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For over 30 years, the Journal of the Society for Provision of Education in Rural Australia has reported research and practice discourses associated with rural, regional and remote education, with the aim of impacting policy and practices relating to education in rural Australia. The journal, originally named Education in Rural Australia, commenced in 1991 and, with an increasingly international focus, changed to the Australian and International Journal of Rural Education in 2012. This article critically synthesises the content of the Journal, which includes 500 unique contributions. The articles were placed into an NVivo project and coded using themes derived from word frequency counts. The critical analysis identifies nine perennial themes that appear regularly throughout the 33 volumes: aspiration, success and achievement; community and relationships at the centre of rural education; curriculum, pedagogy and assessment; deficit discourses; equity, rights and justice; parents and family; resourcing and funding; rurality and place, and teacher preparation. In addition, the analysis identifies trending issues, which wax and wane over the Journal’s life. This article highlights the Journal’s important and sustained contribution to research evidence for rural education. From the perennial and trending issues, it is possible to see the interconnections and influences between themes, but also the absence of discourses in certain areas that calls for future research. The analysis has policy implications for education stakeholders, particularly given that some of the concerns raised by the articles in the Journal remain largely unanswered more than 30 years on. This article calls for change and challenges policy makers to address issues that we already know exist and have provided possible solutions. [ABSTRACT FROM AUTHOR]

The legume genus, Glycine, which includes the Asian annual cultivated soybean, also includes a group of Australian perennial species comprising the subgenus Glycine. Because the subgenus Glycine represents the tertiary gene pool for one of the world's most important crops, the group has been the target of collection and study for decades, resulting in a steady growth in the number of formally recognized species, from six in the 1970s to over 20 at present, as well as a number of additional informal taxa. These studies have also produced a system of nuclear diploid "genome groups" corresponding to clades in molecular phylogenies. The aptly named G. remota is known only from a single isolated population in the Kimberley region of northwestern Australia and was named only in 2015. The species is unique within Glycine in having unifoliolate leaves; its discoverers hypothesized that G. remota, if diploid, is related to species of the I-genome that are also native to the Kimberley region. We produced low coverage short-read genome sequencing data from an herbarium specimen of G. remota. Genome size estimates from the sequencing data suggests that G. remota is a diploid, while ploidy estimation is inconclusive likely due to the history of whole genome duplication in Glycine. Phylogenomic analyses of genome-wide SNPs, as well as phylogenetic analyses of the low copy nuclear gene (histone H3D), the entire ribosomal RNA cistron, and the internal transcribed spacer all placed the species unequivocally in the diploid I-genome clade. A complete plastome sequence was also generated and its placement with a plastome phylogeny is also consistent with membership in the I-genome. [ABSTRACT FROM AUTHOR]

Aim: Exotic perennial grasses (EPGs) are significant invaders of native grassy communities. We sought to determine how the profile of invading perennial grasses varies among different climatic regions and different grassy communities, to understand at which scale management is best undertaken. We investigated whether invader occurrence was related to specific plant traits. Location: New South Wales, Australia. Method: Field surveys of EPGs at 139 sites from nine grassy communities across four regions were assessed for variation in invasion profiles amongst regions and communities. We used a ranking of invasion risk based on plant characteristics to identify grasses likely to be more invasive and tested whether this ranking predicted the level of invasion in the survey. Results: Using multivariate analysis, we found that all communities were significantly invaded. These assemblages were distinct regionally, and for most plant communities. Five widespread invaders were established in all regions and communities. Invasion by pasture grasses (termed trade‐off species) was the most significant threat, coupled with capacity to develop long‐term seed banks and use allelopathy. Species with higher risk rankings were recorded in more sites, although a few grasses had much greater occurrences than their ranking predicted. Conclusions: Grassy communities across all regions were invaded by a suite of EPGs, some that have not been considered as problematic previously. Higher levels of invasion were associated with higher ranked species based on plant traits, indicating that our risk assessment is valuable as a management prioritization tool. Findings support community level management, although some species are important widespread invaders and could be managed at larger scales. Differences in species assemblages compared to nearby agricultural areas confirm different invasion pathways, with significant invasion from pasture grasses. Aided by the risk assessment tool, we propose that EPG management in native communities considers the climatic, community (including surrounding) and species level for prioritization. [ABSTRACT FROM AUTHOR]

Perennial grain crops have been proposed as environmentally sustainable alternatives to annual grain crop systems that currently dominate the world's major breadbaskets. Proponents emphasize the potential of perennial grains to mimic natural systems and thereby reduce soil erosion, nutrient losses, and degradation of soil quality although need for adequate grain yield is also recognized as a prerequisite for success. Here we assess progress since 2005 (16 y) towards development of perennial grain systems with sufficient productivity to be seen as competent alternatives to annual wheat on the prairies and plains of North America and Australia. Based on reports published in refereed journals, we see little evidence that yield of Intermediate Wheatgrass or perennial wheats have improved to the point they are viable alternatives. Slow progress is attributed to lack of minimum grain yield targets for economic viability, lack of designated target regions where perennial grains are most likely to be competitive against annuals, selection methods that focused on components of yield rather than yield per se (i.e. on an area basis), and relatively small R & D investment compared to resources given to genetic and agronomic improvement of major annual grain crops. Given current status, we conclude that perennial grains will require substantial R & D investment and several decades if they are to achieve sufficient yield potential and yield persistence to become more than a niche crop for upscale health food markets in wealthy countries. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is considered the most important pasture species in temperate agriculture, with over six million hectares of sown area in Australia alone. However, perennial ryegrass has poor persistence in some environments because of low tolerance to a range of both abiotic and biotic stresses. To breed perennial ryegrass, cultivars with greater persistence and productivity may require evaluation of genotypes over a number of years. Persistence assessment in pasture breeding depends on manual ground cover estimation or counting the number of surviving plants or tillers in a known area. These methods are subjective and labour intensive, which may limit data collection in large‐scale breeding programs. With the rapid development of sensors and image processing algorithms, image‐based high‐throughput phenotyping (HTP) is becoming commonplace in the breeding of major food crops. Image‐based HTP approaches consist of the deployment of a wide range of sensors on ground‐based or airborne platforms and data analysed through image processing pipelines. Image‐based HTP shows high potential for use in pasture phenotyping in breeding programs and may be able to reduce timeframes for releasing new cultivars. Moreover, existing image‐based HTP approaches could be further developed to include precise tools for phenotyping pasture persistence traits such as pasture senescence, botanical composition, pathogen and pest resistance. In this study, we reviewed existing image‐based HTP approaches in precision agriculture and discussed their feasibility for perennial ryegrass persistence estimation in pasture breeding. Although the paper focuses on application in perennial ryegrass, the principles equally apply to other perennial forage species. [ABSTRACT FROM AUTHOR]

