Invasive species continue to increase their economic and biodiversity impacts globally, with multi-trillion-£ costs to economies since 1970. Invasive terrestrial plants, such as Japanese knotweed, account for a significant proportion of costs, and cause declines in biodiversity and key ecosystem functions. Further, these species impinge on agricultural, recreational and development land, causing major issues with building projects, housing and planning.
Control and eradication of the knotweeds (e.g.,Japanese, Giant, Himalayan and Bohemian) is a seemingly intractable problem, exacerbated by potential future restrictions on chemical control, principally glyphosate. Physical control (e.g., uprooting) is successful with some species (e.g. Himalayan Balsam) and we at QUB have piloted biological control of invasive plants with our collaborator “EcoSeeds Strangford”, with planting of bespoke mixtures of native plant species. Further, “Practical Waste Solutions (PWS)”, our funding industrial partner, have developed physical-chemical control of knotweeds, with sorting and removal of the vegetative and rhizomal fragments. In addition, QUB collaborates with “INVAS Biosecurity”, who apply chemical and physical methods to knotweed control. We thus propose through this highly collaborative QUB/PWS/Ecoseeds/INVAS Biosecurity CAST project to integrate and optimise the control of invasive alien plants with biological, physical and chemical control techniques, blending ecological theory and practical solutions.
The main objectives of the PhD are to develop:
(1) biological control of Japanese knotweed using ecological theories of native seedling founder and priority effects and competition for resources, based on ecological theory (e.g. Tilman’s R* theory of resource competition) to optimise the mixtures of native plants that resist/extirpate the invader;
(2) chemical control of Japanese knotweed, utilising state-of-the-art nano spraying, transferring technology surrounding medical application of nano materials to the current project;
(3) physical control of Japanese knotweed with sieving and crushing techniques that remove/destroy viable vegetative and rhizomal fragments that can cause reinfestation;
(4) alternatives to chemical control (in order to pre-empt any restrictions on e.g. glyphosate) such as use of temperature extremes (dry ice, steam, heat torches); and
(5) assessments of damage and management costs of invasive plants and other biological invasions.
We will utilise existing datasets from PWS and INVAS Biosecurity regarding sites of Japanese knotweed control efforts and survey those sites for regrowth. We will use a sample of such sites to run factorial experiments to examine the influence on knotweed eradication success of single and combinations of our biological, physical, chemical and alternative techniques on dependent variables such as knotweed regrowth, development, and rhizomal and vegetative spread. Data on costs associated with invasive plants in Ireland and abroad will be compiled and synthesized to inform management strategies. The research will thus be an entirely new nexus among academia, industry, practice and policy, integrating ecological theory with technological advances and practical outcomes.
This project will be co-supervised by Professor Jaimie Dick and Dr Ross Cuthbert (Queen's University School of Biological Sciences).
Specific skills/experience required: Full training will be provided, but a background in ecological management would be beneficial. Experience with field-work, especially with plants, would also be useful. The student would preferably have a full driving licence, or at least have access to suitable means of transportation.
Start Date: 1 October 2023
Duration: 3.5 years
How to apply: Applications must be submitted online via: https://dap.qub.ac.uk/portal/user/u_login.php
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