Context Cultural fire has recently been returned to semi-arid grasslands on Dja Dja Wurrung Country in southern Australia. However, its ecological effects on plant species in these modified grasslands have not been previously documented. Aims To assess the response of Maireana species to the return of a cultural fire regime in a long-unburnt grassland. Methods We measured the density, height, and proportion of fruiting of two Maireana species across three fire treatments (burnt twice, burnt four times, and long-unburnt) at a semi-arid grassland in central Victoria, Australia. Data were collected from 10 4-m2 quadrats per treatment. Key results Cultural burning significantly increased the density of two Maireana species compared with the unburnt treatment. For Maireana enchylaenoides, both plant height and fruiting proportion were significantly higher in the burnt treatments than in the unburnt treatment. While Maireana humillima showed no substantial height differences among treatments, the proportion of fruiting individuals was significantly greater in the burnt treatments. Conclusions Cultural fire promotes favourable conditions for Maireana species, enhancing both density and reproductive output. Implications This study has highlighted the potential of cultural fire to support the recovery of native grasslands where First Nations management has been disrupted, increasing native plant species abundance. Contrary to previous assumptions, both Maireana species resprout after fire and thrive under frequent low-intensity burning.
Context Conservation of threatened flora is best underpinned by structured monitoring and experimental programs that provide an understanding of population trends, demographic responses to threats, and the effectiveness of threat mitigation. Obtaining this information can be challenging for species with extremely small population sizes or extents where operational adaptive management may be deemed too high-risk and experimental manipulations logistically challenging to robustly implement. Aims To understand population trends in the critically endangered Ptilotus pyramidatus in the context of weed threats and weed management, in what at the time was the only known population. Methods Fixed quadrat ramet counts were conducted over 6 years across three treatments: (1) a largely weed-free Reference; (2) a Weedy treatment with high cover of Sparaxis bulbifera; and (3) a Weeded treatment with manual S. bulbifera removal after the first year of monitoring. In a glasshouse, the impact of exposure of P. pyramidatus to the herbicide metsulfuron methyl was tested. Key results Abundance of P. pyramidatus ramets remained similar over time and was significantly greater in Weeded plots, noting that random plot effects explained most variation. Glasshouse P. pyramidatus was susceptible to metsulfuron methyl. Conclusions Over the monitoring period, no consistent directional change in P. pyramidatus ramet abundance was detected. Application of metsulfuron methyl for S. bulbifera control will need robust testing on potentially sacrificial P. pyramidatus individuals in a field context before it could be considered for use in P. pyramidatus habitat. Implications Understanding impacts of threats and effectiveness of threat mitigation can assist in prioritising management resources.
Context Instream plants play important roles in river ecosystems, yet their ecology remains poorly understood. Improved understanding of the factors influencing their distribution is needed in flow-regulated rivers to guide effective environmental flow management and restoration. Aims We investigated instream plant occurrence, richness, and extent across seven lowland flow-regulated river systems in Victoria, Australia, testing whether patterns could be predicted by flow (discharge, frequency of high flow events and the number of zero-flow days) and non-flow variables (turbidity, riparian canopy shading, and livestock grazing). Methods Instream plants were identified to species and mapped as polygons at 44 sites. At each site we calculated extent, assessed as the length of each species polygon divided by the site length, and species richness. Flow variables were calculated from flow gauges. Non-flow variables were obtained from site-level observations and aerial mapping. Key results Many sites had either one (25% of sites) or zero (18%) species of instream plants present. Assemblages across all systems were dominated by just two species: (1) Cycnogeton procerum; and (2) Vallisneria australis. Richness was generally higher where turbidity was low. Extent had a unimodal relationship with the frequency of high flow events and declined with the number of zero-flow days. Conclusions Sites with perennial flow, intermediate frequencies of high flow events, and low turbidity appear most likely to support instream plants. Implications Environmental flows are likely to best support instream plant communities where they can improve water quality, and/or in drier systems where they can be used to reduce the duration of no flow periods.
