ABSTRACTThe time interval between fires is a critical component of the fire regime that affects plant species persistence in fire‐prone ecosystems. Fire intervals that are too short or too long may not support regeneration from seed banks or resprouting. Fire intervals that support adequate regeneration may also vary with other factors such as climate, herbivory, and population structure. Using field data on flowering and canopy seed banks, we modelled post‐fire reproduction for woody fire‐killed (obligate seeding) and resprouting species under varying rainfall and herbivory along a 35‐year fire age chronosequence in Banksia woodlands in southwestern Australia. We found that fire‐killed species attained reproductive maturity rapidly after fire with predicted juvenile periods (time to 50% flowering) of 1.5–2.3 years for shrubs and 4 years for trees. Resprouting species had similar juvenile periods to fire‐killed species (1–3.5 years for resprouting shrubs, 4.4 years for resprouting trees). Reproduction varied with rainfall and herbivory with juvenile periods at least doubling under low rainfall or high herbivory for some species. Serotinous species produced cones (woody fruits containing seeds) shortly after flowering commenced, with some evidence of seed bank decline in the oldest sites. While reproduction was clearly correlated with time since fire, plant size was a much stronger predictor. Some species form multi‐cohort populations which can introduce large variation into post‐fire reproductive trajectories, and this should be considered when making decisions about fire intervals that may impact species persistence. This study provides critical information to assess fire interval‐related threats for Banksia woodlands and suggests that woody species of these woodlands are generally tolerant of a wide range of fire intervals. Only the slowest‐maturing, fire‐killed species (Banksia prionotes, Proteaceae) may require fire intervals > 10 years to reduce immaturity risk under the least favourable growing conditions, and this species often occurs in discrete patches in the landscape such that fire management can be tailored accordingly.

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.

Plants possess intriguing mechanisms to cope with environmental stresses and disturbances, and respond to stimuli due to their sessile nature. Banksia attenuata, a tree or shrub species native to southwestern Australia, integrates numerous traits to persist and regenerate through reoccurring bushfires. A key trait of Banksia is that of serotiny: Plants can retain seeds for many years within the canopy protected inside durable seed pods (follicles), with seed release commonly triggered by the heat of bushfire, and subsequent rainfall. Here, we show that the tissue of the two follicle valves is arranged in layers, which not only counteract as a hygroscopic bi-layer, but prevent delamination as their opposed physical properties converge toward the interface. Moreover, a shape-memory effect of the active layer stores energy after the first opening step for the second opening step, ensuring delayed seed release only after the fire is extinguished. Detailed experiments reveal how structure, composition and physical properties of the tissue layers facilitate first longevity and later the complex autonomous seed release. Based on these findings, two numerical models illustrate the mechanics of the layers more deeply. These results highlight the importance of graded material properties for the function of natural actuators.

In dipteran glow-worms (genus Arachnocampa) bioluminescence is produced by cells of the Malpighian tubules. Light is used to lure prey into sticky webs secreted by the larvae. Larvae can regulate the intensity of the emitted light so neural control of the glow is likely, either acting directly on the light-emitting cells or through regulation of oxygen access to the light organ. Here we describe the innervation, musculature, and tracheal supply in relation to the three-dimensional structure of the light organ, cryptonephridial complex and hindgut using serial section light microscopy and micro computed tomography (μCT). We also use video macrophotography to observe light emission in live larvae. Tracing of trachea in serial sections showed no structures that could actively restrict air supply to the mass of trachea termed the reflector. A bilateral pair of nerves lie alongside the Malpighian tubules and give rise to branches that innervate the hindgut and musculature. A network of muscles surround the light organ. A cryptonephridial complex anterior to the light organ is surrounded by a connective tissue sheath. The fact that the cryptonephridial complex is a plesiomorphic trait in Keroplatidae, the majority of which are not bioluminescent, suggests that the light organ is evolutionarily derived from the complex. We also propose that the cryptonephridial complex has a water conservation function in Arachnocampa because the larvae are potentially water-restricted. The three-dimensional reconstruction of the light organ provides morphological context for ongoing investigations of the biochemistry of light production and the physiological regulation of light output.

