conference – Grantham Ecology

Midlands Bat Conference 2014

May 14, 2014Grantham EcologyLeave a comment

The Bat Conservation Trust runs an annual Bat Conference in September each year which is attended by bat groups, enthusiasts and professionals from around the country. They also hold regional conferences once every two years and this year’s Midlands conference was at the end of April. The focus of the conference is not exclusively based in the region, but has talks from local bat group members and researchers as well as spotlight talks from the various bat groups in a region so that neighbouring groups can find out about projects which others in the area are involved in.

Morgan Bowers talking about the Brumbats Flight Cage at the BCT Midlands Bat Conference 2014 (image borrowed from the BCT Twitter feed)

The Warwickshire Barbastelle Project

Lois Browne gave an inspiring talk on the Warwickshire Barbastelle Project which has been running in Warwickshire for the last two years. This project studied the behaviour and habits of one of the rarest bat species in the UK through trapping and radio-tracking as well as traditional acoustic survey techniques. The study colony roosts in an ancient woodland site but forages further afield, leaving the woods and foraging in a valley to the south as well as around lakes and woodland fragments within 5km of the roost. Non-breeding bats were found to travel further to feed; up to 7km from the roost. Some bats were found to have very traditional routes which they stuck to each evening when they left the wood to reach their foraging grounds. Boxes erected as part of the project were used by the barbastelles, including use by maternity colonies. They found the Colin Morris design to be used preferentially. The project also carried out targeted work to enhance the local habitat for barbastelles, informed by the findings of their study. So far they have planted 800m of hedgerows and standards to improve connectivity, are developing three new wildflower meadows and have built a new pond.

Emergence behaviour of Natterer’s and brown long-eared bats

Rachel Fryer gave a talk on the emergence behaviour of Natterer’s and brown long-eared bats. She observed two known maternity roosts once a week between May and September and recorded each emerging bat to identify the earliest emergence time, the median emergence time and the number of bats emerging, and correlated this with environmental variables. The earliest emergence times proved interesting with records earlier than the textbook examples. The median emergence time for Natterer’s was 60-64 minutes after sunset whilst brown long-eared bats left a little earlier with a median emergence time of 44-49 minutes after sunset. The number of bats emerging were found to fluctuate between nights – this could relate to some bats remaining in the roost or the colony being split between different roost sites. However, there was a correlation between the number of brown long-eared bats emerging and the average wind speed with fewer bats emerging on windier nights. The light levels also seem to influence emergence behaviour with brown long-eared bats emerging later under higher light levels; and Natterer’s bats emerging earlier when there was higher cloud cover. This empirical information on the emergence characteristics is valuable as existing published information is often sparse and often doesn’t specify whether the time relates to the earliest or the median emergence time.

Species Distribution Modelling for Bechstein’s Bats

A talk given on behalf of Lia Gilmour from the University of Bristol shared the results of Species Distribution Modelling of Bechstein’s bats and the use of the results to identify further suitable habitat for this rare species. The principle behind this modelling is to look at the conditions in which the bats are found and identify further locations where these conditions are present. In theory therefore, if the SDM is modelling correctly, the bats may be found in these locations. This model found four key variables which appeared to be important: the presence of broadleaf/mixed woodland, a relatively low summer rainfall, a minimum January temperature of >7 degrees and a relatively high temperature range. This corresponds well with the southern distribution of this woodland dwelling bat. The model appeared to work well as new records were found to fall within the optimal or marginal suitability distributions predicted by the model. This is a valuable tool in targeting the search for further Bechstein’s colonies to those locations where the bats are most likely to be found. It will however only identify further habitat like the ones in the bats are known to dwell and so new colonies may still be found in unexpected locations outside of the current or accepted range. This problem is further exacerbated for the Bechstein’s as so much of the distribution is known from targeted surveys using acoustic lures to capture and identify the bats. These surveys were largely carried out in locations where the bats were most likely to be found – specifically broadleaf woodland sites in the south of the country and this will have influenced, in turn, the predictions of the models. It is a case of don’t look; don’t find and the risk with this approach is that more borderline sites may be overlooked if the limitations of the methodology are not appreciated.