Context Infrastructure, mining and agricultural projects may impact threatened plant species, through direct removal along with habitat degradation and fragmentation. Commonly, project proponents and regulators must assess potential impacts and agree on appropriate mitigations and recovery actions. Semi-arid zones of south-east Queensland’s ‘Brigalow Belt’, Australia, have been impacted by industry, extensive clearing, and land modification despite little known about much of their flora. Significant areas are now under Native Title, providing new opportunities for engagement, capacity building, and land management options. Here, we use the little known and vulnerable shrub Westringia parvifolia, which occurs in Queensland’s ‘Brigalow Belt’, to demonstrate some key elements of impact assessment and recovery. Aims This study aimed to increase knowledge of the distribution of W. parvifolia populations to enable better conservation and management, and identify its potential to be impacted by proposed developments. Methods Field-based demographic studies and species distribution modelling assessed the spatial distribution of the impacts and conservation opportunities. We trialled propagation methods and produced species distribution models overlaid onto Native Title and development footprints to advise recovery and/or offsetting needs. Genetics studies identified the diversity and distinctiveness of potentially impacted populations. Key results Population sizes are highly variable, ranging from <100 to thousands of plants. Suitable habitat and area of occupancy were restricted in distribution, but remaining populations were scattered widely within this. Diversity was relatively high, and showed little differentiation among populations despite their present isolation, with little genetic differentiation among populations. We propagated by cuttings and established local propagation capacity by First Nations caring for country rangers Conclusions We found considerable high-quality suitable habitat within Bigambul Native Title land. Implications We identified impacted plants and suitable offsetting and recovery planting locations, and advised of genetic considerations to reduce potential for outbreeding depression and maximise genetic diversity.
Context Translocations of threatened plants aim to establish self-sustaining populations. For long-lived species and for species where regeneration occurs post-fire, assessments of self-sustainability must consider the seedbank and fire response, in addition to standard plant growth and reproductive output metrics, before translocation success can be evaluated. Additionally, comparison to wild reference populations should be used to benchmark performance of translocated plants, yet long-term studies of this type are rare.Aims To determine whether 15- and 16-year-old translocations of the threatened long-lived perennial Acacia cochlocarpa subsp. cochlocarpa that recruits after fire, have been successful.Methods We measured plant height, width and reproductive output of two translocated and one wild reference population of A. cochlocarpa subsp. cochlocarpa and assessed the presence, distribution and longevity of its soil seedbank. Fire was applied to a 16-year-old translocation to evaluate the impact on adult plant survival and recruitment.Key results Translocated populations had similar growth characteristics, produced intact seed at similar rates, and had a soil seed-bank comparable to that of the wild population. The translocated population regenerated following fire by recruiting large numbers of seedlings and there was some resprouting of adults.Conclusions Our findings indicated translocation success for A. cochlocarpa subsp. cochlocarpa. Our study highlighted the value of long-term data for assessing translocation success of threatened plant species in fire-prone environments.Implications Ongoing management of translocated threatened species in fire-prone regions should consider how fire can be applied to support population stability or expansion.
Context Images on currency have varied over the time fiat money has been used. Initially money had intrinsic value based on metal content, but its value became increasingly reliant on that assigned to it by the issuing authority. Both coins and notes typically have images. Some, such as heads of state, indicate guarantees of value but others represent socially significant features, including plants.Aims We aimed to examine the biogeographic patterns of plant categories that have been depicted on coins and banknotes to identify any trends in the symbolism of the designs on banknotes and coins for different parts of the world.Methods We collected currency items and used web searches to compile information about plant images used on money from currently recognised modern and ancient countries.Key results Governments give serious consideration to currency design because the images can be considered to provide a sense of community or national 'belonging'. Plants most commonly depicted on currency are food plants, many of which are also emblems or motifs of the state. The images need to be recognisable to the users of the currency as there is normally no explanation of the importance of the organism or even its name. Currencies from different regions of the world have different patterns of plant types.Conclusions It is unclear how observant people are of the images on currency. However, almost all countries or states have plant emblems that are very recognizable.Implications With the current trend towards digital money there is a threat that cherished state emblems may disappear from public consciousness.
