Royal Botanic Garden Sydney

Abstract. Microbial communities, comprising phototrophic and heterotrophic microorganisms, play a crucial role in global biogeochemical cycles. However, existing biogeochemical models rarely take into account the complex interactions between these groups, usually focusing on competition for resources instead. In this work, we introduce the Microbial Community Model (MCoM), a framework for simulating the dynamics of diverse microbial communities. MCoM incorporates a wide range of interactions, such as cross-feeding, metabolite effects, and competition for nutrients. The model differentiates between dissolved organic nutrients (DON) and carbon (DOC), accounts for phytoplankton and heterotrophic bacterial species-specific organic matter release and uptake profiles, and simulates the impacts of bacterial metabolites on phytoplankton growth. Implemented as a box model, MCoM tracks phototrophic and heterotrophic biomass, active metabolites, DOC, DON, and inorganic nutrients through non-linear differential equations, enabling the exploration of emergent properties and feedbacks. We demonstrate the model's capabilities through simulations of experimental data of pairwise co-cultures of heterotrophic and phototrophic microorganisms, and find overall good agreement. Due to the scalable implementation, interaction matrices for larger, i.e. hundreds, of microbial groups can easily be realised. We show examples for such applications of MCoM in assessing emergent dynamics, including periodic succession patterns and multi-stability. MCoM provides a versatile, scalable, and customizable platform for assessing the range from pairwise interactions to complex microbial communities and their impact on biogeochemical fluxes.

Abstract Plant translocations are used to mitigate extinction risk but are often unsuccessful, partly due to a failure to take the ecology and threats of species into account. For the endangered Caladenia formosa we used an integrated method that incorporated identification of the pollinator(s), possible threats, and population demographics to determine a suitable translocation site and subsequent management interventions. The thynnine wasp Phymatothynnus pygidialis, the sole pollinator, removed and deposited pollen while feeding from the labellum on small amounts of sucrose. We translocated 179 symbiotically propagated, flowering plants to a site where this pollinator was present and monitored the translocation and a wild site for 8 years. Monitoring revealed herbivory (6.4%) and florivory (11.8%) was high in the wild population, but negligible in the fenced translocated population. Protection from florivory enhanced fruit set in the translocation (37.2 ± 3.1% SE) compared with the wild (27.5 ± 6.5% SE) site. Population viability analysis informed the decision to supplement, which boosted overall fruit production. We demonstrate the importance of an integrated approach to translocations and highlight the role of monitoring to elucidate threats, prioritize actions and contribute to growing evidence for pollinator specialization in rewarding orchids.

This is the first comprehensive investigation on the pollen morphology of Pseudanthus , a small genus within the Picrodendraceae, comprising nine species all endemic to Australia. This study presents the pollen morphology of eight out of the nine currently accepted Pseudanthus species using light and scanning electron microscopy. Pollen from five of the species (incl. subspecies) are described here for the first time. Pollen from different Pseudanthus species appears alike, sharing many overlapping features, including sculpture patterns observed with both LM and SEM. However, detailed examination reveals species-specific differences such as size and aperture number, that aid in discriminating pollen of the individual species. In general, Picrodendraceae pollen is mostly isodiametric to oblate, spherical to spheroidal in shape, and either exhibits a pantoporate or stephanoporate aperture configuration, as well as echinate sculpture. Although, Pseudanthus pollen shares these morphological features, being isodiametric to slightly oblate, pantoporate, and echinate, the pollen of this genus can be differentiated from other closely related Picrodendraceae ( Kairothamnus , Micrantheum , Neoroepera , Scagea , and Stachystemon ) based on set of traits observed with combined LM and SEM. • The first comprehensive study of Pseudanthus pollen with combined LM and SEM. • Complete genus coverage is provided including first-time description of five species. • Pseudanthus pollen is pantoporate, echinate, and 14 to17 μm in diameter. • Diagnostic pollen traits aid in distinguishing Pseudanthus from other Picrodendraceae. • Species-specific differences assist in discriminating individual Pseudanthus species.

