The Pearl-bordered Fritillary butterfly population is declining, with a 66% reduction since 1976 and loss of 61% of occupied habitat since 1970. There are now only 12 established colonies in southeast England. However, targeted management of habitat within 2km of colonies from 2007-2011, including management of woodland rides and clearings, led to an increase in the Pearl-bordered Fritillary population and the recolonization of 2 additional sites. While intensive effort can help recover at-risk species populations, long-term management is still needed to sustain them.

1. South Downs National Park Authority
A species on the brink
Pearl-bordered Fritillary
Dan Hoare
Butterfly
Conservation

2. 70% of butterflies are in decline
Thomas, J.A. et al. 2004, Science 303, 1879.
Datasets from last 20-40 years

3. Habitat specialists (blue) and wider
countryside species (red)

4. Woodland (green) and
farmland (brown)

5. Woodland butterflies by habitat
0
50
100
150
200
250
1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009
Index(1985=100)
Rides
Clearings
Mature
All
-80%

6. Pearl-bordered Fritillary

8. Declining abundance
• 66% population
decline since 1976
• 46% decline from
1995-9 to 2005-9

9. Declining distribution
• 61% distribution
decline 1970-2004
• 43% decline in
occupied 10km
squares in 10 years

10. South East colonies since 1995

11. South East colonies
• 12 established sites (more than 50 extinctions since 1990s)
• 2 recent colonisations on chalk grassland
• 3 ongoing reintroductions

12. Landscape boundary
Woodland sites
Landscape-scale species conservation

13. Landscape boundary
Unmanaged 2007
Managed 2007
Tytherley Woods 2007

14. Landscape boundary
Unmanaged 2007
Managed 2007
Pearl-bordered Fritillary 2007
Pearl-bordered Fritillary 2007

15. Landscape boundary
Unmanaged 2007
Managed 2007
Pearl-bordered Fritillary 2007
2km focal area around colonies
Targeted management 2007-11

16. Landscape boundaryLandscape boundary
Unmanaged 2010
Managed 2010
Pearl-bordered Fritillary 2007
2km focal area around colonies
Targeted management 2007-11

17. Pearl-bordered Fritillary
colonisations 2008-2011
Landscape boundary
Unmanaged 2010
Managed 2010
Pearl-bordered Fritillary 2007
2km focal area around colonies
Colonisations 2008-11

18. South East colonies
• species can be brought
back from the brink with
targeted effort
• species responses
demonstrate the success of
habitat management
• but it takes a lot of effort...

19. Biological Records Centre