|Alexander Stuart Watt|
21 June 1892|
|Died||2 March 1985
|Institutions||University of Cambridge|
|Alma mater||University of Aberdeen|
|Known for||cyclic succession in ecology|
|Notable awards||Linnean Medal (1975)
Fellow of the Royal Society
Watt was born on an Aberdeenshire farm and went to school at Turriff Secondary School and Robert Gordon's College, Aberdeen. He graduated as M.A. and B.Sc. (in agricultural science) from the University of Aberdeen in 1913. He then went to University of Cambridge to work on beech forest under Arthur Tansley and obtained a M.S. in 1919 (after interruption by military service 1916-1918). He was appointed lecturer of forest botany and forest zoology at the University of Aberdeen. He continued his research on southern English beech forest in vacations and obtained a PhD from the University of Cambridge in 1924. In 1929, he became lecturer of forestry at this university and, when this undergraduate subject was given up, lecturer of forest botany – “a title which scarcely reflected his wide interest in and influence on plant ecology”. He retired from university in 1959, but continued work – publishing in the Journal of Ecology as late as 1982, 63 years after his first publication in this journal. He accepted to be visiting lecturer at the University of Colorado in 1963 and visiting professor at the University of Khartoum in 1965. In 1970, he co-organized a symposium science in nature conservation. He was president of the British Ecological Society 1946-1947. Fellow of the Royal Society since 1957. He was awarded the Linnean Medal of the Linnean Society in 1975.
Watt’s 1947 paper Pattern and process in the plant community in the Journal of Ecology, being his presidential address to the British Ecological Society, is a true citation classic in scientific ecology. The paper describes the plant community "as a working mechanism, which maintains and regenerates itself". The view it advocated that a plant community consists of a mosaic of phases differing in the stage of the life cycle of the dominant species, with correlated effects on the accompanying species. One of the examples given by Watt concerns the dynamics between grasses and dwarf-shrubs in sandy heathland. The 50th anniversary of the paper was celebrated by a special issue of the Journal of Vegetation Science 
Watt published a long series of scientific papers in the New Phytologist under the collective heading "Contributions to the ecology of bracken" (1940–1971). Watt was a posthumous co-author of the substantive account on bracken in the Biological Flora of the British Isles. Watt wrote a series of preliminary drafts that were extended and updated by his co-author.
- Greig-Smith, P. (1990). "Alexander Stuart Watt. 21 June 1892-2 March 1985". Biographical Memoirs of Fellows of the Royal Society. 35: 404–423. doi:10.1098/rsbm.1990.0019.
- "Dr Alexander Stuart Watt, F.R.S. 1982-1985". Journal of Ecology. 74 (1): 295–300. 1986. JSTOR 2260365.
- "The Oxford Dictionary of National Biography". 2004. doi:10.1093/ref:odnb/31812.
- Grieg-Smith, P. (1982) A.S. Watt, F.R.S.: A biographical note. Pp. 9-10 in Newman, E.I., The plant community as a working mechanism. Special publication series of the British Ecological Society No. 1; Blackwell Scientific Publ., Oxford.
- Watt, A. S. (1919). "On the Causes of Failure of Natural Regeneration in British Oakwoods". Journal of Ecology. 7 (3): 173–203. doi:10.2307/2255275.
- Duffey, E. & A.S. Watt (1971) The scientific management of animal and plant communities for conservation. The 11th symposium of The British Ecological Society, University of East Anglia, Norwich, 7–9 July 1970. Blackwell Scientific Publ., Oxford.
- Watt, A. S. (1947). "Pattern and Process in the Plant Community". Journal of Ecology. 35 (1): 1–22. doi:10.2307/2256497.
- Current Contents no. 30, 1986
- McIntosh, R.P. (1989). "Citation classics of ecology". The Quarterly Review of Biology. 64 (1): 31–49. doi:10.1086/416129.
- Maarel, E. V. D. (1996). "Pattern and Process in the Plant Community: Fifty Years after A.S. Watt". Journal of Vegetation Science. 7 (1): 19–28. doi:10.2307/3236412.
- Marrs, R. H.; Watt, A. S. (2006). "Biological Flora of the British Isles: Pteridium aquilinum (L.) Kuhn". Journal of Ecology. 94 (6): 1272–1321. doi:10.1111/j.1365-2745.2006.01177.x.
- Watt, A. S. (1981). "A Comparison of Grazed and Ungrazed Grassland a in East Anglian Breckland". Journal of Ecology. 69 (2): 499–508. doi:10.2307/2259680.
- Watt, A. S. (1981). "Further Observations on the Effects of Excluding Rabbits from Grassland a in East Anglian Breckland: The Pattern of Change and Factors Affecting it (1936-73)". Journal of Ecology. 69 (2): 509–536. doi:10.2307/2259681.