Heath Fritillary (Melitaea athalia)
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© Nick Greatorex-Davies
In Britain the Heath Fritilllary has much declined is a very rare and highly localised butterfly occuring in sunny situations where the vegetation is sparse and the microclimate at ground level is particularly warm, such as in recent coppice or on moorland edges. Depending on habitat the caterpillars feeds on a range of foodplants including Cow-wheat (Melampyrum pratense) and Ribwort Plantain (Plantago lanceolata). (For further details on this species see http://www.butterfly-conservation.org/).
Status details :
Status since 1981 is Rapid decline with a decrease of -90.8%
Status over the last 20 years is Rapid decline with a decrease of -82.2%
Status over the last 10 years is Rapid decline with a decrease of -82.1%
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 :
Abundance of this rare UK BAP priority species has significanly declined on monitored sites. The Heath Fritillary has a very restricted range in the UK and is only recorded at a small number of UKBMS sites. At a number of these sites, in particular those within the Blean Woods complex in Kent, suitable habitat managment has been put in place and Heath Fritillary populations have responded positively resulting in this decline lessening - at a number of these sites the butterfly regularly produces three figure indices. However, the short-term trend still remains a significant decline. It has been recorded at over fifty sites since monitoring began, but sadly has disappeared from a number of these sites with only half this number now producing site indices. Insufficient creation of suitable open habitat at this woodland site is considered to be the main cause of this decline.
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, Heath Fritillary has been recorded from 155 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 46 sites, with an average index of 276 individuals per site.
For 33 of these sites, Heath Fritillary has been recorded well enough to calculate annual indices of abundance in more years, allowing trends to be calculated.
In 2017, 1355 individuals were recorded from 9 sites, producing annual indices at 19 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
|Stable sites (10)|
|Increasing sites (3)|
|Declining sites (22)|