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Extruded pellets containing activated carbon (AC) can be used to sow native seeds while simultaneously applying herbicide to control invasive species. Incorporating AC in pellets has been demonstrated to protect native seeds; however, there may be unintended detrimental impacts to seedling emergence. We aimed to optimize seed position within pellets to maximize emergence and survival of the perennial shrub Jacksonia furcellata. Seeds were positioned at 2 mm (top), 6 mm (middle), and 12 mm (bottom) within pellets (with or without AC), sown on or below the soil surface, and compared to non‐pelleted seeds sown under the soil surface in the equivalent positions (2, 6, and 12 mm depth). Trays were treated with a pre‐emergent herbicide (Simazine) or left unsprayed. Emergence (without herbicide) was significantly higher from seeds positioned at the bottom of pellets without AC sown on the soil surface (70%), compared to non‐pelleted seeds sown at the bottom (12 mm below the soil surface; 57%). However, emergence was inhibited when seeds were positioned in the middle (6 mm) of pellets with AC (32%). When treated with Simazine, survival was highest from seeds positioned at the bottom of pellets with AC (60%), compared to pellets without AC (15%) and non‐pelleted seeds sown at the bottom (12 mm below the soil surface; 15%). Jacksonia furcellata seeds positioned at the bottom of pellets, sown on the soil surface, shows promise to minimize negative impacts to emergence, and maximize herbicide protection. Further testing with additional species is required to refine pellet production (e.g. recipe, extrusion, and shape) for optimal emergence. [ABSTRACT FROM AUTHOR]

As human activities destroy and degrade the world's ecosystems at unprecedented scales, there is a growing need for evidence‐based methods for ecological restoration if we are to preserve biodiversity and ecosystem services. Mining represents one of the most severe anthropogenic disturbances, often necessitating intensive intervention to restore the most basic attributes of native ecosystems. Despite examples of successful mine‐site restoration, re‐establishing native vegetation in these degraded landscapes remains a significant challenge. Plant ecophysiology—the study of the interactions between plants and the environment—can provide a useful framework for evaluating and guiding mine‐site restoration. By understanding the physiological mechanisms that allow plants to establish and persist in these highly disturbed environments, practitioners may be able to improve restoration outcomes. Specifically, methods in plant ecophysiology can inform site preparation and the selection of plant material for restoration projects, aid in monitoring restoration progress by providing additional insight into plant performance, and ultimately improve our ability to predict restoration trajectories. Here, we review the challenges and benefits of integrating an ecophysiological perspective to mine‐site restoration in Western Australia, a global hotspot of biodiversity and mining operations. Using case studies and examples from the region's diverse ecosystems, we illustrate how an ecophysiological approach can guide the restoration of some of the world's most severely disturbed landscapes. With careful selection of study species and traits and consideration of the specific environmental conditions and stressors within a site, the restoration ecophysiology framework outlined here has the potential to inform restoration strategies across ecosystems. [ABSTRACT FROM AUTHOR]

Mining activities alter soil physicochemical and biological properties that are critical for plant establishment. Revitalisation of soil biological properties via microbial inoculations can potentially be adopted to improve vegetation restoration. Here, we evaluate the feasibility of using beneficial microorganisms in the form of commercially available inoculants to enhance plant performance in a non‐toxic and infertile mine‐waste substrate, using pigeon pea [Cajanus cajan (L) Millsp.] as a test plant. Six treatments were established to investigate the effects of inoculants (Bradyrhizobium spp., microbial mix and uninoculated controls) and water availability (low and moderate) in a factorial design over 6 months. Plant performance was determined by physiological parameters (leaf gas exchange, leaf carbon, nitrogen and stable isotopes) and growth (height and biomass). Plant xylem sap phytohormones were measured to determine the plants' physiological status and effects of inoculation treatments. Results revealed that water had a greater effect on plant growth than inoculation treatments. Inoculation treatments, however, improved some physiological parameters. This study suggests that physical conditions such as soil moisture and nutrient availability may occlude more subtle (direct or interactive) effects of beneficial soil microbes on plant growth and plant condition. Prior knowledge on the biological and physicochemical properties of the soil to be amended, and on plant species‐specific responses, would be needed to customise microbial inoculants for maximum benefits to ecological restoration, to support future adoption of this practice. [ABSTRACT FROM AUTHOR]