Two blind-passage show-caves in the Waitomo district of New Zealand, Ruakuri Cave and Aranui Cave, have been monitored for the impact of visitors on their environment, especially focusing on partial pressures of carbon dioxide because high levels cause speleothem degradation. In Ruakuri Cave, annual cycles of daily mean pCO2 correspond with annual cycles of visitor numbers, both peaking in summer. The origin of the high pCO2 had been assumed to be anthropogenic due to respiration from visitors. Prolonged intervals with no visitation during the Covid-19 pandemic saw the daily mean pCO2 continuing to show the annual cycle, suggesting a natural source where CO2 entered under certain conditions. Finer scale monitoring in the Drum Passage of Ruakuri Cave and the Fairy Walk of Aranui Cave showed that when the outside air was warmer than the cave air, the pCO2 increased and it rapidly decreased to near outside concentrations when outside air temperatures fell below the cave temperatures. Levels could be high at certain locations within Ruakuri Cave, for example, spot measurements within a breakdown at the Drum Passage section showed pCO2 values as high as 8000 ppm. We hypothesised that when outside air was warmer than cave air the temperature difference caused air to flow through breakdown zones and possibly epikarst, transporting soil gases, including CO2, and heat. When the outside air was cooler, air flowed inward through a low-level entrance bringing pCO2to near-external levels. Although there are no obvious higher entrances in the two caves, they mimic the chimney-effect ventilation that predominates in nearby Waitomo Glowworm Cave where air flows between a lower and upper entrance at a speed and direction determined by the temperature difference. Neither Ruakuri nor Aranui Caves have obvious upper entrances to allow a through-flow of air, but both caves end in breakdown zones through which the air is assumed to percolate. These observations demonstrate that there is a source of carbon dioxide in the air flowing into these two blind-ended passages when downflow conditions are likely to prevail but not during upflow conditions.

Glowworms are the bioluminescent larvae of a group of dipteran insects related to fungus gnats. They require sheltered, consistently moist conditions and are found in aggregations on the walls and ceilings of caves and near streams in wet forests where they attract flying insects as prey. The Waitomo Glowworm Cave in New Zealand receives many thousands of visitors each year to see the colony of the glowworm, Arachnocampa luminosa. The cave climate is managed to ensure the glowworms are not harmed by influxes of dry air, as happened in the 1970s. To monitor the population and warn of catastrophic population declines, time-lapse photographic monitoring of the glowworm population began in 2011 using a permanent, fixed camera. Photographs are taken 30 min apart. The population exhibits synchronised diurnal cycles of bioluminescence intensity. The time of the acrophase (the peak) of the diurnal cycle varied seasonally between 5 pm in early southern spring and 8 pm in summer. Cross-correlation analyses with cave and water temperatures incorporating time lags suggest that this annual cycle could be related to changes in the composition or density of prey insects. Annual cycles also occur in the number of glowing larvae and their overall intensity. In most years, the numbers are lowest in winter and increase in spring to produce the brightest display through summer. The summer peak is not seen every year and autocorrelation of the 13-year time series of count shows signs of a 3- to 4-year cycle beyond the annual periodicity. The availability of prey in the cave chamber could influence the annual cycles in glowworm density, underscoring the need for a deeper knowledge of the bionomics of prey species, mainly Chironomidae (non-biting midges). The photographic monitoring has proven to be a useful component of the management of the glowworm population.

