Marsh Fritillary (Euphydryas aurinia)
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© Nick Greatorex-Davies
The rare Marsh Fritillary has declined severely in Britain and Ireland. The British population is one of the largest for this species in Europe where it is protected under Annex II of the 1979 Bern Convention and the EC Habitats and Species Directive. It is a species of damp or calcareous grassland occurring in distinct colonies or as metapopulations where it's main foodplant Devil's-bit Scabious (Succisa pratensis) grows. (For further details on this species see http://www.butterfly-conservation.org/).
Status details :
Status since 1981 is Stable with a decrease of -11.3%
Status over the last 20 years is Stable with a decrease of -30.9%
Status over the last 10 years is Stable with a increase of 47%
Log collated index plot
This chart shows the index of abundance (LCI = Log Collated Index) over time. It shows fluctuations in
populations from year to year, and is scaled so that the average index over the whole series is equal to 2
(horizontal line). For greater detail about how this index is derived, click on the green question mark above.
Trend description :
Numbers of this protected species have increased, though not significantly, on monitored sites in the UK. Much of this can be attributed to the implementation of successful habitat management at a number of sites, particularly those in the Wessex Downs in Dorset. It also appears to be doing well in Northern Ireland. Unfortunately there are still a large number of sites where the population has all but disappeared and/or is significantly declining, particularly in Wales where it has significantly declined on monitored sites. At individual sites numbers fluctuate considerably in a cyclic fashion thought to be largely due to interaction with its host-specific parasites; two species of Braconid wasp of the genus Cotesia. There is no overall synchrony in the fluctuations between the sites and the effects are probably staggered across sites over a number of years as can be seen in the great annual variation illustrated in the collated plots.
This map shows the distribution between 1995 and 2016. Data is derived from the Butterflies for the New Millenium dataset via the NBN Gateway
This chart shows the average number of butterflies seen on transects between Arpil and October across all sites (fitted values from a Generalised Additive Model). The blue line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.
This map shows symbols for the mean abundance at transect sites, with the colour of the symbol reflecting the level of abundance. Means are over all years. Grey background squares are the occupied cells as shown by the Butterflies for the New Millenium over the previous ten year period.
In total, Marsh Fritillary has been recorded from 188 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 232 sites, with an average index of 45 individuals per site.
For 89 of these sites, Marsh Fritillary has been recorded well enough to calculate annual indices of abundance in more years, allowing trends to be calculated.
In 2018, 2643 individuals were recorded from 36 sites, producing annual indices at 48 of these.
Links to counts
This map shows the trend in abundance at particular transect sites for which data has been received within the last five years. Trends (increasing, declining or stable) are assessed at sites where the species has more than five years of annual index data. Use the option boxes below to view plots for individual sites.
Links to lists of sites with particular statuses
|Colonised sites (1)|
|Extinct sites (10)|
|Stable sites (93)|
|Increasing sites (13)|
|Declining sites (24)|