Context Biological invasions diminish the structures of ecosystems and biological functions. In this regard, Cyperus aromaticus (Cyperaceae) (Navua sedge), a native of Africa, recently established along the coastal regions of far north Queensland (FN-QLD), Australia, forming extensive monospecific stands and affecting both agricultural and natural landscapes.Aims This study examined the changes in soil physico-chemistry and differences in plant tissue chemical profile of C. aromaticus and its co-occurring pasture species in invaded landscapes of varying land-use types.Methods Across many C. aromaticus invaded sites in FN-QLD (N = 14), we collected above-ground vegetation and soils in invaded and nearby non-invaded patches. We also set up a microcosm trial in which C. aromaticus and a desirable pasture grass species (Urochloa humidicola) were grown individually in potted soils, and changes in soil chemistry were monitored for 3 years.Key results Neutral effects of C. aromaticus invasion were detected in soils of active agricultural lands, but significant differences occurred in other land-use types (roadside, riparian corridor, abandoned agricultural land) and in the microcosm trials. The plant tissues of C. aromaticus are higher in many micronutrients (e.g. sulfur, copper, aluminium, iron, zinc) than those of co-occurring pasture species. Significantly higher lignin concentration, but lower forage quality of fibre, cellulose, and hemicellulose were also detected in C. aromaticus.Conclusions C. aromaticus invasion is associated with changes in soil processes and systems, but its effect can be obscured by land-use (e.g. anthropogenic) practice. In invaded landscapes, the changes in soil chemistry and observed differences in tissue composition between C. aromaticus and co-occurring pasture grasses might lead to positive plant-soil feedback, thus promoting the establishment and further spread of the weed. Additionally, the lower forage quality of C. aromaticus reinforces the need to manage the weed, especially in grazing landscapes.Implications These findings highlight the capacity of C. aromaticus weed to modify soil processes and ecosystem functions, reinforcing its threat to both ecological integrity and agricultural productivity in north-eastern Queensland.
A lack of standardised sampling protocols prevents functional traits from expressing their full potential to advance plant ecology, biogeography, and evolutionary biology. Handbooks providing protocols for standardised measurements of plant functional traits allow researchers to tackle large-scale ecological questions but have traditionally focused on vegetative traits such as leaves, stems and roots. This handbook provides standardised protocols for 58 reproductive traits of flowers (10 traits), fruits (6 traits), seeds (36 traits) and seedlings (6 traits). It is the first effort to standardise sampling for relevant reproductive traits to better understand processes, such as pollination, frugivory, seed dispersal, seed longevity, germination, and seedling establishment. The protocols were designed to embrace the global diversity of ecological contexts experienced by flowers, fruits, seeds, and seedlings and incorporate methods for temperate to tropical, dry to moist and fire-prone to fire-sensitive ecosystems. We offer general guidelines for sampling, storing, and processing reproductive traits. Before laying out the protocol, we briefly describe each trait functionality, trade-offs, and sources of variability to give a broad context. Standardised protocols to estimate reproductive plant traits will unlock the full potential of plants to mitigate land-use and climate-change impacts, and support restoration of degraded ecosystems.
Context Post-fire seedling demography and the effect of trunk scorching on large trees were investigated in rainforest in the Border Ranges region, New South Wales, after a major fire in 2019-2020.Aims To examine changes in post-fire seedling demography and diversity in rainforest in the early post-fire period, investigate compositional turnover of the seedling population, replacement of stem mortality by seedlings in resprouter species, and measure bark damage and repair in canopy trees.Methods Seedling density, diversity, and turnover were monitored in permanent plots, 1 and 3 years after fire. Seedling density was examined in relation to functional groups and rainforest types. Fire effects on canopy trees, including bark scorching, fire scars, and bark regrowth, were examined 3 and 5 years post-fire.Key results Seedling populations in rainforest were characterised by very low density, increasing density and diversity with time since fire and rapid compositional turnover; number of species with seedlings rose from 150 in Year 1 to 215 in Year 3; 79% of 258 resprouter species exhibited turnover above replacement and 21% were below; 62 resprouter species recorded no seedling recruitment, but most populations were buffered by high rates of resprouting. Trunk fire scars showed partial bark regeneration after 5 years.Conclusion The woody flora of rainforest displayed a moderate degree of resilience to a single low-intensity fire through strategies of resprouting, seedling recruitment, and bark repair.Implications If fires are infrequent, low intensity and followed by adequate rainfall, such as in the 2019 fire disturbance, rainforest can potentially recover from fire damage.
