Seedling recruitment in Mediterranean ecosystems is constrained to brief periods when temperature and water availability are jointly favourable, yet the climatic drivers that define this germination window remain poorly resolved. We quantified ex situ germination and in situ emergence for 10 taxonomically and functionally diverse Banksia woodland species from the Southwest Australian Floristic Region and related these responses to soil microclimate and meteorological conditions. Seeds were incubated across a temperature gradient (5-40 degrees C) to estimate maximum germination (Gmax), optimal temperature (Topt), upper thermal limit (Tmax), and time to 1% germination (T1). The same species were sown into remnant Banksia woodland and monitored for emergence through the 2021 wet season alongside high-frequency soil moisture and temperature measurements. Across species, germination thermal optima were generally cool (mean Topt 15.7 +/- 1.5 degrees C; range 7.0-26.0 degrees C) with moderate upper thermal limits for germination (mean Tmax 27.1 +/- 1.6 degrees C). Field emergence commenced shortly after soils became persistently hydrated and weekly moisture balance (rainfall minus pan evaporation) shifted from negative to positive, indicating that evaporative demand is a decisive regulator of emergence timing. Laboratory-derived traits were predictive of field performance: maximum germination and maximum emergence were positively correlated (R2 = 0.48), and T1 in the laboratory strongly predicted T1 in the field (R2 = 0.68), although emergence was consistently slower in situ. These findings show that integrating moisture balance with laboratory germination traits provides a practical framework for timing seed-based restoration to coincide with periods of sustained positive moisture balance.'

ABSTRACT Seed germination of species in arid zones is shaped by climatic extremes, which include high temperatures, prolonged drought and episodic rainfall. Halophytic plants, such as samphires, face additional pressure from fluctuating salinity. It is anticipated that current physiological thresholds will be surpassed for many species because of climate change, resulting in disrupted plant recruitment patterns as seed germination windows narrow or shift. Our study aimed to determine the timing of germination opportunities for the threatened samphire Tecticornia lylei and understand the effects that climate change may have on future recruitment. We assessed the germination responses of seeds to light, temperature, water and salinity stress. The comparative effects of salinity and water stress under increasing temperatures were also observed, as were responses to freshwater exposure characteristic of episodic rainfall. We found seeds removed from fruits commenced germination more rapidly, but other treatments assessed had minimal effect on final germination percentages. Tecticornia lylei germinated optimally in cooler conditions under constant darkness, but also had capacity for strong germination in fluctuating light/dark photoperiods. Low numbers were observed to germinate at higher temperatures, and under water stress which caused greater delays than salinity stress, with increasing temperatures exacerbating these effects. However, ungerminated seeds responded rapidly to freshwater treatment, even after exposure to stress levels that surpassed thresholds for germination, this being suggestive of the action of a priming effect. While Tecticornia lylei has a broad thermal window for germination in very low stress environments, it narrows substantially as osmotic stress increases. High rainfall events during cooler seasons are therefore critical to reduce salinity and increase soil moisture for sufficient time for seeds to germinate in high numbers.

Energetics is considered a fundamental 'currency' of ecology and the way that metabolic rate (MR)-the rate of energy expenditure on biological processes-scales relative to the size of the organism can be both an adaptive benefit and a constraint in mediating the energetic demands of ecological processes. Since few investigations have examined this relationship for angiosperm seeds, we measured standard metabolic rate (SMR) of 108 species' seeds, spanning a broad suite of species. We used fluorescence-based closed-system respirometry at temperatures between 18°C and 30°C, based on optimal germination conditions, and Q10 corrected to 20°C. The allometric relationship for SMR as a function of seed mass was 0.081 × M0.780 with ordinary least squares regression and 0.057 × M0.746 with phylogenetic generalized least squares regression. This relationship is consistent with the pervasive metabolic allometry documented for both vegetative plants and domesticated cultivars (n = 14) which had higher SMR residuals than wild species (seven weeds and 87 Australian native species). For native species, seed SMR was strongly related to measures of increasing environmental aridity (annual mean temperature and precipitation, and precipitation in the wettest quarter), consistent with seeds from arid environments having a high MR to supply energy needed to germinate rapidly. By comparing SMR of seeds for diverse angiosperm species, we provide insights into inter-relationships of physiology, distribution, climate and domestication on seed ecology and suggest that energetics represents a valuable addition to established functional trait libraries for seed biology.

