Addressing drivers of dieback in an endangered shrub species, Persoonia hirsuta

Abstract

Persoonia hirsuta Pers. (Proteaceae) is an Endangered shrub species endemic to the Sydney Basin region of New South Wales. This species has been in significant decline over the past two decades and is presently threatened by urban development, limited seedling recruitment, and observed dieback (a condition in which a plant begins to die from the tips of its leaves or backwards often owing to disease or an unfavourable environment) of a presently unknown cause. Understanding what causes dieback and limits new seedling recruitment is critical for the successful conservation and management of this species. The overarching goal of this research is to address key biological knowledge gaps associated with this species biology and explore potential drivers of dieback with an aim to improve the conservation and management of this species. My thesis has identified that soil pathogens, fire severity and climate change and/or environmental extremes may be involved in driving dieback and decline for P. hirsuta. However, further research is necessary to explore the intricacies of how these factors are involved in driving dieback. Additionally, these threats necessitate further conservation actions and improved management recommendations for this species. Therefore, the information in this PhD thesis has been prepared to serve in part of a NSW Threatened Species Scientific Committee Conservation Assessment as the combined results from this thesis, and other work suggest this species is eligible to be up listed to Critically Endangered. The increased understanding of ecological processes affecting dieback and decline gained from this thesis will inform future research activities and conservation recommendations for this species through improved delivery of adaptive management strategies such as translocations. Additionally, the novel strategies employed throughout thesis may improve future research associated with addressing possible drivers of dieback in native ecosystems.

Date of Award	2022
Original language	English