Nick Isaac, Tom August & Gary Powney Trends in British Biodiversity since

Biodiversity in Crisis

Target 12 By 2020 the extinction of known threatened species has been prevented and their conservation status, particularly of those most in decline, has been improved and sustained.

Population time-series Annual estimates of status Taxonomically restricted How do we know if the targets have been met? Red List indices Many species Temporally-imprecise Botham et al (2011) UK Butterfly Monitoring Scheme Annual Report 2011.

Biological records: the third way Volunteer citizen scientists have been recording biodiversity for centuries A rich source of data for measuring change But the data are biased in space and time

Atlases: Stock & change in distribution

Biodiversity change using atlases Thomas, JA et al. (2004). Comparative losses of British butterflies, birds, and plants and the global extinction crisis. Science, –81

Estimating trends from biological records Data Trends

Trends in British Biodiversity since 1970 What proportion of species are declining? What are the net changes in biodiversity? Which taxa are doing best/worst? Are common or rare species faring best? Number of species Quantitative trends for >5000 species No bird or mammals!

Status of British Biodiversity since 1970 More species show significant increases (19%) than declines(14%)

Significance = Power More significant trends are apparent in groups with most data Dragonflies & Damselflies Moths Long-horn beetles Soldier Beetles Hoverflies Vascular Plants

Trends in British Biodiversity Good news: Median change +2.4%; Net change +4% Bad news: >1000 species would qualify as VU or worse

Median Comparative patterns among taxa Below the line: Rare species are doing better than common (& vice versa) Median % change Net % change

Conclusions Mixed news about the UK biodiversity More increases than declines Many species in steep decline Big losses among some groups, especially ladybirds & centipedes Substantial biotic homogenisation We can report against CBD targets for a much greater range of taxa than previously possible

Acknowledgments Colin Harrower, David Roy, Helen Roy, Michael Pocock, Chris Preston Mark Hill, Arco van