Restoration of arid vegetation is an essential and difficult task, making the selection of the right methods for restoration an important choice. One way to determine which methods would be most effective is by accessing the accumulated knowledge of restoration practitioners, which is often unreported in the scientific literature. This study created an online survey asking questions of practitioners on the effectiveness of different methods for arid restoration, including how effective they are at promoting restoration and their financial and labour inputs. The survey was distributed to arid restoration practitioners within Australia, with a focus on the southern areas, and found that the methods most commonly used are ones that appear most effective at promoting restoration and are generally the most highly recommended. The cost and labour input did not correlate with the most used or most recommended method, suggesting that these are secondary factors and are not necessarily the most important concerns for the survey respondents. While mechanical direct seeding was indicated to have lower financial and labour inputs, both it and hand-planting were indicated to be similar in restoration ability and were both highly recommended. Grazing control methods and chemical weed control were also indicated to be effective at restoration, likely due to damage that grazing and weed competition can inflict upon plantings. Pre-seeding treatments were found to be both effective at restoration and have low labour and cost requirements, making them one of the most highly recommended methods. Soil amendments, such as water-holding gels and biochar, despite being low-to-moderate in terms of cost and labour input, were not indicated to be effective at restoration and were subsequently not highly recommended. Though some general trends could be found, respondents also commonly pointed out that the choice of methods will often depend on the site-specific conditions.

Direct seeding is a potentially valuable method for restoration in arid areas due to its low cost and labor input but suffers from the drawback of reduced survival rates, which may lead to planting failure. As such, the addition of soil amendments may be one way to increase planting success rates. This study investigated whether the addition of three types of soil amendments (fertilizers, hydrogels, and microbial inoculants) would be able to increase the emergence and survival times of direct seeding works in the semiarid Mallee region of north‐west Victoria, Australia. Seed from four native species were mechanically directly seeded into three sites across the Mallee region, along with different combinations of soil amendments. Emergence and survival time were recorded for 1 year, and the soil properties at each planting location were analyzed. The results showed that only the two larger‐seeded species ( Acacia ligulata and Callitris gracilis ) were able to emerge, while the two smaller‐seeded species ( Eucalyptus calycogona and Melaleuca lanceolata ) showed no emergence. Soil amendments had no effect on either seedling emergence or survival time. Instead, seeding location had a significant outcome for both seedling emergence and survival. It was found that locations that showed the highest emergence did not necessarily show the highest survival. Low soil nutrient sandplains contained the highest seedling emergence counts. The longest surviving seedlings were in locations with slightly higher nitrogen levels for A. ligulata seedlings, while C. gracilis survived longest in highly sandy soil under a slightly cooler, wetter climate.

Solanaceous species are crops of economic importance in Western Australia that also face challenges from poor soil quality, a warming and drying climate, and soil-borne pathogens. This study explored the potential of Solanum symonii , a native Western Australian species, as a rootstock for tomato ( Solanum lycopersicum ) and eggplant ( Solanum melongena ) to enhance their resilience to local growing conditions. There are no prior published reports of native Western Australian species as rootstock in commercial horticulture. Propagation trials using seeds and cuttings of S. symonii were conducted, followed by grafting trials to evaluate compatibility with tomato and eggplant scions. Grafted plants were grown in a greenhouse and subsequently transferred to a high tunnel for fruit yield assessment. Graft survival, leaf chlorophyll content, and fruit yield were measured. Results demonstrate long-term graft compatibility, despite 50% early graft failure, with no adverse effects on subsequent fruit production. These findings suggest S. symonii has potential as a novel rootstock for solanaceous crops in Western Australia if early graft survival can be improved. The results demonstrate the need for further research on S. symonii and other native Australian Solanum as rootstocks to address biotic and abiotic challenges in horticulture.