Societal Impact Statement Conservation seed banks maintain collections of many seed‐bearing plant species, providing germplasm and data to support management of wild populations. However, a proportion of plant species produce seeds that are difficult to collect, dry, store and utilise; these are known as ‘exceptional’ species. Here we tested a framework for identifying exceptional species, to document examples and provide case studies within the Australian flora. We present a workflow that may be used to identify additional exceptional species, and direct efforts to establish appropriate collection types (seeds and/or living collections, tissue culture or cryopreservation) for their ex situ conservation. Summary Seed banking is well established to contribute to the conservation of many seed‐bearing plant species ex situ for future use in restoration, translocation, agriculture and horticulture. In Australia, over 67% of currently listed threatened plants are represented in conservation seed banks. However, there are challenges to conserving the full extent of plant diversity in seed banks, with growing recognition that we need to think beyond conventional seed banking methods to conserve ‘exceptional’ plant species that are difficult to collect, store and germinate. We examine how the framework for identification of such species can be applied to the Australian flora, using examples from the recently published guidelines for ‘ Plant Germplasm Conservation in Australia ’ and case studies and data arising from the Australian Academy of Science Fenner Conference on the Environment ‘Exceptional Times, Exceptional Plants’ . We present a workflow to assist conservation decision‐makers and practitioners in identifying exceptional species and overcoming barriers to storage of germplasm, enabling appropriate ex situ collection types to be established via seeds, living collections, tissue culture, cryopreservation or a combination of these. Australia's seed conservation sector continues to expand, with increasing expertise, facilities and networks established to conserve a diversity of plant species; however, resolving the challenges relating to each exceptionality factor requires significantly more time, labour and collaboration than current capacity allows. Understanding the barriers to conservation and production of healthy plants, via germination or other methods of propagation, is a critical component of conserving species long‐term and ultimately returning plants to the landscape.

QuestionsAnnual species have evolved sets of germination cues that are thought to be predictive of the post-germination environment. In naturally patchy environments, germination microsites often vary considerably in the amount of light they receive and in the diurnal temperature fluctuations they experience. However, whether species' differential germination responses to light and temperature are associated with their spatial patterns of occurrence remains largely untested.LocationMediterranean-climate woodlands in Southwest Western Australia.MethodsWe surveyed species' occurrences in annual plant communities in 150 quadrats across gradients of canopy cover and litter cover. Nineteen species recorded in this survey were then included in a germination experiment that manipulated (1) Light vs Dark (12 h light or continuous dark) approximating seeds near the soil surface vs those covered by litter and (2) Cold vs Warm temperature regimes (7/18 degrees C and 7/24 degrees C) approximating diurnal fluctuations experienced in shaded vs sun-exposed microsites, respectively.ResultsIn the germination experiment, six species had highest germination probabilities in the Light treatment (regardless of temperature), five in Cold + Light, one in Warm + Light, two were indifferent to the treatments, and four did not germinate at all. Binomial linear mixed-effects models showed that species' maximum responses to light and temperature did not explain their spatial distributions along canopy cover and litter cover gradients, contrary to theoretical expectations of germination being a strong driver of species' occurrences.ConclusionsDespite variation in species' responses to experimental treatments, no association was found with their field microsite associations. Germination strategies in our system were wider than expected for Mediterranean systems. Our results support that germination cues are not strong drivers of microhabitat associations in this system. Species may "select" microsites via germination cues that predict future habitat quality. We investigated germination responses to light and temperature as drivers of species' associations with tree and litter cover in a guild of winter annuals in Western Australia. Species responded differently to experimental light and temperature treatments, but these responses did not explain their microsite associations in the field.image

Context Seeding is common practice for ecological restoration, but establishment rates can be low. For seeds to successfully establish they must transition through early life stages of germination, emergence, and (initial) survival. Examining these demographic processes for seeds sown under a range of abiotic conditions can identify failure points and inform techniques to improve seed use. Aims Here we quantified seed and seedling life-stage transitions in five reconstructed soils across four varying levels of simulated rainfall using five species (Acacia hilliana, Acacia inaequilatera, Indigofera monophylla, Triodia pungens, and Triodia wiseana) commonly seeded for mined land restoration of the Pilbara bioregion in north-west Western Australia. Methods Germination, emergence, and survival were measured over a 6 week period and transition probabilities between each life-stage transition were modelled for each treatment combination. Key results For four species, both rainfall amount and/or soil substrate significantly influenced germination probability. Rainfall was the more significant determinant, with germination greatest under the higher rainfall regimes of 120–280 mm, irrespective of soil type. Following germination, emergence of both Acacia spp. was positively influenced by soils containing topsoil, suggesting the microenvironment of soils containing topsoil was most favourable during this emergence phase. The effect of substrate was less clearcut for I. monophylla and Triodia spp, where emergence was most limited in substrates comprised solely of overburden waste material and the lowest rainfall regime exacerbated emergence failure, relative to germination success. When compared to the well-watered, 100% topsoil substrate, seedling survival of all species was most constrained in the 100% overburden waste, demonstrating these reconstructed mining substrates compromise seedling recruitment. Conclusions This study underscores that successful seedling recruitment in this ecosystem is dependent on frequent, and repeated, rainfall events above a certain threshold (≥120 mm) and highlights the beneficial effects of sowing seeds in a substrate containing topsoil. Implications Future seeding technologies should focus on improving the moisture relations of the microsite to offset the recruitment challenges experienced by seeds sown in hostile growing environments such as the overburden wastes tested here.

