Surviving small: genetic diversity, symbiosis and resilience in orchid populations

Qualification type: PhD

Project start date: 1 October 2026

Location: Kew Gardens, Richmond (London) and Imperial College London, United Kingdom

Funding for: UK Students / International Students

Funding amount: fees and stipend at UKRI rates (for the academic year 2026-27, the stipend rate is £21,805, plus the £2,000 London allowance). Please note: this funding amount typically increases with inflation each academic year. Research costs, including travel for fieldwork, consumables and molecular sequencing are included. The project is funded by a philanthropic donor.

Deadline for application: Sunday 31 May 2026, 12 noon

Online Interviews will be held on Friday 19 June 2026

Project Title: Surviving small: genetic diversity, symbiosis and resilience in orchid populations

Many plant species are declining as habitats shrink and environmental pressures intensify. A long‑standing principle in conservation biology is that small populations are inherently vulnerable: they lose genetic diversity, become less resilient to change, and face a heightened risk of extinction. Yet some species persist for decades as small, scattered populations, apparently defying this expectation.

This project investigates how such persistence is possible, using the woodland orchids of the genus Cephalanthera – the red helleborine (C. rubra), sword‑leaved helleborine (C. longifolia), and white helleborine (C. damasonium) – as a model system. All three species are declining in Britain and survive today in small populations.

By combining modern genomic approaches with field surveys of fungi, pollinators and population dynamics across Britain and mainland Europe, the project will identify the mechanisms that allow small populations to survive, and the limits of that resilience. The findings will directly inform conservation strategies for Cephalanthera, and other rare species increasingly forced to persist in small populations as biodiversity loss accelerates.

The research will examine three interacting factors that may underpin their resilience:

• Life‑history traits such as long lifespan, dormancy, and clonal growth, which may buffer the loss of genetic diversity and create a “genetic extinction debt” where populations appear stable despite underlying vulnerability.

• Pollination strategies, ranging from food deception to self‑pollination, which influence reproductive success and genetic diversity.

• Dependence on mycorrhizal fungi, essential for orchid germination and growth, and potentially a major constraint on where populations can persist.

The studentship 

The PhD project will have the following objectives:

1. To estimate genome‑wide genetic diversity and its relationship to population size and fragmented species distribution in several European populations of the three Cephalanthera species;

2. To assess the influence of pollination strategies on population size and distribution;

3. To characterise fungal communities across orchid life stages in selected populations of the three species.

The PhD project will offer comprehensive training in molecular biology techniques, conservation genetics, and assessment of symbiotic interactions with fungi and pollinators, preparing the candidate for the successful completion of their PhD, but also for a competitive edge in their future career in academia or industry. Additional opportunities for training are available at RBG Kew and Imperial College London.

Collaboration with conservation stakeholders at the science-policy interface will also be possible through the applied components of the project and the international consortia in which the supervisory team is involved.

Project supervisors

Dr. Roberta Gargiulo, Royal Botanic Gardens, Kew https://www.kew.org/science/our-science/people/roberta-gargiulo

Prof. Mike Fay, Royal Botanic Gardens, Kew https://www.kew.org/science/our-science/people/michael-fay

Prof. Martin Bidartondo, Imperial College London https://profiles.imperial.ac.uk/m.bidartondo

The candidate

We are seeking a graduate (BSc or MSc or equivalent) who is driven by curiosity for cross-cutting themes in biology. The ideal candidate will possess basic molecular biology and fieldwork skills. This position is open to UK and international candidates. International candidates will need to be eligible to apply for a UK student visa (https://www.gov.uk/student-visa).

Essential skills/attributes

• Applicants must hold (or expect to obtain) an Upper Second (2:1) or First Class Honours degree (or equivalent for international applicants) in a biological or related science. Candidates with a Master’s degree in addition to a BSc may be given preference.

• Eligibility to travel to other countries within the distribution of the study species.

• The project will require the successful candidate to be able to conduct laboratory and field work and computer-based analyses.

• Applicants must meet the higher-level English Language requirements at ICL (https://www.imperial.ac.uk/study/apply/english-language/).

Desirable skills/attributes

• Training will be provided as required, but experience of molecular techniques, bioinformatics, pollination biology and/or mycorrhizal studies will be considered an advantage.

•  Full driver’s license.

How to apply 

Please send CV, personal statement, and contact details of two referees directly to r.gargiulo@kew.org by Sunday 31 May 2026, 12 noon.

After the interview, the successful candidate will need to register as a postgraduate student at https://www.imperial.ac.uk/admin-services/ict/self-service/admin-systems/my-imperial/.

Terms and conditions

The studentship will cover home or international fees and stipend at UKRI rates for a maximum of four years full-time, subject to institutional regulations.

Informal Enquiries

Informal enquiries about this collaborative project can be sent to r.gargiulo@kew.org