Background: Podocarpus drouynianus is an ecologically unique, taxonomically distinct range-restricted gymnosperm that occurs exclusively within Mediterranean woodlands in the south-west of Western Australia. Limited information is known about this species regarding seed dormancy, germination, and seed desiccation sensitivity. Aims: This study aimed to determine whether P. drouynianus seeds possess dormancy, quantify the responses of seeds to a range of incubation temperatures and examine seed desiccation sensitivity (i.e. recalcitrance) after exposure to different conditions to understand recruitment dynamics in a seasonally dry environment and ex situ seed storage. Methods: Fresh diaspores (seeds enclosed within an indehiscent epimatium) were collected upon maturity for experimentation. Diaspores and extracted seeds were assessed for viability, moisture content and embryo size with a subset of diaspores placed at various incubation temperatures to investigate germination response. Additional diaspores were placed under a range of storage conditions and assessed regularly for viability, moisture content and germination. Results: Upon hydration, fresh diaspore germination commenced rapidly (similar to 5 days) at several temperatures with maximum germination (0.88 germination proportion) achieved at 15 degrees C or 20 degrees C. Seeds were found to have morphological dormancy as embryos grew prior to radicle emergence. Fresh diaspores and seeds had a high moisture content ( > 56% - fresh weight basis) and viability (0.96 viability proportion) which declined to 45% MC and 0.75 viability proportion following storage for 42 days at 5 degrees C and 10% eRH. Conclusions: Podocarpus drouynianus diaspores germinate readily over a broad range of temperatures but were found to lose viability due to desiccation sensitivity when placed in either a cool (5 degrees C) dry environment (similar to 10% eRH) for 42 days or in warm (25 degrees C) ambient (similar to 40% eRH) conditions for 60 to 90 days. These findings are crucial for informing potential management strategies for P. drouynianus, particularly as the climate warms and dries across the south-west Australian biodiversity hotspot.

Australia is home to a rich assemblage of samphires (Tecticornia and Salicornia spp.) which are largely endemic, inhabiting saline and semi-saline areas across climatically diverse regions. While these plants are adapted to harsh conditions, they are vulnerable to the effects of climate change which is anticipated to exacerbate existing management and environmental pressures. Despite the threatened and priority status of many samphires, there is an overall lack of knowledge surrounding their distribution, ecology and responses to environmental threats, data which we believe is critical to support their conservation and management. We have compiled and critically assessed peer-reviewed and online grey literature and databases to provide an overview of threatened and poorly known samphires in Australia, with particular reference to their distribution, threats and ecological responses. Of the 58 species and 19 subspecies recorded in Australia, two are federally listed as threatened, eight have a formal conservation listing in at least one state or territory, and 25 are recognised as data deficient or priority taxa. Five samphire communities are also listed as threatened and seven are considered Priority Ecological Communities. We found gaps in data relevant to these threatened and priority species, with 40

Direct seeding of restorative plants is a difficult task in arid environments due, in part, to the low moisture levels inherent to these areas. This barrier to restoration has stimulated a number of methods to help combat this issue, including the burial of seeds just below the soil surface, the addition of fertiliser and the use of other suitable low-cost soil amendments aimed at improving germination and survival. This study examines the effects of burial depth and application of soil amendments on seedling emergence under different watering regimes on four semi-arid zone species. The soil amendments used were hydrogel (EarthCare Water Crystals), fertiliser (Osmocote), and a commercial soil microbial inoculant (Bactivate5). It was found that, while heavier seeded species were able to emerge from deeper below the soil surface, all seeds in the study preferred to emerge from shallow burial depths of around 6-10 mm. Soil amendments were shown to have minimal effect on emergence rates, regardless of the watering regime, while the watering regime was found to have the largest impact. Seedlings under a low watering regime (30% water holding capacity) were found to have the lowest emergence rate, while a moderate watering regime (55% water holding capacity) produced the highest emergence across most species. Results obtained from this study suggest that shallow burial of seeds 6-10 mm below the soil surface, as opposed to surface placement or deeper burial, may enhance emergence for the species tested. Although the soil amendments did not improve plant species emergence, amendment application may still be beneficial for developing seedlings by enhancing seedling resilience to adverse growing conditions such as moisture stress or extreme temperatures.