Perennial pastures are the dominant feedbase in many regions of the world, and offer several advantages when compared with an annual pasture system. In Western Australia (WA) there has been a concerted effort over seven decades to develop new perennial pasture options and expand the adoption of suitable species. The agricultural region of WA (i.e. south-western Australia) is characterised by a Mediterranean climate where the 5–7 month summer drought has proved a considerable challenge with only a small number of the many promising species being adopted commercially. Research, development, and extension have covered a wide range of herbaceous perennial legumes, leguminous and native shrubs, herbs, and temperate and warm season grasses. This paper reviews the literature to determine whether a perennial pasture must satisfy the following criteria to be successful and widely adopted in south-western Australia: (i) sourced from a similar Mediterranean environment and adapted to the target soils; (ii) have a relative advantage over the annual-based system it replaces; (iii) a robust management package; and (iv) a viable seed supply. The findings of this review highlight that perennial pastures must indeed satisfy multiple criteria to be commercially successful. Notably, the requirement for the source of the germplasm to have a good match between climate and soils is less clear because some of the commercially successful species come from diverse environments. We conclude with some key learnings for future perennial pasture development as climate change intensifies the research challenge and the drive for producers to adapt. In Western Australia, there has been a concerted effort to develop new perennial pasture options. Research, development, and extension have covered a range of herbaceous perennial legumes, leguminous and native shrubs, herbs and temperate and warm season grasses. Overall, this search has proved to be a considerable challenge in a Mediterranean environment with many promising species having little or no commercial impact, and only a small number of species have had widespread commercial adoption. This review explores the key requirements for perennial species to become more than a niche pasture in a Mediterranean climate. [ABSTRACT FROM AUTHOR]

Tropical perennial grasses are an important forage option in the frost prone, summer dominant rainfall zone in eastern Australia. These pastures commonly lack a companion legume and are, at best, irregularly fertilised with nitrogen; therefore, their production potential is not realised. We conducted a study during 2012–16 to evaluate the productivity and persistence of a range of cultivars/lines of eight tropical and two temperate perennial legumes in mixes with digit grass (Digitaria eriantha cv. Premier) at two sites (Bingara and Manilla) in the northern inland region (North-West Slopes) of New South Wales. The sites were subjected to dry conditions during the assessment period, with the Bingara site receiving <25th percentile rainfall for 2 years of the study. Lucerne (Medicago sativa) was the most productive companion legume, with mixes producing 16–18 and 38–46 t dry matter (DM)/ha at the Bingara and Manilla sites respectively. Cultivars of Desmanthus spp. were less productive, with the best performing in mixes producing 13 and 21–23 t DM/ha at Bingara and Manilla respectively. These cultivars were also persistent and readily recruited new seedlings. Their persistence was similar or superior to lucerne, which appeared to be declining, especially at the Manilla site. Mixes of burgundy bean (Macroptilium bracteatum) and digit grass produced 14–17 t DM/ha at the sites but DM tended to decline during the course of the experiment, especially at the Manilla site. Stylosanthes spp. and Chamaecrista rotundifolia had poor persistence, generally failing within 1–2 years of sowing. Therefore, we recommend lucerne and Desmanthus virgatus cvv. Marc and JCU 2 as suitable perennial legumes in mixes with digit grass during drought conditions. Tropical perennial grasses are an important forage option in the frost prone, summer dominant rainfall zone in eastern Australia, but their production potential is not realised owing to lack of nitrogen fertility. We evaluated a range of tropical and temperate perennial legume species in mixes with digit grass in the northern inland region of New South Wales over 4 years with below average rainfall. Under these conditions, lucerne and Desmanthus virgatus were the most productive and persistent species. [ABSTRACT FROM AUTHOR]

The aphid Aploneura lentisci is widespread in Australia and New Zealand, living all year round on roots of its secondary grass hosts. The fungal endophyte (Epichloë festucae var. lolii), strain AR37 in Lolium perenne is known to greatly reduce populations and was a likely reason for the superior growth and persistence of this association previously observed in the field. Aphid populations were quantified in a field trial near Ballarat, comparing yields of perennial ryegrass infected with eight different endophyte strains and an endophyte-free (Nil) control in a common ryegrass background (Grasslands Samson (G. Samson)). AR37 and another endophyte strain, AR5, had significantly fewer aphids than all other endophytes. These differences were significantly related to yield increases taken before and after sampling that persisted until the end of the trial. In a pot trial comparing commercially available ryegrass-endophyte combinations with equivalent Nil controls, aphid numbers were lower on G. Samson AR37 and Banquet II with AR5 (Endo®5) than on all other cultivar-endophyte combinations. Compared with Nil controls, the common toxic strain in G. Samson, and two strains in Trojan also reduced aphid numbers. The AR5 endophyte produces the alkaloid ergovaline but high concentrations of this in roots of potted plants could not account for differences in root aphid numbers. Root concentrations of epoxyjanthitrems, the only known alkaloids produced by AR37, were low and unlikely to be the cause of resistance to A. lentisci. An aphid, Aploneura lentisci , that feeds on grass roots is widespread in pastures in New Zealand and Australia. This paper reports data confirming that perennial ryegrass infected with a strain of Epichloë fungal endophyte, AR37, is highly resistant to this aphid and shows that another endophyte strain, AR5, gives the same level of control. Suppression of high aphid populations by these endophytes in the field at Ballarat resulted in a 37% increase in pasture production over endophyte-free ryegrass over a 5-month period. [ABSTRACT FROM AUTHOR]

