News of wildlife and other issues
The Wren Conservation Group held their monthly practical work session in Aldersbrook Exchange Lands – once the Old Sewage Works – on Sunday 6th January. The task was to do some clearance of invasive bramble and some litter-picking, starting just inside the entrance from the lane by the riding-stables.
I elected to do some litter-picking, and armed with rubbish-sacks and a long-handled gripper, began to work my way along the boundary with the Empress Avenue (Aldersbrook) Allotment site.
There were a few bits of rubbish adjacent to the track – typically beer-cans, and perhaps not unexpectedly many with Central European brand names – but it really wasn't too bad. However, immediately adjacent to the boundary fence it was a different matter. Here, all manner of materials had been dumped, including drinks cans, of course, but ranging through plastic bags, netting material, glass, corrugated plastic roof coverings and broken flower pots. The last is a bit of a clue, for almost all of this material had been dumped from the allotments. In some parts there were – as they say - 'literally' mounds of stuff.
Now I would have thought that in essence people that hold allotments would also be people that had some degree of ecological outlook, but that appeared not to be the case. In fact I knew this not to be the case, because it was years ago that I first complained about this lack of respect for the allotment's neighbour, Epping Forest.
The task of clearing much of this accumulated waste was really too much for the Wren Group, and I suggested to the practical work leader that perhaps we should not even attempt it. In fact we collected 15-20 sacks full, plus some stuff too big to fit into sacks.
Individual allotment holders – almost certainly a minority – who are guilty of this fly-tipping should be taken to task by the allotment committee. If this doesn't work then possibly London Borough of Redbridge should bring the committee to task. And what of Epping Forest? The City of London have a responsibility to manage the Forest in an appropriate way, and they have certainly failed for years in this particular respect. I've included a photograph that I took in March 2008 which shows the problem then, and I suggest that all that has happened since is that the rubbish of then is now submerged under more recent stuff.
How can we get a grip on this problem as individuals if those who have, or have been given, responsibility are not carrying it out?
Paul Ferris, 6th December 2013
Back to Bombardier Beetles
On Friday 5th October 2007, having just attended Newham General Hospital to have a broken arm put in a sling, I joined a group of volunteers working nearby to rescue a colony of beetles.
Apart from the awkwardness of trying to unearth and capture a beetle about the size of a medium ladybird from a heap of brick-rubble using only one arm, the task was an enjoyable one – and a potentially important one considering the probable fate of these creatures.
The beetles were Streaked Bombardiers Brachinus sclopeta, and this was the only known colony in Britain. As you may have guessed, the site was due for redevelopment.
My mind has returned to this event because of two articles in the latest (2011/2012) issue of the Essex Field Club's annual journal – the Essex Naturalist. One article “The state of brownfields in the Thames Gateway” discusses the importance what are now termed “brownfield sites” - areas have typically become abandoned after industrial use and where nature has returned to colonise the various habitats and substrates left behind. We would have called these “debris” or “bomb-sites” after the second world war, and to us children they were very much our playgrounds. It is possible that memories of the weeds that we played amongst and caught butterflies and ladybirds gave me my first interest in wildlife.
It is only in recent years, perhaps, that the present day equivalent of these debris have become recognised as havens for a great variety of plants and animals that have otherwise become scarce in our built-up and disturbed surroundings.
So it was on such a site that in 2005 entomologist Richard Jones* discovered a population of a beetle that had been considered extinct in Britain since 1928, and the site was to be developed. The second article “The Beetle Bump: innovative urban habitat creation” describes the efforts put in under the auspices of the University of East London and Buglife to collect 61 Bombardier Beetles and to move them to a specially created habitat and nature reserve nearby. Moving species to a habitat created by man is fraught with difficulties and there are few examples of successful transfers of invertebrates, so this was a rescue attempt carried out as a last resort - and with perhaps little hope of success.
So – was it a success? The original mound of bricks and rubble where the Bombardier's lived has now grown into riverside apartments, and in 2010 the beetles were found to still be living in the mound developed in 2007. One female was also found in Mile End Park, which does suggest that there might be other colonies. In 2012 the mound was searched again, but none were found. However, on another mound a couple of hundred metres away a population was found - but this site was was due for imminent development. In May, Buglife organised another rescue and 15 beetles were transferred to yet another specially constructed site using over 60 tonnes of bricks, chalk and rubble, sown with wildflowers. This is on part of the UEL Docklands Campus site, and the site will be monitored by Buglife and UEL to check the progress of the Streaked Bombardier beetles.