In many plants, pollinators are attracted to the flowers by scent. Among plants, Banksia (Proteaceae) is exceptional in being pollinated by several functional groups of vertebrates, including honeyeater birds, members of two marsupial orders, and rodents. Here, we test the hypothesis that in Banksia interspecific variation in the frequency of floral visitation by functionally different vertebrate pollinators can be explained by floral scent traits. We used GC-MS to analyse floral volatiles of nine co-occurring Banksia species and tested for correlations between floral visitation by vertebrate pollinators quantified through camera trapping and (i) the abundance in floral headspace of three candidate mammal-attracting compounds, and (ii) overall scent richness (number of volatiles detected). Visitation by non-flying mammals, but not birds, was positively correlated with scent richness, aligning with general trends for other functional groups of pollinators that use olfaction when foraging for nectar. Visitation by native and introduced mice, but not by Honey possums, was correlated with median abundance of 3-methyl-1-nitrobutane and 2-methyl-1-nitrobutane - structural isomers of 1-nitropentane, a known semiochemical in Black rat that is attractive to both sexes. Further, the known rodent semiochemicals, sulcatone (6-methyl-5-hepten-2-one) and 2-methylbutanoic acid were detected in species frequently visited by mice. Our results demonstrate that within mixed-vertebrate pollination systems, the frequency of visitation by functionally different vertebrate pollinators can be partially explained by interspecific variation in floral scent chemistry. While behavioural tests are needed to confirm attractiveness of specific compounds, our results provide the first evidence for chemical adaptation to pollination by rodents in Australian flora.

Abstract Climate models require boundary condition information, such as vegetation and soil distributions because they influence the mean state climate, and feedbacks can significantly influence regional climate and climate sensitivity to CO 2 forcing. Information about past distributions comes primarily from the paleobotanical record, which is often supplemented by a vegetation model to fill data gaps. For recent past periods such as the Pliocene, a quantitative suitability assessment of these vegetation model simulations is sufficient. However, the Miocene Climate Optimum spanning 16.9–14.7 Ma was the warmest period on Earth over the last ∼25 million years and models struggle to reproduce those conditions for the range of paleogeographies and CO 2 concentrations tested, particularly at high latitudes. Here we bring together the Miocene modeling and data communities to update previous vegetation reconstructions used for climate modeling with a new regional approach that relaxes the requirement for a single model simulation to be used, blending instead simulations forced by different paleogeographies and CO 2 concentrations. This ensures the simulated vegetation is first, and foremost, consistent with the paleorecord and provides a baseline for future comparisons. The reconstruction shows global increases in forest cover at all latitudes as compared to today and extensive C 3 grasslands across the high northern latitudes. Data gaps at high latitudes are filled with vegetation models forced by higher CO 2 concentrations than were required at lower latitudes consistent with the inability of current models to simulate Miocene high latitude warmth.

Summary Tree species worldwide are under threat from non-native pathogens that impact forests and the ecosystem services they provide. Myrtle rust, caused by Austropuccinia psidii , is one example, first detected in Australia in 2010. This fungal pathogen infects immature tissue from a wide range of Myrtaceae hosts, including the wetland foundation species Melaleuca quinquenervia . Durable restoration action for this species would preferentially incorporate disease resistant individuals. Our aim for this study was to provide a molecular assay to identify and select resistant individuals and seed lots for restoration. We conducted artificial inoculation of a panel of seedlings and measured their immune responses to myrtle rust. We then performed whole genome sequencing (3.2M common SNPs) and conducted a Genome Wide Association Study ( N = 492), which revealed clusters of significantly associated SNPs in three chromosomal regions, including clusters of putative R genes. Associated SNPs were filtered to a panel of 1,049 for a highly accurate genomic prediction model ( R = 0.83). This provides a relatively inexpensive approach to identifying resistant individuals or seed lots for restoration and a template for managing myrtle rust impacts while maintaining population genetic diversity.