Summary: Exotic perennial grasses (EPGs) pose a significant risk to native communities globally. With over 2,200 species in Australia, understanding which characteristics enable high threat invasions, and comparing between functionally similar EPGs, can help prioritise species management. We developed a framework of risk and used the literature to rank 21 EPGs considered a threat to plant communities in New South Wales, while also evaluating the reliability of information currently available. Characteristics were scored within five broad categories that distinguish invasiveness: Arrival, Establishment, Persistence, Impact and Distribution. These included aspects of reproductive biology, competitive ability and environmental tolerance. The risk assessment was effective in assessing key characteristics of invasion. EPGs with an economic benefit (trade‐off species) were more likely to have reliable research and frequently ranked as high‐risk invaders in natural habitats due to the overlap of characteristics important in invasion with those considered important in agriculture. Lack of formal scientific research hindered assessment for some species, and some traits had been poorly assessed in the literature. High uncertainty was associated with key characteristics for Establishment, Persistence and Impact. Uncertainty in key characteristics revealed a need for improved integration of less formal research validated by more formal scientific research. This may lead to more informed decisions in the management of EPGs in native habitats and assist in early control of EPGs not yet assessed. [ABSTRACT FROM AUTHOR]

We have estimated the average genetic diversity of two Glycine annual and six perennial species based upon 76 orthologous gene sets and performed phylogenetic analysis, divergence analysis and tests for departure from neutrality of the eight species using 52 orthologous gene sets. In addition, 367 orthologous gene sets were used to estimate the relationships of 11 G. canescens accessions. Among the perennials, G. canescens showed the highest nucleotide diversity. The other perennials, except for G. tomentella, had higher nucleotide diversity than the two annuals. Phylogenetic analysis of the Glycine showed a similar genome grouping with the previous report except for G. cyrtoloba and G. stenophita which formed a sister clade in the study. Divergence analysis supported the phylogenetic relationships that G. falcata was the most divergent from G. max, followed by G. cyrtoloba, G. syndetika, G. tomentella D3, G. stenophita and G. canescens. Most genic sequences were homogeneous in the levels of polymorphism and divergence between G. max and other Glycine species based on the HKA test, thus, Glycine perennials may have experienced a very similar evolution as inferred by trans-specific mutation analysis. The greater genetic diversity of most perennial Glycine species and their origins from the warmer and drier climates of Australia suggests the perennials maybe a potential source of heat and drought resistance that will be of value in the face of climate change. [ABSTRACT FROM AUTHOR]

Summary: It remains uncertain how perennial grasses with different photosynthetic pathways respond to fire, and how this response varies with stress at the time of burning. Resprouting after fire was examined in relation to experimentally manipulated pre‐fire watering frequencies. We asked the following questions: are there response differences to fire between C3 and C4 grasses? And, how does post‐fire resprouting vary with pre‐fire drought stress?Fifty‐two perennial Australian grasses (37 genera, 13 tribes) were studied. Three watering frequencies were applied to simulate increasing drought. Pre‐fire tiller number, tiller density, specific leaf area and leaf dry matter content were measured as explanatory variables to assess response.Most species (90%) and individuals (79%) resprouted following experimental burning. C4 grasses had higher probabilities of surviving fire relative to C3 grasses. Responses were not related to phylogeny or tribe. High leaf dry matter content reduced the probability of dying, but also reduced the re‐emergence of tillers.Post‐fire tiller number increased with increasing drought, regardless of photosynthetic type, suggesting that drought plays a role in the ability of grasses to recover after fire. This has implications for understanding the persistence of species in landscapes where fire management is practiced. [ABSTRACT FROM AUTHOR]

Perennial grains are being developed to improve the environmental sustainability of grain production systems. However, to maximise their commercial viability, a clearer understanding of their food processing properties is required. In this study, the functional properties of selected perennial wheat breeding lines grown at sites in central New South Wales, Australia, were compared to each other and an annual bread wheat cultivar. Lines were assessed for grain yield parameters, rheological properties (wholemeal and refined flour), starch properties, milling yield and refined flour baking quality. Perennial wheats were found to differ from expected behaviours attributed to annual wheat, offering novel combinations of grain characteristics. Despite softer grain and rheological tests indicating only moderate gluten strength, several lines exhibited better baking performance than the conventional bread wheat control. Furthermore, flour water absorption was found to decrease with increasing grain hardness, the opposite of that normally observed for annual wheat. The results demonstrated that with appropriate breeding and selection, perennial wheat offers good potential for baking. [Display omitted] • Perennial cereals offer potential to improve the environmental sustainability of grain production. • Perennial wheat end-use function diverged from presumptive tests for baking quality applied to annual wheat. • Soft grained perennial wheats with moderate gluten strength exhibited good baking performance. • For perennial wheats, milling yield and flour hydration were found to decrease with increasing grain hardness. [ABSTRACT FROM AUTHOR]

Genotype-by-environment interaction (G×E) is commonly observed in perennial ryegrass species and significantly impacts dry matter yield (DMY) performance across environments. Variation in DMY of perennial ryegrass cultivars and their distinct responses to different environments directly influence the profitability of the Australian dairy industry. In this study, we implemented a separate two-way factor analytic strategy to fit multi-environment-multi-harvest data collected from 18 trials spanning 14 years to account for the G×E effects across complex pasture environments in south-eastern Australia to achieve accurate DMY predictions. Three mega-environments were identified, and the seasonal and environmental DMYs of 126 cultivars or breeding lines (defined by a combination of varieties and endophytes) were predicted. Statistical differences in DMY performance and crossover G×E effects in cultivar rankings were observed among the three mega-environments. Several high-yielding cultivars specific to each mega-environment were also identified. The analysis demonstrated the importance of accounting for G×E effects when predicting the DMY of perennial ryegrass and highlighted the potential for identifying high-yielding cultivars specific to mega-environments. The research rationalizes implementing an appropriate independent pasture trialling system to generate necessary data for the dairy industry and could further facilitate dairy farmers to select suitable cultivars based on their specific environments and perennial ryegrass breeders when accounting for the genetic relationship of cultivars. • G×E impacts perennial ryegrass cultivar rankings and breeding strategies. • Factor analytic model is a robust tool for analysing G×E. • Analysing G×E provides accurate DMY prediction and facilitates identifying high-yielding cultivars. • Identified 3 mega-environments and predicted DMYs for 126 cultivars. • Appling an independent trialling system is necessary to identify environmental-specific cultivars. [ABSTRACT FROM AUTHOR]