Back to brownfield sites again, then. Between 2005 and 2008 Buglife and English Nature (now Natural England) collaborated on a project called 'All of a Buzz in the Thames Gateway'. This resulted in a clearer understanding of the importance of brownfield sites, 450 of which were assessed in Thames Gateway. Of these, 198 were recognised as being of High or Medium potential for invertebrate biodiversity. Despite this recognition, less than half of these remain intact, and even these may be at risk of development.
Does this have any bearing on our much more localised Wanstead wildlife? Well, I think it does. I can't think of any long-term sites in the area that might be called brownfield sites; any that might have been have been at the least tidied-up by now. One area that does come to mind though – and might be relevant when thinking on bits of land that are perhaps less appealing to our tidy minds and sense of aesthetics – is the fairground site on Wanstead Flats. There were a variety of reasons why many of us didn't want a “muster station” built there for the Olympics – but pretty low down on these was the disturbance to wildlife. Oh, yes – I appreciate the concerns that were raised about the skylark population, and this was an important factor – but the half-day out-of-season wildlife assessment as far as I know took little or no account of the invertebrates that may have lived there.
Biodiversity is a popular term now, but perhaps we should be thinking a little more about this on a local basis. We need a variety of habitats for all of our local plants and animals, and the visiting ones that we get. More and more the birders are beginning to look at some of the other creatures around us, but we still have a vastly long way to go to really build up our knowledge of what species we have here. Whilst that is being undertaken, let's also remember that they can only live here if they have the variety of habitats in which to do so. Maybe we should be creating some? Surely we should not be destroying any.
My thanks to the Essex Field Club and to the Authors of the articles for the information used here.
Paul Ferris, December 2012
References and links
The state of brownfields in the Thames Gateway. Jamie Robins and Sarah Henshall.
The Beetle Bump: innovative urban habitat creation. Stuart Connop.
Essex Naturalist No. 29 (New Series) for the year 2011/2012. http://www.essexfieldclub.org.uk
Buglife – The Invertebrate Conservation Trust, Peterborough. http://www.buglife.org.uk
* Richard Jones ("Bugman Jones") http://bugmanjones.com/
Moth trapping in 2012
It was in 2005 and 2006 that I last put out a moth trap in my garden, which is south of Wanstead Flats and adjacent to Manor Park Cemetery at TQ 413 860. This was part of a moth trapping exercise instigated by the three members of East London Nature. This was to investigate the moth-species that might be found in this part of East London, and the result was that over a hundred species were identified. For more information on this, click here.
This year – 2012 – I put the moth trap out on occasions between 24 February and 22 August. The weather in 2012 was not very conducive to moth-trapping, but whenever I was able and the weather permitted, the trap was set out. I was aware of another problem, too; the lamp of the trap was old, and they apparently do lose their attractiveness (to moths, that is).
East London Nature did have another trap available, one that had been bought for a school project, but the lamp was missing. As this trap was a more powerful one, I obtained the necessary lamp and eventually set it up in the garden.
Considering the inclemency of the weather throughout much of the year the results compared favourably with those of 2005/6. A total of 742 (identified) moths were trapped comprising 154 species. This was clearly better than the previous years and there are a number of reasons why this should be. One is the more powerful lamp that was used compared to 2005/6. Another was the availability of the excellent book which describes and illustrates the micro moths – the "Field Guide to the Micro Moths of Great Britain and Ireland" by Sterling, Parsons and Lewington (British Wildlife Publishing Ltd.). The third perhaps was my own skills in identification based on previous experience – but that was probably negligible.
During 2012 a moth trap was also put out by Tim Harris in his garden on the Lake House Estate near to Bush Wood (TQ 402 870), at the other end of Wanstead Flats to me. Tim's trap was set out for a longer period than mine and probably on more nights - from 23 February to 13 November. The trap was consistently a higher light-output one – comparable to the second of the two that I used - and these factors may well have resulted in the higher numbers caught in the Lake House trap during the year, a total of 1576 (identified) specimens and 170 identified species.
It is interesting to compare results, and Tim has created a pdf file summarising these which is available here.
My own results have been laid out on a spreadsheet of a similar nature to those of 2005 and 2006. These are all available from here.
Paul Ferris, December 2012
Bats in Wanstead Park
One of the most popular events organised by the Wren Wildlife and Conservation Group are bat walks. Why people should want to go out to meet at sunset on a not-necessarily warm evening - possibly to get bitten by midges and mozzies into the bargain - to experience a creature that even if they do catch sight of they'll not really be able to see in any detail, may be a bit of a mystery.
I suspect that part of it is because the whole experience includes aspects that are less common now than once was the case. The bats themselves are perhaps slightly mysterious creatures, and much less commonly seen than would once have been the case. Even being out in the open at night, other than in a town with street-lights, is a somewhat rare experience for many. There is a sense of adventure - hunting down a strange creature – and perhaps wonder, that such creatures may be seen locally.
