He is experienced in the recording, analysis, interpretation and statistical modelling of ecological change in temperate ecosystems, with an emphasis on vascular plants. He has led projects investigating large-scale changes in plant species composition, often focused on four key questions about ecological change over the last approximately 100 years of human domination: what has changed and where; why have the changes occurred; do they matter; and, can we use the answers to develop models that may help estimate future states?

Simon instigated and manages the development of the MultiMOVE package of realised niche models for British plant species and designed and co-wrote the MAVIS software program for assignment of vegetation to the National Vegetation Classification which has over 3,500 users in Britain. He recently ran the third GB-wide broadleaved woodland resurvey and analysis of change. Simon is an enthusiastic botanist having been a member of the Botanical Society of Britain & Ireland since 1990 and has served as an elected member of BSBI council. He is currently BSBI plant recorder for an area covering the lumpy glory of Jura, the balmy machair of Colonsay, the relatively populous Islay and a number of uninhabited outlying islands. He also took over as Land-Use Group Leader in December 2019.

A recent project to assess 1,300 plants that contribute to services and functions in British ecosystems resulted in an online application to allow users to examine and assess the niche model for their favourite plants.