Growth rate, proportion of leaf and stem and nutritive value of sown tropical perennial grasses have not previously been documented for the dryland, frost-prone summer-dominant rainfall region of eastern Australia. An experiment was conducted in northern inland New South Wales with Chloris gayana (Rhodes grass) cv. Katambora and Digitaria eriantha (digit grass) cv. Premier, and compared to Sorghum bicolor ssp. bicolor x S. bicolor ssp. drummondii (forage sorghum). The grasses were harvested every 2 or 6 weeks and fertilized at five rates of nitrogen (N; 0-300 kg N ha−1) over two growing seasons (September-May), 2006-2007 and 2007-2008. Growing season rainfall was below median for both years of the experiment and growth rate was highly variable, reflecting variable rainfall. Sorghum generally had the highest growth rate. Digit grass generally had higher growth rates than Rhodes grass, was more responsive to growing season rainfall, commenced growth earlier and had a longer growing season. Nitrogen application extended the growing season of both perennial grasses. Growth response to N application was minimal when rainfall was low and response following significant rainfall was higher for fertilized than unfertilized grasses. In general, the proportion of green leaf was greater than green stem, although the proportion of stem increased when defoliation interval increased. Nutritive value of the perennial grasses was higher in leaf than stem and declined during the growing season. Differences between the grasses were slight, but indicated that fertilized digit grass defoliated at 2-week intervals had higher growth rate and nutritive value than Rhodes grass. [ABSTRACT FROM AUTHOR]

Changing the mix of land uses in agricultural systems affects the benefits enjoyed by humans. Such benefits range from food and water to aesthetic and spiritual benefits. If one aim of land-use decision-making is to maintain or improve the quality of human lives, the consequences of proposed changes must be evaluated across all benefits that contribute to human well-being. This is a challenging task. Difficulties include classifying benefits to minimise double-counting, objective quantification of disparate benefits, and the costs of analyses. The reported work addresses these issues by testing a new classification of benefits and using expert elicitation to reduce assessment costs. Compared to current agricultural systems, the impacts of the two perennial plant technologies assessed were generally either neutral or positive with respect to the flow of benefits. At low cost, the benefits analysis informs stakeholders of the impacts of proposed land-use changes and the breadth of issues that need to be considered by decision-makers. [ABSTRACT FROM PUBLISHER]

In 2050, which aspects of ecosystem change will we regret not having measured? Long-term monitoring plays a crucial part in managing Australia's natural environment because time is a key factor underpinning changes in ecosystems. It is critical to start measuring key attributes of ecosystems - and the human and natural process affecting them - now, so that we can track the trajectory of change over time. This will facilitate informed choices about how to manage ecological changes (including interventions where they are required) and promote better understanding by 2050 of how particular ecosystems have been shaped over time. There will be considerable value in building on existing long-term monitoring programmes because this can add significantly to the temporal depth of information. The economic and social processes driving change in ecosystems are not identical in all ecosystems, so much of what is monitored (and the means by which it is monitored) will most likely target specific ecosystems or groups of ecosystems. To best understand the effects of ecosystem-specific threats and drivers, monitoring also will need to address the economic and social factors underpinning ecosystem-specific change. Therefore, robust assessments of the state of Australia's environment will be best achieved by reporting on the ecological performance of a representative sample of ecosystems over time. Political, policy and financial support to implement appropriate ecosystem-specific monitoring is a perennial problem. We suggest that the value of ecological monitoring will be demonstrable, when plot-based monitoring data make a unique and crucial contribution to Australia's ability to produce environmental accounts, environmental reports (e.g. the State of the Environment, State of the Forests) and to fulfilling reporting obligations under international agreements, such as the Convention on Biological Diversity. This paper suggests what must be done to meet Australia's ecological information needs by 2050. [ABSTRACT FROM AUTHOR]

A new species of perennial, trifoliolate Hydrocotyle (H. rivularis H.Eichler ex Henwood) from south eastern Australia is described and compared to other trifoliolate species from Australia and New Zealand. A distribution map and illustrations of the new species are provided. [ABSTRACT FROM AUTHOR]

Solanum elaeagnifolium (silverleaf nightshade) is an invasive perennial weed in Australia, with aerial growth commencing in spring from either the perennial root system or the soil seedbank, with senescence occurring in autumn. A total of 642 S. elaeagnifolium individuals were collected at flowering from 92 locations in south-eastern Australia to study morphological variation and its implications for management. Large morphological variation was found between individuals from different locations. Leaf length, width and area ranged from 1.44 to 10.6 cm, 0.39 to 4.09 cm and 0.41 to 25.8 cm2 respectively. Plants from higher rainfall regions were significantly taller and had larger leaves, suggesting a possible correlation between rainfall and morphology. Scanning electron microscopy comparison of leaf surfaces showed lower trichome and stomatal densities on the adaxial surface (67.0 ± 3.3 trichomes mm−2 and 603.4 ± 29.2 stomata mm−2 respectively) than on the abaxial surface (131.9 ± 7.2 trichomes mm−2 and 813.7 ± 30.5 stomata mm−2 respectively). The morphological plasticity of S. elaeagnifolium highlighted in this study could probably contribute to its adaptability and partly explain its establishment and continuing expansion in Australia. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated three possible reasons for low ground cover in an inter-patch in woody encroachment in semi-arid south-eastern Australia: (1) grazing by large herbivores, (2) competition with woody plants for resources, and (3) the smooth, crusted soil surface impeding litter lodgement and germination of seeds. Grazing exclusion, trenching (cutting roots of woody plants to 30 cm depth) and surface soil disturbance treatments were established in October 2008, and herbaceous ground cover and litter cover were measured after three, 16 and 30 months. Perennial grass cover in the ungrazed area was higher in trenched plots than in untrenched plots. Perennial grass cover in the grazed area was very low in trenched and untrenched plots. Herbaceous ground cover increased over time in ungrazed and trenched plots, much more than in grazed or untrenched plots. Soil disturbance did not affect herbaceous ground cover. Herbaceous ground cover was low in all treatments (<10%). Both grazing and cutting roots of woody plants affected herbaceous ground cover in this study. Herbaceous ground cover increased when roots of woody vegetation were severed (in the absence of grazing), indicating that herbaceous ground cover and woody vegetation compete for resources. [Copyright &y& Elsevier]