Context Pilostyles are a genus of endoparasitic plants specific to the Fabaceae family. In Australia, three species are restricted to the South-west floristic region.Aims This study aimed to assess the use of resource-selection functions (RSFs) on populations of Pilostyles hamiltoniorum to understand host preference to the known host species of Daviesia.Methods Forty sites were chosen along the known distribution of P. hamiltoniorum, and infected and uninfected hosts were recorded at each site. The Manly resource-usage function was applied to the data to assess host use in populations of P. hamiltoniorum.Key results Only 9 of the 40 sites had populations large enough to assess host use. Out of these surveys, Pilostyles presented high preference for four hosts species, namely, Daviesia angulata, D. physodes, D. preisii and D. rhombifolia, with D. decurrens, observed to be the least favoured host.Conclusion Resource-selection indices showed to be a potential tool in understanding host preference within the genus Pilostyles, with evidence here indicating that host use is not equal within the environment.Implications The patterns of host use show that there are some unknown factors between each host affecting infection, along with the identification of strongly preferred hosts that could lead to future research in ex vitro cultivation.

This study investigates the germination requirements of 12 plant species native to the Argyle region of the east Kimberley, a biodiverse monsoonal tropical region characterized by high temperatures, high evaporation, and episodic seasonal rainfall. The research involved quality assessment of mature seeds, followed by dormancy alleviation and laboratory‐based germination to determine the responses of seeds to a range of temperatures (5–40°C) in terms of germination speed (T10), mean germination time, and maximum germination proportion. Data were then modeled to calculate the optimal temperature to support germination for each species. The results showed that germination rapidly commences in response to a wide range of temperatures typical of the wet season (November–February) in the east Kimberley, though germination for most species was still high (>50%) after exposure to temperatures as low as 15°C. Mean optimal temperature for germination across all species was 25.8 ± 1.5°C, with minimal variation between most species, the exception being Dodonaea physocarpa , which preferred cooler temperatures (Topt = 14.0°C). The speed of germination was also rapid (T10 = 1–3 days) across all species at the optimal germination temperature. The findings suggest that temperature is not a limiting factor for germination in this region and that the onset and intensity of the wet season are the most significant factors determining successful germination, emergence, and seedling establishment. The study underscores the importance of species‐specific understanding of environmental temperatures required for seed germination in seed‐based restoration efforts and informs the planning of direct seeding works, thus enhancing restoration outcomes.

Seed germination responses for most narrow-range endemic species are poorly understood, imperilling their conservation management in the face of warming and drying terrestrial ecosystems. We quantified the realized microclimatic niches and the hydrothermal germination thresholds in four threatened taxa (Tetratheca erubescens, Tetratheca harperi, Tetratheca paynterae subsp. paynterae and Tetratheca aphylla subsp. aphylla) that are restricted to individual Banded Ironstone Formations in Western Australia. While T. aphylla subsp. aphylla largely failed to germinate in our trials, all other species demonstrated extended hydrothermal time accumulation (186-500 degrees C MPa days), cool minimum temperatures (7.8-8.5 degrees C), but broad base water potential thresholds (-2.46 to -5.41 MPa) under which germination occurred. These slow germination dynamics are suggestive of cool and wet winter months, where soil moisture is retained to a greater capacity in local microsites where these species occur, rather than the warmer and drier conditions in the surrounding arid environment. Hydrothermal time-to-event modelling showed that each species occupied unique hydrothermal germination niches, which correspond with the microclimatic differences the species are exposed to. Our results provide a baseline understanding for environmental and germination thresholds that govern the recruitment, and ultimately the population structure and persistence, of these short-range endemic plants. In addition, our results can aid future conservation, as well as restoration actions such as translocation to bolster population numbers and to mitigate against losses due to anthropogenic disturbance and global environmental change.

