the five most common skink species indicated species-specific relationships with tree-condition measures, time since last fire, site litter cover, distance to drift fence from E. wandoo trees, understorey vegetation density and the density of coarse woody debris. Conclusions Abundance and species diversity of the reptile communities in E. wandoo woodlands were strongly related to time since last fire, E. wandoo tree condition and habitat characteristics such as site litter cover and the density of coarse woody debris. Implications Decline in the condition of E. wandoo trees and the fire events in E. wandoo woodlands are both mechanisms of change correlated with reptile habitat and resources. Future management of E. wandoo woodlands may include reducing prescribed fire events in areas demonstrating symptoms of tree decline, to conserve reptile abundance and species richness.

Grass roots suicide prevention in rural Western Australia (WA)

BackgroundOne Life Suicide Prevention Strategy is the rebranded WA Suicide Prevention Strategy focusing on what communities can do to prevent suicide. One Life has operated in the South West region...

Mycotoxins produced by Fusarium spp. associated with Fusarium head blight of wheat in Western Australia

An isolated occurrence of Fusarium head blight (FHB) of wheat was detected in the south-west region of Western Australia during the 2003 harvest season. The molecular identity of 23 isolates of Fusarium spp. collected from this region during the FHB outbreak confirmed the associated pathogens to be F. graminearum, F. acuminatum or F. tricinctum. Moreover, the toxicity of their crude extracts from Czapek-Dox liquid broth and millet seed cultures to brine shrimp (Artemia franciscana) was associated with high mortality levels. The main mycotoxins detected were type B trichothecenes (deoxynivalenol and 3-acetyldeoxynivalenol), enniatins, chlamydosporol and zearalenone. This study is the first report on the mycotoxin profiles of Fusarium spp. associated with FHB of wheat in Western Australia. This study highlights the need for monitoring not just for the presence of the specific Fusarium spp. present in any affected grain but also for their potential mycotoxin and other toxic secondary metabolites.

Inter-annual variability and longer-term changes in the wave climate of Western Australia between 1970 and 2009

Quantifying the long-term variability in wave conditions incident on a coastline is critical for predicting its resilience to future changes in the wave climate. In this study, a 40-year wave hindcast of the southern Indian Ocean has been created to assess the inter-annual variability and longer-term changes in the wave climate around Western Australia (WA) between 1970 and 2009. The model was validated against measurements from five wave buoys located along the WA coast. Changes in the mean annual significant wave height, 90th percentile wave height, peak period and mean wave direction were assessed, and the tracks of all wave events generating wave heights above 7 m were digitised and analysed for significant changes. Results show strong annual and inter-annual variability in the mean significant wave height, the 90th percentile wave height and the number of large events (wave height > 7 m) that impact the WA coastline. A significant positive trend in annual mean wave height was found in the southwest region of WA over the 40-year simulation. This appears to be due to an increase in intensity of the storm belt in the Southern Ocean which is associated with an increasing positive polarity in the Southern Annular Mode. However, no significant trends were found in the 90th percentile wave height or the number of large wave events impacting Western Australia. Although the number of large wave events in the southern Indian Ocean have increased, their potential to impact the coastal regions of Western Australia are reduced due to storm tracks being located further south, therefore balancing the number of large wave events reaching the WA coast.

Historical biogeographical patterns in continental Australia: congruence among areas of endemism of two major clades of eucalypts.

Published phylogenies of two eucalypt clades, red bloodwoods Corymbia subgenus Corymbia and eudesmids Eucalyptus subgenus Eudesmia (Myrtaceae), were combined for an analysis of historical biogeographical area relationships within continental Australia. The method of paralogy-free subtree analysis was used to eliminate geographical paralogy; the paralogy-free subtrees were coded as characters for parsimony analysis to find the minimal and area cladogram, which proved to be informative of a continent-wide pattern. The eucalypt fossil record and molecular dating studies allow an interpretation of the biogeographical history in terms of major vicariance events that date from the early Paleogene. The summary area cladogram shows the wet jarrah forest region of South-West Western Australia, a region of high endemism, as the earliest to differentiate from all other areas, isolated by marine inundation across southern Australia and climatic cooling in the Late Eocene-Early Oligocene. From about this time, regionalization continued, with warmer conditions and monsoonal climate developing in central and northern Australia, and cooling in the south-east. Northern and eastern humid and semi-humid areas were related as a track, but with increased aridity in the interior of the continent, the monsoonal climate contracted northwards. The Australian Monsoon Tropics (AMT: Kimberley, Top End, Arnhem, Cape York and inland north-east Queensland) differentiated from eastern areas (Queensland wet tropics to McPherson-Macleay). Our results also show all arid and semi-arid regions as related, suggestive of a historically cohesive interior biota rather than repeated colonizations of the interior from the periphery of the continent. Climate largely differentiates hot arid areas in the north (Pilbara, Northern and Central deserts) from arid areas in the south (south-west interzone, Wheatbelt, Goldfields and Great Victoria Desert). © The Willi Hennig Society 2010.