Mining activity causes major changes in site topography, soil physical and chemical properties, hydrology, and biological assemblages. Reassembling plant communities in these highly altered environments is dependent on interactions between environmental drivers and management intervention techniques through time, yet the long‐term effects of these interactions have rarely been quantified. This study examined a 19‐year‐old, postmining woodland restoration chronosequence in southwest Australia to understand plant community compositional development in postmine restoration sites. We tested the effects of environmental drivers (rainfall regimes, site aspect, slope) and management intervention techniques (substrate ripping and material properties) in terms of four restoration criteria: species richness, plant density, vegetation cover, and compositional similarity to reference sites. Irrespective of environmental drivers or management intervention techniques, vegetation cover increased through time, while plant density and species richness declined. Bray–Curtis similarity to reference communities remained unchanged. Within these trends, ripping and first‐year rainfall significantly affected restoration criteria outcomes; species richness and plant density were greatest when rainfall in the first winter immediately following site restoration was low but followed by a high summer rainfall. The most effective ripping depth was dependent on rainfall, deep‐ripped sites performed best when rainfall was high, and nonripped sites performed best under low‐mean rainfall conditions. Measured restoration criteria had not reached the levels of the target reference community after 19 years, which may be attributable to the still‐developing vegetation structure. This emphasizes the importance of assessing postmining restoration outcomes over longer time frames (>>5 years) with implications for determining appropriate, time‐dependent completion criteria. [ABSTRACT FROM AUTHOR]

Recruitment for many arid‐zone plant species is expected to be impacted by the projected increase in soil temperature and prolonged droughts associated with global climate change. As seed dormancy is considered a strategy to avoid unfavorable conditions, understanding the mechanisms underpinning vulnerability to these factors is critical for plant recruitment in intact communities, as well as for restoration efforts in arid ecosystems. This study determined the effects of temperature and water stress on recruitment processes in six grass species in the genus Triodia R.Br. from the Australian arid zone. Experiments in controlled environments were conducted on dormant and less‐dormant seeds at constant temperatures of 25°C, 30°C, 35°C, and 40°C, under well‐watered (Ψsoil = −0.15 MPa) and water‐limited (Ψsoil = −0.35 MPa) conditions. Success at three key recruitment stages—seed germination, emergence, and survival—and final seed viability of ungerminated seeds was assessed. For all species, less‐dormant seeds germinated to higher proportions under all conditions; however, subsequent seedling emergence and survival were higher in the more dormant seed treatment. An increase in temperature (35–40°C) under water‐limited conditions caused 95%–100% recruitment failure, regardless of the dormancy state. Ungerminated seeds maintained viability in dry soil; however, when exposed to warm (30–40°C) and well‐watered conditions, loss of viability was greater from the less‐dormant seeds across all species. This work demonstrates that the transition from seed to established seedling is highly vulnerable to microclimatic constraints and represents a critical filter for plant recruitment in the arid zone. As we demonstrate temperature and water stress‐driven mortality between seeds and established seedlings, understanding how these factors influence recruitment in other arid‐zone species should be a high priority consideration for management actions to mitigate the impacts of global change on ecosystem resilience. The knowledge gained from these outcomes must be actively incorporated into restoration initiatives. [ABSTRACT FROM AUTHOR]

To achieve global ambitions in large scale ecological restoration, there is a need for approaches that improve the efficiency of seed-based interventions, particularly in overcoming the bottleneck in the transition from germination to seedling establishment. In this study, we tested a novel seed-based application of the plant stress modulator compound salicylic acid as a means to reduce seedling losses in the seed-to-seedling phase. Seed coating technology (encrusting) was developed as a precursor for optimising field sowing for three grass species commonly used in restoration programs, Austrostipa scabra, Microlaena stipoides, and Rytidosperma geniculatum. Salicylic acid (SA, 0.1mM) was delivered to seeds via imbibition and seed encrusting. The effects of SA on seed germination were examined under controlled water-limited conditions (drought resilience) in laboratory setting and on seed germination, seedling emergence, seedling growth and plant survival in field conditions. Salicylic acid did not impact germination under water stress in controlled laboratory conditions and did not affect seedling emergence in the field. However, seedling survival and growth were improved in plants grown from SA treated seeds (imbibed and encrusted) under field conditions. When SA delivery methods of imbibing and coating were compared, there was no significant difference in survival and growth, showing that seed coating has potential to deliver SA. Effect of intraspecific competition as a result of seedling density was also considered. Seedling survival over the dry summer season was more than double at low seedling density (40 plants/m2) compared to high seedling density (380 plants/m2). Overall, adjustment of seeding rate according to expected emergence combined with the use of salicylic acid via coating could improve seed use efficiency in seed-based restoration. [ABSTRACT FROM AUTHOR]

