Australian Tree Research Articles

Encouraging residents’ stewardship of street trees in Australia’s capital city, Canberra

ABSTRACT In Canberra, Australia’s capital city, an urban forest strategy was introduced to foster the role of urban forests as nature-based solutions to climate change. One of its goals is to engage residents in the stewardship of neighbourhood street trees, which requires an understanding of residents’ perceptions of and attitudes towards street trees and their willingness to play a stewardship role. This research explores these issues for Canberra residents who engaged with the pilot Street Forestry Program and considers implications for initiatives encouraging stewardship of urban street trees. It draws from a survey of 137 residents and 190 vote cards returned as part of the Program, participant observation at the Program’s engagement events, and ten interviews of residents by the senior author. Survey and interview results suggest a widespread view among respondents that street trees are important for a variety of reasons – around 70% of survey respondents reported that they engaged in stewardship behaviour towards street trees. The main factors identified as influencing stewardship behaviour were individual motivations, perceptions, attitudes and values; personal circumstances; and government policies and programs. These were incorporated into a model of stewardship behaviour developed for cities in the United States, adapted to incorporate values and place attachment. The findings of this study inform the Australian Capital Territory Government’s goal of fostering urban tree stewardship in the Canberra community and the achievement of similar goals and programs elsewhere. Governments should engage in a suite of best practices to encourage stewardship by residents. These include a sustained commitment to community engagement, the strengthening of stewardship education, and collaboration with neighbourhood groups. Given that the Street Forestry Program and this study were limited and targeted in scope, there are opportunities for further research in this topic area, with larger and more representative sample populations.

Chromosome-level genome assembly of the Australian rainforest tree Rhodamnia argentea (malletwood).

Myrtaceae are a large family of woody plants, including hundreds that are currently under threat from the global spread of a fungal pathogen, Austropuccinia psidii (G.Winter) Beenken, which causes myrtle rust. A reference genome for the Australian native rainforest tree Rhodamnia argentea Benth. (malletwood) was assembled from Oxford Nanopore Technologies (ONT) long-reads, 10x Genomics Chromium linked-reads, and Hi-C data (N50 = 32.3 Mbp and BUSCO completeness 98.0%) with 99.0% of the 347 Mbp assembly anchored to 11 chromosomes (2n = 22). The R. argentea genome will inform conservation efforts for Myrtaceae species threatened by myrtle rust, against which it shows variable resistance. We observed contamination in the sequencing data and further investigation revealed an arthropod source. This study emphasises the importance of checking sequencing data for contamination, especially when working with non-model organisms. It also enhances our understanding of a tree that faces conservation challenges, contributing to broader biodiversity initiatives.

Caerin 1.1 and 1.9 peptides halt B16 melanoma metastatic tumours via expanding cDC1 and reprogramming tumour macrophages

BackgroundCancer immunotherapy, particularly immune checkpoint inhibitors (ICBs) such as anti-PD-1 antibodies, has revolutionised cancer treatment, although response rates vary among patients. Previous studies have demonstrated that caerin 1.1 and 1.9, host-defence peptides from the Australian tree frog, enhance the effectiveness of anti-PD-1 and therapeutic vaccines in a murine TC-1 model by activating tumour-associated macrophages intratumorally.MethodsWe employed a murine B16 melanoma model to investigate the therapeutic potential of caerin 1.1 and 1.9 in combination with anti-CD47 and a therapeutic vaccine (triple therapy, TT). Tumour growth of caerin-injected primary tumours and distant metastatic tumours was assessed, and survival analysis conducted. Single-cell RNA sequencing (scRNAseq) of CD45+ cells isolated from distant tumours was performed to elucidate changes in the tumour microenvironment induced by TT.ResultsThe TT treatment significantly reduced tumour volumes on the treated side compared to untreated and control groups, with notable effects observed by Day 21. Survival analysis indicated extended survival in mice receiving TT, both on the treated and distant sides. scRNAseq revealed a notable expansion of conventional type 1 dendritic cells (cDC1s) and CD4+CD8+ T cells in the TT group. Tumour-associated macrophages in the TT group shifted toward a more immune-responsive M1 phenotype, with enhanced communication observed between cDC1s and CD8+ and CD4+CD25+ T cells. Additionally, TT downregulated M2-like macrophage marker genes, particularly in MHCIIhi and tissue-resident macrophages, suppressing Cd68 and Arg1 expression across all macrophage types. Differential gene expression analysis highlighted pathway alterations, including upregulation of oxidative phosphorylation and MYC target V1 in Arg1hi macrophages, and activation of pro-inflammatory pathways in MHCIIhi and tissue-resident macrophages.ConclusionOur findings suggest that caerin 1.1 and 1.9, combined with immunotherapy, effectively modulate the tumour microenvironment in primary and secondary tumours, leading to reduced tumour growth and enhanced systemic immunity. Further investigation into these mechanisms could pave the way for improved combination therapies in advanced melanoma treatment.