Societal Impact StatementCollections of dried plant specimens (herbaria) provide an invaluable resource for the study of many areas of scientific interest and conservation globally. Digitisation increases access to specimens and metadata, enabling efficient use across a broad spectrum of research. The value of physical specimens is enhanced by digitisation, but these specimens remain fundamental for the study of traits not yet captured digitally. We investigate the requirements for physical access and the curation and facilities needed to maximise specimen use and value. We present recommendations to ensure that specimens and data are both fully accessible to support research into global challenges.SummaryHerbarium management has traditionally focused on providing direct access to the physical specimens, but this scope must now expand to also embrace digital collections. Advances in technologies such as artificial intelligence and high‐throughput genomics are increasing the amount of information that can be extracted from specimens, and it is becoming commonplace to provide digital access to specimen images and collection metadata. These developments are facilitating the use of herbarium collections to inform conservation planning and in studies plant and fungal taxonomy, distribution and evolution. This paper examines how herbaria are transitioning from physical specimen‐centric collection management practices to increasingly digitised curation, and the effects that digital availability of data are having on demands for physical access. We provide a set of recommendations to institutions holding herbarium collections. We emphasise the critical importance of further digitising herbaria of all sizes; the need to ensure that historical inequalities in deposition of specimens are not perpetuated; and that the capacity to utilise new technologies must be further developed, especially in biodiverse regions from which most herbarium collections are derived.To improve access to collection data, herbarium managers need to more rigorously adopt community‐agreed data standards, and more strongly support open access platforms such as the Global Biodiversity Information Facility either directly or through regional coalitions. As digitisation and open data access increase, herbaria will need to offer users with seamless hybrid access to physical and digital records while continuing to develop their collections to advance research and conservation.

Abstract Effective water and wetland management for waterbirds during nesting events benefits from knowledge of nesting timing, staging, duration, and associated foraging locations. Such information can inform managers about when, where, and for how long management actions such as environmental watering or predation protection are needed to support specific nesting stages. This is particularly relevant for species nesting in aggregations that are dependent on flooding of key sites to initiate and complete their nesting cycles, such as ibis and spoonbills. These species are frequently targeted for adaptive water and wetland management to support successful breeding events and can be bioindicators of wetland change. However, obtaining on-ground nesting data for highly mobile species in remote or inaccessible sites can be difficult. To solve this problem, we used GPS satellite telemetry to track nesting events for 3 species that frequently nest together in remote wetlands managed with environmental water: Threskiornis spinicollis (Straw-necked Ibis), T. molucca (Australian White Ibis), and Platalea regia (Royal Spoonbill). This is the first time that satellite telemetry for these highly mobile species has been used to analyze: (1) nest stages and nest attendance patterns; (2) distances travelled to forage during nesting; and (3) timing and duration of nesting events. We found both intra- and inter-species variation in nest attendance patterns and foraging distances. There were changes in nest attendance and foraging distance patterns corresponding with transitions between each of the 4 main nest stages: (1) nest establishment; (2) incubation; (3) immobile chicks; (4) mobile chicks. We discuss how this information can be used to implement strategic conservation management of waterbird populations and habitats including environmental watering, nest protection, and predator control.

ABSTRACTIn photoperiod sensitive plants, the timing of phenological events depends primarily on day length rather than temperature, precipitation or other environmental variables. This may make these photoperiod sensitive species less able to respond to climate change as their phenologies are more tightly controlled by day length conditions, which remain constant into the future, than by changing climatic conditions. We measured germination under three light treatments (short‐day, long‐day and equal light and dark) to quantify species' germination photoperiod sensitivity. We developed a novel metric that provides a continuous measure of germination photoperiod sensitivity for 67 plant species across a range of locations, habitats and growth forms. Of the 67 species, four species had significantly more seeds germinate in the long‐day treatment, three species had significantly higher germination in the short‐day treatment, and four species had significantly higher germination in the intermediate‐day treatment. We then used this metric to quantify the relationships between germination photoperiod sensitivity (as quantified from the laboratory tests and calculated metric) and phylogeny, seed size, growth form, latitude, leaf area index (LAI) and ecosystem type. We also quantified the relationships between flowering photoperiod sensitivity (as quantified by a literature review) and the same ecological/environmental predictor variables as were tested against germination photoperiod sensitivity. There were no significant relationships between photoperiod sensitivity in germination or flowering and species' biogeography, phylogeny or other functional traits. Our findings suggest that photoperiod sensitivity is likely to be important in a range of different locations and in different types of species.