Background and aims Little is known about the evolutionary and ecological drivers of carnivory in plants, particularly for those terrestrial species that do not occur in typical swamp or bog habitats. The Mediterranean endemic Drosophyllum lusitanicum (Drosophyllaceae) is one of very few terrestrial carnivorous plant species outside of Australia to occur in seasonally dry, fire-prone habitats, and is thus an ecological rarity. Here we assess the nutritional benefits of prey capture for D. lusitanicum under differing levels of soil fertility in situ. Methods We measured the total nitrogen and stable nitrogen and carbon isotope ratios of D. lusitanicum leaves, neighbouring non-carnivorous plant leaves, and groups of insect prey in three populations in southern Spain. We calculated trophic enrichment (ε 15N) and estimated the proportion of prey-derived nitrogen (%Nprey) in D. lusitanicum leaves, and related these factors to soil chemistry parameters measured at each site. Key results In all three populations studied, D. lusitanicum plants were significantly isotopically enriched compared with neighbouring non-carnivorous plants. We estimated that D. lusitanicum gain ~36 %Nprey at the Puerto de Gáliz site, ~54 %Nprey at the Sierra Carbonera site and ~75 %Nprey at the Montera del Torero site. Enrichment in N isotope (ε 15N) differed considerably among sites; however, it was not found to be significantly related to log10(soil N), log10(soil P) or log10(soil K). Conclusions Drosophyllum lusitanicum individuals gain a significant nutritional benefit from captured prey in their natural habitat, exhibiting proportions of prey-derived nitrogen that are similar to those recorded for carnivorous plants occurring in more mesic environments. This study adds to the growing body of literature confirming that carnivory is a highly beneficial nutritional strategy not only in mesic habitats but also in seasonally dry environments, and provides insights to inform conservation strategies for D. lusitanicum in situ. [ABSTRACT FROM AUTHOR]

Restoration of native plant communities through direct seeding often experience low seedling establishment success rates, partly due to competition with invasive weed species. To improve seeding success, herbicides can be applied to control weed competition, however, this can have negative impacts on the seeded species. Activated carbon (AC) can be incorporated into newly developed seed enhancement technologies to adsorb herbicides and increase seedling tolerance. This study expands upon research completed to date, by developing new formulations of extruded pellets containing AC, aiming to provide increased protection to seeded species and increase herbicide selectivity. We tested six extruded pellet formulations, which included two pellet formula variations, and three quantities of AC, to examine the impact on emergence (without herbicide) and mortality (with herbicide) of Lolium rigidum Gaudin (annual ryegrass). Extruded pellet formulations containing a superabsorbent polymer (3%) and AC (10%) did not impede emergence (79%), in the absence of herbicide, similar to the non‐pelleted seeds (81%). This extruded pellet formulation increased seedling tolerance to Simazine (a pre‐emergent, soil applied herbicide) application, with mortality reduced from 96% in non‐pelleted seeds, and 77% in pellets containing no AC, to 22% in pellets containing AC. The results from this study demonstrate that AC extruded pelleting can be used as a restoration seeding technology by protecting seeds from the negative effects of pre‐emergent herbicide applications. Field evaluations with native seeds will mark an important step forward to ensure seed enhancement technology options, such as AC extruded pelleting, are available for restoring natural plant communities in restoration programs. [ABSTRACT FROM AUTHOR]