Alcathoe Bat in the UK

Phil Brown has been undertaking research using DNA analysis of small myotis species bats. A cryptic species was recently identified in 2010 called the Alcathoe bat which is very similar to Brandt’s and Whiskered bats and, whilst known on the continent since 2001, was not known to exist in England. One of the aims of Phil’s research was to see whether these bats could be identified outside of their current known range of Sussex, Surrey and North Yorkshire. 70 sites were surveyed and 395 bats were caught of which 39 were whiskered/Brandt’s/Alcathoe (WAB). This targeted capture and DNA collection was supplemented by samples sent in by other bat workers around the country with the result that a total of 110 WAB samples were tested. 95 of these were found to be whiskered bats; 10 were found to be Brandt’s bats; and 5 were found to be Alcathoe. Sadly, these five bats were all found in Sussex/Surrey and so there remain no records in between their current known locations towards the north and south of the country.

Brumbats Flight Cage

Morgan Bowers from Brumbats gave an inspirational and enlightening talk on the new flight cage they have had built. This allows the bat carers to assess the health and abilities of rescued bats, gives the bats opportunity to exercise and to behave in a more natural manner, and allows them to be rehabilitated and soft-released with a more supportive environment if they take a little longer to build their abilities. This also saves the perennial bat carer issue of bats getting loose in the house and hiding in the most unlikely places – including inside a hoover! The flight cage is a good training tool as well as it offers a safe environment for new bat carers to learn their rehabilitation and handling skills. You can find out more about the flight cage here with some videos to watch too! Another blog on the conference can be found on the Brumbats page here.

White Nose Syndrome in the UK

The last talk of the day was given by Alex Barlow on White Nose Syndrome in the UK. This is a devastating disease in the USA which has seen mortality rates in hibernation sites of 97% for the little brown bat and 49% for the big brown bat. The syndrome is caused by a fungus which infects the bats and gives a characteristic white nose where the mycelium grows. The presence of the fungus leads to increased evapotranspiration and loss of electrolytes which effectively dehydrates the bat and it rouses out of torpor to drink – some bats have even been observed trying to eat snow. The survival of a bat through the winter is a finely balanced process and this wakening uses a large amount of the winter reserves of the bats which then can not find food to replace the energy they have lost. There were serious fears that this disease may spread to other locations but surveys and sampling across Europe have found the fungus but have not recorded any associated mass mortality events. DNA analysis of the fungus has found significant genetic diversity in Europe which suggests that it is endemic to the continent, whilst those in the USA are all genetically similar, suggesting it is a recent introduction. This may mean that the European bats have co-evolved alongside the fungus and will therefore be able to cope with it, whilst it is a novel pathogen to bats in the US and they have suffered badly from its effects. Further active surveys for the fungus are taking place through 2013/14 with 25 sites selected across the UK, especially those used for tourism or caving. The current state of knowledge allows us to be cautiously optimistic that this fungus should not lead to the same level of devastation in the UK as has been seen in the US.

Spotlight Talks on Local Bat Groups

The spotlight talks from the local bat ground included Lincolnshire all the way across to Warwickshire, Worcestershire and Derbyshire taking in Leicester and Rutland, Nottinghamshire and Birmingham and the Black Country on the way. A range of projects are underway including NBMP monitoring of roosts; the Nathusius pipistrelle project for which Nottinghamshire and Derbyshire are amongst the pilot groups; the BrumBats Batlas project which aims to extend their knowledge of bat distribution across the area; and a range of public engagement events including bat walks and talks. For more information on the activities of all of these groups, check their pages which are all linked above. Whatever your level of interest, there will be something to get involved with wherever in the Midlands you are!

BCT Artificial Light and Wildlife Symposium 2014

April 22, 2014Grantham Ecology1 Comment

The Artificial Lighting and Wildlife conference was held in London on the 20th and 21st of March 2014. It’s scope included effects on a range of wildlife but, being sponsored by BCT, bats were a key focus. Full details of the symposium can be found here. This is a short piece I wrote up for the local bat group but I’ve added in the references and a couple of illustrative photographs below!

Artificial lighting is ubiquitous and almost universally accepted – we have street lights for crime prevention and traffic safety; architectural lighting of statues and churches; lighting of industrial sites to allow work to continue 24/7; and light spill from inside houses. Three scary facts which illustrate this are:

#1 Artificial lighting increases globally at a rate of 6% per year;
#2 There are 7.4m street lights in the UK and;
#3 20% of UK energy expenditure goes on lighting.

