Investigating the spread of dieback disease in fragmented kauri ecosystems

The Bio-Protection Research Centre, Lincoln University, New Zealand is inviting applications for a PhD studentship to examine how complex interactions between plants, insects and microbes can affect the success of invasive species.

This is an exciting opportunity for a student to contribute to understanding and management of an invasive plant pathogen threatening the future of New Zealand’s culturally iconic tree species, kauri (Agathis australis). The student will become an integral member of a national research team in the Centre’s Ecosystem Networks project http://bioprotection.org.nz/research/ecosystem-networks, and be involved in a high profile project of national significance to New Zealand’s biodiversity.

The successful candidate will investigate the effects of landscape changes on the spread and virulence of Phytophthora agathidicida (PTA), which is implicated in the catastrophic disease plaguing kauri in New Zealand. Currently, research is assessing the spread and virulence of PTA and we will extend this to increase understanding of abiotic and biotic factors that influence pathogen invasion fronts across changing landscapes, such as regenerating forests.

Background

Diseases caused by new or emerging plant pathogens can have severe detrimental impacts on economically and culturally significant plant species. In New Zealand, native kauri trees are currently under threat from kauri dieback, a disease caused by the pathogen PTA. P. agathadicida first came to the attention of scientists when local kaitiaki (stewards) Māori noticed trunk lesions. Following its discovery in 1974, PTA (reclassified in 2015) has been found in several notable forests used for recreation and conservation. It is particularly prevalent in kauri forest fragments found within agricultural settings, and is the primary cause of dieback in New Zealand’s northern native forests.

Researchers in the Centre are investigating the persistence of PTA in soils in order to better understand how PTA becomes established and spreads. We are addressing two key questions:

1) Are forest fragments in agricultural settings more susceptible to pathogen invasion and establishment due to disrupted interaction networks?
2) Do pathogens undergo rapid evolutionary adaptation to increase pathogenicity once established in forest fragments?

Understanding the importance of soil ecological networks will underpin the development of strategies to restrict the spread of PTA and play a key role in protection of New Zealand’s iconic species from future incursions of diseases. A key aspect of this programme is liaising with Māori community groups and iwi (tribes) who are mandated to protect and enhance the well-being of these forests, which also includes the integration of traditional ecological knowledge into research.

The research will be undertaken jointly with Scion who have extensive experience in plant pathology diagnostics and surveillance, in particular dieback, and researchers at University of Otago who are investigating drivers of fundamental chemotaxis responses in plant pathogens such as P. agathidicida. The student will also liaise closely with researchers at Auckland Council Botanical Gardens involved in kauri conservation programmes. Find out more about kauri dieback at http://www.kauridieback.co.nz