Educated at Shene County Grammar School (London SW14), at Reading University (1971-74) and at Royal Holloway College, London University (1975-78). Was employed from May 1979 as an invertebrate zoologist with the Biological Survey Team of the National Trust (based in Cirencester, Glos), latterly becoming Team Leader; since 2003, a freelance ecological consultant. His main interest is in saproxylic invertebrates but he also co-ordinates the Soldier Beetles, Jewel Beetles & Glow-worms Recording Scheme (Provisional Atlas published in 2003). He was the county Coleoptera Recorder for Gloucestershire until re-locating to Exeter in 2003. He is now the county Coleoptera Recorder for Cornwall. He is a member of the Editorial Board of The Coleopterist and an Associate Editor of the Journal of Insect Conservation. A member of the European committee of three which oversees the Symposia and Workshops on the Conservation of Saproxylic Beetles, which run every other year; also Honorary Specialist Advisor to the IUCN on European Saproxylic Beetles.
Personal collection consists of 28 storeboxes of mostly British and Irish material. A high proportion of the specimens are from western Britain. Some of the Welsh specimens have been lodged with the National Museum of Wales; other material is with the National Museum of Scotland in Edinburgh.
Publications exceed 650 and include: ‘The population ecology of some woodland carabid beetles, with particular reference to their dispersive behaviour’ (PhD Thesis, 1986, available on-line at https://repository.royalholloway.ac.uk/items/ed4c46b0-bbb8-4f5e-8697-b9d09211b8d1/1/; ‘The deadwood fauna of Cornwall’ Brit.J.Ent.nat.Hist., 1993, 6, 97-101; ‘The saproxylic invertebrates of historic parklands: progress and problems’ jointly with P.T. Harding, in: Kirby K.J. & Drake C.M. (eds.) Dead wood matters: the ecology and conservation of saproxylic invertebrates in Britain. English Nature Science, 1993, 7, 58-73; ‘The use of saproxylic invertebrates in the selection and evaluation of areas of relic forest in pasture-woodlands’ jointly with P.T. Harding, Brit.J.Ent.nat.Hist., 1994, 7 Suppl. 1, 21-26; ‘The use of freshly downed timber by insects following the 1987 storm.’ In: K.J. Kirby & G.P. Buckley (eds.) Ecological responses to the 1987 Great Storm in the woods of south-east England. English Nature Science, 1994, 23; ‘Historic parks and pasture-woodlands: the National Trust resource and its conservation’. In: D.J, Bullock & H.J. Harvey (eds.) The National Trust and nature conservation: 100 years on. Biological Journal of the Linnaean Society, 1995, 56 (Supplement), 155-175; ‘The links between forest history and biodiversity: the invertebrate fauna of ancient pasture-woodlands in Britain and its conservation’ in: Kirby KJ & Watkins, C (eds) The Ecological History of European Forests. CABI, 1998, 73-80; ‘The invertebrates of Britain's wood pastures’ British Wildlife, 1999, 11, 108-117; ‘The Saproxylic Quality Index: evaluating wooded habitats for the conservation of dead-wood Coleoptera’ with AP Fowles & RS Key, Col., 1999, 8, 121-141; ‘The invertebrates of living and decaying timber in Britain and Ireland – a provisional annotated checklist’, English Nature Research Report, 2002, 467; ‘A review of the invertebrates associated with lowland calcareous grassland’ English Nature Research Report,2003, 512; ‘Revision of the Index of Ecological Continuity as used for saproxylic beetles’, English Nature Research Report, 2004, 574; ‘Surveying terrestrial and freshwater invertebrates for conservation evaluation’ with C.M. Drake, D.A. Lott & J Webb, Natural England Research Report, 2007, NERR005; ‘The special importance of traditional orchards for invertebrate conservation, with a case study of the BAP priority species the Noble Chafer Gnorimus nobilis’ Landscape Archaeology and Ecology, 2008, 7, 12-18; ‘European Red List of Saproxylic Beetles’ with A. Nieto, 2010, Luxembourg: Publications Office of the European Union; ‘The Noble Chafer and Traditional Orchards - an old-growth species in the English cultural landscape’ British Wildlife, 2011, 23, 17-22; ‘The beetles in decaying wood in Ireland. A provisional annotated checklist of saproxylic Coleoptera.’ With R. Anderson, Irish Wildlife Manuals. National Parks and Wildlife Service, Department of the Arts, Heritage and the Gaeltacht, Dublin, Ireland, 2005, 65; ‘Ancient trees, grazing landscapes and the conservation of deadwood and wood decay invertebrates.’ In: Rotherham I (ed) Trees, Forested Landscapes and Grazing Animals. A European Perspective on Woodlands and Grazed Treescapes, 2013; ‘A review of the scarce and threatened beetles of Great Britain. Buprestidae, Cantharidae, Cleridae, Dasytidae, Drilidae, Lampyridae, Lycidae, Lymexylidae, Malachiidae, Phloiophilidae and Trogossitidae’. Species Status No. 16, Natural England Commissioned Report, 2014, NECR134; ‘A review of the scarce and threatened beetles of Great Britain. The darkling beetles and their allies. Aderidae, Anthicidae, Colydiidae, Melandryidae, Meloidae, Mordellidae, Mycetophagidae, Mycteridae, Oedemeridae, Pyrochroidae, Pythidae, Ripiphoridae, Salpingidae, Scraptiidae, Tenebrionidae & Tetratomidae (Tenebrionoidea less Ciidae)’ with Dodd, S. & Denton J. Species Status No. 18, Natural England Commissioned Report, 2014, NECR148.
There are 31 pages of correspondence with Colin Johnson in MUNHM (Box 12) dated between 1983-2001.
Alexander was elected FRES in 1978, joined the British Ecological Society in 1975, a Member of the Chartered Institute of Ecology and Environmental Management, and a Chartered Environmentalist (since 2005). Recipient of the Marsh Award for Insect Conservation in 2005 (RES). Council Member & Trustee, British Entomological & Natural History Society, 2005-2006 & 2013-14. He is listed by James (2018) as providing a special contribution. He lives at 59 Sweetbrier Lane, Heavitree, Exeter EX1 3AQ. (KNAA 6.8.2017, MD 1/22).