Seed size and <i>Azospirillum brasilense</i> Ab-V5 and Ab-V6 inoculation influences germination and early seedling vigor of <i>Acacia mearnsii</i>

Acacia mearnsii is an Australian native tree species commercially grown in Africa and South America that produces tannins and woodchips. Its seed size varies, which may impact the germination and initial growth of seedlings. In its turn, Azospirillum brasilense inoculation is known to improve the growth of several crops. However, there are few studies the effects of A. brasilense inoculation on the germination and initial growth of forestry species. The present study evaluated the influence of seed size and A. brasilense Ab-V5 and Ab-V6 inoculation on germination and initial growth of A. mearnsii. Small seeds reduced the mean germination time (MGT) by 5.2% and the time to 50% germination (T50) by 23.8% in comparison to large seeds. On the other hand, seedlings that originated from large seeds had a seedling vigor index (SVI) 18.6% higher than those that originated from small seeds. Azospirillum brasilense inoculation increased the germination percentage by 20.9%, germination speed by 91.8%, root length (RL) by 35.8%, and root fresh weight by 20.5%. Additionally, it decreased MGT by 8.2% and T50 by 37.6%. The combination of large seeds and A. brasilense inoculation increased RL by approximately 50% and SVI by 62.1%. Thus, the use of A. brasilense inoculation favors germination and seedling vigor in A. mearnsii, showing to be a promising strategy for obtaining more uniform seedlings in forest nurseries.

Soil density specification ranges to optimise plant water use and root growth for phytocapping and urban greening projects

Soil density or compaction is one of the key variables that need to be specified for designed soil profiles as part of urban greening. Examples include land rehabilitation (mining), waste containment (phytocapping), stormwater infrastructure (bioretention basins) and green infrastructure (green roofs and street trees). This study investigates the impact of a range of specified soil densities on plant water use and root development. Native Australian plant species selected for the study include: the C4 and C3 grasses, Themeda triandra and Microlaena stipoides respectively; the Eucalyptus trees, E. camaldulensis and E. cladocalyx; and the nitrogen-fixing pioneer trees, Acacia mearnsii and Allocasuarina verticillata. The plants were established at four soil density (compaction) levels: 72, 77, 82, and 87 % MDD (maximum dry density) in tall cylinders with weekly plant water use measurement over 8 months. Root growth was analysed using WinRhizo image analysis. The experimental results were used to create generalisable models for root length density (RLD), root diameter and plant water use. The models for RLD and plant water use were parabolic in nature, revealing clear optimum ranges that could be used to guide soil density specification. Root diameter provided additional insight into the allocation of resources to root thickening above a threshold soil density of 87 % MDD, indicating plant allocation of resources towards penetrating highly compacted soils. There were correlations between plant water use and RLD that were moderate and significant, particularly for grasses. Notably, T. triandra had the greatest mean RLD, thickest roots and plant water use at 16.8cm/cm3, 0.18 mm and 10mm/week, respectively. Findings demonstrate that RLD and plant water use can be optimised together within practically achievable soil density specification ranges that are sensitive to the pitfalls of both excessively low and excessively high soil densities. Recommended soil density specification ranges include: 75–82 % MDD with plant performance within 5 % of optimum (considered excellent), 74–84 % MDD with plant performance within 10 % of optimum (considered good) and 73–85 % MDD with plant performance within 15 % of optimum (considered fair). Within these ranges, plant water use and root growth performance is well balanced with practical achievement of the soil density ranges. Due to the use of %MDD, the modelled results can be usefully generalised for any soil type. Implementation of these specifications for urban greening and phytocap projects will optimise plant growth, transpiration and hydrological function while maintaining root networks essential for establishing and maintaining resilient living infrastructure.

