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Gatekeeper/Hedge Brown (Pyronia tithonus)
© Nick Greatorex-Davies
The Gatekeeper is a common species of sheltered grassland such as adjacent to scrub, along hedgerows, woodland edges and rides where its larvae feed on a range of fine and medium-leaved grasses. The butterfly is expanding its range in Britain. (For further details on this species see http://www.butterfly-conservation.org/).
Family: Satyridae
Status: Stable
Status details:
Status since 1976 is Stable with a decrease of -10.1%
Status over the last 20 years is Stable with an increase of 53.5%
Status over the last 10 years is Stable with an increase of 12.8%
Back to the topLog 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:
The collated indices show no significant trend indicating overall stability in numbers. However there have been large fluctuations in abundance over the monitoring period in an apparently cyclic fashion. There is often with a high degree of synchrony in fluctuations between sites across the country indicating that weather conditions have a particularly strong impact on this butterfly. In the years 1985-88 the butterfly experienced a huge decline following its highest index of the series in 1984, but this was followed by three years of increase that took it to a well above average level. This decline and increase corresponded well with a decline and increase of several other species of the browns (Satyrinae).
Distribution...
This map shows the distribution between 1995 and 1999. Data is derived from the Butterflies for the New Millenium dataset via the NBN Gateway (www.searchnbn.net).
View the distribution on the NBN GatewayPhenology...
Phenology plot
Phenology plot
This chart shows the average number of butterflies seen on transects between Arpil and October. The black line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.
Abundance...
Abundance
This map shows symbols for the mean abundance at transect sites, with the size of symbol reflecting the level of abundance. Means are over all years.
Coverage
In total, Gatekeeper/Hedge Brown has been recorded from 799 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 914 sites, with an average index of 176 individuals per site.
For 438 of these sites, Gatekeeper/Hedge Brown has been recorded well enough to calculate annual indices of abundance in 6 or more years, allowing trends to be calculated.
In 2006, 89986 individuals were recorded from 536 sites, producing annual indices at 425 of these.
