www.ukbutterflies.co.uk

Hi all - here's an official statement on habitat management at Noar Hill and I, for one, appreciate the time that Dan has taken to put things in context of a bigger conservation picture:

Blackthorn management at Noar Hill – a perspective from Butterfly Conservation
Dr Dan Hoare, Senior Regional Officer 04.03.14
dhoare@butterfly-conservation.org

"In response to concerns about blackthorn management this winter at Noar Hill, and its impact on Brown Hairstreak, I thought it would be worth providing a bit of background information.

Hampshire & Isle of Wight Wildlife Trust, who manage Noar Hill, have to balance the management requirements of a whole range of wildlife (including Brown Hairstreak, Duke of Burgundy and other scarce butterflies) and weigh up necessary habitat management against possible short-term impacts on particular species in particular areas of the site. In this instance, the HIWWT Reserve Manager specifically sought advice in advance from Butterfly Conservation on their plans for blackthorn management this winter. HIWWT staff and volunteers carried out an egg survey ahead of the management this year, which helped them identify several clumps of blackthorn with a high density of eggs on that could retained to minimise the damage to this species. The northern end of the site, including ‘the triangle’ are especially favoured by Brown Hairstreak and in fact the planned scrub management here had been postponed for the last two winters to limit damage to this butterfly at the egg stage. But eventually these areas of scrub do need to be cut, as part of the planned rotational management, to prevent the loss of the grassland that they are encroaching on. We recommend and support a programme of regular cutting, on rotation, so that different areas are cut each year, scrub edges on the site move back and forth from year to year and there is always new fresh growth springing up, which is what the butterfly needs.

I sympathise with visitors who are concerned by damage on particular areas where they saw a given butterfly recently, but the Brown Hairstreak is a butterfly that breeds extensively over a large landscape and the loss of individual patches of scrub, and the eggs they support, will have little or no impact on the population as a whole. Many hundreds of eggs are laid (particularly in a good year for the species, as 2013 was) and most will not make it through to adulthood next year due to predators, parasites, fungi and other factors. Eggs remain easy to find in and around Noar Hill this winter, on the reserve itself and for several kilometres around in hedges and small blackthorn patches.

Habitat management inevitably causes some loss (and may mean observers need to look elsewhere next season), but what is important for the long-term health of the population is a rotational management system across a wide area that ensures a continuous supply of young blackthorn in a variety of situations. This is what HIWWT are working hard to try and produce. Indeed they are part of a new agreement between several organisations, including Butterfly Conservation, the National Trust, the South Downs National Park Authority and Game & Wildlife Conservation Trust, to work together in a Selborne Landscape Partnership to improve habitats in the area for Brown Hairstreak, Duke of Burgundy, farmland birds and a range of wildlife.

I would reassure butterfly enthusiasts that HIWWT are spending a lot of time, effort and money on trying to maintain the fabulous site at Noar Hill for Brown Hairstreak and other wildlife. Please do continue to pass on your wildlife records and observations, including where you’ve seen a species this year, and what you think worked or didn’t work from previous management. There are also plenty of volunteering opportunities in the area with HIWWT, Butterfly Conservation and other organisations if you want to get involved, contribute your ideas and experience and help make the area even better in future."

Cheers,

- Pete

Hi Pete, thanks for that information and thanks to Dan for giving us the overall picture of ongoing habitat management at Noar Hill. We fully understand the reason behind the management practises carried out at Noar Hill and appreciate a lot of hard work is put into maintaining the habitat for the diversity of wildlife species there. However, we believe it could further benefit the Brown Hairstreak population at Noar Hill if, prior to the necessary scrub management being carried out, there was some form of notice given, perhaps a message on Butterfly Conservation's website? This way, interested persons would be given the chance to collect the eggs that would otherwise be lost, and those that were successfully reared through to adults would be released back onto the site. Not trying to tread on anyone's toes here, but considering only about 1 egg in 100 in the wild will reach adulthood, surely the opportunity to make a difference, albeit a small one, by home-rearing, makes sense.
We have, at present, 15 Brown Hairstreak eggs which we found on cut pieces of blackthorn at Noar Hill, and hope that the odds, in our controlled conditions at home, are going to be far better. We hope, therefore, to release some adults back onto the reserve at Noar Hill this summer. We are also aware that other people are doing the same thing, which can only be a positive step, because these eggs would otherwise have perished.