Bio-functional properties of Jilungin (Terminalia canescens).

Jilungin (Terminalia canescens) is a native Australian plant and the Indigenous "Nyul Nyul" people of the Kimberleyregion of Western Australia use its leaves to make herbal tea. Due to the rise in the popularity of drinking Jilungin tea among the consumers in Australia and internationally, it is important to study the nutritional and health-beneficial properties as well as safety of Jilungin leaves. This study aims to determine the nutritional composition, anti-nutritional factors, antimicrobial and antidiabetic properties of Jilungin leaves. Also, the phytochemical profiling using UHPLC-MS/MS (Ultra-performance liquid chromatographymass spectrometry) and antioxidant activity of Jilungin methanolic extracts and herbal infusion were investigated. The safety of the leaves and infusion was also investigated by using in vitro mammalian cell lines (Caco2, HT29, and HepG2) through cell viability assays. The leaves are rich in dietary fiber (43.9%) and linoleic acid (30.4% of total fatty acids). Phytochemical profiling revealed ellagic acid, geraniin, pedunculagin, and punicalagin as the major bioactive compounds. The results also demonstrated that Jilungin has strong antioxidant and antidiabetic activities. A significant (p<0.01) strong positive correlation was observed between the high antioxidant activity of Jilungin infusion with the major bioactive compounds. Jilungin extracts (50mg/mL) exhibited strong antimicrobial activity against Staphylococcus aureus and Bacillus cereus. Its infusion and methanolic extract were safe on the studied cell lines (Caco-2, HT29, and HepG2) at higher concentrations of 66.6 and 98mg/mL, respectively. Therefore, Jilungin teas or infusions could be a safe and effective way to promote health and well-being. PRACTICAL APPLICATION: Jilungin tea is very popular among consumers in Australia and is gaining popularity worldwide. The current study will increase knowledge on the nutritional aspects and safety of the Jilungin use.

A telomere-to-telomere Eucalyptus regnans genome: unveiling haplotype variance in structure and genes within one of the world’s tallest trees

BackgroundEucalyptus regnans (Mountain Ash) is an Australian native giant tree species which form forests that are among the highest known carbon-dense biomasses in the world. To enhance genomic studies in this ecologically important species, we assembled a high-quality, mostly telomere-to-telomere complete, chromosome-level, haplotype-resolved reference genome. We sampled a single tree, the Centurion, which is currently a contender for the world’s tallest flowering plant.ResultsUsing long-read sequencing data (PacBio HiFi, Oxford Nanopore ultra-long reads) and chromosome conformation capture data (Hi-C), we assembled the most contiguous and complete Eucalyptus reference genome to date. For each haplotype, we observed contig N50s exceeding 36 Mbp, scaffold N50s exceeding 43 Mbp, and genome BUSCO completeness exceeding 99%. The assembled genome revealed extensive structural variations between the two haplotypes, consisting mostly of insertions, deletions, duplications and translocations. Analysis of gene content revealed haplotype-specific genes, which were enriched in functional categories related to transcription, energy production and conservation. Additionally, many genes reside within structurally rearranged regions, particularly duplications, suggesting that haplotype-specific variation may contribute to environmental adaptation in the species.ConclusionsOur study provides a foundation for future research into E. regnans environmental adaptation, and the high-quality genome will be a powerful resource for conservation of carbon-dense giant tree forests.

Comparative analysis of genetic diversity in wild and restored subtropical rainforest trees: Argyrodendron trifoliolatum, Ficus watkinsiana, and Diploglottis australis