Abstract: Restoration of commercial pine plantations to native ecosystems is increasing globally. This study investigated the abiotic and biotic factors in a postpine (Pinus pinaster) ecosystem that could potentially limit successful restoration of highly biodiverse Banksia woodlands. Soil abiotic conditions were analysed across a 7‐year postpine chronosequence and compared with a reference Banksia woodland soil to assess soil legacy issues. Ten native species were grown in postpine soils and monitored for germination and growth responses. Three species were selected and grown in the presence of an invasive species, Ehrharta calycina, to assess biotic impacts on seedling emergence, establishment, physiology, and drought response. Analysis revealed no differences in soil abiotic conditions along the chronosequence in comparison with the reference soil, apart from increasing organic carbon along the chronosequence (p = .003). Germination was not impeded in postpine soils, but seedling growth responses varied among species and soils. Seedling emergence was not affected by the presence of E. calycina; however, seedling growth measurements were significantly reduced (20%–78% decline). Physiological function (stomatal conductance) of native seedlings prior to drought treatment was not impeded, though when grown with E. calycina under drought 2 species, Banksia menziesii and Corymbia calophylla, exhibited a more rapid loss of physiological function. This case study examines abiotic and biotic limitations to Banksia woodland restoration success in postpine environments, suggesting postpine soils are not a barrier to restoration, and highlight the importance of preventing E. calycina from becoming established. [ABSTRACT FROM AUTHOR]

Abstract: Restoration of degraded arid and semi‐arid land faces the challenge of reinstating vegetation communities exposed to limited and variable rainfall events that in combination with a deficit of original topsoil may exceed thresholds for seedling development. In a series of glasshouse experiments, we evaluated variation in drought responses of (i) 21 arid zone plant species from the mining intensive Pilbara region of Western Australia in an original topsoil substrate and (ii) four selected species (Acacia inaequilatera, Acacia spondylophylla, Eucalyptus leucophloia and Triodia epactia) in three different soil substrates (topsoil, overburden material and a blend of both soil materials) that may be considered as an alternative substrate for restoration. Seedling drought responses were tested using ecophysiological indicators (e.g. stomatal conductance and leaf water potential (Ψleaf) at the time of stomatal closure, among others) during soil drying. Our results showed that plant life form and morphological traits interact with ecophysiological indicators to show that trees are significantly less tolerant to drought‐related stress than shrubs and herbs (p ≤ 0·05). When grown in overburden material seedlings experienced a decline in overall plant growth (87% in T. epactia and 62% in E. leucophloia) and ecophysiological drought tolerance. These responses are evidence of the low quality of the overburden substrate, which has a depleted nutrient content and low water retention capacity. Overall, this study highlights the sensitivity of early seedling development and the importance of facilitating seedling recruitment and survival to secure successful arid zone restoration. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Translocation of threatened species is challenging in semiarid environments, especially when seeds are the principal means of in situ establishment. Worldwide, the overall success of translocations using seeds is highly variable and generally unpredictable. Most seed-based translocations are embarked upon with limited understanding of the species' seed biology or the nuances of the local abiotic environment in which to guide restoration approaches. For instance, within Australia just 14% of threatened species translocations use directly sown seeds and consequently, to improve the chances of restoration success, both the seed biology and the influence of the abiotic environment need to be adequately understood. Weinvestigated these aspects in Ricinocarpos brevis R.J.F.Hend. & Mollemans - a short-range Banded Ironstone endemic - by focusing on a series of laboratory and field experiments to understand the key drivers of dormancy alleviation and germination promotion, as well as in-situ conditions of natural and recipient translocation sites. Fresh seeds were found to have high viability, fully developed linear embryos and possess physiological dormancy, with enhanced germination when exposed to smoke water, karrikinolide (KAR[sub 1]) and gibberellic acid (GA[sub 3]). Under laboratory conditions, seeds germinated over a range of temperatures (15-30°C), but germination was suppressed by light and highly sensitive to water stress. Seeds had reduced germination when sown on the soil surface, but could emerge from up to 13 cm in depth. Under field conditions, in-situ emergence was <2%. Using in-situ emergence results, soil loggers and rainfall data, we developed a model of the recruitment bottlenecks faced by this species under in-situ conditions, an approach that provides useful insights to assist future translocations. Understanding seed biology and seed ecology enables better insights into the principal bottlenecks restricting in-situ emergence and consequently restoration success, leading to the development of more effective approaches for conserving other threatened flora in future. [ABSTRACT FROM AUTHOR]

