Biotic and abiotic filters of weed invasion in New Zealand scrublands

Lincoln University is offering an exciting PhD opportunity, funded by a New Zealand Tertiary Education Commission grant to Bioprotection Aotearoa. This is a fantastic opportunity for a student to work on cutting-edge research addressing the role that biotic interactions (seed dispersers, seed predators, soil pathogens) play in limiting or facilitating plant invasions.

Background

Plant invasions are a major burden on the biodiversity and economy of New Zealand¹. The search for the factors facilitating plant invasions has proven elusive largely because researchers have attempted to seek general rules that apply across all invaded ecosystems².

This project takes the novel approach of focusing on the biotic and abiotic processes acting to drive plant invasions in a single, relatively homogenous yet widespread ecosystem in New Zealand: the manuka/kanuka shrublands. These shrubland ecosystems are of significant cultural value to Māori and are increasingly being valued for the economic benefits they bring through honey production. Thus, understanding the drivers of plant invasion of these ecosystems will be of considerable relevance to local and indigenous communities.

Research within this PhD will apply state-of-the-art experimental approaches to examine how the role of plant mutualists (e.g., seed dispersers, mycorrhizal fungi) and antagonists (e.g., herbivores, soil pathogens) act at different spatial scales to determine plant invasions³. The successful candidate will join one of the world’s leading research groups studying plant invasions and benefit from a stimulating academic and supportive environment.

Research aim

The aim of this PhD is to quantify how biotic and abiotic factors interact to filter biological invasions in a single ecosystem type. It aims to address the following questions:

• What plant traits (e.g., dispersal mode, shade tolerance, growth rate) underpin invasion success or failure⁴
• Which factors (e.g., dispersal, seed survival, seedling establishment) are most limiting to plant invasions⁵
• How do aspects of the ecosystem (e.g., age, fragmentation etc.) influence levels of invasion.

Experiments quantifying seed rain, seed bank, seed and seedling survival of a range of weeds within manuka/kanuka understorey to determine the primary limits on establishment of different functional groups of plants. Existing soil seed banks, survival of buried seed and seed predation will be assessed in paired manuka/kanuka vs grassland sites. Selected weed species (encompassing a range of shade-tolerance) will be planted as phytometers to examine growth and survivorship. Glasshouse experiments will attempt to tease apart the role of shade and soil biota in limiting germination and establishment of a range of weed species commonly found in the landscape. Data from field and glasshouse experiment will be used to assess how the different barriers interact to limit establishment of certain plant functional groups.

• Hulme PE (2020) Plant invasions in New Zealand: global lessons in prevention, eradication and control. Biological Invasions 22, 1539–1562)
• Fridley JD, Jo I, Hulme PE & Duncan RP (2021) A habitat-based assessment of the role of competition in plant invasions. Journal of. Ecology 109, 1263– 1274.
• Pyšek P, Bacher S, Kühn I, Novoa A, Catford JA, Hulme PE, Pergl J, Richardson DM, Wilson JRU & Blackburn TM (2020) MAcroecological Framework for Invasive Aliens (MAFIA): disentangling large-scale context dependence in biological invasions. NeoBiota 62, 407–461.
• Hulme PE & Bernard-Verdier M (2018) Comparing traits of native and alien plants: can we do better? Functional Ecology 32, 117–125
• Dawson W, Burslem DFRP & Hulme PE (2009) Factors explaining alien plant invasion success in a tropical ecosystem differ at each stage of invasion. Journal of Ecology, 97, 657-665

Besides their own research, the student will attend courses and workshops in relevant transferable skills such as scientific writing and project management as well as participate in the biennial Bioprotection Aotearoa Conference, weekly seminar series and group meetings.

Prerequisites and application process

Applicants for this project should hold a first class or high 2A honours degree, or Masters, in a relevant area, preferably with interest in plant ecology or weed invasions and experience in undertaking field studies or experiments. The position is open to applicants of any nationality, provided they are fluent in English, able to obtain a student visa and eligible for admission to the PhD program at Lincoln University, New Zealand. Applications should include evidence of qualifications and research experience, together with a curriculum vitae and contact details of three academic referees who can be contacted. Applications should be supported by a cover letter that states a) why you are interested in continuing your studies to obtain a PhD; b) what specific aspects of this particular PhD attracted you; and c) how your qualifications and experience would map onto the proposed research.

Please email complete applications to Philip Hulme before November 20^th 2022. Preferred candidates would then need to apply to study at Lincoln University and meet the institutional criteria for entry prior to the scholarship being confirmed.

Background

Bioprotection Aotearoa is a national Centre of Research Excellence that exists to train the next generation of bioprotection researchers and to deliver world-class research that protects the productive and natural landscapes of Aotearoa New Zealand.  Our mission is to educate our nation’s future bioprotection leaders by collaborating to conduct pioneering, multi-disciplinary research that addresses the environmental challenges Aotearoa New Zealand is facing.  We draw on our collective academic strengths to develop new and innovative solutions that protect our productive and natural landscapes from climate change, pathogens, pests and weeds.  Our kaupapa is guided by a unique mātauranga Māori and science framework – Te Taiao-a-rangi – which supports a holistic, systems-level approach to achieving intergenerational environmental sustainability. This PhD is funded by, and sits within, the Bioprotection Aotearoa science programme.

Besides their own research, the student will attend courses and workshops in relevant transferable skills such as scientific writing and project management as well as participate in the biennial Bioprotection Aotearoa Conference, weekly seminar series and group meetings.

Funding Notes

The three-year (36-month) scholarship provides an annual stipend of NZ$28,000 a year tax-free, covers full university fees, and includes approximately NZ$5,000 a year towards operating expenses.

Location: Lincoln
Institution: Lincoln University, New Zealand
Supervisor: Dist Prof Philip Hulme
Discipline: Invasion biology
Research: Pou 3: Nuku-a-rangi, project 3.2
Apply to: Email complete applications to Philip Hulme, [email protected]
Application deadline: November 20th 2022