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A fundamental requirement of sustainable forest management is that stands are adequately regenerated after harvesting. To date, most research has focused on the regeneration of the dominant timber species and to a lesser degree on plant communities. Few studies have explored the impact of the regeneration success of dominant tree species on plant community composition and diversity. In this study, we quantified the influence of variability in tree density and climatic and edaphic factors on plant species diversity in montane regrowth forests dominated by Eucalyptus regnans in the Central Highlands of Victoria in southeastern Australia. We found that Acacia density shaped plant biodiversity more than Eucalyptus density. Edaphic factors, particularly soil nutrition and moisture availability, played a significant role in shaping species turnover and occurrence. Our findings suggest that the density of Acacia is a key biotic filter that influences the occurrence of many understorey plant species and shapes plant community turnover. This should be considered when assessing the impacts of both natural and anthropogenic disturbances on plant biodiversity in the montane forests of southeastern Australia. [ABSTRACT FROM AUTHOR]

Austropuccinia psidii is an introduced plant pathogen known to have caused significant declines in populations of several Australian native Myrtaceae species. However, limited research has focused on the impacts of the pathogen on plant communities in the aftermath of its invasion. This study investigated the relationship between disease impact level, plant species diversity, and functional richness in seedling communities in a wet sclerophyll forest in southeast Queensland. A clear shift was found from early colonizer Myrtaceae species in the mid- and understory to a more diverse non-Myrtaceae seedling community indicative of secondary succession. Comparisons of key Myrtaceae species and the seedling community suggest that there may also be a shift towards species that produce drupes and larger seeds, and overall, a current reduction in fruit availability due to the dramatic loss of previously dominant species. Seedling diversity showed no significant correlation with tree mortality, possibly due to favorable rainfall conditions during the study period. The more subtle changes in forest composition, such as changes in fruit type and availability due to myrtle rust, however, could affect the visitation of local bird species in the short term and certainly reduce the store of early colonizing native shrub and tree species. [ABSTRACT FROM AUTHOR]

The diversity of terrestrial vascular plants plays a key role in maintaining the stability and productivity of ecosystems. Monitoring species compositional diversity across large spatial scales is challenging and time consuming. Airborne hyperspectral imaging has shown promise for measuring plant diversity remotely, but to operationalise these efforts over large regions we need to advance satellite-based alternatives. The advanced spectral and spatial specification of the recently launched DESIS (the DLR Earth Sensing Imaging Spectrometer) instrument provides a unique opportunity to test the potential for monitoring plant species diversity with spaceborne hyperspectral data. This study provides a quantitative assessment on the ability of DESIS hyperspectral data for predicting plant species richness in two different habitat types in southeast Australia. Spectral features were first extracted from the DESIS spectra, then regressed against on-ground estimates of plant species richness, with a two-fold cross validation scheme to assess the predictive performance. We tested and compared the effectiveness of Principal Component Analysis (PCA), Canonical Correlation Analysis (CCA), and Partial Least Squares analysis (PLS) for feature extraction, and Kernel Ridge Regression (KRR), Gaussian Process Regression (GPR), and Random Forest Regression (RFR) for species richness prediction. The best prediction results were r = 0. 76 and RMSE = 5. 89 for the Southern Tablelands region, and r = 0. 68 and RMSE = 5. 95 for the Snowy Mountains region. Relative importance analysis for the DESIS spectral bands showed that the red-edge, red, and blue spectral regions were more important for predicting plant species richness than the green bands and the near-infrared bands beyond red-edge. We also found that the DESIS hyperspectral data performed better than Sentinel-2 multispectral data in the prediction of plant species richness. Our results provide a quantitative reference for future studies exploring the potential of spaceborne hyperspectral data for plant biodiversity mapping. [ABSTRACT FROM AUTHOR]

Aim: In Australia, natural grasslands largely occur on fertile clay soils and have consequently been extensively cultivated since European settlement. Other studies have demonstrated that passive restoration of subtropical grassland is possible in environments where there is substantial native remnant vegetation in the surrounding landscape. This study examined a chronosequence of abandoned fields to investigate the recovery of fragmented grassland in a matrix of cultivated land with significant exotic species that may impede succession. Location: Darling Downs, Queensland, Australia. Methods: In this study we surveyed a chronosequence of ex‐cultivated subtropical grasslands in Queensland's Darling Downs, where only 1% of the original grasslands remain. Floristic surveys were carried out in 80 fallow sites up to 51 years old, and data were compared with 16 previously surveyed remnant grasslands on the same land type. Results: Richness of native species increased with time since cultivation and approached, but did not reach, that of remnant grasslands after 51 years, whereas the richness of exotics declined with time since cultivation. Rainfall and grazing positively and negatively affected exotic plant abundance respectively and these factors had no significant direct or indirect effect on the native species richness. In terms of composition, fallow grasslands supported 54% of the native plant species from remnant grasslands after 51 years. The native perennial grasses Dichanthium sericeum and Aristida leptopoda were the only dominant species in the remnants that were present in more than 60% of the fallow grasslands. Of the species from remnants that were "missing" from fallow sites, most were native perennial forbs and grasses. Compositional dissimilarity of fallow grassland to remnant grasslands remained high after 51 years (78%). Grassland species that are uncommon in nearby hill woodlands were preferentially absent in fallow grassland and this partly explains the slow compositional recovery. Conclusion: In a highly fragmented landscape, passive restoration is only partially effective. The restoration of grassland is probably enhanced by repositories of native seeds from hill woodlands that are too rocky to cultivate. However, some species may have to be actively reintroduced to achieve complete recovery. In this landscape, where grazing is a dominant land use, exotic species do not seem to impede succession. [ABSTRACT FROM AUTHOR]