Since European settlement of Australia, substantial areas of subtropical rainforest have been cleared. More recently, effort is being made to restore areas of this ecological community. The financial investment and increasing reliance on ecological restoration in biodiversity conservation justifies a need for better understanding of how to improve success at the genetic level. This research measures genetic diversity (allelic richness [Rs], expected heterozygosity [He], and inbreeding using Wright's coefficient [FIS]) for expected neutral DNA markers in three Australian subtropical rainforest trees—White booyong (Argyrodendron trifoliolatum), Watkin's fig (Ficus watkinsiana), and Native tamarind (Diploglottis australis). Wild and restored populations of these species were compared in two neighboring regions in Northeast New South Wales (the Tweed Caldera and the Big Scrub). There were no statistically significant differences in Rs or He between wild and restored populations for any of the target species. Inbreeding was significantly higher in one of the restored versus wild population comparisons: F. watkinsiana in the Tweed (restored F = 0.20; wild F = −0.02; p = 0.01). The comparable levels of genetic diversity observed in restored and wild populations targeted in this study are likely due to informed practitioner perspectives and practices, staged plantings over several years, and high genetic diversity and low genetic differentiation within source populations.

Extraction and Surface Activity of Australian Native Plant Extracts: Alphitonia excelsa

Saponin surfactants extracted from plants have significant potential applications in many industries. The interfacial properties of extracts of Alphitonia excelsa, a native Australian plant rich in saponins, have been characterised to assess their suitability as dual-purpose foaming and antibacterial additives. Two sources of the plant (Adelaide Botanic Gardens and homelands of Chuulangun Aboriginal Corporation) were investigated to look for alteration of properties as a result of differences in cultivation and geographic location. Two methods of saponin extraction (water and water/ethanol mixtures) were investigated to determine differences in extraction efficiency and performance. Distinct differences were observed between the traditional analytical analysis (for saponin content) of the extracts based on source and extraction method; however, these differences were not as stark when considering the effect of the extracts on air–water interfacial tension and dilatational rheology, with extraction method proving to be the single biggest factor in extract efficacy. The data obtained point toward the presence of an altered array of surface-active species (different relative amounts of particular saponins in the water/ethanol extracted material) as a function of the extraction method. All extracts presented some antibacterial effect, albeit modest. This work highlights that the extraction method needs to be carefully considered and tailored for a given application.

Antibacterial and Antibiofilm Properties of Native Australian Plant Endophytes against Wound-Infecting Bacteria.

The wound management field faces significant challenges due to antimicrobial resistance (AMR) and the complexity of chronic wound care. Effective wound treatment requires antimicrobial dressings to prevent bacterial infections. However, the rise of AMR necessitates new antimicrobial agents for wound dressings, particularly for addressing bacterial pathogens like methicillin-resistant Staphylococcus aureus (MRSA). Endophytic fungi, known for producing diverse bioactive compounds, represent a promising source of such new agents. This study tested thirty-two endophytic fungi from thirteen distinct Australian native plants for their antibacterial activity against S. aureus. Ethyl acetate (EtOAc) extracts from fungal culture filtrates exhibited inhibitory effects against both methicillin-sensitive S. aureus ATCC 25923 (MIC = 78.1 µg/mL) and MRSA M180920 (MIC = 78.1 µg/mL). DNA sequence analysis was employed for fungal identification. The most active sample, EL 19 (Chaetomium globosum), was selected for further analysis, revealing that its EtOAc extracts reduced S. aureus ATCC 25923 biofilm formation by 55% and cell viability by 57% to 68% at 12 × MIC. Furthermore, cytotoxicity studies using the brine shrimp lethality test demonstrated low cytotoxicity up to 6 × MIC (25% mortality rate) with an LC50 value of 639.1 µg/mL. Finally, the most active sample was incorporated into polycaprolactone (PCL) fiber mats via electrospinning, with resultant inhibition of S. aureus species. This research underscores the potential of endophytic fungi from Australian plants as sources of substances effective against common wound pathogens. Further exploration of the responsible compounds and their mechanisms could facilitate the development of wound dressings effective against MRSA and innovative biofilm-resistant electrospun fibers, contributing to the global efforts to combat AMR.