A general prediction of ecological theory is that climate change will favor invasive nonindigenous plant species (NIPS) over native species. However, the relative fitness advantage enjoyed by NIPS is often affected by resource limitation and potentially by extreme climatic events such as drought. Genetic constraints may also limit the ability of NIPS to adapt to changing climatic conditions. In this study, we investigated evidence for potential NIPS advantage under climate change in two sympatric perennial stipoid grasses from southeast Australia, the NIPS Nassella neesiana and the native Austrostipa bigeniculata. We compared the growth and reproduction of both species under current and year 2050 drought, temperature and CO2 regimes in a multifactor outdoor climate simulation experiment, hypothesizing that NIPS advantage would be higher under more favorable growing conditions. We also compared the quantitative variation and heritability of growth traits in populations of both species collected along a 200 km climatic transect. In contrast to our hypothesis we found that the NIPS N. neesiana was less responsive than A. bigeniculata to winter warming but maintained higher reproductive output during spring drought. However, overall tussock expansion was far more rapid in N. neesiana, and so it maintained an overall fitness advantage over A. bigeniculata in all climate regimes. N. neesiana also exhibited similar or lower quantitative variation and growth trait heritability than A. bigeniculata within populations but greater variability among populations, probably reflecting a complex past introduction history. We found some evidence that additional spring warmth increases the impact of drought on reproduction but not that elevated atmospheric CO2 ameliorates drought severity. Overall, we conclude that NIPS advantage under climate change may be limited by a lack of responsiveness to key climatic drivers, reduced genetic variability in range-edge populations, and complex drought-CO2 interactions. [ABSTRACT FROM AUTHOR]

This study investigated the effect of elevated CO2 on the post-fire resprouting response of a grassland system of perennial grass species of Cumberland Plain Woodland. Plants were grown in mixtures in natural soil in mesocosms, each containing three exotic grasses ( Nassella neesiana, Chloris gayana, Eragrostis curvula) and three native grasses ( Themeda australis, Microlaena stipoides, Chloris ventricosa) under elevated (700 ppm) and ambient (385 ppm) CO2 conditions. Resprouting response after fire at the community- and species-level was assessed. There was no difference in community-level biomass between CO2 treatments; however, exotic species made up a larger proportion of the community biomass under all treatments. There were species-level responses to elevated CO2 but no significant interactions found between CO2 and burning or plant status. Two exotic grasses ( N. neesiana and E. curvula, a C3 and a C4 species respectively), and one native grass ( M. stipoides, a C3 species) significantly increased in biomass, and a native C4 grass ( C. ventricosa) significantly decreased in biomass under elevated CO2. These results suggest that although overall productivity of this community may not change with increases in CO2 and fire frequency, the community composition may alter due to differential species responses. [ABSTRACT FROM AUTHOR]

The impact of deferred grazing (no defoliation of pastures for a period generally from spring to autumn) and fertilizer application on plant population density, ground cover and soil moisture in a hill pasture (annual grass dominated, with Australian native grasses being the major perennial species) were studied in a large-scale field experiment from 2002 to 2006 in southern Australia. Three deferred grazing strategies were used: short-term deferred grazing (no defoliation between October and January each year), long-term deferred grazing (no defoliation from October to the autumn break, that is the first significant rainfall event of the winter growing season) and optimized deferred grazing (withholding time from grazing depends on morphological development of the plants). These treatments were applied with two fertilizer levels (nil fertilizer and 50 kg P ha−1 plus lime) and two additional treatments [continuous grazing (control) and no grazing for year 1]. Deferred grazing increased ( P < 0·05) perennial grass tiller density compared with the control. On average, the tiller density of the three deferred grazing treatments was 27-88% higher than the control. There was a negative ( P < 0·01) relationship between perennial and annual grass tiller density. Fertilizer application increased ( P < 0·05) legume plant density. The densities of annual grasses, legumes, onion grass ( Romulea rosea) and broadleaf weeds varied between years, but perennial grass density and moss cover did not. The ground cover of the deferred grazing treatments in autumn was on average 27% higher than the control. Soil moisture differed between treatments at 15-30 cm depth, but not at 0-15 depth over autumn and winter. The results imply that deferred grazing can be an effective tool for rejuvenating degraded native pastures through increases in native grass tiller density and population and through improving farm productivity and sustainability. [ABSTRACT FROM AUTHOR]

Abstract: Patterns of plant diversity were examined across 24 ironstone ranges in arid south western Australia. The high levels of beta diversity displayed between ranges primarily resulted from high turnover of perennial species and was not influenced by the lower species richness on the more arid ranges. The variance in composition of the vegetation across the ranges was evenly distributed between the broad spatial pattern and environmental factors measuring climate gradients, local site variables and soil chemistry. In contrast broad scale spatial and climatic gradients were most important in explaining the variance in perennial species richness. Ranges along the boundary of the Arid Zone appear to have acted as refugia during the climatic cycles of the Tertiary with several hotspots of species endemism and taxa with distributions centered on these ranges. On the more arid ranges these specialist ironstone taxa are largely absent. The variation in richness of these specialists taxa was strongly influenced by patterns in soil chemistry in addition to the broad scale spatial and climate gradients. The concentration of the ironstone specialist taxa is largely coincidental with the most prospective areas for iron ore mining and this will provide considerable challenges in conserving these unique ecosystems. [Copyright &y& Elsevier]

Spring herbage mass of 80 mostly annual and biennial legumes was evaluated regionally on the North-West Slopes of New South Wales, Australia in ungrazed plots at three sites (Curban, Terry Hie Hie and Moree) in 1998 and 1999. Of the cultivars tested, Trifolium vesiculosum cvv. 'Cefalu' and 'Zulu' and T. resupinatum cv. 'Prolific' at the Moree and Terry Hie Hie sites, and T. resupinatum cv. 'Nitro' at the Curban site generally performed better than the standard 'test' cultivars of T. subterraneum cv. 'Junee' and T. brachycalycinum cv. 'Clare' and Medicago sativa cvv. 'Aquarius' and 'Aurora'. T. michelianum (5) and (11), T. isthmocarpum (SA 8410) and T. glanduliferum (CPI 87182) also had superior performance to many of the other entries and could be considered for further testing and evaluation in this region. [ABSTRACT FROM AUTHOR]

