David has had lifelong scientific interests in the fields of plant and soil science, mycology, and pollution biology. His particular specialism is in the area of plant-fungal root symbioses-mycorrhizas. He has investigated the biology of this symbiosis in natural, agricultural and forest ecosystems, placing emphasis on elucidation of nutritional roles of the symbionts. He has spent most of his scientific career at the University of Sheffield where he is currently Emeritus Professor of Plant and Soil Sciences but has held visiting research Professorships at the Universities of Cape Town, California (Berkeley) and most recently, (2010-15), Western Australia.
David has supervised 50 PhD students and published over 300 scientific papers. He has been a Thomson-Reuters and ISI Highly Cited researcher for 15 years and has an h-index of 65. He has served on the editorial boards of Science, Philosophical Transactions of the Royal Society, Advances in Botanical Research, Trees, Plants Today
He was Chair of the Board of Trustees at Rothamsted Research (2003-2008) and served as a Board member for 13 years. He chaired the Board of the Macaulay Institute and was a Board member from 2003-2009. He Chaired the Research Advisory Board of the Forestry Commission’s Forest Research Division for 5 years (2006-2011), has been a member of Council of NERC and of the International Advisory Board to the Joint Infrastructure Fund at the Wellcome Trust. He has Honorary Doctorates of Science (DSc) from the universities of Lund (Sweden), Hull and Sheffield. He was awarded the Kempe Prize in Ecology in Sweden in 2002 and an Honorary member of the British Ecological Society in 2007.
David was elected to a Fellowship of the Royal Society in 1990 and served as Biological Secretary and Vice President of the Society from 2003-2008. He was knighted for services to Biological Science in 2008.