Questions: The impact of invasive plant species on native diversity varies with spatial scale, with some invaders leading to broad‐scale diversity declines and others to only local declines. These discrepancies may reflect the invaders" capacity to reduce niche opportunities across spatial scales which can be associated with their functional traits. We investigated impact‐scale relationships and trait‐based mechanisms, in areas invaded by the exotic perennial grass species, Bothriochloa pertusa. We examine root traits specifically, as below‐ground competition was considered particularly important to the success of this species. Location: Grassy "ironbark" woodlands of eastern Queensland, Australia. Methods: We examined plots with varying degrees of invasion by B. pertusa, at multiple spatial scales (up to 1,000 m2) and analysed changes to the species–area relationships (SARs) with increasing invader cover. Changes to SARs were assessed in relation to the invaders" effect on rare (low patch occupancy) and common species in the community. In a separate analysis within the same habitat, we collected root cores across a gradient of invader cover and analysed changes to community root traits that were considered important correlates of competition for space and nutrients. Results: Invasion‐induced reductions in diversity were pervasive at all scales investigated, and this was associated with a proportionally greater effect on rare species in the community. In the separate root analysis, changes in community root traits with increasing invader cover were potentially indicative of more intense competition for resources rather than space. Conclusions: The observed regional‐scale dominance of B. pertusa and associated declines in diversity warrant serious concern for the conservation of native plant communities and species in a region already at risk from other anthropogenic threats. Intense competition for below‐ground resources is likely a contributing mechanism to the success of B. pertusa in this study system. Experimental examination of this and other mechanisms would help to validate these findings. [ABSTRACT FROM AUTHOR]

A new species is described in the Mucorales family Syncephalastraceae: Syncephalastrum contaminatum , isolated as an in vitro culture from a laboratory contaminant. The species has variable copies of the internal transcribed spacer (ITS) regions, requiring cloning of these regions prior to Sanger sequencing before subsequent use in phylogenetic comparisons with other fungi. The genome of the strain was sequenced using short paired-reads to yield a draft genome of 28.6 Mb. Syncephalastrum contaminatum is distinguished by diverse DNA sequences at several loci from the other species of Syncephalastrum , including only 81% sequence identity with its ITS regions to that of S. racemosum. Its merosporangium produces four or more asexual spores and the genome sequencing information suggests that the species is heterothallic. The identification of this species highlights the limited knowledge about the early lineages of fungi both in Australia and globally. • New species Syncephalastrum contaminatum was isolated as a laboratory contaminant. • A draft whole genome sequence was generated for this zygomycete. • The species differs from others in Syncephalastrum based on DNA sequence. [ABSTRACT FROM AUTHOR]

Wildfires in forested ecosystems are increasing in severity and extent. The adaptations many plants have acquired in response to their natural fire regime may not be sufficient to allow some species to persist. This could impact the forest understorey and its seed bank, which are vital reservoirs of biodiversity, and forest resilience in the face of global change. We present a case study of the montane forests of south-eastern Australia, an area subjected to an increase in frequency and severity of fires. We utilise field surveys and a soil seed bank germination study to investigate if short-interval, high-severity wildfires affect the understorey diversity in montane forests, and if the extant vegetation and the soil seed bank exhibit contrasting responses. We consider species diversity and plant functional traits to explore plant diversity in long unburned sites, and sites with one, two or three short-interval, high-severity fires in the past 25 years. With increasing fire frequency, we found a decrease in total species richness, Shannon's diversity, and the richness of resprouters in the soil seed bank, contrasting a lack of response in the extant vegetation. Increased fire frequency shifted the species composition and the frequency of plant functional groups of both extant vegetation and soil seed bank towards a decrease in clonal resprouters and increase in grasses and other upright herbs. The frequency of wind-dispersed perennials and short-lived seeders and exotics increased sharply following single high severity burn, particularly in the soil seed bank, and remained elevated relative to long unburnt with subsequent fire. The combined species (extant vegetation plus soil seed bank) pool mirrored shifts in the frequency of functional groups in extant vegetation and soil seed bank. These findings highlight the importance of considering the soil seed bank when examining the effects of fire on fire-prone forests. Although a lack of response in the extant vegetation may be a buffering effect of the soil seed bank, the shift in the frequency of plant functional groups in the combined species pool suggests this cannot be maintained indefinitely. The increase in frequency and abundance of species characteristic of early successional states has implications for increased flammability and potential positive feedbacks between past fire and future fire, especially in a warming and drying climate. These shifts were independent of the fire response strategy of eucalypt canopy species raising significant questions of whether artificial re-seeding programs should extend beyond the current focus on obligate seeding forests and an obligate seeding tree. • Soil seed bank plant species richness and diversity (H') decreases with increasing frequency of high-severity fire. • Extant vegetation richness and diversity remained stable with increasing fire frequency. • Shift in frequency and abundance of species to those characteristic of early successional states. • Shifts in understorey species independent of fire response of overstorey eucalypts. • Implications for the focus of artificial re-seedings programs. [ABSTRACT FROM AUTHOR]

