Virtual science seminars

Hear from world-renowned speakers and scientists from the Botanic Gardens and other organizations.

Scientist Amanda Rollason with plant tissue culture specimens at the Australian PlantBank

Held at The Calyx, our science seminars are now virtual. Catch up on our previous live-streamed seminars and hear from world-renowned speakers and scientists from the Botanic Gardens of Sydney.

Bringing Science and Horticulture Together

The Sunda-Sahul Floristic Exchange

Untangling the effects of the Sunda-Sahul Floristic Exchange on the evolution of the Southeast Asian and northern Australian flora. 

The convergence of the Sunda continental shelf (Peninsular Malaysia and parts of Indonesia and the Philippines), the Sahul continental shelf (Australia and New Guinea), and Wallacea from c. 25 Mya is one of the most significant events in global biogeography.

The collision resulted in widespread geological change in the region, and facilitated the exchange of Sundanian and Sahulian floras that had evolved in isolation (the ‘Sunda–Sahul Floristic Exchange’ (SSFE)). This exchange has fascinated scientists since the time of Alfred R. Wallace, whose observations of disjunct Sundanian and Sahulian biota in the region sparked the field of biogeography itself. Yet despite the long history of research on the topic, much remains to be understood about the effects and drivers of the SSFE — knowledge that is critical for understanding why the flora of the region is the way it is today, and  how best to conserve it. 

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A Corymbia calophylla story

A Corymbia calophylla story – genomics, traits, and adaptations.

The climate of southwestern Australia has already shifted and will continue to change in the future, making some plant species vulnerable to novel conditions.

This rapid change in climate will likely create a mismatch between genotype and environment. Therefore, understanding the evolutionary capacity and patterns of local adaptation of a foundation species is critical for the maintenance of the species and the collective biodiversity associated with it. Collections of the co-dominant tree Corymbia calophylla (marri) were used to study its adaptive potential by applying landscape genomics, glasshouse, and common garden methodologies. The presence of high recombination rates, substantial gene flow, standing variation within and near genes, and phenotypic plasticity demonstrate that marri is equipped with the genomic tools to adapt to future climates. However, generation times for trees are often long and overlapping, so it is difficult to imagine a scenario where adaptive response can occur fast enough to meet the pressures from rapid climate change. Therefore, it is critical to maintain the many roles of marri through proactive approaches such as assisted gene migration that increase local genetic variation associated with environment.

Dr Collin Ahrens from the Royal Botanic Garden Sydney and the University of New South Wales presented his work in an online seminar given on Tuesday, 13 Apr 2021. Watch again this seminar in the video below:

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Saving our Species

Strategic decisions and opportunities: science for Saving our Species. 

Making decisions isn’t easy – New South Wales has over 1000 threatened species and communities; how do we use the resources available to make the biggest difference for the most species?

Saving our Species is the New South Wales government’s flagship framework for Threatened Species Conservation. Since its inception, cost-effective conservation has been one of the program’s core values. Yet, conservation decisions are among the most difficult to make – they are frequently characterised by a lack of information, and the stakes are very high, with potential extinction an ever-present worry. This has led Saving our Species to engage decision scientists and environmental modelling teams in a number of collaborative projects to answer common conservation questions, such as “which sites will provide the best security for species over the long term?” and “where should we invest limited resources across the state to benefit the most threatened species?” The results are tools that can be shared and used across the state, with the aim of maximising the impact for threatened species and communities. Come along and learn about tools like Site Centaur, Conservation Hotspots, DiversiPhy and others, and the cutting-edge research that is supporting resource allocation across New South Wales.

Dr Stephanie Stuart from the NSW Department of Planning, Industry and Environment presented her work in a seminar at The Calyx, Royal Botanic Garden Sydney on Tuesday, 18 May 2021. Watch this seminar again in the video below.

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The Mind of the Honeybee

The honey bee has evolved as the consummate generalist pollinator, and has become perhaps the most important insect pollinator of our food crops. Here I will talk about how honey bees think, and how we know how they think. I discuss how their thought processes influence their flower visits, and how bees’ long coevolution with flowers has shaped a bee type of intelligence.

