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1. Fire has long shaped biological responses of plants and plant communities in many ecosystems; yet, uncontrolled wildfire frequently puts people and infrastructure at risk. Fuel or hazard reduction burning outside of the historic fire season is a common and widespread practice aimed at reducing the risk of high-severity fires, which ideally also considers biodiversity values. Within fire-prone systems, seed banks are critical for plant species' regeneration, and seeds are typically adapted to survive the passage of fire and to regenerate in response to cues associated with historic fire regimes. However, species-specific tolerances to the heat from fire exist; likely influenced by a range of physical, physiological, and morphological seed traits, which may differ between seasons. The identification of these tolerances and associated seed traits may inform fire and species management. 2. We determined the lethal temperatures for seeds in relation to their moisture content, and other key traits that we hypothesised may be associated with survival. Seeds from 14 native species and 4 species non-native to fire-prone Mediterranean climate Banksia woodlands of south-west Western Australia were exposed to temperatures between 50 and 180°C for 3 min at three different moisture contents. The temperature at which half the seeds were killed (T50) was estimated using nonlinear modelling. Seed mass, seed shape, embryo type, plant resprouting ability, seed storage syndrome, and native/non-native status were quantified and modelled for their relationship with T50. 3. Increased moisture content was a significant predictor of elevated seed mortality. Seeds with higher moisture (95% relative humidity [RH]) content perished at much lower temperatures. Seeds with low moisture content (15% or 50% RH) were able to survive significantly higher temperatures (median increase of 38 and 31°C higher respectively). Seeds with basal embryos showed significantly lower T⁵⁰ than other embryo types. 4. Synthesis. Seeds with elevated moisture contents have lower lethal temperature thresholds, leading to increased seed mortality during fire events when seeds (and soils) are moist. Thermal tolerance varied among coexisting species within this fire-prone system. These data suggest potential concern for the impacts of aseasonal burning practices (i.e., cool/wet season burning), and highlight the importance of taking seed moisture content into account when planning and implementing prescribed burning.

Background and aims Belowground interspecific plant facilitation is supposed to play a key role in enabling species co-existence in hyperdiverse ecosystems in extremely nutrient-poor, semi-arid habitats, such as Banksia woodlands in southwestern-Australia. Manganese (Mn) is readily mobilised by Banksia cluster root activity in most soils and accumulates in mature leaves of native Australian plant species without significant remobilisation during leaf senescence. We hypothesised that neighbouring shrubs are facilitated in terms of Mn uptake depending on distance to surrounding cluster root-forming Banksia trees. Methods We mapped all Banksia trees and selected neighbouring shrubs within a study site in Western Australia. Soil samples were collected and analysed for physical properties and nutrient concentrations. To assesses the effect of Banksia tree proximity on leaf Mn concentrations [Mn] of non-cluster-rooted woody shrubs, samples of similarly aged leaves were taken. We used multiple linear models to test for factors affecting shrub leaf [Mn]. Results None of the assessed soil parameters showed a significant correlation with shrub leaf Mn concentrations. However, we observed a significant positive effect of very close Banksia trees (2 m) on leaf [Mn] in one of the understorey shrubs. We found additional effects of elevation and shrub size. Conclusions Leaf micronutrient concentrations of understorey shrubs were enhanced when growing within 2 m of tall Banksia trees. Our model predictions also indicate that belowground facilitation of Mn uptake was shrub size-dependent. We discuss this result in the light of plant water relations and shrub root system architecture.

Unseasonal fire occurrence is increasing globally, driven by climate change and other human activity. Changed timing of fire can inhibit postfire seedling recruitment through interactions with plant phenology (the timing of key processes, e.g., flower initiation, seed production, dispersal, germination), and therefore threaten the persistence of many plant species. Although empirical evidence from winter-rainfall ecosystems shows that optimal seedling recruitment is expected following summer and autumn (dry season) fires, we sought experimental evidence isolating the mechanisms of poor recruitment following unseasonal (wet season) fire. We implemented a seed-sowing experiment using nine species native to fire-prone, Mediterranean-climate woodlands in southwestern Australia to emulate the timing of postfire recruitment and test key mechanisms of fire seasonality effects. For seeds sown during months when fire is unseasonal (i.e., August–September: end of the wet winter season), seedling recruitment was reduced by up to 99% relative to seeds sown during seasonal fire months (i.e., May–June: end of the dry summer season) because of varying seed persistence, seedling emergence, and seedling survival. We found that up to 70 times more seedlings emerged when seeds were sown during seasonal fire months compared to when seeds were sown during unseasonal fire months. The few seedlings that emerged from unseasonal sowings all died with the onset of the dry season. Of the seeds that failed to germinate from unseasonal sowings, only 2% survived exposure on the soil surface over the ensuing hot and dry summer. Our experimental results demonstrate the potential for unseasonal fire to inhibit seedling recruitment via impacts on pregermination seed persistence and seedling establishment. As ongoing climate change lengthens fire seasons (i.e., unseasonal wildfires become more common) and managed fires are implemented further outside historically typical fire seasons, postfire seedling recruitment may become more vulnerable to failure, causing shifts in plant community composition towards those with fewer species solely dependent on seeds for regeneration.