Ephemeral gilgai wetlands of the stony-plains of arid Australia have a relatively high diversity of native plant species and are extensively utilised for livestock grazing. We sampled the standing vegetation (SV) and germinable soil seed bank (SSB) of 40 gilgais, comparing gilgais near and far from watering points, and continually stocked versus rarely stocked. Despite historically heavy stock grazing, we found no significant differences in native species richness between treatments, indicating the general resilience of gilgai vegetation. One contributing factor is the abundance of Atriplex nummularia ssp. omissa . Cover of this long-lived shrub did not differ significantly between treatments and was positively correlated with “highly palatable” species’ cover, suggesting that it may act as a nurse species. In contrast, two other long-lived species, Atriplex vesicaria and Astrebla pectinata , had significantly reduced cover or were absent near to watering points. These and other long-lived species had a poorly developed SSB and thus limited ability to regenerate from seed if killed by sustained heavy grazing. The absence of fifteen locally rare species (including 12 short-lived species) from water-near gilgais indicates the need for more intensive survey to determine whether the proliferation of watering points poses a threat to such species. [ABSTRACT FROM AUTHOR]

After an 11-year period of exceptional specimen acquisition, we evaluated the robustness of the Western Australian Herbarium Specimen Database in elucidating patterns of diversity and phytogeographic maps of the Southwest Australian Floristic Region (SWAFR). Using rarefaction strategies to compensate for sample bias and a novel approach to multivariate classification and site ordination, we generated maps of floristic provinces and districts in the SWAFR. A 33% increase in specimen numbers and 10% additional taxa were recorded in the study area (SWAFR and 75 km inland buffer) over the 11 years, although historical biases in collecting patterns tended to persist. Although floristic district concepts were robust, regional and provincial concepts were more equivocal. We therefore opted for broad delineations rather than geographically precise ones. We propose a novel phytogeographic map, adding a new floristic province (Kalbarri), five new districts and other boundary adjustments for and in the SWAFR. The updated SWAFR has 8379 native vascular plant taxa (82% species and 18% subspecies), of which 47% are endemic and 49% have been described since 1970. Biodiversity indices generated from collections data should be used cautiously. In contrast, the new phytogeographic regionalization of the SWAFR is robust at the district level. Despite shortcomings, herbarium collections provide the best information available for broadscale analyses of plant diversity. [ABSTRACT FROM AUTHOR]

Aim Biodiversity studies typically use species, or more recently phylogenetic diversity ( PD), as their analysis unit and produce a single map of observed diversity. However, observed biodiversity is not necessarily an indicator of significant biodiversity and therefore should not be used alone. By applying a small number of additional metrics to PD, with associated statistical tests, we can determine whether more or less of the phylogeny occurs in an area, whether branch lengths in an area are longer or shorter, and whether more long or short-branched endemism occurs in an area, than expected under a null model. Location Australian continent. Methods We used a phylogeny sampling 90% of Australia's angiosperm genera, and 3.4 million georeferenced plant specimens downloaded from Australia's Virtual Herbarium ( AVH), to calculate PD, relative phylogenetic diversity ( RPD) and relative phylogenetic endemism ( RPE). Categorical analysis of neo- and palaeo-endemism ( CANAPE) and randomization tests were performed to determine statistical significance. Results We identify several combinations of significant PD and endemism across the continent that are not seen using observed diversity patterns alone. Joint interpretation of these combinations complements the previous interpretations of Australia's plant evolutionary history. Of conservation concern, only 42% of the significant endemism cells found here overlap with existing nature reserves. Main conclusions These spatial phylogenetic methods are feasible to apply to a whole flora at the continental scale. Observed richness or PD is inadequate to fully understand the patterns of biodiversity. The combination of statistical tests applied here can be used to better explain biodiversity patterns and the evolutionary and ecological processes that have created them. The spatial phylogenetic methods used in this paper can be also be used to identify conservation priorities at any geographical scale or taxonomic level. [ABSTRACT FROM AUTHOR]

Woody plant demographics provide important insight into ecosystem state-shifts in response to changing fire regimes. In Australian tropical savannas, the switch from patchy landscape burning by Aborigines to unmanaged wildfires within the past century has been implicated in biodiversity declines including the fire-sensitive conifer, Callitris intratropica. C. intratropica commonly forms small, closed-canopy groves that exclude fire and allow recruitment of conspecifics and other fire-sensitive woody plants. C. intratropica groves provide a useful indicator of heterogeneity and fire regime change, but the mechanisms driving the species' persistence and decline remain poorly understood. We examined the hypothesis that C. intratropica population stability depends upon a regime of frequent, low-intensity fires maintained by Aboriginal management. We combined integral projection models of C. intratropica population behaviour with an environmental state change matrix to examine how vital rates, grove dynamics and the frequency of high- and low-intensity fires contribute to population stability. Closed-canopy C. intratropica groves contributed disproportionately to population growth by promoting recruitment, whereas singleton trees accounted for a larger proportion of adult mortality. Our patch-based population model predicted population declines under current fire frequencies and that the recruitment of new groves plays a critical role in the species' persistence. Our results also indicated that reducing fire intensity, a key outcome of Aboriginal burning, leads to C. intratropica population persistence even at high fire frequencies. These findings provide insight into the relationship between ecosystem composition and human-fire interactions and the role of fire management in sustaining the mosaics that comprise 'natural' systems. [ABSTRACT FROM AUTHOR]