Context Ammopiptanthus mongolicus is an endangered evergreen shrub distributed primarily in the Alxa-Ordos region in north-western China, requiring urgent conservation efforts.Aims This study aimed to assess the genetic diversity and population structure of A. mongolicus across its natural range, to develop effective conservation strategies.Methods Single nucleotide polymorphism (SNP) loci obtained by double-digest restriction site associated DNA (ddRAD) sequencing were used to estimate the genetic diversity and structure of the species for designing effective conservation strategies.Key results A moderate level of genetic diversity (mean He = 0.17) was detected for the species, and 15 sampled populations were clustered into three genetic groups by genetic structure analysis.Conclusions The moderate gene flow may have helped A. mongolicus maintain a moderate level of genetic diversity, whereas small population sizes, restricted pollen and seed dispersal, and geographic isolation may have contributed primarily to the observed genetic differentiation for the genetic groups.Implications On the basis of the results, we have provided useful conservation strategies for this species.
Context As fire severity and extent increase, recovery of fire-sensitive species in plant communities may rely increasingly on seed rain and dispersal from adjacent unburnt areas. The role dispersal plays in driving recovery trajectories is surprisingly understudied. How traits drive dispersal can contextualise compositional differences and indicate recovery trajectories.Aims This paper investigated seed rain in recently burned mesic forest, and the role of traits in driving post-fire recovery across a gradient of fire severities.Methods We placed seed traps at two locations in the Blue Mountains, located in south-eastern Australia. All seeds that fell into seed traps were collected and identified each month for a year, 3 years following fire of differing severities. We then compared species diversity of seed collections with extant vegetation and measured the minimum dispersal distance each species was likely to have travelled. Variable selection was used to identify which traits affected dispersal distances.Key results Rainforest species were generally lacking from recently burned sites in both extant vegetation and the seed rain. Composition of the seed rain indicated that dispersal occurred primarily from local sources, with minimum distance travelled largely determined by life form, dispersal type and dispersal height. Differences in species richness and composition between unburnt sites and sites burnt at differing severities was observed in both extant vegetation and in the seed rain.Conclusions Increasing fire severity suggests lengthening recovery times, with recolonisation from unburnt areas being minimal and slow.Implications The commonality of local dispersal highlights the importance of surviving individuals for maintaining diversity and replenishing populations.
Over the past few centuries, over 900 plant species globally have gone extinct in the wild; however, there are also hundreds of species that have been rediscovered after previously being considered extinct. We report the rediscovery of Ptilotus senarius A.R.Bean (Amaranthaceae) in northern Queensland, Australia, through the citizen science platform iNaturalist, 58 years after the last collection, and present photographs of the species. We discuss the strengths of iNaturalist that assist rediscoveries of extinct and long-lost plant species, including the facilitation of records from private land, rapid data availability, and its large network of botanical experts. We provide recommendations for accelerating species rediscovery through the platform.
Context The Brazil nut tree (Bertholletia excelsa Bonpl., Lecythidaceae) produces one of the main non-timber forest products from the Brazilian Amazon. Mature Bertholletia excelsa trees are tall, wide, and have well-developed crowns, characteristics that favor the occurrence of vascular epiphytes.Aims In this study, we evaluated the richness and vertical distribution of vascular epiphytes in the Ipa & uacute;-Anilzinho Extractive Reserve, a protected area located in the Deforestation Arc of the Brazilian Amazon, aiming to assess the importance of B. excelsa for the epiphyte community.Methods We compared species richness, abundance, alpha diversity, floristic composition and vertical distribution of vascular epiphytes in two groups of host trees, namely, B. excelsa and neighboring overstory trees (other 19 species).Key results The richness of vascular epiphytes was similar between the two groups, but epiphyte abundance and diversity were higher on B. excelsa. The floristic composition also differed; ferns were most frequent on B. excelsa and orchids on the neighboring host trees. Epiphytes were more abundant in the inner overstory of both groups of host trees. However, only B. excelsa had epiphytes on the lower trunk. Regarding specificity, we found the same number of generalist and specialist species (11 species), a result that contradicted the expectation of finding more generalist species.Conclusions We conclude that B. excelsa is a good host tree for vascular epiphytes in the Amazon Forest, exhibiting greater diversity, hosting a high richness of species (18 species), high abundance of vascular epiphytes and locally monospecific species.Implications In view of the importance of B. excelsa and neighboring overstory trees for vascular epiphytes and the need for their conservation, we recommend further investigations of isolated populations of Brazil nut trees in managed areas.