Climate change is increasing the frequency and intensity of drought, and seedling response to a recurrent pattern of drought stress is necessary to understand vegetation establishment patterns in particularly for ecological restoration and conservation projects. A controlled environment study investigated seedling physiological response of framework Mediterranean tree species to simulated successive droughts. Six-month-old seedlings were grown in 1.0 m tall pots to emulate deep soil profiles and subjected to a well watered treatment and a drought treatment consisting of an initial 60 day drought (water withholding), followed by 120 days of re-watering and a subsequent 60 day drought. Soil water access, soil water content, maximum root depth and xylem water potential were assessed through successive harvests. To assess seedling response to multiple droughts, gas-exchange and chlorophyll fluorescence measurements were taken every 15 days after each drought, and multiple times throughout re-watering. No seedling mortality was observed during the initial drought, whereas 100% mortality of all species occurred within 48 days of the second drought. Seedling gas exchange and water potential decreased with decreasing water availability but was dependent on the isohydric or anisohydric behaviour of individual species. An absence of sustained photoprotection during the second drought phase heightened photodamage to foliar tissues resulting in a more rapid decrease of g[sub s] and leaf water potential. Therefore, biphasic drought proved detrimental to seedling establishment by reducing physiological resilience, highlighting the severity of future climate change predictions towards the regeneration capacity of Mediterranean ecosystems. Increasing drought events may further exacerbate the currently high seedling mortality patterns observed in restoration programs. This paper demonstrates a catastrophic decrease in physiological resilience of three Mediterranean tree species during the seedling establishment phase to successive droughts. An understanding of plant functional requirements through critical development stages will enable restoration practitioners to overcome high failure rates and improve biodiversity outcomes generally. [ABSTRACT FROM AUTHOR]

Limited success of restoring framework banksia-woodland species has been attributed to the failure of seedlings to establish deep root systems before the onset of the summer drought. The present glasshouse study investigated how optimising nutrient application during nursery production may increase new-root production after outplanting. Two experimental streams were established to (1) optimise nutrient application rates during nursery production and (2) utilise nutrient-loading techniques to improve root production of Banksia menziesii R.Br., Banksia attenuata R.Br. and Eucalyptus todtiana F.Muell after outplanting. Optimal nutrient-application rates were determined by measuring plant growth and internal nutrient responses to eight application levels of slow-release fertiliser (0-18kgm-3, nitrogen (N):phosphorus (P):potassium (K)=17:1.6:8.7). Nutrient-loading treatments utilised seedlings that had been grown under common industry fertiliser conditions (3kgm-3 native Osmocote, N:P:K=17:1.6:8.7) supplied with 'low' or 'high' loading doses of liquid Thrive continuously over 6 weeks, immediately before outplanting. Seedlings from both experiments were then outplanted to 1-m-deep poly-pipe tubes containing habitat soil. After 12 weeks, plants were harvested and new-root production and shoot growth were measured. Optimal concentrations of slow-release fertiliser for maximum outplanting success as indicated by increased root investment (root:shoot ratio and new-root production) were 8-12kgm-3 for all species. Nutrient loading increased N and P concentrations of plants by up to 80% and 127%, respectively, by luxury nutrient consumption, and after planting, nutrient-loaded seedlings produced 1.5-fold the biomass of conventionally fertilised seedlings, this being the result of greater root productivity. In conclusion, optimising nursery nutrient regimes for framework species may increase root-growth potential, assisting in improving plant establishment in restoration programs. Increasing seeding root growth potential is a critical factor in determining restoration success of banksia-woodland systems. Optimising nutrient regimes during nursery production provides an opportunity to increase root growth of Banksia and Eucalyptus species when outplanted into field conditions. [ABSTRACT FROM AUTHOR]

Seasonal drought and heavily impeded soils reduce restoration success in Mediterranean-type postmine soils, where up to 90% seedling mortality has been observed after 2 years. To alleviate these barriers, amendments were incorporated into the soil profile of a freshly mined sand quarry. Within the quarry, three 223 m2 replicate sites contained two substrate amendments: 12% v/v native-sourced mulch or gravel incorporated within the top 50 cm of the soil profile. Three remnant sites provided a 'natural' reference system. Seeds of two autochthonous trees, Banksia attenuata (R.Br.) and B. menziesii (R.Br.) were sown across all treatments. Soil impedance, moisture, and seedling stomatal conductance were monitored for 2 years, at which point seedlings were excavated, and nutrient concentration, root morphology, and soil chemical properties were measured. Roots in all restoration treatments were restricted to the top 40 cm of the profile due to increases in soil impedance, regardless of amendment, compared to >70 cm in the natural system. Seedling mortality was greatest after the second summer in the control and inorganic amendment treatments, with stomatal conductance indicating severe drought stress. Survival in the organic treatment was 24-42% greater than the control, with higher soil moisture and stomatal conductance rates 2.5 times that of the control. The increased soil water retention by a native-sourced mulch was shown to improve postmine restoration success for these native trees. [ABSTRACT FROM AUTHOR]