Aim To unravel the genetic processes involved in a case of invasion by one species, the self-incompatible Cakile maritima Scop. (Brassicaceae) in Australia, as it has replaced a related prior invader, Cakile edentula (Bigelow) Hook. Location Southern and eastern coastlines of Australia. Methods Genetic diversity within and between populations was characterized at a continental scale using microsatellite ( SSR) markers to examine nuclear diversity and cleaved amplified polymorphic sequence ( CAPS) markers to examine chloroplasts. DNA was sourced from 24 populations of C. maritima along its putative invasion trajectory and, for comparison, from four populations of C. edentula that are currently being invaded by C. maritima. Analysis of Molecular Variance and a Bayesian assignment method were used to explore the data. Results No evidence was found for progressive loss of diversity in C. maritima in the putative direction of range expansion. Western and south-eastern populations of C. maritima have almost certainly resulted from independent introductions, although there is evidence of very limited gene flow from west to east. There was considerably greater, spatially structured variation in the south-east, suggesting multiple introductions of C. maritima to that region. We found evidence of hybridization and introgression from C. edentula into C. maritima, both in the two regions where they are currently sympatric and elsewhere. Main conclusions The invasion history of a species spreading in a largely one-dimensional habitat can still be highly complex and difficult to interpret. Regional patterns of variation in C. maritima indicate several introductions from different parts of the native range, limited gene flow from the first introduction eastwards and genetic drift within Western Australia. There has also been bi-directional gene flow between this species and C. edentula. The significance of the introgression from C. edentula into C. maritima with respect to natural selection, however, remains to be determined. [ABSTRACT FROM AUTHOR]

Ptilotus (Amaranthaceae) is an Australian genus with over 100 species, most of which occur in arid Western Australia. Ptilotus has been a taxonomically difficult genus; despite rigorous morphological studies into the genus over many years, previous workers have found it difficult to delimit infrageneric groups due to inconsistent morphological variation. With the goal to establish a phylogenetic framework for the genus, 100 taxa were sampled, including 87 Ptilotus spp, and the ITS nrDNA and matK cpDNA were sequenced. The phylogeny was reconstructed using Bayesian, maximum likelihood and maximum parsimony analyses on separate and concatenated datasets. Morphological characters were assessed and compared to clades on the phylogeny to identify synapomorphies and aid in the construction of an infrageneric classification. A diversification rate analysis was used to identify rate shifts in speciation across the phylogeny. Four major clades of the monophyletic Ptilotus were resolved, three small clades together comprising 27% of sampled taxa and a large, diverse clade comprising the remaining 73%. Four floral synapomorphies were identified as uniquely occurring within the latter, although none were common to all taxa in the clade. The diversification rate analysis identified a probable rate shift at the base of Ptilotus, indicating that the genus may have undergone a rapid diversification early in its evolution. This rapid diversification provides a plausible explanation for the lack of consistent variation in morphology among the major clades. [ABSTRACT FROM AUTHOR]

Ecosystem services are typically valued for their immediate material or cultural benefits to human wellbeing, supported by regulating and supporting services. Under climate change, with more frequent stresses and novel shocks, 'climate adaptation services', are defined as the benefits to people from increased social ability to respond to change, provided by the capability of ecosystems to moderate and adapt to climate change and variability. They broaden the ecosystem services framework to assist decision makers in planning for an uncertain future with new choices and options. We present a generic framework for operationalising the adaptation services concept. Four steps guide the identification of intrinsic ecological mechanisms that facilitate the maintenance and emergence of ecosystem services during periods of change, and so materialise as adaptation services. We applied this framework for four contrasted Australian ecosystems. Comparative analyses enabled by the operational framework suggest that adaptation services that emerge during trajectories of ecological change are supported by common mechanisms: vegetation structural diversity, the role of keystone species or functional groups, response diversity and landscape connectivity, which underpin the persistence of function and the reassembly of ecological communities under severe climate change and variability. Such understanding should guide ecosystem management towards adaptation planning. [ABSTRACT FROM AUTHOR]

A lectotype is here designated for Actinotus paddisonii R.T.Baker (Apiaceae: Mackinlayoideae), a species occurring in Queensland, New South Wales and possibly Western Australia [ABSTRACT FROM AUTHOR]

Both the public and the scientific perception of an island's value are important in deciding its future, with regard to the levels of access, protection and funding for research. There is a popular belief that the preservation of islands equates to the slightly idiosyncratic conservation of unique remote habitats, where the value of any island is its isolation. However, by understanding how scientists use islands, a different picture emerges; islands may be seen also as integrated, or representative fragments of the world that contribute to biodiversity and scientific theory far beyond their narrow geographical boundaries. Here, we broadly review the full scope of values science places on islands. We resolve four central perspectives by which scientists view islands, based on how islands are incorporated into their research: (i) species-level studies; (ii) island-level studies; (iii) islands as model systems; and (iv) islands as part of a global network. Recognising this diverse value system helps enlarge our understanding of islands and reforges their importance to the public and policy makers. [ABSTRACT FROM AUTHOR]