Abstract: Arbuscular mycorrhizal (AM) fungi convey well documented benefits to plant growth in domesticated species. We investigated AM in Solanum centrale, a desert shrub of central Australia and traditional food for Indigenous Australians. AM were observed in roots of S. centrale from wild and cultivated stands of different ages and management regimes. Greenhouse seedlings grown in sterilised sand were provided with no or minor additions of phosphorus, with or without AM fungi. Inoculated seedlings not fertilised with phosphorus exhibited moderate AM formation. Added phosphorus resulted in an absence of AM. Inoculation did not significantly affect dry weight, root length and plant height of seedlings fertilised with phosphorus but significantly increased the size of unfertilised seedlings. Inoculation significantly increased root phosphorus content, decreased root to shoot ratio and decreased root biomass at all phosphorus additions, despite the absence of observable AM. Thus it appears AM fungi in the root zone influenced certain plant characteristics, regardless of phosphorus nutrition. Overall, S. centrale benefited from the presence of AM through increased phosphorus uptake, but only when the seedlings were growing in soil with extremely low available phosphorus. The response was immediate in our experimental system and is likely to be important in the wild. [Copyright &y& Elsevier]

The salinisation of agricultural land, natural habitats, water resources and non-agricultural infrastructure is a serious problem in southern Australia. A number of government programs have attempted to reduce the substantial costs of degradation. For such interventions to be justified, the level of salinity resulting from private landholder decisions must exceed the level that is optimal from the point of view of society as a whole, and the costs of government intervention must be lower than the value of benefits gained by society . This research adapts an existing hydrological/economic model representing external costs from dryland salinity affecting any biological or physical asset. The model is used to identify those variables that have the biggest impact on the net-benefits possible from government intervention. The key variables that have the biggest impact on net-benefits of dryland salinity mitigation are the value of the off-site asset and the lag time before the onset of dryland salinity in the absence of intervention. In many cases, the off-site hydrological and economic benefits from planting perennial vegetation are small, so that the returns from perennial plants need to be almost as high as those from traditional annual crops and pastures, if they are to be worth growing. [ABSTRACT FROM AUTHOR]

Abstract: An understanding of soil seed bank processes is crucial for understanding vegetation dynamics, particularly in ecosystems experiencing frequent disturbance. This paper examines seed bank dynamics in a tropical savanna in northern Australia, an environment characterised by frequent fire and highly seasonal rainfall. In particular, we examine the contribution of seed bank processes to the high level of resilience shown by grass-layer vegetation in relation to fire. We assess the spatial congruence between seed bank composition and extant vegetation, document temporal variation in the germinable seed bank over the annual dry season, test the effects of laboratory-applied heat and smoke treatments on seed germinability, and determine the effect of experimental fires on seed bank composition. Although dominant species were shared, the composition of the germinable seed bank was significantly different to that of extant vegetation, with approximately half the extant species not being detected in the seed bank. The density and species richness of germinable seeds was significantly greater in the late dry season than the early dry season, with annual grasses showing particularly high levels of seed dormancy in the early dry season. The density and species richness of germinable seeds in the seed bank was significantly enhanced by laboratory-applied treatments of smoke and especially heat, driven by the response of legumes. However, fire had no significant effect on the density or species richness of germinable seeds in the field, indicating soil temperatures during fire were too low to overcome physical dormancy, or burial was too deep to experience adequate heating or smoke exposure. Our results provide a mechanistic understanding of the persistence of annual grasses and forbs in an environment subject to frequent fire and highly seasonal rainfall, and, together with the sprouting capacity of perennial grasses, explain the high resilience of savanna grass-layer plants in relation to fire. [Copyright &y& Elsevier]

Rural populations in Australia are in decline and rural farm businesses now endure chronic labour shortages. Livestock enterprises traditionally require more labour than their cropping counterparts and this threatens future increases in their intensity and scale. The influence that labour scarcity has on the profitability of mixed-farming systems in the Central Wheatbelt of Western Australia is investigated in this study. When labour supply is assumed to be non-limiting, perennial plants are profitable where their out-of-season production sustains a sizeable breeding flock in a prime-lamb enterprise. However, when labour supply is limited and labour demand is defined as a function of enterprise mix, cropping activity increases and livestock production decreases. In addition, the proportion of the farm planted with perennial pasture declines. This has implications for natural resource management, with perennial pasture helping to prevent soil erosion, decrease waterlogging, and reduce recharge to saline watertables. Efforts to improve the labour efficiency of livestock production are therefore highly pertinent if perennial pastures are to offset land degradation on a broader scale. [ABSTRACT FROM AUTHOR]

Background and Aims: In Australia, honey-bees have invaded systems that evolved without social insect pollinators, where many plants are adapted to vertebrate pollination. Behavioural differences between pollinators are likely to influence mating patterns, but few studies have examined this empirically in long-lived, woody, perennials. It was shown previously that outcrossing rates in Grevillea macleayana vary among populations. Here tests were conducted to determine whether the behaviour of birds and honey-bees differed between a population previously found to be highly outcrossed and two inbreeding populations. [ABSTRACT FROM PUBLISHER]

Perennial ryegrass (PRG) is an important forage grown on dairy farms in temperate regions globally, including south-eastern Australia. A forage value index (FVI) providing information on the seasonal production of commercially available PRG cultivars is currently available. Despite the importance of the nutritive value of pasture in dairy farm systems, the nutritive characteristics of PRG cultivars are not currently included in the FVI as they are not routinely measured in cultivar evaluation trials. This study investigated differences between cultivar functional groups (diploid and tetraploid). It also examined differences between individual cultivars within seasons at four locations in south-eastern Australia and examined how trial location affects cultivar ranking. Samples were collected from existing cultivar evaluation trials over a 3-year period and analysed for nutritive characteristics. There were differences (p < 0.05) between diploids and tetraploids for metabolisable energy (ME) and neutral detergent fibre (NDF) in each season at each location with a few exceptions in summer and autumn. Crude protein (CP) differed between functional groups in some seasons at some sites. Spearman rank correlations within season were strong for ME between trial locations (r = 0.78–0.96), moderate to high for NDF (0.51–0.86) and variable for CP (−0.69–0.56). These findings provide guidance on methods for implementing nutritive value testing in cultivar evaluation trials and support the imminent inclusion of ME in the Australian FVI. The ranking of cultivars for ME was more consistent across trial sites compared to NDF and CP, suggesting the latter two traits, in particular CP, are more sensitive to environmental influences. Based on these results, we do not recommend the inclusion of CP as an individual trait in the Australian FVI. A significantly larger dataset and further research on the genotype by environment interactions would be needed to reconsider this. The addition of ME in the Australian FVI will lead to better cultivar choices by farmers and could lead to more targeted perennial ryegrass breeding programs. [ABSTRACT FROM AUTHOR]

