Richard Chadd FLS (died 5 November 2021) was a British ecologist and biologist.^[1]

Chadd was a freshwater ecologist. He worked as a senior environmental monitoring officer with the Environment Agency.^[2] He was an active member and recorder with the Lincolnshire Naturalists' Union, serving as its recorder of fresherwater invertebrates from 2003 onwards and as its president in both 2005 and 2020.^[1] At the time of his death he was a board member of the Freshwater Biological Association^[3] and of The Riverfly Partnership.^[4] Chadd was a Fellow of the Linnean Society.

• Dunbar, M.J., Pedersen, M.L., Cadman, D., Extence, C., Waddingham, J., Chadd, R., and Larsen, S.E. 2010. "River discharge and local-scale physical habitat influence macroinvertebrate LIFE scores". Freshwater Biology 55: 226-242. doi:10.1111/j.1365-2427.2009.02306.x
• Dunbar, M.J., Warren, M., Extence, C., Baker, L., Cadman, D., Mould, D.J., Hall, J. and Chadd, R. 2010. "Interaction between macroinvertebrates, discharge and physical habitat in upland rivers". Aquatic Conservation: Marine and Freshwater Ecosystems 20: S31-S44. doi:10.1002/aqc.1089
• Mathers, K.L., Chadd, R.P., Dunbar, M.J., Extence, C.A., Reeds, J., Rice, S.P., and Wood, P.J. 2016. "The long-term effects of invasive signal crayfish (Pacifastacus leniusculus) on instream macroinvertebrate communities", Science of the Total Environment 556: 207-2018.
• Chadd, R. and Eversham, B. 2010. "Other invertebrates", in Maclean, N. (ed) Silent Summer: The State of Wildlife in Britain and Ireland. Cambridge University Press.
• Chadd, R. 2010 "Assessment of Aquatic Invertebrates", in Biological Monitoring in Freshwater Habitats, 63-72.