Professor Andrew Barron from Macquarie University presented his work in an online seminar on Tuesday, 15 Jun 2021. Watch again this seminar in the video below:

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Six people in the bush, holding persoonia hirsuta plants ready for translocation
Bringing Science and Horticulture Together

Bringing Science and Horticulture Together – Perspectives From Living Plant Collections. Living collections can also be used to safeguard the genetic diversity of natural plant populations giving them excellent conservation value. 

Botanic gardens around the world are excellent places of education, science, and horticulture. Living plant collections are a great opportunity for botanic gardens to engage with and educate the public and communicate their scientific and horticultural expertise.

Living collections can also be used to safeguard the genetic diversity of natural plant populations giving them excellent conservation value. However, not all living plant collections in botanic gardens have scientific value. 

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State of the Flora of Australia

The Flora of Australia provides a synthesis of the nation’s native and naturalised vascular plant diversity. 

The Flora of Australia provides a synthesis of the nation’s native and naturalised vascular plant diversity. It started in 1981 as a hard-copy series of volumes but in November 2017 it went digital (, where information can be regularly maintained.

The Flora is a work in progress with ongoing additions and revisions, and to date it contains about 16,500 profiles. The online Flora platform has an interactive infrastructure where digital Flora treatments are managed as a collection of taxon profiles. 

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An Evolution Revolution

An Evolution Revolution: The rapid evolution of an introduced plant. 

Introduced species are changing much faster than we thought, and in surprising ways. Since arriving in Australia in the 1930s, the South African beach daisy Arctotheca populifolia has undergone a suite of striking changes in morphology, physiology, defence and life-history. With so many rapid evolutionary changes in this introduced plant, we now ask the intriguing question: could Australia have a new species on its coastline?

In this seminar I will present some of the key findings from my PhD which I completed at UNSW in 2019. We used genetic data to locate the original South African source population, and then set up a common-environment glasshouse experiment to compare four introduced Australian populations with their South African source population.

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Conservation of Cycas in Australia

New approaches to the conservation genetics of the genus Cycas in Australia. 

More than sixty percent of cycad species are threatened with extinction, with many existing in small and isolated populations. As a result, understanding their diversity is imperative for their conservation to ensure long-term survival.

In order to understand the diversity of cycads, genetics plays a fundamental role in helping us to identify how populations differ from one another. Australia represents a diversity hotspot for cycads where there are many different species and also many large, clustered and undisturbed populations. This research used next generation DNA sequencing technologies to understand the genetic diversity of cycad populations in the Northern Territory in Australia, namely: Cycas armstrongii, C. calcicolaC. maconochiei ssp. maconochiei and a single hybrid population C. armstrongii x maconochiei. The results of this research revealed new insights into the genetic diversity, and genomic history of our study species which will aid in their future conservation. However, not all genetic diversity of populations was represented in ex-situ botanic garden collections, presenting concerns for their future conservation and reintroduction. The results of this research though conservation management plans will have far-reaching significance for the conservation of these species and their populations, by guiding structured acquisition of seeds from the wild so that genetic diversity can be preserved in botanic gardens. Ultimately this ensure the survival of these wonderful plants for future generations in Australia.

Dr James Clugston from the Royal Botanic Garden Sydney presents his work in the video below (online seminar talk given on Tuesday, 6 October 2020).

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The delayed rise of angiosperms

The delayed rise of angiosperms (flowering plants). 

The diversification of extant flowering plants was delayed for 37–56 million years after the origin of families, with an average longer delay in tropical ecosystems than in arid and temperate ecosystems.