Abstract The present study aimed to characterize key physico-chemical and mineralogical attributes of magnetite iron (Fe) ore tailings to identify potential constraints limiting in situ soil formation and direct phytostabilization. Tailings of different age, together with undisturbed local native soils, were sampled from a magnetite mine in Western Australia. Tailings were extremely alkaline (pH > 9.0), with a lack of water stable aggregate and organic matter, and contained abundant primary minerals including mica (e.g., biotite), with low specific surface area (N 2 -BET around 1.2 m2 g−1). These conditions remained relatively unchanged after four years' aging under field conditions. Chemical extraction and spectroscopic analysis [e.g., X-ray diffraction (XRD) and synchrotron-based Fe K edge X-ray absorption fine structure spectroscopy (XAFS) analysis] revealed that the aging process decreased biotite-like minerals, but increased hematite and magnetite in the tailings. However, the aged tailings lacked goethite, a compound abundant in natural soils. Examination using backscattered-scanning electron microscope - energy dispersive X-ray spectrometry (BSE-SEM-EDS) revealed that aged tailings contained discrete sharp edged Fe-bearing minerals that did not physically integrate with other minerals (e.g., Si/Al bearing minerals). In contrast, Fe minerals in native soils appeared randomly distributed and closely amassed with Si/Al rich phyllosilicates, with highly eroded edges. The lack of labile organic matter and the persistence of alkaline-saline conditions may have significantly hindered the bioweathering of Fe-minerals and the biogenic formation of secondary Fe-minerals in tailings. However, there is signature that a native pioneer plant, Maireana brevifolia can facilitate the bioweathering of Fe-bearing minerals in tailings. We propose that eco-engineering inputs like organic carbon accumulation, together with the introduction of functional microbes and pioneer plants, should be adopted to accelerate bioweathering of Fe-bearing minerals as a priority for initiating in situ soil formation in the Fe ore tailings. Graphical abstract Unlabelled Image Highlights • Magnetite Fe ore tailings were strongly alkaline and lack of organic carbon. • Biotite weathering in the tailings without amendments were very slow. • Fe oxides in the tailings lacked association with Al-/Si- minerals for aggregation. • Natural weathering of the tailings resulted in little physicochemical improvements. • Pioneer plants and microbes would be required to accelerate tailings weathering. [ABSTRACT FROM AUTHOR]

Topsoil replacement is a standard procedure in restoration of mined landscapes as it provides a source of propagules via the soil seed bank, as well as provides favourable physical, chemical and microbiological properties for plant establishment. With the availability of topsoil frequently limited in mining, soil cover designs that maximise the use of this resource across the newly-created surfaces after mining should be considered. In this paper, we examine the use of different soil covers and their influence on seedling recruitment for restoration of a Threatened Ecological Community (TEC) with limited topsoil. The properties of a standard topsoil and topsoil diluted with waste-rock to optimise spread were compared between two topsoil sources with different textures and a fine-textured waste material that is a mining by-product. We studied the physicochemical and hydrological traits of five soil covers (unblended TEC topsoil; TEC topsoil mixed with waste rock; fines; fines mixed with waste rock, and waste rock) with two TEC topsoil sources (plateau and hillslope). Soil characterisation included texture, gravel content, soil surface crust strength, soil moisture and temperature, and surface infiltration. Finally, we quantified seedling emergence for four key taxa sown ( Acacia acuminata, Allocasuarina acutivalvis , Melaleuca nematophylla, Waitzia nitida ) and the seedling community arising from the topsoil seedbank and naturally dispersed seeds, and related this emergence with the soil properties. The standard topsoil cover promoted the greatest seedling emergence showing marked differences between the two topsoil provenances. Importantly, the addition of waste rock to topsoil did not compromise the ability of topsoil to support seedling emergence and is therefore a useful strategy to maximise this resource. Overall, our results show the importance of hydrological properties of soil covers for seedling recruitment and highlight the importance of topsoil selection in restoration success. [ABSTRACT FROM AUTHOR]

