This report presents the first comprehensive review of the status of British mammal populations for over 20 years. The population size, range size, temporal trends and future prospects of Britain’s 58 terrestrial mammals are assessed. Island races and feral mammals are excluded from the main review, but are considered in the appendix.
The geographical ranges of 18 species have increased since 1995, 4 have declined, and 22 have remained stable. A lack of data prevented the assessment of the remaining 14 species. Population sizes have increased since 1995 in 15 species, 9 have declined, and 4 have remained stable. A lack of data prevented the assessment of the remaining 30 species.
The report highlights an urgent requirement for more research to assess population densities in key habitats, and to assess the percentage of potentially suitable habitat where a given species actually occurs: at present, uncertainty levels are unacceptably high. It is possible that declines in many species are being overlooked because a lack of robust evidence precludes assessment. Finally, effective and evidence-based strategies for mammal conservation and management must be developed.