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.

Acacia species (‘acacias’ or ‘wattles’) are primarily found in Australia, where they occur across the continent and occupy a wide range of habitats. While acacias are dominant in arid environments, centres of species richness occur in south-western Australia, the McPherson–Macleay Overlap and the Central Coast in eastern Australia. Nearly half of the many centres of endemism occur in the south-western Australian centre of species richness. Acacia makes up 5% of the listed threatened plant species in Australia and most threatened taxa occur in centres of species richness, with nearly half occurring in south-western Australia. Acacias dominate many ecosystems, and several acacia-dominated ecological communities are listed as threatened. Many threats affect multiple species and ecological communities, including changed fire regimes, land clearing, habitat fragmentation and degradation, and grazing by herbivores. Active management of these threats is required with in situ and ex situ recovery actions involving direct threat management and promoting natural regeneration, as well as translocation of threatened species and ecological restoration of species and habitats, supported by ex situ seed banking. Acacia species generally have impermeable seeds that require heat treatment or scarification to germinate, and typically regenerate following fire. They also show a range of levels of genetic diversity and differentiation among populations and are self-incompatible or have mixed mating systems. Many species can also reproduce asexually through suckering or resprouting, which may be advantageous in arid environments, and apomixis (the development of an embryo without fertilization) is also known to occur in some Acacia species. Knowledge of seed biology and genetics provides important information for implementation of effective management and conservation of acacias.

Post‐mining scenarios present challenges for restoration in a wide range of environments, especially in the context of climate change. The source of seed for restoration has been an issue of intense focus, as seed provenance can impact plant fitness and restoration outcomes. However, post‐mining landscapes require substrate reconstruction prior to vegetation re‐establishment. Critically, the relative importance of provenance and substrate in ecosystem recovery has been rarely quantified in a statistically rigorous framework. We established a large provenance trial with Banksia attenuata and Eucalyptus todtiana at two Western Australian mine sites in post‐mining reconstructed and adjoining un‐mined substrates. We show that site and substrate were 4 and 26 times more important than provenance in explaining survival for B. attenuata and E. todtiana , respectively. At one site, there was 100% mortality in the post‐mining substrate but high survival and no clear provenance effect in the un‐mined substrate. At the second site, there was again no clear provenance effect, but E. todtiana survival was higher in the post‐mining than un‐mined substrate. Our results show that post‐mining substrate changes can overwhelm provenance issues. Consequently, where substrates are highly impacted, alternative restoration targets and/or greater investment in substrate research are needed to improve restoration outcomes. Due to the thousands of mines across the world, this is an internationally relevant finding with important implications for investment into global ecosystem recovery.

Larvae of the genus Megalopyge (Lepidoptera: Zygaenoidea: Megalopygidae), known as asp or puss caterpillars, produce defensive venoms that cause severe pain. Here, we present the anatomy, chemistry, and mode of action of the venom systems of caterpillars of two megalopygid species, the Southern flannel moth Megalopyge opercularis and the black-waved flannel moth Megalopyge crispata . We show that megalopygid venom is produced in secretory cells that lie beneath the cuticle and are connected to the venom spines by canals. Megalopygid venoms consist of large aerolysin-like pore-forming toxins, which we have named megalysins, and a small number of peptides. The venom system differs markedly from those of previously studied venomous zygaenoids of the family Limacodidae, suggestive of an independent origin. Megalopygid venom potently activates mammalian sensory neurons via membrane permeabilization and induces sustained spontaneous pain behavior and paw swelling in mice. These bioactivities are ablated by treatment with heat, organic solvents, or proteases, indicating that they are mediated by larger proteins such as the megalysins. We show that the megalysins were recruited as venom toxins in the Megalopygidae following horizontal transfer of genes from bacteria to the ancestors of ditrysian Lepidoptera. Megalopygids have recruited aerolysin-like proteins as venom toxins convergently with centipedes, cnidarians, and fish. This study highlights the role of horizontal gene transfer in venom evolution.