The dryland agricultural landscape of north-west Victoria, Australia, includes isolated remnants of eucalypt woodland that are exposed to ongoing disturbance from sheep grazing and cropping activity. Biological soil crusts are a functionally important feature of these woodland communities. We used a modern form of regression (boosted regression tree (BRT) models) to investigate relationships between crust abundance and environmental and landscape variables. We also investigated whether the use of broad morphological groups of crust organisms is more informative than simply measuring total crust cover. Remnant size was the single most influential variable for crust abundance, with negligible crust cover in small patches (\5 ha). The BRT model also identified relationships between crust abundance and available P, soil C and perennial grass. We argue that disturbance from stock grazing and camping is the mechanism driving these relationships. Other variables related to crust abundance were proximity to the windward edge, litter cover and tree cover. Morphological groups showed a differential response to some variables, suggesting assessment of total cover may mask important patterns in community structure. Crust disturbance represents a serious issue for maintenance of ecosystem function in the study region, particularly loss of crusts from small remnants because the majority of remnants are small. [ABSTRACT FROM AUTHOR]

The spatial distributions of most species are aggregated to varying degrees. A limited number of studies have examined the effects of spatial aggregation on interspecific and intraspecific interactions, generally finding that spatial aggregation can enhance coexistence between species by reducing the capacity for interspecific competition. Less well studied are the effects of spatial aggregation on complementarity (i.e. differences in resource use strategies) and resource use. Our primary hypothesis was that spatial aggregation reduces the complementarity between species owing to: (i) less interspecific interactions as a result of spatial separation; and (ii) less differences between species as a result of phenotypic plasticity. We further postulate that these negative effects of spatial aggregation on complementarity will reduce resource use by the community. Here we test these hypotheses in a pot experiment in which we applied three levels of spatial aggregation to three sets of two-species mixtures of herbaceous perennial plant species from native grasslands of south-eastern Australia. Both root and shoot biomass were significantly affected by spatial aggregation, although the nature of these affects depended upon the species involved, and the relative strengths of interspecific versus intraspecific competition. Complementarity between species in the distribution of their green leaves decreased significantly as spatial aggregation increased for one of the species mixtures, providing some evidence in support of our hypothesis that aggregation reduces complementarity through phenotypic plasticity. Spatial aggregation also altered light interception and use of soil moisture resources, although these effects were dependent on the species involved. We suggest that clear effects of spatial aggregation on complementarity and resource use may be obscured by the idiosyncratic way in which neighbour identity influences plant growth and hence plant size, limiting the ability to generalize, at the community level, any underlying effects of spatial pattern on ecological process. [ABSTRACT FROM AUTHOR]

1. Ecological invasions are often associated with persistent changes to underlying ecological processes. Restoration of invaded communities is dependent on manipulation of these processes to favour the target species composition and impart resistance to further invasion. We applied these principles to extensively degraded grassy woodlands in temperate agricultural regions of Australia, where widespread invasion by mediterranean annuals is related to altered ecological processes such as soil nutrient cycling. 2. We investigated carbon supplementation and spring burns, in association with re-establishment of native perennial grasses, as potential management tools for manipulating nitrogen cycling, soil seed banks and establishment conditions in degraded woodland understoreys. Through these mechanisms we aimed to enhance native cover and increase resistance to invasion by exotic annuals. 3. In two contrasting degraded remnants, repeated sucrose applications temporarily reduced soil nitrate to inferred pre-European levels, which dramatically reduced growth of exotic annuals and enhanced native perennial abundance. Repeated spring burns did not reduce soil nitrate but reduced exotic annual grasses through effects on soil seed banks and/or establishment conditions. 4. Spring burns and carbon supplements both significantly enhanced establishment of Themeda australis, a dominant tussock grass prior to European settlement. Combinations of T. australis seed addition and either spring burning or carbon supplements enhanced native plant abundance more effectively than treatments without seed addition. 5. Within 18 months of their establishment, T. australis seedlings significantly reduced soil nitrate in some treatments, providing a preliminary indication that re-establishment of a dense sward of this species may restore ecosystem function to a low-nitrate state that favours native perennials over exotic annuals. 6. Synthesis and applications. Ecological restoration can be viewed as targeted intervention in species–environment interactions, whereby ecological conditions are manipulated to enhance establishment or vigour of key species, and these species in turn help restore ecological processes that favour the target species composition. In grassy ecosystems re-establishing a perennial sward of appropriate native tussock grasses may be critical for restoring pre-disturbance nitrogen cycles and improving resistance to invasion by exotic annuals. Carbon supplements and spring burns facilitate this process through complementary mechanisms. [ABSTRACT FROM AUTHOR]

We investigated what factors lead to invasion of exotics or re-colonization of native perennial grasses in the South Australian mid-north grasslands. We manipulated 160 experimental quadrats by clipping, irrigation and seed addition and assessed recruitment by exotics in an area dominated by perennial grasses and perennial grass recruitment in an area dominated by exotics. Treatment effects differed with season for exotics: their biomass increased with irrigation in autumn and seed addition in winter. However, in both periods other factors, probably soil properties, also had a strong effect. We detected no perennial grass seedlings in the quadrats over 1 year, possibly due to unsuitable environmental conditions or persistent high competition levels. Under controlled conditions the presence of the invasive annual Avena barbata had a strong negative effect on the recruitment of the native perennial Austrodanthonia caespitosa at any moisture and nutrient availability. Avena also germinated faster and more frequently than Austrodanthonia, especially at low soil moisture. During an imposed drought Austrodanthonia seedlings survived longer in the absence of Avena. The results suggest that annual exotics are highly responsive to resources and can quickly invade areas, while the re-colonization of invaded areas by native grasses requires a complex (and less likely) rainfall regime. [ABSTRACT FROM AUTHOR]