Invasive plants significantly threaten native plant biodiversity, yet the mechanisms by which they drive species losses and maintain their own dominance are poorly known. We examined the effects of alien grass invasion ( Stenotaphrum secundatum) on (1) abundance and frequency of occurrence, (2) reproductive effort (flowering) and output (fruit production) and (3) soil seed banks for three focal native plants that are characteristic of endangered coastal forest of south-eastern Australia. First, we sampled and compared the foliage cover abundance and frequency (proportion of sites occupied) of the focal natives across invaded and non-invaded (reference) sites ( n = 20). We then intensively sampled reproductive effort and output (range of 5-9 sites per species), and density of propagules within the soil (using a standard glasshouse 'emergence' method; n = 26) for each species. Invasion was associated with reduced population sizes of all species within the standing vegetation but did not affect population frequency (i.e. proportion of sites where each species was present). Reproductive effort and output were about 75 % lower at invaded than native sites for all species. However, invasion had no effect on propagule densities of the focal natives within the seed bank, despite the substantial reduction in their reproduction. This indicates that the ultimate driver of population declines across invaded landscapes is post-settlement recruitment limitation from the seed bank (e.g. low rates of germination and seedling survival) rather than a reduction in the arrival and storage of propagules at invaded sites. Removal of Stenotaphrum alone might thus be sufficient to stimulate the recovery of native populations from the seed bank. [ABSTRACT FROM AUTHOR]

Question Climate change is driving shifts in the composition of vegetation but the lack of controls and confounding spatial factors pose challenges for detecting the climate signal in observed changes through time and space. We tested whether climate can be isolated as a driver of spatial vegetation composition at the landscape scale in mediterranean southern Australia by considering landscape factors (e.g. soil gradients) and spatial structure (relative geographic isolation). The aim was to develop principles for selecting spatial analogues for climate change and provide a spatially predictive baseline for monitoring. Methods A landscape-scale monitoring transect spanning 550 km was established. Whole community presence/absence of vascular plant species in plots was modelled as a multivariate response to environmental and spatial variables. Species and phylogenetic composition-environment relationships were also explored using indirect gradient approaches, partial correlations and distance decay models. Results A total of >2900 occurrences of >400 plant species were recorded. Relative vegetation composition was predicted by mean temperature and soil properties, such as electrical conductivity and texture. Spatial structure was critical, as decay in compositional similarity with geographic distance and spatial autocorrelation of nested plots were involved in turnover patterns. The rate of change in species composition with changes in temperature equated to complete species turnover within the habitats sampled. Conclusions The influence of climate on spatial variation in vegetation composition can be quantified, accounting for distance decay. Landscape gradients (particularly soil properties) tended to be orthogonal to climate and explained some turnover. Spatial analogues for climate change would need to be similar in soil properties and not too geographically distant. Composition resulting from more extreme climate change scenarios may have no spatial analogue due to the importance of neutral distance decay at larger spatial scales in determining compositional differences. We illustrate these principles with a sequence of warming, drying analogues. The spatial transect provides a framework for monitoring composition by directly incorporating temporal data and using spatial analysis to inform the expected direction of compositional shifts with climate change. [ABSTRACT FROM AUTHOR]

Abstract: The significance of variation in fire severity is not well understood for bryophyte species richness and composition. This is despite fire being a major factor in determining bryophyte richness and composition in temperate forests. We documented the species richness of mosses and liverworts in 42 sites of Mountain Ash (Eucalyptus regnans) forest in eastern Australia. We compared two age classes: long unburned stands and 72year old stands following a major fire in February 2009. Within these two age classes, we surveyed sites of contrasting fire severity: (1) unburned, (2) subject to moderate severity fire (intact canopy) and (3) subject to high severity fire (burned canopy). At each site, we surveyed bryophytes in 10m×100m transects, which was large enough to include a variety of microhabitats. Roughly 60% of the variation in species richness (r 2 =0.61, p <0.001) and composition (R =0.57, p <0.001) was explained by fire severity. High severity fire removed all bryophytes and only pioneer species were present 2years later. In contrast, the moderate severity fire sites were often species rich because they harboured pioneer bryophytes and species associated with long unburned forest. A key finding was the importance of small unburned patches that contained understorey trees and logs for boosting bryophyte richness. Practices such as salvage logging that remove biological legacies are inconsistent with the conservation of bryophyte diversity in this landscape. [Copyright &y& Elsevier]