Thinking the Other: From Terra Australis Incognita to Terra Nullius

At the end of the 18th century, when Sir Joseph Banks, president of the Royal Society, recommended Botany Bay in Australia as an “advantageous” site to establish a new British penal colony, he did so with the knowledge that the east coast of the country was inhabited by Indigenous Australians, having traveled to the South Continent with Lieutenant James Cook. As a naturalist and imperial botanist on board the Endeavour, Banks’s primary duty had been to identify and classify Australian flora and fauna. Yet, the multiple observations that he made based on his interactions with Aboriginal people also contributed to establish his influence in scientific and political circles at the turn of the 19th century. Banks’s ethnographic accounts recorded in his Endeavour Journal shed light on his mind-set and convictions during his time in Australia as well as his impressions that later played their part in making him the greatest proponent of settlement in New South Wales and motivating the decision to colonize the country. In a time when exploration records significantly shaped the perceptions of the public about human nature and the beliefs and theories of the scientific community on questions of race and otherness, the writings of Joseph Banks offer a window into science and history in the making. As the scientific exploration of distant lands progressively gave way to political and economic interests, the transition from geographical othering to racial othering in the representation of Indigenous Australians turned Terra Australis Incognita into terra nullius.

Predicting key water stress indicators of Eucalyptus viminalis and Callitris rhomboidea using high-resolution visible to short-wave infrared spectroscopy.

Drought is one of the main factors contributing to tree mortality worldwide and drought events are set to become more frequent and intense in the face of a changing climate. Quantifying water stress of forests is crucial in predicting and understanding their vulnerability to drought-induced mortality. Here, we explore the use of high-resolution spectroscopy in predicting water stress indicators of two native Australian tree species, Callitris rhomboidea and Eucalyptus viminalis. Specific spectral features and indices derived from leaf-level spectroscopy were assessed as potential proxies to predict leaf water potential (Ψleaf), equivalent water thickness (EWT) and fuel moisture content (FMC) in a dedicated laboratory experiment. New spectral indices were identified that enabled very high confidence linear prediction of Ψleaf for both species (R2 > 0.85) with predictive capacity increasing when accounting for a breakpoint in the relationships using segmented regression (E. viminalis, R2 > 0.89; C. rhomboidea, R2 > 0.87). EWT and FMC were also linearly predicted to a high accuracy (E. viminalis, R2 > 0.90; C. rhomboidea, R2 > 0.80). This study highlights the potential of spectroscopy as a tool for predicting measures of plant water noninvasively, enabling broader applications for monitoring and managing plant water stress.

Spontaneous reoccurrence of Batrachochytrium dendrobatidis infections in Australian green tree frogs (Litoria caerulea) following apparently successful heat therapy: Case report.

Heat therapy has been reported as a safe, effective, and readily available treatment method for heat-tolerant frogs infected with Batrachochytrium dendrobatidis (Bd). We treated wild-caught Australian green tree frogs (Litoria caerulea) infected with Bd using two periods of elevated ambient room temperature (28.2-30.3°C for 7 weeks followed by 28.9-34.1°C for 4 weeks). Frogs exhibited persistent and even increasing infection loads in the first treatment period despite prolonged exposure to elevated temperatures, likely due to the presence of cooler microenvironments within their enclosure (25.5-27.0°C). All frogs eventually returned negative qPCR tests for Bd at the end of the second treatment period, but detectable infections reoccurred one month after frogs were returned to standard housing temperatures (21.2-28.7°C). Our findings suggest that elevated ambient temperature alone might not eliminate Bd in vivo but can reduce infections loads such that they are undetectable by qPCR analysis of skin swabs. Additional factors, such as cooler microenvironments within enclosures or relative humidity, may influence the success of heat therapy. We recommend further research into the combined effects of temperature and humidity during heat therapy and emphasize the importance of accurate temperature measurements as well as post-treatment monitoring at Bd-permissive temperatures to confirm successful clearance of infections.

Response to the detection of Rugonectria castaneicola and Rugonectria wingfieldii sp. nov. on Quercus in Australia.

Here we report on the detection and surveillance response to two Rugonectria species found in Sydney, Australia, in 2015. Both Rugonectria castaneicola and R. wingfieldii sp. nov. were found in association with cankers on Quercus robur (English oak). The fungi were initially found to be localised on amenity trees in northern Sydney, New South Wales, and as they were new detections for Australia, eradication was considered. Ongoing surveillance across the Sydney basin, regional New South Wales, and the Australian Capital Territory, however, indicated that they were already well established. Species identities were confirmed through morphological examination and molecular barcoding, with the subsequent analysis undertaken to classify R. wingfieldii sp. nov. This study provides the first records of Rugonectria found in association with canker on Oak trees in Australia. Citation: Trollip C, Carnegie AJ, Anderson C, Priest MJ, Gorrie B, Daly A (2024). Response to the detection of Rugonectria castaneicola and Rugonectria wingfieldii sp. nov. on Quercus in Australia. Fungal Systematics and Evolution 13: 123-130. doi: 10.3114/fuse.2024.13.06.