Diagnosing the Dry: Historical Case Notes from Southwest Western Australia, 1945–2007

Long regarded for its reliable winter rainfall, the Southwest region of Western Australia was beset by unexpected dry conditions in the early 1970s whose persistence was baffling. The gradual growth of scientific interest in the region's rainfall, as this article contends, was strongly influenced by political, social, and economic concerns about the challenges posed by drought and climate change. The experience of rainfall decline coincided with international scientific and political interest in the global climate and the perception that it was deviating from its "normal" state. Indeed, this extended "dry" provided an Australian link to international concerns regarding anthropogenic global warming. This article argues that the historical, political, and economic importance of the Southwest's agricultural industries has led policy makers and researchers to perceive the region's changing climatic conditions as pathological and in need of diagnosis.

Assessment of apparent nonstationarity in time series of annual inflow, daily precipitation, and atmospheric circulation indices: A case study from southwest Western Australia

The southwest region of Western Australia has experienced a sustained sequence of low annual inflows to major water supply dams over the past 30 years. Until recently, the dominant interpretation of this phenomenon has been predicated on the existence of one or more sharp breaks (change or jump points), with inflows fluctuating around relatively constant levels between them. This paper revisits this interpretation. To understand the mechanisms behind the changes, we also analyze daily precipitation series at multiple sites in the vicinity and time series for several indices of regional atmospheric circulation that may be considered as drivers of regional precipitation. We focus on the winter half‐year for the region (May to October) as up to 80% of annual precipitation occurs during this “season”. We find that the decline in the annual inflow is in fact more consistent with a smooth declining trend than with a sequence of sharp breaks, the decline is associated with decreases both in the frequency of daily precipitation occurrence and in wet‐day amounts, and the decline in regional precipitation is strongly associated with a marked decrease in moisture content in the lower troposphere, an increase in regionally averaged sea level pressure in the first half of the season, and intraseasonal changes in the regional north‐south sea level pressure gradient. Overall, our approach provides an integrated understanding of the linkages between declining dam inflows, declining precipitation, and changes in regional atmospheric circulation that favor drier conditions.

Using MODIS imagery, climate and soil data to estimate pasture growth rates on farms in the south-west of Western Australia

Remote sensing of vegetation and its monitoring using the normalised difference vegetation index (NDVI) offers the opportunity to provide a coverage of agricultural land at a large scale. The availability of MODIS NDVI at a resolution of 250 m provided the opportunity to evaluate the hypothesis that pasture growth rate (PGR) of individual paddocks can be accurately predicted using a model based on MODIS NDVI in combination with climate and soil data and a light-use efficiency model. Model estimates of PGR were compared with field measurements of PGR recorded in grazing enclosure cages collected over 3 years from six farms located across the south-west region of Western Australia. The estimates attained from the model explained 70% of the variation in PGR for individual paddocks on farms over the 3 years of the study, with an average error at the paddock scale of 10.4 kg DM/ha.day over all growing seasons and years. Across all farms studied, there was generally good agreement between satellite-derived PGR and ground-based measurements, although estimates of PGR varied between years and farms. The model explained 47% of the variation in pasture growth early in the season (from break of season to end of July), compared with 62% late in the season (from August to pasture senescence). The present study demonstrated that PGR for individual paddocks can be predicted at weekly intervals from MODIS imagery, climate and soil data and a light-use efficiency model at an accuracy sufficient to facilitate on-farm pasture and livestock management.