Tuesday 6 October 2015

Sounding out the Lay of the Land- An Interview with Alison Fairbrass by Charlie Hearst

Alison Fairbrass is a PhD student at University College London (UCL) researching within a new and exciting branch of science; soundscape ecology. Although using sound to study nature is nothing new, as anyone who’s surveyed bats or listened to bird songs can attest, this field is novel in the sheer scale it operates on. Whilst acoustic ecology tends to be more species focussed, soundscape monitoring takes in the orchestration of all the different sounds (biological, geophysical and man-made) within a landscape in order to understand the environment on much broader terms. Although there has been recent interest in soundscape monitoring, there has not been much effort to apply this method to urban ecosystems. Attendees to this year’s National Bat Conference may have seen Alison present her work on developing technology for monitoring urban soundscapes; fortunately for those who didn’t we were able to catch her for a few words about her work.
What was your first introduction to bats?
After graduating I worked for an urban ecology research group in Birmingham. One of the projects they were looking at was the persistence of bats in the city; how the connectivity of the urban green spaces affected where they foraged. So I worked on that project, first of all analysing quite a large data set of bat recordings, processing that to identify what species they recorded and then spent a summer running around gaps and tree lines filled with different intensities of light to see whether light and gaps between tree lines caused by road constructions affected bat movement through the city.
 Can you tell us a bit about your work?
Biodiversity in cities is incredibly important. It provides plenty of services for populations. But it’s really difficult to know what we have. Monitoring biodiversity anywhere is tricky, but it’s particularly hard in an urban setting; the land is divided into tiny little parcels owned by different parties; there are plenty of safety issues; and the equipment gets stolen. I’m working on new technology for monitoring biodiversity in cities. The aim is to make it easier to monitor urban nature over large spaces and time periods by using acoustic recordings. So obviously I’m interested in bats as you can survey them by their echo location calls in the ultrasonic landscape. But there are other animals in the lower frequencies such as birds, invertebrates and land mammals. So I’m working out whether there’s a way you can stick a recorder out in your garden or park and use that to understand what you have there in terms of biodiversity.
What advantages does acoustic surveying have over more traditional visual ID methods?
One of the selling points is the reduced resources involved in monitoring. If you can make that initial investment of sticking up recorders in the first place, leave them for long periods and if you have the technology to process that data in an automated way, then you will make huge savings in the long term in getting what is a massive amount of information. The issue is it’s not as if people are doing that now with huge costs. No one’s doing it anyway. It’s not happening. So there’s been recognition that we need more understanding of ecological populations to conserve them, without that data we’re blind.
Another advantage is that you effectively have a historical snapshot of what a place sounded like acoustically. If you store that data in somewhere like the biological records centre, then it can be used by others down the line. There’s loads of things I’m sure I’m never going to do with the soundscape data I’m collecting now, but when it’s archived and hopefully publicly available, there’ll be tonnes of questions that other people will be interested to use it for.
So it’s a quicker and cheaper method of surveying. Is it more efficient and accurate?
There are a few studies where people have tried to compare the data from human surveyors and from automatic recordings; it’s as good, if not better. There’s an awful lot of human error that can be involved in doing a survey, what one person sees, hears and thinks is one thing, but that can vary a great deal between surveyors. So using technology could be a way of removing that subjectivity from monitoring.
Any horror stories?
Not me personally, but I have had the police call on me once in Birmingham. I was just doing a bat survey and someone saw me when looking out of their window and got suspicious. I guess it can look pretty suspect when lurking around a neighbourhood hiding non-descript black boxes in places. 
Could this work feed into how human generated sounds such as traffic affect biodiversity?
That’s one thing I’m quite interested in looking at from the data that I’m recording in London at the moment; how the presence of particular human sounds at a site relates to the biotic sounds that we record. Maybe there are certain anthropogenic sounds that can be used in complement to biotic sounds to tell us what the nature of the environment is as well. For example there are a few interesting studies where it’s been shown that birds and some insects change the way they call due to anthropogenic sounds. 
Are there ways around measuring the presence of species that aren’t typically noisy?
That’s one question I will be working on over the next year; what the noisy species can tell us about the quiet ones. The idea is that you should be able to use the noisy species and everything else in the soundscape to understand what the environment is like including the quiet things like plants and small invertebrates. So that’s exactly the kind of relationship I’ve been looking at everywhere I’ve made recordings by also surveying the local environment. Hopefully, I can try and understand the interaction between the two to find if sound can be reliably used as a measure of an environment as a whole. 
Back to developing your software, what does that entail?
A lot of programming. I had to improve my ability to manage large data sets and work with them to pull out information. Luckily I’ve had some help with computer scientists here at UCL. I guess it’s about understanding how you can characterise different types of sound; identifying and differentiating between natural and anthropogenic sounds; geophysical sounds like rain and wind; sounds between and within a biodiversity group and see how you can get to a more taxonomic group level. Trying to work out how I can do that is really what I’m tackling at the moment.
The next stage from that, and I’m sure this is what people are usually interested in, is getting species ID. I wouldn’t really do that, that’s a whole PhD in of itself, but my work can feed into existing tools such as iBat which can do pretty good European bat species identification.  What I’m aiming for is getting index measures of biodiversity in an urban environment, like a kind of summary or quick snapshot of the ecology of the habitat on a community scale. Those kinds of measures can be used over long periods of time to measure trends in biodiversity. 
Any surprises from your study?
What was interesting is that every location I surveyed in London, even the most central locations like right on Tottenham court road had bats. Even at sites where no birds were recorded for an entire week, we still got bats; they’re pretty amazing, almost like an urban adapted taxonomic group. Another was just how much anthropogenic sound there is in the ultrasonic frequency range, of course we dominate the lower ranges, but something like a breaking vehicle can go really high in pitch. So I think ultrasonics should also be considered when discussing conservation and noise pollution, as animals such as bats use those frequencies. 

