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@drnickisaac. Trends in British Biodiversity since 1970. Nick Isaac, Tom August & Gary Powney. Biodiversity in Crisis.
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@drnickisaac Trends in British Biodiversity since 1970 Nick Isaac, Tom August & Gary Powney
Target 12By 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.
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. • Population time-series • Annual estimates of status • Taxonomically restricted
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
Biodiversity change using atlases Thomas, JA et al. (2004). Comparative losses of British butterflies, birds, and plants and the global extinction crisis. Science, 303 1879–81
Estimating trends from biological records http://figshare.com/articles/Extracting_trends_from_citizen_science_data_BES_version_/778699 Method 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? Quantitative trends for >5000 species No bird or mammals! Number of species
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 Hoverflies Vascular Plants Long-horn beetles Soldier Beetles
Trends in British Biodiversity 1990-2000 Good news: Median change +2.4%; Net change +4% Bad news: >1000 species would qualify as VU or worse
Comparative patterns among taxa Below the line: Rare species are doing better than common (& vice versa) Net % change Median Median % 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
https://github.com/BiologicalRecordsCentre http://bit.ly/18wTrrK
Acknowledgments Colin Harrower, David Roy, Helen Roy, Michael Pocock, Chris Preston Mark Hill, Arco van Strien @drnickisaac