Cheers,

Mike

HI Mike - yes, I was quite relieved to see the explanation and the fact that BC is fully-aligned on the habitat management at Noar Hill.

With regard to egg rescues - I suggest you contact Hampshire Wildlife Trust directly to see what might be possible. I'm afraid I have no contacts that I can connect you up with - but I'm sure their office can! Let us know how you get on.

Cheers,

- Pete

Hi Pete
many thanks for following up on this and it is very reassuring that someone as knowledgeable as Dan is comfortable with the management regime at Noar Hill, and also that Butterfly Conservation was consulted before the thinning took place.
I guess it always looks drastic when you see this sort of activity, and to a butterfly enthusiast to find eggs as rare as BH that have been severed from their host plant and left unviable is distressing - but I guess in the grand scheme of things there will always be many more left unscathed.
I too have a dozen or so ova that I rescued so i think there may well be a grand ukb release at some time in August
I would support mikes idea that if somehow a rescue egg hunt could be organised prior to any future management, whilst It might be small beer in the grand scheme of things, at least we would feel that we had done one thing to mitigate any losses?
Kind Regards
Mark.

Unfortunately this is a problem that I have commented on regularly for the last 20 years. Large areas of blackthorn have been cut most winters and bonfires lit over the cut stands with the result that that no regrowth has occurred. The result is that not only has the numbers of Brown Hairstreaks dropped markedly in this time but areas of bushes that sheltered orchids have been replaced by general scrub, notably on the area that was scraped to chalk some years ago. Recently the annual winter destruction has been reduced but I am not looking forward to my first visit this year.

It is always difficult to get the balance right in situation such as these. Sadly with so few natural areas left in this country we have to manage those areas to keep them as humans think best. This usually results in us trying to maintain these areas "frozen in time" preventing the natural progression to scrub and woodland.
Up here, much of our coastal grassland has been taken over by Sea Buckthorn. There is much speculation over whether this is native or introduced up here. Regardless, if it is left unchecked, it will take over completely, killing out the grasses and flowers and stifling the establishment of trees. It creates lovely, impenetrable thickets for birds to nest in and the berries are a great winter food source for birds. In recent years we have been removing a lot of Sea Buckthorn to try to return areas to coastal grassland. This has had a very positive impact on wild flowers and hopefully a consequent knock on for invertebrates and birds.
It will be a constant battle to keep some areas of Sea Buckthorn for coastal protection and to provide shelter for wildlife, but stopping it spreading, which it does very rapidly. We have many willing volunteers to help out with this.
Being a local authority, we manage various inland sites as well. These tend to be mostly grassy hills, which are not suitable for arable crops and which have become magnets for the public to walk and take in the views. Historically these areas were grazed, but recently they were left un-grazed because of the many dog walkers, etc. However, we have found that gorse has taken over and the grass has become thick, shading out other flowers. We have therefore removed much of the gorse and re-introduced grazing - sheep, cattle or ponies depending on the site. This has had an immediate positive impact for the wild flowers, but we have had many complaints from the public. Bird watchers are concerned about the loss of nesting sites for birds, dog walkers don't like being followed by intimidating stock and many of the paths have become a little churned up.
I am very interested to see how this management will impact on butterfly numbers. A couple of years ago we had our first Small Skippers appear on a local nature reserve where the Sea Buckthorn had been reduced. Now that we have sheep grazing there, I am concerned that the loss of tall grass may impact on the Small Skippers.
In other areas where we have a lot of Ringlets and Meadown Browns I worry that trampling and heavy grazing over the winter will kill off their caterpillars. Hopefully not, though.
It is early days and given the mixed weather we have had in recent years it is difficult to know what the impact of this management is, but surely it will be better to maintain areas for wild flowers, grassland and scattered scrub than to let these areas be taken over by Sea Buckthorn and Gorse.