Context To effectively translocate threatened orchids it is recommended that they are propagated symbiotically with their mycorrhizal fungi. The terrestrial orchid genus Corunastylis has over 25 threatened species, yet there is no information on the identity of the mycorrhizal fungi or symbiotic propagation.Aims To identify the mycorrhizal fungi associated with two endangered species, C. insignis and C. branwhiteorum, and determine effective symbiotic germination methods.Methods Fungi were cultured from roots of Corunastylis at two sites for each species, one of which was shared between species. To estimate taxonomic diversity, 25 fungal isolates were sequenced and identified by comparison with known operational taxonomic units (OTUs) through a combination of phylogenetic analysis and sequence divergence of the internal transcribed spacer (ITS) sequence locus. Further, we tested whether germination varies among growth media, seed accession, and isolates of the same OTU of mycorrhizal fungus.Key results Both species formed mycorrhizal associations with Rhizoctonia (Ceratobasidiaceae), C. insignis with OTU T and U and C. branwhiteorum only with OTU U. We found that modified oats medium without sucrose (MOM) led to significantly greater germination than did MOB medium where oatmeal was substitued with wheat bran or MOB plus coconut water medium (P < 0.05). There was significant variation in germination among mycorrhizal isolates within the same putative species (OTU).Conclusions Both species can be readily symbiotically germinated to adult plants by using Rhizoctonia OTU T and U, significantly improving conservation options for these species.Implications As isolates differ in their germination ability, we recommend ensuring that a range of isolates are included in symbiotic propagation for translocation to maintain diversity and potential to adapt to edaphic conditions.
Context. Determining the age of culturally, historically or ecologically significant trees in Australia is hampered by a lack of annual tree growth rings in many species. In central Queensland, land clearing has decimated primary brigalow (Acacia harpophylla F.Muell. ex Benth.) forests and very little information about the age or growth rates of old brigalow trees in remnant forests is available to guide conservation and management. Aims. Determine the first quantitative estimates of age and growth rates of mature brigalow trees. Methods. We used radiocarbon dating of sequentially collected wood from the bark to the pith of four sampled trees. Key results. It is likely that three of the four standing-dead trees (-25 cm diameter at breast height) sampled began growing in the last quarter of the 19th century (1841-1881 Common Era (CE),-150 years old), with one tree likely to have begun growth in the mid-20th century (1938 CE). All died in the early 21st century. The trees showed consistent growth rates of 1.3 mm year(-1), and two trees also displayed short periods of rapid growth (4-8 mm year(-1)), which are likely to be associated with canopy openings. Conclusion. Brigalow trees take up to 150 years to mature. In-series radiocarbon dates are critical in dating trees such as these, because their true age is likely to be before the bomb-spike but within the radiocarbon plateau from-1650 to 1950 CE. Implications. The lag time between tree establishment and maturity (-100 years) favours restoration that is based around assisting naturally regenerating brigalow through management rather than undertaking tree planting activities because of the inherent risk of failure owing to climate.
Context Germination, a critical stage in plant's life-cycle, is under the strong influence of climate (e.g. temperature, precipitation and seasonality) and seed reserves.Aims Considering the importance of this stage, we explored the relationships among seed mass, germination attributes (germination percentage, lag, and rate) and the climate experienced by a range of Australian annual species.Methods Seeds of 58 Australian annuals from a wide range of habitats were sourced from seed companies and seed mass was determined. Climate data for the species' natural distribution were obtained from Atlas of Living Australia. Germination tests were performed under different treatments in growth cabinets to break potential seed dormancy. The following relationships were explored using statistical analysis: (1) seed mass and climate of natural distribution, (2) seed mass and germination attributes and (3) germination attributes and climate of natural distribution.Key results We found greater seed mass in species from hotter and drier environments. We found no relationship between seed mass and germination percentage, but a positive relationship between seed mass and germination speed. Lower germination percentage was observed in species from hotter and drier environments as well as environments with more variable rainfall. Moreover, germination speed was greater in species from drier environments and environments with lower rainfall variability.Conclusions In our studied species, germination speed was significantly related to both climate of natural distribution and seed mass, whereas germination percentage was related only to climate. In dry environments, there is a trade-off between germination percentage and speed (lower germination percentage with faster germination speed) because few seeds germinate in response to sporadic rainfall events, but do so quickly to ensure seedling establishment during the short period of moisture availability. This contrasts with germination in climates with high rainfall seasonality, where lower germination percentage with slower germination speed avoids germination of all seeds prior to potentially unfavourable conditions, therefore avoiding seedling mortality.Implications Knowledge of how germination and seed mass change with climatic conditions, regardless of the species, can help predict the distribution of plant species under future climate change scenarios.