The primary goal of restoration is to create self-sustaining ecological communities that are resilient to periodic disturbance. Currently, little is known about how restored communities respond to disturbance events such as fire and how this response compares to remnant vegetation. Following the 2003 fires in south-eastern Australia we examined the post-fire response of revegetation plantings and compared this to remnant vegetation. Ten burnt and 10 unburnt (control) sites were assessed for each of three types of vegetation (direct seeding revegetation, revegetation using nursery seedlings (tubestock) and remnant woodland). Sixty sampling sites were surveyed 6 months after fire to quantify the initial survival of mid- and overstorey plant species in each type of vegetation. Three and 5 years after fire all sites were resurveyed to assess vegetation structure, species diversity and vigour, as well as indicators of soil function. Overall, revegetation showed high (>60%) post-fire survival, but this varied among species depending on regeneration strategy (obligate seeder or resprouter). The native ground cover, mid- and overstorey in both types of plantings showed rapid recovery of vegetation structure and cover within 3 years of fire. This recovery was similar to the burnt remnant woodlands. Non-native (exotic) ground cover initially increased after fire, but was no different in burnt and unburnt sites 5 years after fire. Fire had no effect on species richness, but burnt direct seeding sites had reduced species diversity (Simpson's Diversity Index) while diversity was higher in burnt remnant woodlands. Indices of soil function in all types of vegetation had recovered to levels found in unburnt sites 5 years after fire. These results indicate that even young revegetation (stands <10 years old) showed substantial recovery from disturbance by fire. This suggests that revegetation can provide an important basis for restoring woodland communities in the fire-prone Australian environment. [ABSTRACT FROM AUTHOR]

The spectacular diversity of sclerophyll plants in the Cape Floristic Region in South Africa and Australia's Southwest Floristic Region has been attributed to either explosive radiation on infertile soils under fire-prone, summer-dry climates or sustained accretion of species under inferred stable climate regimes. However, the very poor fossil record of these regions has made these ideas difficult to test. Here, we reconstruct ecological-scale plant species richness from an exceptionally well-preserved fossil flora. We show that a hyperdiverse sclerophyll flora existed under high-rainfall, summer-wet climates in the Early Pleistocene in southeastern Australia. The sclerophyll flora of this region must, therefore, have suffered sub- sequent extinctions to result in its current relatively low diversity. This regional loss of sclerophyll diversity occurred at the same time as a loss of rainforest diversity and cannot be explained by ecological substitution of species of one ecological type by another type. We show that scierophyll hyperdiversity has developed in distinctly non-Mediterranean climates, and this diversity is, therefore, more likely a response to long-term climate stability. Climate stability may have both reduced the intensity of extinctions associated with the Pleistocene climate cycles and promoted the accumulation of species richness by encouraging genetic divergence between populations and discouraging plant dispersal. [ABSTRACT FROM AUTHOR]

Appropriate selection of environmental variables is critical to the performance of biodiversity models, but has received less attention than the choice of modelling method. Online aggregators of biological and environmental data, such as the Global Biodiversity Information Facility and the Atlas of Living Australia, necessitate a rational approach to variable selection. We outline a set of general principles for systematically identifying, compiling, evaluating and selecting environmental variables for a biodiversity model. Our approach aims to maximise the information obtained from the analysis of biological records linked to a potentially large suite of spatial environmental variables. We demonstrate the utility of this structured framework through case studies with Australian vascular plants: regional modelling of a species distribution, continent-wide modelling of species compositional turnover and environmental classification. The approach is informed by three components of a biodiversity model: (1) an ecological framework or conceptual model, (2) a data model concerning availability, resolution and variable selection and (3) a method for analysing data. We expand the data model in structuring the problem of choosing environmental variables. The case studies demonstrate a structured approach for the: (1) cost-effective compilation of variables in the context of an explicit ecological framework for the study, attribute accuracy and resolution; (2) evaluation of non-linear relationships between variables using knowledge of their derivation, scatter plots and dissimilarity matrices; (3) selection and grouping of variables based on hypotheses of relative ecological importance and perceived predictor effectiveness; (4) systematic testing of variables as predictors through the process of model building and refinement and (5) model critique, inference and synthesis using direct gradient analysis to evaluate the shape of response curves in the context of ecological theory by presenting predictions in both geographic and environmental space. [ABSTRACT FROM PUBLISHER]

Knowledge of species compositional turnover, the rate of change in the number of species shared between locations along geographic and environmental gradients, is important for conservation planning. Spatially global models relating species and environmental turnover are well established. However, to date there has been no explicit assessment of the effects of geographical variation in parameters (spatial non-stationarity) and directional dependence (anisotropy) on these models. Such processes are well known to affect other geospatial analyses. Here, we assess how these affect the shape, goodness of fit and composition of species turnover–environment relationships. We use the eastern Australian distribution of species in the Myrtaceae, an important family of vascular plants in the region. We obtained distribution data for Myrtaceae species from herbarium records and corresponding environmental attributes (mean of 1 km gridded cell values aggregated to 10 km grid cells). Species compositional turnover was quantified using the Sørensen pairwise dissimilarity index. The turnover–environment relationship was analysed using generalised dissimilarity modelling (GDM), a purpose-designed statistical regression technique. The data were divided into three sets of spatially local subsamples: 27 rectangular east–west-aligned coastal–inland bands, 8 north–south coastally aligned bands and 12 symmetrical omnidirectional blocks. A separate GDM was fitted to each spatially local subsample. The results display marked evidence of spatial variation in the shape, goodness of fit and composition of local species turnover–environment relationships, with this variation appearing strongly directional. The observed spatial structure of local biodiversity–environment relationships, expressed as species compositional turnover, is unsurprising considering both the steep east–west environmental gradients associated with Australia's eastern ranges and the known decreasing sampling intensity in the same direction. Local spatial non-stationarity and anisotropy are expected outcomes irrespective of the chosen turnover index, study taxa or statistical model used. Currently, it is difficult to separate genuine biogeographic effects from data bias. Future analyses could better account for the observed spatial structure of both biodiversity–environment relationships and data bias by incorporating directionality in data subsampling strategies and explicit biogeographic predictors in model design. [ABSTRACT FROM PUBLISHER]