Questions: How do plant functional trait abundance and diversity in urban remnants of a rapidly urbanizing city change with fragmentation? Is there a delayed functional response to fragmentation? Location: Thirty remnant Banksia woodlands, Perth, Australia. Methods: We used GLMM to examine the effects of remnant age and area, and their interaction, on the relative abundance and functional diversity (FD) of five plant functional traits: growth form, pollination, seed dispersal, nutrient acquisition and regeneration strategies. We then used fourth-corner analysis to examine the influence of a wider set of fragmentation-related factors on trait abundances. Results: The functional composition and diversity of Banksia woodlands changed with remnant age, particularly in the smaller remnants. Plants more prone to decline with remnant age were the growth form shrubs, root-clustered trees, herbaceous obligate seeders and understorey species that are insect-pollinated, have seeds dispersal internally by animals and have arbuscular or ericoid mycorrhizas. In contrast, plants more prone to persist were growth forms trees, sedges and rushes, ectomycorrhizal trees, herbaceous resprouters, wind-pollinated and root-clustered understorey species. FD increased with remnant age in the growth forms and overstorey, but declined among the herbaceous and shrub pollination and nutrient acquisition traits. Conclusions: Functional traits that consistently signalled the plant community response to fragmentation were growth form, pollination and dispersal. This functional response was largely delayed, suggesting a \"functional extinction debt\", which will lead to a further decline of plants with vulnerable trait states in the future, especially in the small- and medium-sized remnants. Our study illustrates the vulnerability of small remnants to changes in community assembly and ecosystem function due to fragmentation. Furthermore, it exemplifies how a functional trait approach is valuable to understand the impacts of urbanization on remnant plant communities, before local extinctions may occur. Finally, the study shows how cities' fragmentation history and biogeographic settings provide an important context influencing plant functional responses to urbanization-related processes.

The ability of restored sites to recover from subsequent disturbances is a key component of restoration success. Resilience is achieved when a restored site returns to its pre‐disturbance state, rather than shifts to a different one. In restored fire‐prone ecosystems, the drivers of post‐fire plant responses and resilience of plant assemblages to fire are underexplored. Exploration of these responses is used to predict and measure the resilience of restored ecosystems to disturbance, including whether the disturbance response was desirable or not. We implemented fine‐scale experimental fires in a post‐mining restoration chronosequence 14–27 years of age in Banksia woodlands, Western Australia. We sought to understand the effects of restoration age, fire impact, and soil conditions on post‐fire regeneration and survival of restored Banksia woodland plant assemblages. To assess early‐stage resilience to fire, we calculated four descriptors of ecosystem state: plant species density, species diversity, rarefied richness and functional redundancy, and compared how these changed following fire across the restoration ages and in comparison to nearby reference Banksia woodland. Ordinations and indicator species analyses were used to compare restored and reference sites. In restoration sites, restoration age, fire impact and soil conditions had little effect on plant regeneration and survival. Changes in diversity, rarefied richness and functional redundancy pre‐ to post‐fire in restored sites were typically similar to or less than that observed in reference sites. Broadly, our findings demonstrate the incomplete resilience of restored Banksia woodland to fire. Resprouters typically demonstrated poor resilience, through significant decreases in diversity and rarefied richness following fire in restored sites. They were under‐represented in restored Banksia woodlands, so further investigations into the establishment of resprouters in restored environments are required. Our findings also highlight the importance of utilising reference data and a broad range of descriptors to fully understand responses of restored plant assemblages to fire.

The efficacy of a commercial microbial inoculant for improving the performance of 10 Western Australian woodland plant species was evaluated. Across all investigated species, inoculation had small effects on plant growth. Within each species, inoculation did not result in significant biomass gain, and effects on nitrogen nutrition and photosynthesis were variable and minimal. Abstract 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 (δ15N and δ13C) 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.

QUESTIONS: Translocation of topsoil and its seed bank for ecological restoration is increasingly popular. How representative is the soil seed bank of the extant vegetation at the source site? What influence does the transfer process have on germinant density, species and plant functional type composition? Does smoke and heat treatment of transferred topsoil enhance germination and potential for restoration success? LOCATION: Banksia woodland of the Swan Coastal Plain, Western Australia. METHODS: To assess the efficacy of topsoil transfer for return of native plant species, we measured topsoil seed bank characterisitcs in situ proir to vegetation clearing, and immediately after transfer of the topsoil to an adjacent, degraded mediterranean‐type woodland in southwest Australia. Glasshouse germination of topsoil samples from 24 pre‐ and 24 post‐transfer plots was used to quantify the effects of transfer and soil depth on germinant density, species richness, plant functional types and seed bank similarity to in situ vegetation. Application of germination cues (heat + smoke) was used to explore the impact of topsoil transfer on seed germination and emergence. RESULTS: Topsoil transfer significantly reduced germinant densities (pre‐transfer 1692–4239 germinants·m⁻², post‐transfer 795–1016 germinants·m⁻²; t = 6.7, P < 0.001) and shifted community structure (MRPP: A = 0.13, P < 0.001), including a reduction of woody species density by 81%. For the majority of functional types, heat and smoke failed to stimulate additional germination post‐transfer, suggesting soil transfer simulated the effect of fire‐related germination cues. CONCLUSION: Although topsoil transfer translocated many viable native seeds, potential restoration success was hindered by reduced germinant densities. This was mostly attributable to a dilution effect associated with mixing of transferred topsoil, so that many seeds were buried too deep to emerge. However, total reductions were greater than expected based on dilution alone, suggesting some seed mortality during the transfer process. Transfer shifted composition towards dominance by annual species, suggesting the need for topsoil transfer to be supplemented by other restoration techniques.

