Cambridge City Wildlife Sites are judged against a variety of criteria before being designated as suitable for inclusion on the register. Mill Road Cemetery was included as it contains a number of indicator plant species for semi-improved neutral/calcareous grassland. Indicator species include Hairy Sedge (Carex hirta), Common Knapweed (Centaurea nigra), Lady’s Bedstraw (Galium verum), Perforate St. John’s Wort (Hypericum perforatum), Field Scabious (Knautia arvensis), Common Bird’s-foot Trefoil (Lotus corniculatus), Mouse-ear-hawkweed (Pilosella officinarum), Burnet-saxifrage (Pimpinella saxifrage), Hoary Plantain (Plantago media) and Salad Burnet (Sanguisorba minor ssp. minor).
The uniqueness of the flora and habitat diversity of the site, as well as its position in the heart of the densely-populated city, is also of importance, as is the educational and recreational use of the site.
Since inclusion on the register, the Cemetery has been found to support a nationally important butterfly species, the White-letter Hairstreak, as well as other rare insects, such as the ichneumon wasp, Callojoppa cirrogaster.