PhD Seminar: Understanding plant rarity through space and time

'Who can explain why one species ranges widely and is very numerous, and why another allied species has a narrow range and is rare? Yet these relations are of the highest importance'.
- Charles Darwin, The Origin of Species (1859, p. 6)

Determining what makes a species rare is a fundamental and alluring question in ecology and conservation. However, we are yet to come to a clear understanding of what makes a plant species rare, why certain plant species become rare, and identify the processes that drive plant rarity.

Meena’s thesis examines the biological and ecological factors associated with plant rarity at a local and global scale. First, she conducted fieldwork to empirically examine how fire regimes, soil properties and plant interactions are associated with rare species across three different vegetation communities in Booderee National Park, south-east Australia, on Wreck Bay/Yuin Country. Second, she presents the results of a systematic literature review examining if specific plant traits and environmental factors were associated with rarity globally. Finally, Meena presents a conceptual framework which indicates that we need to understand the interaction between the biological, ecological and historical drivers influencing plant rarity across time to determine where and why species are rare. She provides a possible roadmap for future avenues of research to understand the environmental processes that influence species rarity.

Meena’s work has shown that conservation strategies for rare plant species need to examine the interactions and changes in rare species abundance within an ecosystem across time. Her work aims to lead to better-informed conservation strategies that improve our assessment of rare species extinction risks and allow early identification of species decline, whether rare or common.

Meena would like to acknowledge that this thesis was primarily done on the land of the Ngunnawal/Ngunawal and Ngambri peoples, as well as on the land of the Yuin and Ngarigo peoples. The fieldwork for this thesis was conducted on Yuin Country and of the Wreck Bay Indigenous community who are the Traditional Owners, and continuing custodians of the land of Booderee National Park. She recognises their continuing connection to Country and that sovereignty of this land has never been ceded.

About the speaker

Meena Sritharan is a PhD student and plant ecologist who loves to try and understand how plants respond to changes in ecosystems. She is (a little) obsessed with looking at the effects of different environmental factors that influence the presence of plants and the interactions among and between plants and other organisms across different vegetation communities.

Prior to undertaking her PhD at the Australian National University, she completed her undergraduate degree in Advanced Science, majoring in ecology and microbiology at UNSW Sydney (on the unceded territory of the Bedegal and Gadigal peoples). She achieved a First-Class honours in plant ecology for her research looking at morphological changes in Australian alpine plants in response to local climate change.

She hopes that her current and future work in plant ecology can assist in making well-informed decisions about the human impacts on environments and work towards conserving native rare species across a wide variety of Australia’s ecosystems.