Trees to remember: culturally modified boab trees in the face of climate change

ABSTRACT Culturally modified trees (CMTs) are a unique form of archaeology and cultural heritage. There are several factors affecting the survival of culturally modified trees in Australia, and these will all likely be exacerbated by climate change. Boab trees (Adansonia gregorii), which are endemic to northwest Australia, have been subject to modification by Indigenous people both prior to and following the settlement of the Kimberley region by European and Anglo-Australians. Many of the potential impacts of climate change on boab tree survival are yet to be determined, but a range of new threats are emerging as potential endangerment. Through the insights of Indigenous knowledge, this paper discusses one particularly significant boab tree in Nyikina Country and how its demise may be linked to erroneous human actions in the recent past. This provides a unique perspective on how the complexities of climate change may be conceptualised through living knowledge and experience.

Seasonal Patterns and Allergenicity of Casuarina Pollen in Sydney, Australia: Insights from 10 Years of Monitoring and Skin Testing

Casuarina (Australian pine, She-oak) is native to Australia and South East Asia and is known for its abundant wind-borne pollen. Despite not being considered a major aeroallergen, some patients report respiratory symptoms upon exposure, with positive skin prick tests (SPT) to Casuarina pollen extract. This study investigates Casuarina pollen dispersal patterns in Sydney, Australia, over a 10-year period, from 2008 to 2018, revealing a bimodal distribution of pollen from September to October (southern hemisphere spring) and February to March (mid-late summer). Analysis of historical SPT data shows 20% of individuals with respiratory allergies reacting positively to Casuarina pollen extract, with almost 90% of these also reacting to grass pollen, suggesting potential cross-reactivity. Notably, there are no exclusive reactions to Casuarina pollen. Understanding the prolonged pollen season underscores the importance of year-round monitoring for accurate characterization. Currently lacking are commercially available skin test extracts or specific IgE assays for Casuarina sensitization, necessitating challenge studies to confirm clinical symptoms directly attributable to Casuarina pollen. By elucidating the seasonal dynamics and meteorological drivers of Casuarina pollen dispersion, alongside the potential allergenicity suggested by skin prick tests, this study paves the way for improved management of Casuarina-related allergies and highlights the critical need for further research on native Australian plant allergens.

Exploring the Anti-Inflammatory Potential of Australian Native Plants Based on their Ethnopharmacological Knowledge.

Inflammation represents the inherent protective reaction of the human body to various harmful agents and noxious stimuli. Standard anti-inflammatory therapy including nonsteroidal anti-inflammatory drugs are associated with several side effects. In the past decades, people rely on medicinal plants for the treatment of inflammation. The traditional utilization of medicinal plants is regarded as a safe, cost-effective, and broadly accepted approach. In this study, anti-inflammatory activity of plants traditionally utilized by the D'harawal people in Australia has been assessed in vitro. Eighty Australian native plants were screened based on the Dharawal Pharmacopeia for their inhibitory effect on the nitric oxide (NO) production in lipopolysaccharides (LPS) and interferon (IFN)-γ stimulated RAW 264.7 murine macrophages for their anti-inflammatory activity. From the eighty ethanolic extracts screened, seventeen displayed potent NO inhibition with an IC50 recorded below 15 μg/mL. The aim of this review was to utilise the ethnopharmacological knowledge and to correlate the anti-inflammatory activity of the seventeen plants with either their known or unknown phytochemicals reported in the literature. In doing so, we have created a snapshot of Australian native plant candidates that warrant further chemical investigation associated with their anti-inflammatory activity.