Background and aims: Legumes of the genus Lessertia have recently been introduced to Australia in an attempt to increase the range of forage species available in Australian farming systems capable of dealing with a changing climate. This study assessed the diversity and the nodulation ability of a collection of Lessertia root nodule bacteria isolated from different agro-climatic areas of the Eastern and Western Capes of South Africa. Methods: The diversity and phylogeny of 43 strains was determined via the partial sequencing of the dnaK, 16srRNA and nodA genes. A glasshouse experiment was undertaken to evaluate symbiotic relationships between six Lessertia species and 17 rhizobia strains. Results: The dnaK and 16S rRNA genes of the majority of the strains clustered with the genus Mesorhizobium. The position of the strains at the intra-genus level was incongruent between phylogenies with few exceptions. The nodA genes from Lessertia spp. formed a cluster on their own, separate from the previously known Mesorhizobium nodA sequences. Strains showed differences in their nodulation and nitrogen fixation patterns that could be correlated with nodA gene phylogeny. L. diffusa, L. herbacea and L. excisa nodulated with nearly all the strains examined while L. capitata, L. incana and L. pauciflora were more stringent. Conclusion: Root nodule bacteria from Lessertia spp. were identified mainly as Mesorhizobium spp. Their nodA genes were unique and correlated with the nodulation and nitrogen fixation patterns of the strains. There were marked differences in promiscuity within Lessertia spp. and within strains of root nodule bacteria. [ABSTRACT FROM AUTHOR]

1. The classical model of long-term ecosystem development suggests that primary productivity is limited by nitrogen (N) on young substrates and phosphorus (P) on older substrates. Measurements of foliar and soil nutrients along soil chronosequences support this model, but direct tests through nutrient-addition experiments are rare. 2. We conducted a nutrient-limitation bioassay using phytometer species grown in soils from five stages of a >2-million-year dune chronosequence in south-western Australia. This long-term chronosequence is located within a region of exceptionally high plant species diversity and has not been previously studied in the context of ecosystem development. 3. Growth of unfertilized phytometers, a proxy for primary productivity, peaked on young soils (hundreds to a few thousand years) and then declined steadily on older soils. This decline was linked to P limitation, and its rapid appearance (<7000 years) compared to other sequences reflects the low P concentration in the parent material. As predicted, growth of canola was N-limited on the youngest soil (stage 1), co-limited by multiple nutrients in stage 2 and increasingly P-limited thereafter. 4. Growth of wheat was P-limited from stage 2 onwards, yet on the youngest soil it was co-limited by potassium (K) and micronutrients - most likely iron (Fe). Nitrogen addition also decreased the root:shoot ratio of wheat such that shoot growth was higher than in the control. We attribute these responses to a parent material that is very low in K and N and strongly alkaline (pH [H2O] > 9), being of a marine origin (i.e. carbonate dunes). Fe is poorly soluble at high pH and K likely plays a role in the secretion of Fe-mobilizing exudates from wheat roots. 5. Synthesis. Our results provide strong support for the long-term ecosystem-development model, particularly with regard to the appearance of P limitation and associated declines in productivity. However, our study also shows that N cannot be assumed to invariably be the most important limiting nutrient in young soils, and it is unlikely to be the only limiting nutrient in calcareous soils. This south-western Australian long-term chronosequence provides an excellent opportunity to explore edaphic controls over plant species diversity. [ABSTRACT FROM AUTHOR]

This study develops a theoretical and empirical framework for optimal conservation planning using satellite land cover data and economic data from a farm survey. A case study is presented for a region within the South-west Australia Biodiversity Hotspot ( Nature 403, 853). This Biodiversity Hotspot is a focus for conservation investment as it combines a relatively high level of biodiversity with severe threat to the biodiversity from agriculture. The conservation planning model developed determines the optimal set of bush fragments for conservation. This model can also be used to assess the trade-off between the budget and a vegetation species metric. Results from the case study show that, without an effective conservation scheme that at least fences fragments, significant plant biodiversity losses will occur in the North East Wheatbelt Regional Organisation of Councils region of the WA wheatbelt over a 10-year period. A perfect price discriminating auction scheme could reduce the costs of conservation by around 17 per cent relative to a fixed-payment scheme; however, a fixed payment on outcome (measured as change in the species metric) scheme represents a viable second-best alternative, to a conservation auction, where conservation spending is spatially targeted. [ABSTRACT FROM AUTHOR]