Variations on this photograph - a satellite image of the earth at night showing the extent of artificial lighting - was the most widely used photograph throughout various talks and rightly so - it serves to show just what an impact we have on the natural environment. — Variations on this photograph – a satellite image of the earth at night showing the extent of artificial lighting – were the most widely used photograph throughout various talks and rightly so – it serves to show just what an impact we have on the natural environment. Photo copyright: NASA

Most bat workers will know of research, such as Emma Stone‘s work in Bristol, which shows that slower flying species such as horseshoe, long-eared and myotis bats tend to avoid light and that lighting their commuting routes can cause severance. Much of the interesting new research at the symposium came from Holland; Herman Limpens looked at whether there are more ‘bat friendly’ lighting spectra and found that amber light caused much less avoidance than white or green light on bats commuting along a dark canal corridor. This was also borne out in analysis of Irish monitoring surveys which found much lower levels of Daubenton’s activity at lit waterway locations. Fiona Matthews from Exeter University put paired static detectors in light and dark locations in a 2km radius around greater horseshoe roosts and found much higher activity levels were recorded in the dark.

Bats can be disturbed when roost entrances are lit: the Life at Night project changed the lighting regimes of churches in Slovenia and achieved significant improvements in both emergence time – horseshoe bats left earlier – and consistency – bats left over a much shorter time period. Kamiel Spoelstra from the Netherlands Institute of Ecology found pipistrelle occupancy rates of boxes to be significantly reduced under white and red light treatments compared with dark.

ddd — The ubiquitous Illuminated Church – the subject of the Life at Night talk (photograph from the Life at Night Project Website http://www.lifeatnight.si/en/)

But the picture is not that simple; some species such as pipistrelles and Leisler’s are actually attracted to streetlight. Their speed makes them less susceptible to predators and anybody who has undertaken moth trapping will know that moths gather at light sources, especially attracted to shorter wavelength and UV light. A fascinating talk by Andrew Wakefield from the University of Bristol added a further dimension to this – he found that the avoidance behaviour usually exhibited by moths in response to a bat echolocation call – a change of course or a power-dive where they drop to the ground – is reduced by 60% under lit conditions making them a much easier prey for bats.

The impact of lighting upon invertebrates was widely discussed; for example it was found that larger moths with larger eyes are most attracted to shorter wavelength light and they are drawn in at 6x levels compared with longer wavelength light. This attraction is well known but the implications are rarely considered; Matt Shardlow of Buglife estimated that a third of interactions between moths and light sources would prove fatal to the insects through exhaustion, collision, heat or predation.

The influence which lighting can have upon the relationships between species was a trend which came out in a number of the talks – the impact then can be considered positive or negative, depending upon your perspective. Parasitoid rates on moth eggs were much higher under lit conditions as the diurnal parasitoid gains the advantage. Redshank increase their foraging in lit areas, favouring the redshank (perhaps?). Similarly, a Leisler’s bat can forage more efficiently, but to the detriment of the moths which are preyed upon. Lighting at night disturbs and disrupts the natural rhythms, dynamics and ecological signals.

A peacock butterfly seeking out a dark place to hibernate.

One of the last talks of the symposium was from Kate Harrington who found evidence for in-combination effects of artificial light and artificial noise on bats – as the two are so often associated such as from traffic along well-lit roads, the potential for this to modify the natural environment more severely is significant.

Several talks discussed the importance of good design in lighting schemes for new developments – light only where it is required, light as low as required and design cut-offs and cowls to avoid unwanted light-spill onto surrounding habitats. The project along the Thames at Richmond is an excellent example of this – this video shows how the lights respond to pedestrians so that they feel they are walking in a pool of lights whilst all around remains dark. The importance of maintaining dark corridors was also an important part of the London 2012 park design.

The copper beech outside the Guildhall on the High Street in Grantham showing the extent to which lighting is a normal and accepted component of our villages, towns and cities.

But new designs are only going to reduce future problems – as I walked back from Grantham station after the conference I was shocked to see the level of light-spill onto hedges, trees, the River Witham and other suitable foraging and commuting habitat. I had never appreciated how much of an effect our lighting of the environment would have upon the species we share it with. BCT will be putting up the videos of the talks and presentations in due course so keep an eye out for the news of their arrival!

BCT Bat Conference 2013

September 24, 2013Grantham Ecology2 Comments

This year’s National Bat Conference, organised and run by BCT, was at Warwick University last weekend. The conference is always held in September and I always come away with a mixture of enthusiasm and regret – it’s a great opportunity to chat to other bat workers, both volunteers and consultants, and listen to some fascinating talks which really inspire you… but it is held just as the main bat season is drawing to an end and there is little time left to go out and carry out the surveys which the conference inspires! I have certainly come away with a few ideas for next spring.