Wanstead Park is a good spot to see them – in fact it is probably one of the better spots in the whole of Epping Forest. To discover what species of bats we have here calls for some level of expertise, and some technology. Without being really expert, it is difficult to recognise bats whilst in flight – and a special license is required to handle them even if caught. We can't usually get a “handle” on a species as it flies by, and sometimes we may not even be able to see them. So we make use of an electronic device known as a bat detector. These may be purchased from specialist suppliers. They work in a way that in some ways is analogous to a radio receiver, picking up the signals that a bat emits and translating those signals into a sound that is audible to the human ear. Where they differ from radios is that whereas these pick up radio frequency (RF) signals, bat detectors pick up the sounds (audio frequencies) that bats make whilst flying. These sounds are known as echolocation. We can't normally hear those sounds as most are at frequencies inaudible to most human ears. (younger people may do better at this, as people often loose the abilities to hear those frequencies which do come within human hearing range with age)
So, armed with a bat detector or two, a goodly crowd may assemble for a bat walk, to get bitten, trip over tree-stumps, possibly get cold and wet. The offset of all this is the pleasure of being in the company of other people, to have a slightly different experience to the norm, and to experience bats.
Tim Harris has been asked by the Bat Conservation Trust to do a series of transects (a regular and formally plotted walk) to try to ascertain whether Nathusius' Pipistrelle is present in Wanstead Park. This species is one of three Pipistrelle bats in the UK, and is the least recorded. We know that we have good populations of the other two: Common Pipistrelle and Soprano Pipistrelle, and Tim and I have had some indication in recent years that the third may be present. The uncertainty lies in the fact that we can only distinguish between the species by the frequencies of their sonar emissions, which is what the bat detectors are receiving.
Until only a few years ago, in the 1990s, even the Soprano Pipistrelle was not known to exist. However, bat detectors will indicate what frequencies the sonar emissions are on and it was realised that some of the Pipistrelles' echolocation sounds were at a slightly higher frequency, and was indeed a separate species. The frequency at which Common “Pips” are best heard is about 45KHz , whilst the Soprano is at about 55KHz. Nathusius', however is at about 39KHz.
Last year in preparation for a transect, Tim and I walked out and timed a route around much of the Heronry Pond in Wanstead Park. This year, Tim obtained a bat detector and recorder which enables better results than simple model bat detectors, and together with Sharon Payne we set out at 19.40 on 9th September to start the transect. The weather was amiable, a quite warm evening though with a somewhat cooling breeze. The transect takes the form of a series of timed stops-and-walks between pre-determined points.
Particularly along the north edge of the lake, we had numbers of bat “passes”, audible on the detectors if not necessarily visible to the eye. There was a mix of the sounds and frequencies indication both Common and Soprano Pipistrelle, but with just a couple of brief and less determined catches of possible other frequencies and species. However, one of the facilities available to us this evening was the ability to record the whole of the proceedings in such a way that a broad frequency-band log of everything picked up by the microphone was recorded for later analysis.
As I have access to analysis software, a couple of days later Tim and I played the recordings into my computer, and confirmed the Common and Soprano species. The two results which were different to these were of a bat which was emitting closer to 40KHz, which is a possible recording of a Nathusius' Pipistrelle, and another nearer to 60KHz which may be one of the larger species of bat.
The results of this transect will be sent to the Bat Conservation Trust for analysis, and we are required to do another transect in September.
Paul Ferris, 14th September 2012
More flower-slashing at Perch Pond
Having not been into Wanstead Park for some while - due to other commitments - my pleasure at re-visiting the place was short-lived ( as is so often the case these days) when I saw that yet again the wild flower display at the east end of Perch Pond had been cut.
see here) that the water-side and emergent flowers along the whole length of this bank provides probably one of the best displays of colour in the whole Park, and undoubtedly one of the better sites for insects such as dragonflies and damselflies that breed and live here. Indeed, making use of the few remaining perching places left after the slashing machine had done its job, a single Hawker dragonfly and - a bit surprising for this time of year - a Banded Demoiselle damselfly were still present.I mentioned back in early June (
I was horrified in June to find that the vegetation had been cut then, and mentioned that this usually happens in August. Well, it has happened in August (or possibly early September). Why - just as it was recovering - has it needed to be cut again? I haven't heard a good reason. Is this really necessary? Is this just a case of ignoring the beauty and importance of such a habitat in favour of just keeping it tidy?
The same thing has happened along the southern arm of the Ornamental waters, with emergent vegetation having been slashed as well as bankside ones. There were a few newly emerged dragonflies around there, but if we keep destroying their habitat, maybe there won't be in the future.
Paul Ferris, 13 September 2012