The Early Cretaceous (145–100 million years ago (Ma)) witnessed the rise of flowering plants (angiosperms), which ultimately lead to profound changes in terrestrial plant communities. However, palaeobotanical evidence shows that the transition to widespread angiosperm-dominated biomes was delayed until the Palaeocene (66–56 Ma). Important aspects of the timing and geographical setting of angiosperm diversification during this period, and the groups involved, remain uncertain. Here we address these aspects by constructing and dating a new and complete family-level phylogeny, which we integrate with 16 million geographic occurrence records for angiosperms on a global scale. We show substantial time lags (mean, 37–56 Myr) between the origin of families (stem age) and the diversification leading to extant species (crown ages) across the entire angiosperm tree of life. In turn, our results show that families with the shortest lags are overrepresented in temperate and arid biomes compared with tropical biomes. Our results imply that the diversification and ecological expansion of extant angiosperms was geographically heterogeneous and occurred long after most of their phylogenetic diversity originated during the Cretaceous Terrestrial Revolution.

Dr Santiago Ramírez Barahona from Universidad Nacional Autónoma de México presents his work in the video below (online seminar talk given on Tuesday, 10 November 2020).

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Completing the plant Tree of Life

Completing the Flowering Plant Tree of Life with Angiosperms353. 

Discovering the tree of life is among the most fundamental of the grand challenges remaining in science today. With new phylogenomic methods, it is now possible to build increasingly complete phylogenetic hypotheses based on broad genomic sampling.

The Plant and Fungal Trees of Life (PAFTOL) project at the Royal Botanic Gardens, Kew aims to generate phylogenomic data for every genus of plant and fungi. In this talk, we report our progress towards completing a genus-level phylogeny of angiosperms. To achieve our goal, we developed the Angiosperms353 toolkit for target sequence capture, with which we have now sequenced over 5000 samples covering more than 30% of the 14,000 angiosperm genera. In addition to the reconstruction of higher-level relationships, we have also gained insights into the application of Angiosperms353 to species-level questions, including within rapid radiations, indicating the great potential of this toolkit in comparative and evolutionary biology. We have also shed light on data recovery on a broad phylogenetic scale. We found that the toolkit yields good quality data across angiosperms and even from challenging samples (such as herbarium specimens up to 200 years old). PAFTOL subscribes to an open data agenda and aims to release its data early and often via the Kew Tree of Life Explorer. This new web portal will provide access to raw data, intermediates (assembled data, alignments, gene trees) and a navigable tree of life based on all released data. The universal nature of Angiosperms353 provides important opportunities for future integration of phylogenomic data. To achieve this, transparent and open mechanisms for collaboration and data sharing will be essential.

Dr William Baker from the Botanic Garden Sydney, Kew presents his work in the video below (online seminar talk given on Wednesday, 16 December 2020).

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The waratah genome

Assembling the waratah reference genome. 

The New South Wales waratah, Telopea speciosissima, is the floral emblem of the state and a striking and iconic Australian flower. The waratah reference genome has just been sequenced and represents a new resource to understand the evolutionary origin and dynamics of the Australian flora.

Previous work on this species has characterised population structure and patterns of divergence and introgression between T. speciosissima and related Telopea species. These studies were performed using a limited set of genetic markers, but point to the great potential of waratah as a model clade for understanding processes of divergence, environmental adaptation and speciation. To undertake genome-wide studies of these processes, a reference genome is needed. However, the distribution of species with sequenced genomes across the plant tree of life is highly uneven, with efforts focused on crops and their wild relatives, and few Proteaceae genomes and no waratah genomes are available. We assembled the first chromosome-level reference genome for T. speciosissima (2n = 22) using Nanopore long-reads, 10X Chromium linked-reads and Hi-C. The assembly spans 824 Mbp, representing 93 % of the estimated genome size, with a scaffold N50 of 69.1 Mbp and 91.1 % of complete embryophyta universal single-copy orthologs (BUSCOs) are present. This genomic resource will enable studies of genome-wide variation in waratah, accelerating our understanding of waratah diversification and evolution, and potentially facilitating the use of powerful marker assisted breeding approaches. Broadly, it represents an important new genomic resource in Proteaceae to support the conservation of Australia's flora.

Ms Stephanie Chen from the University of New South Wales and the Royal Botanic Garden Sydney presented her work in an online seminar given on Tuesday, 16 February 2021. Watch again this seminar in the video below:

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