In grassland reserves, managed disturbance is often necessary to maintain plant species diversity. We carried out experiments to determine the impact of fire, kangaroo grazing, mowing and disc ploughing on grassland species richness and composition in a nature reserve in semi-arid eastern Australia. Vegetation response was influenced by winter–spring drought after establishment of the experiments, but moderate rainfall followed in late summer–autumn. Species composition varied greatly between sampling times, and the variability due to rainfall differences between seasons and years was greater than the effects of fire, kangaroo grazing, mowing or disc ploughing. In the fire experiment, species richness and composition recovered more rapidly after spring than autumn burning. Species richness and composition were similar to control sites within 12 months of burning and mowing, suggesting that removal of the dominant grass canopy is unnecessary to enhance plant diversity. Two fires (separated by 3 years) and post-fire kangaroo grazing had only minor influence on species richness and composition. Even disc ploughing caused only a small reduction in native richness. The minor impact of ploughing was explained by the small areas that were ploughed, the once-off nature of the treatment, and the high degree of natural movement and cracking in these shrink-swell soils. Recovery of the composition and richness of these grasslands was rapid because of the high proportion of perennial species that resprout vegetatively after fire and mowing. There appears to be little conservation benefit from fire, mowing or ploughing ungrazed areas, as we could identify no native plant species dependent on frequent disturbance for persistence in this grassland community. However, the ability of the Astrebla- and Dichanthium-dominated grasslands to recover quickly after disturbance, given favourable seasonal conditions, suggests that they are well adapted to natural disturbances (e.g. droughts, fire, flooding and native grazing). [ABSTRACT FROM AUTHOR]

Abstract: Relationships between fire history, vegetation structure and composition, and invasion by introduced plant species have received limited attention in Australian woodlands. A study in a Mediterranean, fire adapted urban Banksia woodland remnant in the biodiversity hotspot of southwest Australia investigated: (1) Have significant changes occurred in the woodland tree canopy between 1963 and 2000? (2) Do correlations exist between fire frequency and canopy cover? (3) If there is a difference in the vegetation composition of Banksia woodland invaded by the South African Ehrharta calycina (PCe) and Pelargonium capitatum (PCp) compared to largely intact remnants (GC)? and (4) Do correlations exist between vegetation condition, composition, fire frequency and invasion? Aerial photography, processed in a Geographical Information System, was used to establish fire history and changes in canopy cover over time (1963–2000). PCe and PCp sites experienced the greatest number of fires, with a net reduction in canopy cover in all areas experiencing four or more fires (60% of all woodlands). Frequent fire corresponded with a decline in native cover, richness and diversity, a shift from native to introduced species, changes in the relative importance of fire response categories, and loss of native resprouting shrub cover. Life forms of introduced species, which included no trees, shrubs and perennial sedges, contrasted strongly with those of native species, which had poor representation of annual and perennial grasses. Clear ecological and conservation consequences due to the loss of species diversity, changes in fire ecology and invasion have occurred in the Banksia woodlands. This study provides an understanding of the invasion process, enhancing conservation knowledge to improve the adaptive management of the key threatening process of invasion in biodiverse communities. [Copyright &y& Elsevier]

A quadrat-based survey was undertaken on the flora and plant communities associated with the Herbert Lukin Ridge, which is a series of low hills of banded iron formation within the Joyners Find greenstone belt, in the Murchison region of Western Australia. The Herbert Lukin Ridge are is located on a pastoral lease, and mining and exploration tenements covering the entire extent. A total of 191 taxa (species, subspecies, varieties and forms) and 10 hybrids were recorded. Nine taxa of conservation significance were found, seven of these were new records for the area and three of these were notable (> 100 km) range extensions. Significant range extensions (> 200 km) are reported for four taxa not listed as being of conservation significance. One regional endemic was identified for the study area, and one putative new taxon was found. Two species are recommended for an upgrading of their conservation status. Six community types were resolved from classification analysis of floristic composition from 50 sites, covering much of the extent of this greenstone belt. Floristic communities are strongly associated with geomorphology and soil chemistry, with the greatest distinction being between upland and outwash communities. None of the described communities are represented on conservation estate. At present, mineral exploration and mining appear to pose the greatest potential threats to these particular communities. [ABSTRACT FROM AUTHOR]

Relationships between plant invasion and the soil seed bank in highly diverse fire adapted mediterranean woodlands are poorly understood, yet critical for that ecosystem’s conservation. Within the biodiversity hotspot of southwest Australia we investigated the composition and diversity of the Banksia woodland soil seed bank in good condition (GC), medium condition (MC) and poor condition invaded by the South African perennial species Ehrharta calycina (PCe) and Pelargonium capitatum (PCp). The investigation assessed three questions: (1) Do soil seed banks of invaded sites have fewer germinants of native species and more germinants of introduced (non-native) species than sites with minimal invasion? (2) Do soil seed banks show shifts in ecological functional types with invasion? (3) Is the soil seed bank of introduced species persistent? Native species germinants, mainly shrubs and perennial herbs, were highest in GC sites and least in poorer condition sites suggesting a reduction in their numbers had occurred over time. Introduced germinants were dominated by perennial and annual grasses, and annual herbs. E. calycina had the greatest seed density (8328 germinants m−2). More introduced than native germinants occurred in the litter. Rapid germination of introduced species (30% in week 1) compared to native species (4% in week 1) provides the capacity for their early dominance. A limited native soil seed bank and dominant persistent introduced soil seed bank represent great challenges for the structural and functional conservation and restoration of woodland ecosystems. This study provides key new knowledge, applicable to a wide range of ecosystems, to help formulate conservation protocols to control dominant introduced species and conserve and restore biodiverse-rich woodlands. [Copyright &y& Elsevier]