BUTTERFLY CONSERVATION UPPER THAMES BRANCH
Wood White Report 2008
Becky Woodell
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| Photo © Richard Soulsby |
The Wood White is the second most rapidly declining species in the UK.
It is found in only 10-12 tetrads in eight sites in our region. Records were received from two of the known eight sites. Two other sites, Little Linford and College Wood, have had no records for two years. The best site in the three counties is under threat of almost certain development and UTB members are attempting to learn as much as possible about the site and the Wood White requirements there in order to put forward proposals to alleviate the damage.
Habitat Requirements
In March 2008 Butterfly Conservation held a meeting to discuss the status of the Wood White in the UK and to report on recent research into the habitat requirements of the Wood White. Stephen Jeffcoate reported that in the first brood bare ground is important. The butterfly lays its eggs on shorter plants growing in more open places with bare ground which is warmer. This habitat has never been a feature of any site in our region, including Whitecross Green Wood, our most intensively monitored site, where habitat is more like that of an unimproved hay meadow. Previously, bare ground was not mentioned as being important for Wood Whites. Becky Woodell reported on the history and current status of the Wood White and its habitat at Whitecross Green Wood.
In recent years the formerly strong colony at Whitecross has been in steady decline. The habitat is changing to a coarser, denser vegetation although Wood White food plants remain abundant. This vegetation change may be caused by:
1. Lack of grazing since BBOWT bought the wood.
Previously 2 elderly cows grazed there daily. BBOWT attempted to continue grazing with sheep but once the wood was opened to the public there were problems with dogs chasing the sheep and grazing had to be abandoned.
2. Atmospheric nitrogen pollution.
This is caused by cars, industry and agriculture and is high in our area. High nitrogen levels in the soil cause the vegetation to become coarser and denser which would make the microclimate cooler. This could be adversely affecting the Wood White population.
The first Wood White at Whitecross Green was seen on 18th May and the last on 24th June which is a short flight period for this species. The total sightings for 2008 were 26. Of these 12 were in the Visitors' Book and not all can be confirmed.
Future Management
In December Butterfly Conservation and Forest Enterprise held a joint meeting in Northants about the management needs of Wood White in FE sites in Northants and north Bucks. It is hoped that following this meeting better management will be undertaken in any under-managed woods.
How you can help ...
If you visit any Wood White sites this summer (2009) in the Upper Thames region Becky Woodell would very much like to receive the following information: Date, Site name, Site Grid Ref, weather conditions, whether bare ground was present in any amount, number of Wood White seen (including none seen), your name and contact details (e-mail; phone number). If possible try to locate egg laying females and note the species of plant on which they are ovipositing. Butterfly Conservation is carrying out a national Wood White survey in 2009 and your information is helpful. If you are interested in helping with the ovipositing part of the survey, there is a special form for this which Becky will be pleased to send you.
The following woods in Upper Thames region have Wood White colonies and are open to the public:
| College Wood | SP 790330 | Woodland Trust |
| Wicken Wood | SP 733405 | Forest Enterprise |
| Whitfield Wood | SP 644394 | Forest Enterprise |
| Little Linford Wood | SP 834455 | BBOWT |
| Whitecross Green Wood | SP 605145 | BBOWT - This wood is monitored regularly so it is more valuable to help by going to the other sites. |