Grassy woodlands dominated by Eucalyptus species such as E. albens Benth., E. melliodora A. Cunn. ex Schauer, and E. microcarpa Maiden are poorly conserved in Australia, owing to widespread agricultural development. Understorey restoration is vitally important to enhance degraded remnants but no reliable techniques are available to restore herbaceous understorey species over large areas. Reestablishment of dominant native grasses such as Kangaroo grass ( Themeda triandra Forssk.) is particularly important. This study compared Themeda establishment using a variety of sowing techniques across a range of landscape positions in degraded woodlands in central New South Wales. Four localities were sampled at three landscape positions (upper, mid-, and lower slopes). Existing vegetative cover was sprayed with herbicide and removed by mowing. A randomized block experiment was established at each site with five replicates of five seedbed treatments: all four factorial combinations of soil disturbance (disturbed, nondisturbed) and weed control (atrazine, nonatrazine), plus topsoil scalping followed by soil disturbance. After 117 days, all plots were subject to a common herbicide (atrazine) treatment to control weeds. Themeda establishment was not significantly affected by landscape position, despite significant differences in the cover of exotic species among landscape positions. The scalped/disturbed treatment resulted in significantly better establishment at 400 days (18% or 3.9 plants/m2) than the control (8% or 1.8 plants/m2). All other treatments did not differ significantly from the control suggesting that seedbed treatments are not critical to successful Themeda establishment. These results suggest that Themeda swards can be reestablished in degraded woodlands relatively simply. The similarity in outcomes across all landscape positions suggests that general recommendations for “best-bet” establishment methods may prove robust under a wide range of environmental and seasonal conditions. [ABSTRACT FROM AUTHOR]

Development of legume-based farming systems has resulted in Australian agriculture being globally competitive. There is now political pressure for agriculture to become accountable for ‘off-site’ environmental consequences. Farming systems relying on annual species are unsustainable because of a mismatch between the supply and demand of water and N, resulting in N leakage to streams or groundwater. Rainfall in excess of plant requirements coupled with N build-up, permeable soils, limited opportunities for reduction and proximity to surface or groundwater present risks for leakage of NO3–N. We present examples of N leakage from legume systems in southern Australia, where rainfall exceeds 450 mm yr-1, and the evidence suggesting that leakage contributes to stream and groundwater pollution. N build-up in autumn through mineralisation of organic-N from legume-based systems often exceeds 100 kg N ha-1 and N leakage losses can be 15–35 kg N ha-1 yr-1. Stream and groundwater N pollution issues are emerging. Surface water quality problems are already apparent in Victoria although the contribution from legumes, N fertilisers and point sources remains unresolved. Examples of groundwater problems where legumes are a contributing factor have been recorded in New South Wales (NSW), South Australia (SA), Western Australia (WA) and Victoria. In Victoria, areas at risk of N groundwater contamination are found along the Great Dividing Range and in southern Victoria. Groundwater pollution causes concern because once problems are found they take decades to reverse. Stores of N in the unsaturated zone combined with limited N monitoring in groundwater suggests that early detection is unlikely. Solutions for reducing off-site consequences are outlined and include management to prevent water and N leakage happening, capture of N before it reaches waterways or groundwater and low input systems including land retirement. For scientists interested in N fixation and biological mediation, future research areas include increasing the proportion of perennials in farming systems, better control of N supply and demand through improved technology and us of N fertiliser, use of nitrification inhibitors and studies of the potential for N immobilisation and reduction through denitrification, both within and below the root zone. Integrated management strategies that address environmental implications from point/micro-scale to paddock and catchment scales are needed as are considerations of other environmental consequences. Research priorities will change from maximising N fixation for profitability towards balancing profitability and environmental goals for more sustainable systems. [Copyright &y& Elsevier]

Abstract Many populations of herbaceous perennial plants contain seeds stored in a soil seed bank. The contribution of seeds to population persistence is an important parameter in population models but germination rates of known-age seeds are difficult to obtain because individual seeds cannot easily be followed. Although Trachymene incisa Rudge plants produce copious seeds that are dispersed into the soil, the existence of a seed bank has not been confirmed. To quantify the potential for a seed bank fresh seeds of T. incisa were sown into experimental seed banks in the eucalypt-dominated Agnes Banks Woodland in western Sydney, NSW. A recent fire provided the opportunity to compare germination in the burnt and unburnt vegetation. Density of seed sowing and time of maturation/dispersal of seeds were manipulated in 75 seed cages. Emergence of seeds after 5 months was significantly higher for the earliest planting date but after 1 year, germination of seeds planted in the later weeks increased, and the final germination for all weeks was 28%. Density of sowing and the recent fire did not affect emergence. A second experiment planted over a broader time span (9 weeks instead of 3 weeks) confirmed the effect of planting date but also found significant spatial variation on a scale of tens of metres. Laboratory germination rates of over 70% confirmed that the seeds were viable and non-dormant when sown in the field cages. The carry-over of non-germinated seed in the soil seed bank is estimated to be about 70% after 2 years, implying that a cohort of seeds would not be depleted through germination alone for up to 40 years. The potential for a long-lived seed bank in this species is interesting because the plants are also capable of resprouting from their rootstock after fire, giving them characteristics of both resprouters and seeders. [ABSTRACT FROM AUTHOR]

Describes the concurrent changes in plant weight and soil water regimes in herbaceous communities in Central Australia. Great production of perennial communities during periods of prolonged high soil water content; Variation of the weight of annual roots with season as distinct from perennials; Development of two gradients of soil water tension of opposite signs during prolonged drought.

Reports on the description of the seasonal growth characteristics of perennial legumes and annual grass pasture ecosystem in the dry monsoonal region of northern Australia. Identification of phases during which the botanical composition of the ecosystem may change; Presentation of a conceptual model with general applicability for a pasture of perennial and annual species; Examination of the inter-relationships between the identified phases.