The temperature and moisture requirements for reproduction (i.e. seed production and germination) underpin the biogeographical relationships between climate, distribution and population dynamics of plants, particularly narrow range endemic species. We aimed to investigate reproductive outputs and the responses of seeds to temperature and moisture availability across three Banksia arborea populations that are distributed over a narrow range (< 200 km(2)) of semi-arid habitat on banded ironstone formations of Western Australia. We conducted reproductive trait assessments by quantifying follicles per cone, proportion of viable seed and associated seed mass followed by hydrothermal germination assessments for each population to characterise temperature and water stress tolerance. We found the southern-most population, that receives marginally higher rainfall, had heavier seeds (10 +/- 0.02 mg), a cooler optimum temperature (16.1 degrees C) and wider germination capacity under water stress at 10 degrees C and 15 degrees C (Psi(b50) = -0.66 to -0.87 MPa) compared to the two northern populations (Psi(b50) = -0.60 to -0.65 MPa). By contrast, both northern populations had slightly warmer optimum temperatures for germination (16.9-17.5 degrees C) and a higher capacity to germinate under water stress at warmer temperatures of 22.5 degrees C (Psi(b50) = -0.43 to -0.56 MPa, compared to -0.29 MPa). Our work highlights that, even within the specific requirements of a narrow range endemic, different populations adapt to marginally different temperature and water stress tolerances. Warming of the southern populations could impact on future recruitment, and conservation action to promote resilient ecosystems are suggested.

Arid environments have become degraded in recent times through human activity highlighting the need for restoration works to reverse this trend. One of the most common forms of restoration works is revegetation. However, revegetation is difficult in the arid zone due to a combination of environmental factors such as low moisture and extreme temperatures, as well as financial and administrative factors. In this review, we investigated the literature describing various methods available for arid revegetation, and assess their utility for revegetation activities. Each of the methods investigated were found to have potential advantages and disadvantages, though some general trends were observed. Two main planting methods were identified, “out‐planting” and “direct seeding.” Which of these methods to use depends on the conditions of the project being undertaken. Out‐planting appeared to be the most suited approach to smaller scale projects with higher budget availability, whereas direct seeding was more suited to large scale, lower budget projects. Weed control prior to planting was identified as being critical for success in most works, whereas soil ripping was beneficial for direct seeding projects. Among the soil amendments investigated, water‐holding gels were most likely to be beneficial, whereas fertilizers were riskier due to their potential to reduce drought tolerance and increase weed invasion. Microbial inoculation with mycorrhiza showed high potential to improve plant performance but may be held back by the lack of suitable commercial sources. Newer seed technologies, such as synthetic seed coats and pellets, show promise, but this issue still requires further research and development.

The increasing reliance on native seeds for ecological restoration requires the understanding of seed traits across each species, and the testing of novel processing approaches to optimize germination outcomes. Knowledge regarding Australian native seeds is critical due to the high proportion of species manifesting some degree of seed dormancy. The evaluation of approaches to overcome dormancy and identify optimal conditions for promoting germination in native species has significant applications in the restoration of degraded ecosystems. Grasses are an important component of ecosystems in the Australian monsoonal tropics, a bioregion which covers much of northern Australia, yet they are often forgotten or poorly represented when used in restoration. We investigated the effect of seed processing technique and smoke‐based stimulants on the germination of seven species from the Kimberley region, testing three different hypotheses: (1) florets germinate less than extracted caryopses; (2) acid digestion treatments with different exposure times can enhance germination; and (3) smoke‐based treatments can increase both germination and germination speed. Floret removal was generally helpful in improving germination, whereas the response to acid and smoke‐based treatments was varied. Brief acid exposure produced no to low germination improvements, whereas longer acid treatments showed contrasting results, with some species showing significant germination increase and others showing a severe reduction in germination rate. The only species showing a clear positive germination effect of smoke‐based treatments was Triodia bynoei . These results are helpful for restoration practitioners to improve their potential use in current and future restoration programs in the Australian monsoonal tropics.