Several of the talks this year could be grouped broadly into the ‘state of bats’ category. This included the opening talk by Julia Hanmer, the chief executive of BCT, who outlined the work which BCT have undertaken in the last year with a special focus on the work being done to help churches with bats find solutions which allow both to coexist. Lincolnshire Bat Group’s own work in Tattershall Church was held up as a particular example of how the bats could live happily alongside the congregation with input and guidance from experts and this topic was taken up and explored in more detail later in the programme by Laura Bambini who has been been working alongside church wardens and congregations to find out the ways in which bats do genuinely impact upon the running of a church, and what information and support can be provided to alleviate these concerns. This positive work was set sadly against a backdrop of the general anti-environmental ethos of the current government, with Owen Patterson’s name being rightly greeted with boo’s and hisses by a conservation-minded conference congregation. The fact that the Chief Constable who leads on Wildlife Crime is openly anti-bats was another shocking revelation and goes to show just how much prejudice we need to work against.

Pete Charleston heads up the BCT investigations unit and took the stand for the next talk. BCT and Pete in particular are doing great work to combat wildlife crime relating to bats, with regular increases in numbers of referrals and numbers of prosecutions. We are sadly let down at present however by the prosecutors themselves; a recent case where a developer knowingly destroyed six bat roosts and was fined just £35 per offence is grossly disproportionate to the crime committed and serves to send out entirely the wrong message to those who view the protection of our native wildlife as an impediment to their own economic gains – a mantra perpetuated by George Osborne in his recent attacks on protected species legislation.

Leaving politics aside, and on a much more positive note, Lisa Worledge and Helen Miller gave a talk later in the morning on the current research on Pseudogymnoascus destructans in Britain and Europe. This is the fungus responsible for the deaths of huge numbers of bats in hibernation roosts in the USA and there is a fear that the pathogen could cause similar destruction to our native species. The talk concluded that there was cause for cautious optimism that the bats in the UK had in fact co-evolved alongside this fungus and were therefore relatively unaffected by it. The basis for this is the identification of the fungus in environmental samples from across Europe and in the majority of hibernation sites surveyed in the south of England in a recent pilot study, as well as the positive identification of the fungus on a hibernating bat for the first time in the UK, yet without seeing the same devastating effects which are associated with the fungus in the US. The genetic diversity observed in the fungus across Europe suggests that the pathogen has been present and has developed into differing genetic strains across its range, whilst the homogeneity of the fungus genome in the USA suggests a much more recent introduction. The fact that this fungus appears to be novel in the USA would explain why the bats there are being so badly affected in the same way as a new flu strain can strike down half the country. The risk of the disease blighting our UK populations has been cause for concern for a number of years now, and cautious optimism is certainly a better outlook!

The importance of bats within an ecosystem, and the risk of losing such an important species, were highlighted in a talk by Ryszard Oleksy who has been undertaking work on the role of the Madagascar flying fox on forest regeneration in Madagascar. This is a large fruit-eating species, very different to our tiny insectivorous UK species, but the importance of the genera on an ecosystem scale is likely to be similar. The study found that 110 plant species are included within the diet, that seeds which have passed through the digestive system germinate well and that the distance which an individual bat can disperse seeds is significant. The species makes a very effective agent of forest regeneration, linking up isolated forest patches in a fragmented landscape and assisting in the dispersal of a number of endemic plant species.

One issue which is well known to most bat workers now is the risk which breathable roofing membranes (BRM’s) pose to bats roosting within buildings. Bats can easily become entangled in many of these membranes and there are reports of over 100 bats being killed by becoming trapped and dying of dehydration or exhaustion, and yet they are put into new roofs on an almost routine basis, including roofs where known roosts may be present. Stacey Waring gave an excellent talk on her research into this issue, combining a more abstract lab-based tests of the extent to which different membranes on the market become ‘fluffy’ and as such, of risk to bats; with tests of how the membranes performed with captive bats within a rescue centre. All of the membranes tested were found to pose a risk, compared with traditional bitchumen felt, although there is hope that the findings of this study may feed into the design process and more bat-friendly materials may become available in the future.

Geoff Billingham gave a talk on Wolvercote Tunnel in Oxford, outlining the results of a range of surveys and a concept of mitigation designed to ‘flush out’ bats from the tunnel in advance of an oncoming train to avoid them being killed. This relied upon lights being turned on in the centre of the tunnel a few moments before the arrival of a train, and then progressing out to the peripheries with the hope that bats would move ahead of the advancing light. The most concerning figure within this talk, to my mind, is the 5 dead or grounded bats identified in 21 visits to the tunnels. Trail cameras also identified an average of three visits per night from species such as foxes or cats, which would scavenge a bat carcass, making it unlikely that a dead bat would remain for a long time. This rate of killing is significant, considering that the tunnel is 130m long, the trains run at 30mph and they do not run much beyond 10:30pm. If this number of bats are killed in a single tunnel, the number which must perish across the country is highly significant and is likely to have a serious impact upon populations. It also puts into perspective the potential impact of new technologies such as wind turbines, when viewed in comparison with more established and accepted threats which may be of much greater significance.

