Winter works ensure a bounty of butterflies next summer

Large_butterfly_5_harry_clarke_Butterfly (Harry Clarke)

It may seem strange to be thinking about butterflies in December, but Surrey Wildlife Trust (SWT) is busy carrying out habitat management work at Norbury Park (which the Trust manages on behalf of SCC), to create the right conditions for the beautiful insects to flourish next summer.

The woodland is being carefully managed to provide open rides and glades, which will attract more butterfly species than a dark closed-canopy woodland, as will ensuring the open grassland is complimented with a good mixture of scrub,  hedgerow  (which attracts hairstreaks and gatekeepers) and the occasional tree. 

The management is informed by the results of thorough surveys undertaken each year, along the same set route in woodland as well as in grassland areas, so that a good representation of species, specific to these habitats, are recorded.  The route is walked once a week between April and September and, within each predetermined section, any butterflies spotted within five metres of the surveyor are recorded.  The statistics can be analysed at the end of the season or general trends can be detected over a number of seasons.  Any particular habitat management work carried out along the route, like glade creation or hedgerow management, is noted in the survey, to explain the increase in butterfly numbers in that particular area. 

Norbury Park is great for butterflies; fifteen species have been recorded on a regular basis with another six species being occasionally recorded, including the clouded yellow and painted lady (which occur in hot summers); the most common species being meadow brown and ringlet (typical grassland meadow species).  However, the Trust can only do so much, as weather plays an important role in the success of butterflies: fine summer months usually give rise to good numbers (some species, like the marbled white, have two broods in a good dry summer and surveys will pick up these peaks) but the early spring weather is more important, when the butterfly is at egg, pupae and caterpillar stage.  Late frost or long periods of rain can slash the number of butterflies reaching maturity. 

SWT countryside manager, Graham Manning, says: “After many years of watching and recording butterflies I am still enchanted by my first sighting each summer of the silver-washed fritillary, as it flits through the woodland glade created and kept open by the SWT ranger team. It’s with this thought in mind that future management works need to be identified to specifically benefit our butterfly species, so surveying can carry on and prove that populations can be sustained and improved.”

Date published: Tuesday 06 December 2011