Direct seeding has high potential for arid revegetation, but success is limited by decreased germination and seedling emergence. Direct seeding success may be improved through developing an understanding of the germination biology and requirements of species used for these projects. This study looked into the germination temperature and moisture requirements of four semiarid species from Victoria's Mallee ecosystems to understand how their germination biology may advise strategies for future plantings. Temperature's effect on germination was analyzed by incubating the seeds under three different regimes: 30/20, 25/15, and 17/7°C. Moisture requirements were determined by germinating seeds along a water potential gradient created using polyethylene glycol 8000 solutions. Results showed three different strategies employed by the study species: (1) Acacia ligulata has a generalist approach, germinating well in all temperatures with a reasonable tolerance to water stress; (2) Eucalyptus calycongona and Melaleuca lanceolata germinate rapidly under higher germination temperatures and have generally higher water stress tolerance; while (3) Callitris gracilis germinates poorly in hot or dry conditions restricting germination to cooler and wetter conditions. Based on our results, A. ligulata would be the most widely applicable species for direct seeding work based on generalist germination habits. Callitris gracilis appears to do well if planted in cool, wet conditions where the species prefers to germinate but would be intolerant to warm‐weather planting. The ideal planting time for a mixed species planting based on germination requirements would be mid‐autumn, as that is when temperature and moisture levels would be optimal for germination.

Background Phos-Chek WD881A is a short-term retardant used by fire-fighters in Western Australia to suppress and control the movement of fire across the landscape. It is currently applied at a working concentration of 0.1–1%. Aim Our objective was to assess and quantify the impact of the suppressant on seed germination and seedling emergence across eight native and two weed species commonly found in Eucalyptus wandoo woodland. Methods Seeds were exposed to five Phos-Chek concentrations, from 0 to 10% (v/v), in a germination trial in Petri dishes, and three concentrations of 0, 0.1 and 1% (v/v) in a seedling emergence trial. Key findings Increasing concentrations of Phos-Chek both delayed and reduced germination and emergence for all species except Acacia saligna. The sensitivity to Phos-Chek varied among the tested species. Conclusions Phos-Chek had a significant impact on the germination and emergence of native and invasive species, with irreversible damage to seed viability in one taxa (Allocasuarina humilis). Implications It is recommended that applications of Phos-Chek foam remain closer to the minimum recommended concentration (0.1% v/v) to reduce adverse effects on the recruitment of sensitive species, particularly during dry autumns when leaching of this chemical is likely to be limited.

Context In ecosystems where rainfall is episodic or highly seasonal, plant recruitment from a soil-stored seed bank occurs during periods of elevated soil moisture conducive to germination and seedling establishment. The release of seed dormancy in response to environmental conditions has significant consequences for the temperature window over which germination occurs, and as such the timing of germination can vary between years. Aims We aimed to understand in seeds of two species of Rutaceae, Diplolaena dampieri and Rhadinothamnus anceps, how dormancy loss and germination timing is influenced by warm stratification. Methods We tested the germination response to temperatures between 5 and 30°C following increasing durations (1–12 and 4–12 weeks) of warm stratification at 20, 25, or 30°C. Key results Warm stratification for 1–8 weeks at 30°C progressively alleviated seed dormancy in D. dampieri and R. anceps, increasing germination proportion from ~0.1 to ~0.5 in both species. Stratification duration was optimal at 30°C for between 4 and 8 weeks depending on species. Warm stratification was not affected by water stress down to −0.8 Mpa. Application of aerosol smoke did not significantly improve germination, and heat treatments had a negative effect on final germination proportion. Conclusions As dormancy was progressively alleviated, the range of temperatures that support germination increased for D. dampieri and decreased for R. anceps, allowing for confirmation of type 1 and type 2 non-deep physiological dormancy (PD), respectively. Implications Arising from this conclusion, we suggest that in Mediterranean climates, type 1 and 2 PD dictate risk-taking and risk-avoiding ecological strategies by shifting the thermal requirements for germination towards that characteristic of the early- or mid-germination season. Classification of non-deep PD may offer a structured approach to predict how temperature requirements shift during dormancy loss, which will provide insight into seed germination response to year-to-year variation in seasonal environmental conditions.

