In 1975, during the completion of her PhD, Gibby joined the botany department of the NHM. The NHM was still predominantly staffed by male scientists often without PhDs; Gibby recalled being asked if she would prefer to be called Mrs or Miss during one interview, replying 'Doctor will do'.[1]: 1 As part of her work at the NHM, Gibby worked at the Chelsea Physic Garden, researching Pelargonium after meeting Virginia Nightingale, the garden's horticulturist who had a particular interest in the genus.[1]: 1–2 [3] She later worked with Alastair Culham on the evolutionary relationships within the genus.[4]
Gibby's research on Dryopteris continued into the late 1980s but after attending a conference in the United States in 1991, she became more focused on Pelargonium, the filmy fern (Trichomanes speciosum), and European and Macaronesian Asplenium.[1]: 2 She began using enzyme electrophoresis and chloroplast DNA sequencing to discover biogeographical patterns that allowed links between plant species to be confirmed or rejected much more easily.[1]: 2–3
From 1997 to 2000, Gibby was the Associate Keeper of the NHM's Botany Department. In 2000, she joined the Royal Botanic Garden Edinburgh (RBGE) as Director of Science.[1]: 4 According to her Guardian obituary, this made her the "highest serving woman" in the institution's 350-year history.[2] Gibby said that the move shifted her research focus towards conservation issues.[5] In the role, she worked with the University of Edinburgh, the Scottish Crop Research Institute, Scottish Natural Heritage, and helped to develop the first versions of the Scottish Biodiversity Strategy.[1]: 4
Gibby was made a Fellow of the Royal Society of Edinburgh in 2005.[6] In 2009, Gibby was part of the restoration of the fernery at Benmore Botanic Garden, helping to direct the replanting after the building had been restored the previous year.[1]: 4 She wrote a book, The Benmore Fernery: Celebrating the World of Ferns, about the project.[1]: 4–5 She was elected president of the British Pteridological Society, taking up the post in April 2010 and serving until April 2013.[5][7] Gibby had also edited the society's journal Fern Gazette since 2002,[8] and continued to do so until her death in 2024.[2]
Gibby was made a member of the Darwin Expert Committee, an advisory group to the UK Department for Environment, Food and Rural Affairs,[9] in 2009; in 2012, she was reappointed for a second three-year term by environment secretary Caroline Spelman.[10] Gibby was awarded an OBE in the 2010 New Year Honours for services to botany.[11]
Gibby retired in 2012 but continued to work at the NHM London and RBGE as a research associate, collections curator and teacher.[1]: 5 In 2014, she presented evidence to the Science and Technology Committee of the House of Commons on the funding of the Royal Botanic Gardens Kew, representing the UK Plant Sciences Federation.[12]
