Joyce Lambert, who died on May 4 aged 88, deduced that the Norfolk Broads were not created naturally but were man-made, a discovery that has transformed our understanding of the area.
Her interest was aroused in the early 1950s after the stratigrapher JN Jennings suggested that the Broads were naturally formed. Although his views won widespread acceptance, Joyce Lambert, a young botanist studying the plant species of the area, felt instinctively that he was wrong.
Deciding to conduct her own research, she made a series of close-space borings through the silt to the underlying peat, in the course of which she discovered that the watercourses were generally basin-shaped with vertical rather than sloping sides. This suggested that they could not have been natural in origin, but must have been dug out by man.
When she set out her preliminary conclusions in an address to the Norfolk and Norwich Naturalists Society in April 1952, her ideas were greeted with scepticism.
It seemed impossible that so large a volume of material could have been excavated by hand, and no one seemed to have any idea what it might have been used for.
To test the theory, a team of academics was assembled under the auspices of Cambridge University to collaborate with Joyce Lambert on further research. The historical archive revealed that, between the 12th and 14th centuries, there had been a huge demand for peat for fuel in what, by the 14th century, had become one of the most densely populated and prosperous areas of England.
Norwich Cathedral Priory, for example, had used peat turf on a large scale in its kitchens in the early 14th century. Peat was also used in the extraction of salt, an important local industry.
It was discovered that each parish in the Broads area possessed "Turbary rights", which meant that they had the right to dig peat within a specified area.
Ancient Tithe maps showed the boundaries for these rights, and Joyce Lambert realised that these coincided with the shape of each Broad and, in some cases, outcrops from the shore and lines of little islands dotted across the water. Peat-cutting, it seemed, had been carried out on a massive scale, with almost every settlement in the Broads area digging its own pit, or turbary.
Further studies of manorial records revealed that, from the 14th century onwards, references to turves and turbaries gave way to fish and fisheries, suggesting that the peat diggings gradually began to fill with water, making the peat more difficult to extract. The diggings were eventually abandoned and the man-made landscape became transformed into a wetland.
The team's findings, presented in a Royal Geographical Society Paper, The Making of the Broads (1960), vindicated Joyce Lambert's theory and transformed our understanding of the formation of the Broads and our knowledge of the economy of the area in the Middle Ages.
Joyce Lambert was born at Brundall, near Norwich, in 1916 and educated at Norwich High School for Girls. She studied Botany at the University of Wales at Aberystwyth and later took a doctorate at London University.
It was while she was carrying out post-graduate research into the ecology of the Yare Valley Broads that she became interested in their origin. She also published a range of papers about Broadland ecology. Analysis of data which she collected in the Norfolk Broads area highlighted parish boundaries rather than environmental variables in determining species location.
The reason for this, she suggested, lay in the different ways each parish had treated its land in the medieval period. For example, some had done drainage work and others had used fertiliser. These differences had influenced the environment sufficiently to affect the present pattern of species distribution.
In 1961 Joyce Lambert was appointed lecturer in Botany at Southampton University, where she played a leading role in the establishment of studies in environmental sciences and in the development of statistical techniques for mapping and analysing the spread of plant species. She published widely on ecological issues, relating in particular to salt marshes.
After her retirement from Southampton, in 1979 Joyce Lambert returned to live in the house her grandfather had built at Brundall. She continued to work to widen understanding of the Broads, and her research played an influential part in The Land Use and Conservation of Broadland (1992) by Martin George, a former chairman of the Broads Society.
A short, square, vigorous woman, Joyce Lambert was a keen supporter of Norwich City Football Club. She was never happier than when she was out in the field or tending her garden. Although bedridden in her last years, she retained her mental powers to the last and loved engaging friends in philosophical discussions about the meaning of life.
She never married.