Four talks over the weekend discussed the ways in which we can increase our knowledge of the distribution of bats within the UK.

Two focussed on islands – the first of these was studying the distribution of rare woodland bats, specifically Bechstein’s and barbastelle – on the Isle of Wight. Ian Davidson-Watts sampled in 42 different woodlands across the island and used mist nests and harp traps to catch bats and radio-tag them. Two thirds of the woodlands were found to have Bechstein’s present – this is one of the Myotis species and one of the rarest species in the UK – and a number of maternity roosts were subsequently identified. The surveys also identified potentially the largest barbastelle roost within the UK with over 115 individuals counted out. These findings make the Isle of Wight of potentially international significance for rare woodland bats at a landscape level.

Moving to the opposite end of England, Hugh Watson discussed static detector surveys on three islands off the Northumberland Coast to identify the species present. This is an under-recorded area and a total of five species were recorded on the islands with evidence of bats commuting to forage from the mainland.

Two further talks discussed mass-participation bat surveys where a large number of the general public were encouraged to get involved, to learn more about bats and to extend the coverage of bat records within a county.

The Norfolk Bat Survey set up a number of ‘Bat Monitoring Centres’ across the county so that everybody was within 15-20 miles of a station. The public could sign up for the survey and then pick up a static detector which would be put out at a number of locations within a 1km square and left to record the bats which went past. This has enabled bat records to be obtained for a large area of the county, and allowed interested individuals to find out which species fly through their gardens and their local landscape when darkness falls.

The Somerset Bat Group by contrast have designed their Big Bat Survey – a number of transects across landscapes within the county, including the Blackdown Hills and the Mendips, where a group of at least four people would be equipped with bat detectors and would walk the set routes to find out which species were present. Fifty and seventy members of the public took part in the respective surveys, and the results were again invaluable in increasing the knowledge of both the distribution of species within each area and their use of the various habitats present.

The last two talks focussed on technological advances in our approach to bat surveys. The first of these was a talk by John Atanbori of Lincoln University who is using computer vision techniques to automatically pick out bats from a video taken in low light levels and compute metrics such as wing beat frequency, with an aim to using this as a tool for species identification. The characteristics of bats in flight differ between species to a greater or lesser extent, as anybody who has watched the rapid wing-beats of a foraging pipistrelle alongside the broad-winged fluttering of a brown long-eared will know. The project is a work-in-progress but offers a fascinating new avenue of species identification if it can be developed.

The final talk was given by Ian Agranat of Wildlife Acoustics on their latest classifiers for UK bat calls. The aim of this software is to identify a bat call to species level (or genus level in the case of the myotis bats) without a bat worker needing to scan through every single call. The need for this technology is increasing as the price, availability and usefulness of static bat detectors is growing – these provide very cost effective monitoring of a site compared with human surveyors, but they do produce huge amounts of data which needs to be sifted through. The Wildlife Acoustics technology uses machine learning where a large number of identified calls are fed into the software and the algorithms identify differences which split the sound files up by their respective species. This is successful at an 80% accuracy which would significantly speed the process of analysis, whilst still at this stage requiring a certain level of operator confirmation and amendment. It is another exciting avenue of development and another ‘watch this space’.

Workshops were wide-ranging as usual and it is always a shame that you can only pick one or two. I opted for the tree roost field survey workshop with Henry Andrews taught me a number of new things as well as re-enforcing many others with examples and photographs which were invaluable, even after a summer spent up trees and inspecting potential roost sites. In case you haven’t come across his Bat Tree Habitat Key – you can view it for free on his webpage. The key to extending and refining this already invaluable piece of work is to gather more records – calling anybody working on bats and trees to contribute! On the Sunday I opted for Jon Whitehurst’s talk on an Introduction to Species Distribution Modelling – a last minute switch but one which has me itching to try out the techniques he outlined to model bats’ use of the landscape.

As I said at the outset, the only downside to the conference to my mind is that it is at the end of the season and so all of these great ideas and enthusiasm to get out there have to lie dormant through the winter until the spring when the bats come out of hibernation and the survey work can begin again.
Next year’s conference is due to be held at Warwick University again and you can find out more on the BCT’s website here and the BCT blog on the conference proceedings is to be found here. There are photographs from the conference on the BCT’s facebook page here, including the customary after-dinner Ceilidh!