The pollination of 20 common terrestrial orchids was studied in a 60-ha urban banksia and eucalypt dominated woodland in Western Australia. Five years of data (24,000 flowers, 6800 plants) measured fruit set relative to floral areas, capsule volumes, climate, phenology, pollination mechanisms, disturbance tolerance and demography. Pollination varied from 0–95% of flowers, floral displays from 90–3300 mm2 and capsules from 15–1300 mm3 per spike. Pollination traits strongly influenced outcomes, with self-pollination highest (59—95%), followed by sexually deceptive autumn or winter-flowering (18–39%), visual deception (0–48%) and sexually deceptive spring-flowering (13–16%). Pollination was limited by drought in autumn or spring and cool winter temperatures. Some orchids were resilient to drought and one formed seed after the leaves withered. Plant density had the greatest impact on fruit set for orchids forming large groups, especially for sexually deceptive pollination. Consequently, small group average (SGA) pollination was up to 4× greater than overall averages and peak seed production occurred in the best locations for genetic exchange and dispersal. SGA rates and seedpod volumes were strongly linked to clonality, but not to demographic trends. Resource competition limited flowering at higher plant densities and competition within spikes resulted in smaller, later-forming seedpods. Pollination data from co-occurring common orchids identified five evolutionary trade-offs linked to pollination, provided baseline data for rare species and revealed impacts of changing climate.

In Mediterranean ecosystems prescribed burning is commonly employed to reduce the risk or intensity of wildfires. As a consequence, a major challenge for conservation land managers is the development of fire regimes that reduce damaging wildfires and are optimal for biodiversity. The aim of this paper was to develop guidelines for ecological fire regimes using the Banksia woodland on the Gnangara Groundwater System in Western Australia as a case study. Development of the guidelines involved the determination of maximum and minimum fire intervals of key fire response species, analyses of fire history records and estimation of ideal age class distributions at the landscape level. Recommendations included a) adoption of a minimum fire interval of 8–16 years, b) implementation of a burning regime to redress the current skewed distribution (60%: 1–7 years since last fire), c) retention of long-unburnt habitats that are significant for species such as the critically endangered Calyptorhynchus latirostris (Carnaby’s black-cockatoo), and Tarsipes rostratus (honey possum), and d) protection for wetlands that can serve as fire ‘refugia’ for associated species, such as Isoodon obesulus fusciventer (southern brown bandicoot or quenda). The guidelines developed provide a model for the development of ecological burning regimes in other similar ecosystems. The implementation of ecological guidelines normally involves incorporation into fire management planning by fire agencies and often entails complex solutions to conflicting aims. The guidelines are thus valuable for ecologists and land managers, especially in light of an expected significant increase in global fire activity as a consequence of predicted climate change.

Background Prescribed burning is used to reduce fire hazard in highly flammable vegetation types, including Banksia L.f. woodland that occurs on the Swan Coastal Plain (SCP), Western Australia, Australia. The 2016 census recorded well over 1.9 million people living on the SCP, which also encompasses Perth, the fourth largest city in Australia. Banksia woodland is prone to frequent ignitions that can cause extensive bushfires that consume canopy-stored banksia seeds, a critical food resource for an endangered bird, the Carnaby’s cockatoo ( Calyptorynchus latirostris, Carnaby 1948). The time needed for banksias to reach maturity and maximum seed production is several years longer than the typical interval between prescribed burns. We compared prescribed burns to bushfires and unburned sites at three locations in banksia woodland to determine whether low-intensity prescribed burns affect the number of adult banksias and their seed production. Study sites were matched to the same vegetation complex, fire regime, and time-since-fire to isolate fire intensity as a variable. Results Headfire rates of spread and differenced normalized burn ratios indicated that prescribed burning was generally of a much lower intensity than bushfire. The percentage survival of adult banksias and their production of cones and follicles (seeds) did not decrease during the first three years following a prescribed burn. However, survival and seed production were significantly diminished followed high-intensity bushfire. Thus, carrying capacity for Carnaby’s cockatoo was unchanged by prescribed burning but decreased markedly following bushfire in banksia woodland. Conclusions These results suggest that prescribed burning is markedly different from bushfire when considering appropriate fire intervals to conserve canopy habitats in fire-resilient vegetation communities. Therefore, low-intensity prescribed burning represents a viable management tool to reduce the frequency and extent of bushfire impacts on banksia woodland and Carnaby’s cockatoo.