Phytoremediating the air down under: Evaluating airborne particulate matter accumulation by 12 plant species in Australia

AbstractAtmospheric particulate matter (PM) is the most inhaled hazardous air pollutant that can cause adverse health impacts. Plants can remove such contaminants and act as biological filters through phytoremediation. In this study, we screened 12 Australian native species (two deciduous trees, three evergreen shrubs, and seven evergreen trees) growing in three regions to determine their potential in accumulating leaf surface (SPM) and in‐wax PM (WPM). Among the screened species, Lagunaria patersonia (139.22 μg cm−2) was the most effective PM accumulator, followed by Ficus obliqua (131.02 μg cm−2). L. patersonia is an Australian native tree with a dense crown that can efficiently trap PM due to air turbulence between its leaves and branches; broad leaves with a rough texture enhance the plant's ability to trap PM. On the contrary, morphological characteristics like evergreen leaves with hairy appendages may act as an efficient trap for PM in F. obliqua. Due to smoother leaves, the least effective species were F. rubignosa and Eucalyptus saligna. In addition to leaf shape, leaf structures and micromorphology influence PM accumulation. For instance, Pittosporum undulatum accumulated more PM due to its wrinkled and folded leaf structures despite a significantly lower waxes layer. The findings highlight the importance of planting efficient PM accumulator species to shield vulnerable areas from pollution and decrease human exposure to pollutants. The sink capacity of these species can be used in urban tree planning to combat air pollution and improve air quality.

A new species of Australotaenia (Cestoda: Proteocephalidae) from a hylid frog in Australia

A new species of the little-known genus Australotaenia de Chambrier &amp; de Chambrier, 2010 is described from Ranoidea australis (Gray) (Anura: Hylidae), commonly known as the giant frog, northern snapping frog or round frog and which is a burrowing frog species native to Australia. Australotaenia hobbsi n. sp. is the fourth species of the genus, but the first taxon found in a burrowing frog and in northern Australia. The other species were found in Australian tree frogs (Litoria spp.) in southwestern and southeastern Australia, and in the homalopsid snake Enhydris enhydris (Schneider) in Cambodia. Australotaenia hobbsi n. sp. differs from its congeners (i) by the wider strobila (maximum body width 1,750 µm versus &lt; 930 µm), scolex (570 µm versus &lt; 390 µm) and suckers (diameter 215–230 µm versus &lt; 140 µm); (ii) by the smaller relative size of the cirrus sac (12–15% of proglottid width versus 17–33%); (iii) by the absence of a vaginal sphincter (present in the other three species); (iv) different arrangement of the inner longitudinal musculature, which consists of a few individual muscle fibres (in contrast to the fibres grouped in bundles in other species). Australotaenia species and Pangasiocestus romani Scholz &amp; de Chambrier, 2012 from the spot pangasius Pangasius lernaudii Boucourt, both of the subfamily Acanthotaeniinae, are unique among proteocephalids in terms of intermediate uterine development, with a high concentration of chromophilic cells around the tip of the lateral uterine diverticula.

Organic amendments improved soil properties and native plants’ performance in an Australian degraded land

Context Land degradation poses a substantial threat to both the sustainable environment and human health. Efforts towards rehabilitation and remediation often require addition of soil amendments and careful selection of plant species. Aims We assessed the effect of recycled organic amendments on improvement of soil physicochemical properties and performance of native plant species in an Australian degraded soil. Methods A glasshouse pot experiment investigated the effects of compost (CO), biochar (BC), and compost-biochar (COBC) mixture on performance of three native Australian plant species (Eucalyptus tereticornis (EU), Acacia leiocalyx (AC), and Banksia integrifolia (BA)) in a degraded soil. Key results Application of CO, BC, and COBC organic amendments increased soil dissolved organic carbon and microbial biomass carbon contents compared to the control treatment. COBC amendment increased nutrient retention and reduced CO2 emissions compared to CO amendment. BC amendment also resulted in low CO2 emissions similar to the control treatment, where no significant differences were observed. AC outperformed the EU and BA species in biomass production due to its leguminous nature, with amendment application had an insignificant effect on AC performance. Within the EU treatments, the COBC:EU demonstrated the highest biomass production, followed by CO:EU, BC:EU, and CK:EU, respectively. Conclusion All amendments exhibited overall improvements in soil and plant parameters, with more significant outcomes observed with COBC application. However, the observed improvements from biochar application were minimal in this short-term experiment, which may not have allowed for the manifestation of long-term benefits. Implications Further research is warranted to investigate the effects of compost and biochar amendments on diverse soil types and native plant species.