Context The tree fern Dicksonia sellowiana (Dicksoniaceae) is endemic to the Neotropics, threatened with extinction in Brazil. Historical commercial exploitation, the slow growth of the species, and ongoing loss of forest habitat impose significant pressures, whereas its reproductive capacity remains poorly understood.Aims To (1) understand the relationship between spore production and maturation and environmental factors, and (2) evaluate in vitro germination and plantlet development from spores matured in different months to assess temporal reproductive variation.Methods Over a 12-month period, 25 individuals were monitored monthly to record fertile leaves with immature sporangia (FL-IS) and fertile leaves with mature, closed sporangia (FL-MS). Temperature, precipitation, photoperiod, and soil moisture were correlated with phenophases. In vitro spore germination and gametophytic development were assessed.Key results Temperature showed a positive relation with the percentage of plants bearing FL-IS and a negative relation with FL-MS. FL-MS were negatively associated with photoperiod and positively with precipitation. Highest spore germination rates were observed in winter and early spring, with successful gametophyte development in vitro and sporophyte formation on substrate under greenhouse conditions.Conclusions D. sellowiana has been observed to allocate the warmer months of the year to spore production, with spore maturation occurring during periods of lower temperatures, particularly in winter, within the Brazilian subtropical climate.Implications The reproductive pattern described here highlights the importance of low temperatures for spore maturation, which should be carefully considered when assessing population renewal under climate change scenarios and in efforts aimed at the conservation of the species.
Context. Most gymnosperms are dioecious (no self-pollination). It was not known if Wollemia nobilis (monoecious) could produce viable seeds via self-pollination. Aims. In the nearly 30 years since its scientific discovery Wollemia nobilis (Araucariaceae) has been the focus of considerable scientific attention. While this includes several aspects of sexual reproduction, many features of ovulate cone morphology and seed biology have not been investigated. Methods. Various aspects of ovulate cone morphology were quantified, as were seed morphology and germination (e.g. seed moisture content and rate of imbibition), in material from an isolated tree of Wollemia nobilis. Seeds of Agathis microstachya and Araucaria cunninghamii were also examined to allow comparisons across the Araucariaceae. Key results. In Wollemia nobilis most seeds were empty (no formation of a megagametophyte and embryo (M + E)). Empty and filled seeds were morphologically very similar. On average, the fresh weights (FW) of empty and filled seeds were 6.2 and 33.1 mg, respectively. On average, the FW of the M + E was 25.8 mg (78% of seed mass, the other 22% was testa). The average moisture content (FW basis) of the testa and the M + E were 9.6% and 7.0%, respectively. The M + E imbibed water relatively slowly and imbibed, on average, to similar to 110% increase in FW after 48 h. In Agathis robusta and Wollemia nobilis the seeds separated freely from the cone scales. In Araucaria cunninghamii the M + E was an integral part of the bract/scale complex. Conclusions. The seeds examined in this study came from an isolated, almost certainly self-fertilised tree. The seeds were of approximately the same dimensions as those from the wild populations of Wollemia nobilis, while average filled seed FW was greater and less variable. The filled seeds had a high viability and an excised M + E could germinate rapidly. This study shows that Wollemia nobilis can produce large, viable seeds via self-fertilisation. Successful self-fertilisation may be a factor in the low genetic diversity detected in the wild population. Implications. Based on evidence from a single tree it would appear that Wollemia nobilis can produce large, viable, vigorous seeds via self-fertilisation. This has implications for the population structure of this species.