Understanding the relative longevity of different seed lots, perhaps of different species or genotypes, but also following production under different environments or using different cultivation methods, or following different post-harvest treatments, is relevant to anyone concerned with the retention of seed lot viability and vigour during storage. However, different scientists over the years have used different conditions to assess seed lot longevity, as well as different variables as the measure of 'longevity.' Here, we give some of the backgrounds to how two standard protocols, with an open and closed system respectively, were derived, and explain why we consider p(50), defined as the time during storage when seed lot viability, as measured through a germination test, has declined to 50%, is a suitable longevity trait parameter.

Environmentally cued germination may play an important role in promoting coexistence in Mediterranean annual plant systems if it causes niche differentiation across heterogeneous microsite conditions. In this study, we tested how microsite conditions experienced by seeds in the field and light conditions in the laboratory influenced germination in 12 common annual plant species occurring in the understorey of the York gum-jam woodlands in southwest Western Australia. Specifically, we hypothesized that if germination promotes spatial niche differentiation, then we should observe species-specific germination responses to light. In addition, we hypothesized that species' laboratory germination response may depend on the microsite conditions experienced by seeds while buried. We tested the laboratory germination response of seeds under diurnally fluctuating light and complete darkness, which were collected from microsites spanning local-scale environmental gradients known to influence community structure in this system. We found that seeds of 6 out of the 12 focal species exhibited significant positive germination responses to light, but that the magnitude of these responses varied greatly with the relative light requirement for germination ranging from 0.51 to 0.86 for these species. In addition, germination increased significantly across a gradient of canopy cover for two species, but we found little evidence to suggest that species' relative light requirement for germination varied depending on seed bank microsite conditions. Our results suggest that variability in light availability may promote coexistence in this system and that the microsite conditions seeds experience in the intra-growing season period can further nuance species germination behaviour.

Flash flaming has shown promise as a seed enhancement technology that improves the handling properties of bulky or irregularly shaped seed material, which in turn benefits logistical and ecological aspects of large-scale direct seeding. To date, only a small number of grass species, that possess similar morphological characteristics, have been tested. This paper describes the application of flash flaming to diaspores (i.e. the dispersal unit comprising the seed and any surrounding or attached tissues) of 19 diverse dryland species from the Amaranthaceae, Asteraceae, Chenopodiaceae and Poaceae critical to ecological restoration in the mining intensive Pilbara region of Western Australia. Flash flaming parameters for each species were tested to identify and maximise volume and mass reduction, reduce particle cohesiveness and maximise flow through a mechanical seeding device, whilst maximising germination. Flaming of all species resulted in reductions in batch volume and mass, and improvements to flow characteristics. For 17 species, flaming either benefited or did not impact on germinability. For two species in the Amaranthaceae, flaming with the settings tested here resulted in a reduction in germinability; however, flaming enabled the diaspores to pass through a mechanical seeding device enabling mechanical distribution which is critical if the species are to be used in large scale restoration.

Waitomo Glowworm Cave is a highly visited cave where the highlight is viewing the bioluminescence display of a large colony of glowworms. Anthropogenic carbon dioxide build-up in the cave is prevented by management of chimney-effect ventilation aided by a network of microclimate sensors. A cave door prevents ventilationunder drying conditions and promotes it when necessary to clear CO 2 and when inflowing air has high relative humidity. A COVID-19-related nationwide “lockdown” in New Zealand from March 2020 resulted in neither staff nor visitors being present in the cave for 60 days, and provided an opportunity to assess the natural microclimate of the cave, especially the natural variation in partial pressure of carbon dioxide ( p CO 2 ). In addition, comparison to the previous year showed that the presence of people in the cave increased the cave temperatures but the effect was short-lived due to cave ventilation. During the period of lockdown, the daily increase of carbon dioxide partial pressure ( p CO 2 ) due to visitors was absent. When the cave door remained sealed, p CO 2 varied and tended to lie at levels above that of the external atmosphere (410 ppm). Notably, rain events raised p CO 2 by up to 200 ppm (v/v), which appeared to be sourced from both stream water and drip water. These natural CO 2 sources rarely reached the levels associated with cave visitation. The results support current management practices that use door control to enhance cave ventilation when people are in the cave or when natural conditions (high stream levels and high drip-water levels) promote CO 2 outgassing into the cave. Suppressing ventilation outside of those times reduces the risk of introducing dry air that could desiccate the glowworms.