In this study, we focused on understanding key storage traits of seeds from Macrozamia fraseri, an unusual though important species that is impacted by mining. To support current restoration activities, large amounts of seed from M. fraseri have been regularly collected and stored for up to 8 years under standard seed banking conditions (5 degrees C and 20% relative humidity), though in situ recruitment from directly sown seed is poor. To investigate the underlying constraints to germination on demand, we set out to assess the viability of M. fraseri seeds that had been stored in a restoration seed bank from 6 to 66 months. Seed moisture content (MC) (fresh weight basis) was also determined for seeds with different storage histories to ascertain whether M. fraseri seeds display traits (i.e. high MC) that might suggest non-orthodox seed storage behaviour. The youngest seed accession (6 months old) was found to have a high MC (45.8 +/- 5.4%-fresh weight basis), and >50% viability. In comparison, older (>30 months old) accessions were observed to have a marked reduction in both seed MC (10-35% MC) and viability (0-29.4%). While preliminary, we conclude that M. fraseri seeds appear to lose viability during conventional storage with younger accessions displaying both a higher seed MC and viability, compared to accessions stored for longer. Given the significance of these results, future research activities are recommended to better understand the interplay between seed MC and storage environment and how this relates to the seasonally dry Mediterranean climate where this species naturally occurs. As well, storage and propagation approaches are proposed to increase success when using M. fraseri for conservation and restorative activities.

Cochlospermum fraseri ('Kapok', Bixaceae) is a deciduous tree widely distributed throughout semi-arid and monsoon tropical northern Australia, and an important species for ecological restoration in the region. We aimed to better understand the seed biology and ecology of C. fraseri to determine the mechanisms by which seed dormancy might be alleviated, and the conditions that support germination to inform the use of this species in restoration. Dormancy breaking treatments (wet heat, dry heat, scarification) commonly applied to species with physical seed dormancy (PY) were tested along with stratification at 5-35 degrees C (nine treatments). Following dormancy alleviation, seeds were germinated at nine temperatures (5 to 40 degrees C) and five water potentials (0 to -0.8 MPa) to understand environmental thresholds that regulate germination physiology in non-dormant seeds. A proportion of seeds (<0.3) lose dormancy naturally in response to warm (25 to 35 degrees C) moist conditions, which dislodges the hypostase plug that prevents water uptake, whilst neither dry (>= 100 degrees C) nor wet (similar to 100 degrees C) heat were effective. Dormancy loss was also achieved by exposing seeds to concentrated (95-98% v/v) sulphuric acid for 3-7 hours, after which high proportions (>0.75) of germination were observed. Cochlospermum fraseri seeds possess PY, which is alleviated by seasonal temperatures that occur when soil moisture is high, allowing seeds to employ a risk-adverse strategy and maximize establishment success in episodic environments with stochastic rainfall events. The understanding of dormancy alleviation requirements gained here adds to our knowledge of PY worldwide and recruitment dynamics in the Australian monsoonal tropics and will aid land managers and restoration practitioners by informing both seeding sites and optimal time for in situ sowing as well as the potential capacity of this species to form a persistent soil seed bank.