Abstract: Karrikins are a chemically defined family of plant growth regulators discovered in smoke from burning plant material. Karrikins are potent in breaking dormancy of seeds of many species adapted to environments that regularly experience fire and smoke. The recent discovery that karrikins trigger seed germination and control seedling growth in taxa that would rarely experience fire indicates that their significance could extend far beyond fire ecology. This is exemplified by new studies showing that seeds of Arabidopsis thaliana respond sensitively and specifically to karrikins in smoke. These exciting discoveries might be explained if karrikins are produced in the environment by processes other than fire, such as by chemical or microbial degradation of vegetation in response to disturbance of the soil or removal of the plant canopy. Another hypothesis is that plants contain endogenous karrikins that function naturally in the control of seed germination and that species from fire-prone habitats have evolved to respond also to exogenous karrikins. A variant on this hypothesis is that karrikins mimic endogenous plant hormones such as terpenoids that control seed germination. The evidence for these hypotheses is discussed, but whatever the explanation karrikins are now firmly established as an important family of naturally occurring plant growth regulators. [Copyright &y& Elsevier]

Soil microbial inoculants are increasingly being explored as means to improve soil conditions to facilitate ecological restoration. In southwestern Western Australia, highly biodiverse Banksia woodland plant communities are increasingly threatened by various factors including climate change, land development and mining. Banksia woodland restoration is necessary to conserve this plant community. The use of microbial inoculation in Banksia woodland restoration has not yet been investigated. Here, we evaluated the efficacy of a commercial microbial inoculant (GOGO Juice, Neutrog Australia Pty Ltd) for improving the performance of 10 ecologically diverse Banksia woodland plant species in a pot experiment. Plants were subjected to one of two watering regimes (well-watered and drought) in combination with microbial inoculation treatments (non-inoculated and inoculated). Plants were maintained under these two watering treatments for 10 weeks, at which point plants in all treatments were subjected to a final drought period lasting 8 weeks. Plant performance was evaluated by plant biomass and allocation, gas exchange parameters, foliar carbon and nitrogen and stable isotope (δ 15 N and δ 13 C) compositions. Plant xylem sap phytohormones were analysed to investigate the effect of microbial inoculation on plant phytohormone profiles and potential relationships with other observed physiological parameters. Across all investigated plant species, inoculation treatments had small effects on plant growth. Further analysis within each species revealed that inoculation treatments did not result in significant biomass gain under well-watered or drought-stressed conditions, and effects on nitrogen nutrition and photosynthesis were variable and minimal. This suggests that the selected commercial microbial inoculant had limited benefits for the tested plant species. Further investigations on the compatibility between the microorganisms (present in the inoculant) and plants, timing of inoculation, viability of the microorganisms and concentration(s) required to achieve effectiveness, under controlled conditions, and field trials are required to test the feasibility and efficacy in actual restoration environments., Competing Interests: The authors report no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press and the Society for Experimental Biology.)

Defining plant ecophysiological responses across natural distributions enables a greater understanding of the niche that plants occupy. Much of the foundational knowledge of species' ecology and responses to environmental change across their distribution is often lacking, particularly for rare and threatened species, exacerbating management and conservation challenges. Combining high-resolution species distribution models (SDMs) with ecophysiological monitoring characterized the spatiotemporal variation in both plant traits and their interactions with their surrounding environment for the range-restricted Aluta quadrata Rye & Trudgen, and a common, co-occurring generalist, Eremophila latrobei subsp. glabra (L.S.Sm.) Chinnock., from the semi-arid Pilbara and Gascoyne region in northwest Western Australia. The plants reflected differences in gas exchange, plant health and plant water relations at sites with contrasting suitability from the SDM, with higher performance measured in the SDM-predicted high-suitability site. Seasonal differences demonstrated the highest variation across ecophysiological traits in both species, with higher performance in the austral wet season across all levels of habitat suitability. The results of this study allow us to effectively describe how plant performance in A. quadrata is distributed across the landscape in contrast to a common, widespread co-occurring species and demonstrate a level of confidence in the habitat suitability modelling derived from the SDM in predicting plant function determined through intensive ecophysiology monitoring programmes. In addition, the findings also provide a baseline approach for future conservation actions, as well as to explore the mechanisms underpinning the short-range endemism arid zone systems., (© The Author(s) 2024. Published by Oxford University Press and the Society for Experimental Biology.)