Waitomo Glowworm Cave is a highly visited cave where the highlight is viewing the bioluminescence display of a large colony of glowworms. The visitation levels result in the build-up of anthropogenic CO2, to the extent that it could cause corrosion of speleothems. The cave experiences chimney-effect ventilation with air flowing either upward or downward through the main cave chambers depending on air density differences between the cave and the outside environment. Lack of airflow leads to CO2 build-up; however, unrestricted airflow can draw in cool, dry air which is harmful to the glowworms. Consequently, airflow is managed by controlling the opening and closing of a door that seals the upper-most entrance, preventing ventilation under drying conditions and promoting ventilation when it is necessary to clear CO2 and when inflowing air has high relative humidity. A network of microclimate sensors in the cave allows prediction and management of the ventilation pattern. Management leads to asymmetric airflow through the year, which has a flow-on effect on cave temperature. Microclimate monitoring supports the current management practices that use door control to enhance cave ventilation when people are in the cave. Suppressing airflow, especially in winter, reduces the introduction of dry air.

We posit that a better meshing of traditional engineering disciplines and ecological restoration science is central to achieving environmental repair at the scale and pace required to combat globally ever-growing, human caused, land degradation and biodiversity loss. Ecological restoration is an increasingly vibrant endeavour supported by diverse fields of research. But there is a rapidly emerging role for traditional engineering disciplines to design and deploy solutions to the challenges regularly encountered in returning biodiverse plant communities across degraded landscapes of varying characteristics. In order for large-scale restoration to be feasible, increased efficiencies throughout all stages of the restoration process are required. We argue for increased investment into the development of engineered tools and techniques guided by ecology, able to enhance our ability to cheaply, quickly, and effectively restore ecosystems. By conceptualising the overlap between ecosystem service value, traditional economic outcomes and successional land use we seek to explore how investment in new restoration technologies can lead to a net benefit for society and businesses alike. Using terrestrial mining as an example, we highlight engineering issues faced in large-scale restoration and outline how these may be overcome to maximise both economic and ecological outcomes with a particular focus on restorative earthworks and technologies for the direct return of plants.

Rehabilitation of mine sites in semi-arid landscapes is hindered by poor quality mine waste substrates, a byproduct of mining used as alternative growth media. Inorganic soil amendments, such as gypsum and urea, are sometimes used to improve the chemical and physical quality of mine waste substrates and increase native plant establishment. However, limited research is available regarding the medium and long-term effectiveness of these amendments in semi-arid post-mining landscapes. In this study, inorganic amendments were incorporated into two alternative mine substrates (mine waste and a topsoil:waste blend) in large 0.8 m(3) above-ground mesocosms in the semi-arid Pilbara region of Western Australia. These mesocosms were bare soil or seeded with one of two different mixes of plant species to determine how amendments and species diversity altered plant growth and survival, and substrate quality compared to stockpiled topsoil over a 21-month period. The unamended waste had a lower electrical conductivity (EC), soil carbon (C), soil nitrogen (N) and C/N ratio compared to the topsoil. The amendments had a strong initial effect on soil quality, increasing N, soil EC and N-mineralisation in the amended waste compared to all other soil treatments. However, N levels returned to non-amended levels after the first year and the amendments had limited influence on plant growth. Plant survival was higher in the amended substrates with the more diverse plant community, which increased substrate microbial activity to levels significantly greater than the unamended waste. The use of inorganic amendments may be ineffective at increasing long-term substrate quality and growth of native plants but may support seedling survival that in turn will improve soil chemical and biological properties of waste substrates.