Thursday 1 October 2015

2015 National Bat Conference by Charlie Hearst

A collection of enthusiasts running around, flapping their capes to the tunes of Danny Elfman going ‘nananananananana’ was one of multiple misconceptions I endured from friends and family upon informing them that there is such a thing as a Bat Conference. Yes, there’re live bats. No, there isn’t fancy dress. And no, there aren’t late night screenings of Batman (although I did meet an Adam West but I’ll get into that later). The National Bat Conference is not the Goth’s answer to comic-con, but an annual event showcasing the latest in technology and research gone into conserving and understanding this fascinating mammal group.

After a drinks reception hosted by one of the events’ sponsors we head off on a bat walk around campus at the University of Warwick led by, none other than head of the National Bat Monitoring Program, Phillip Briggs. Thanks to the University’s abundance of greenspaces and close proximity to a nature reserve, the place bristles with wildlife. Nowhere is this more evident than by the lakes close to the halls. In the daytime, the water teems with carp whilst swans, coots and moorhens lazily drift along the surface, you may even see the occasional heron fly past. Skip to nightfall and the air seethes with bats in a feeding frenzy. Our bat detectors convert their ultrasonic calls to an audible level treating our ears to a cacophony of smack, knock and fart sounds as the bats acoustically feel their surroundings.  We can see dozens of Daubenton's bats skittering dangerously close to the water surface like mini-hover crafts, chasing down swarms of insects or trawling the water with their elongated feet for larvae. Higher above, common and soprano pipistrelles bank, swoop and dive through the air like little fighter pilots as they hawk midges and mosquitoes.  Even higher, our detectors pick up the low chirps of the common noctule, our largest bat species in the UK.

The next morning, we’re in the lecture theatre anticipating the day of talks and demonstrations. Theme of the day is evolving methods for surveying bats, from the latest hardware to novel survey strategies we are treated to a range of talks from professors, students and professionals (admittedly the work  sells better than the speaker at times, but that’s scientists for you). On the gadget end we’re shown footage of bats shot in stunningly crisp detail by the latest in thermal image technology; the Selex-ES (Merlin Camera).  Currently the only HD infrared camera in the world, sensitive to temperature differences on 0.02 degrees, I think the presenter mentioned liquid nitrogen in the detector, I don’t even know what that means but I want it! At least until I realise I could buy a house for a similar price.

Some of the latest innovations are in developing software, such as a dauntingly ambitious PhD in which a program was developed to automatically ID 87 Mexican bat species from their calls. Another involves a mathematical model for estimating population density just from using bat calls. Bear in mind how many call sequences a single bat going in circles will generate and you’ll appreciate just how impressive an achievement this is. But it’s not all pimped out gear and fancy programming, the genius of some projects lay in their simplicity or resourcefulness. Take the Norfolk Bat Survey for example. For this project, anyone with an interest could rent out high quality bat detectors from monitoring centres that had been set up around Norfolk, survey a designated patch and return their recordings for analysis. Not only has this project succeeded in achieving standardised monitoring on a large-scale (786 square kilometres surveyed since it started in 2013) but has made surveying all the more accessible by tackling obstacles that could otherwise discourage newcomers such as buying equipment, finding a site and analysing recordings.

We finish the day of talks with a series of workshops to choose from. Whether you want to learn how to handle a live bat, work with a software program or make your own felt bat, the variety we’ve had over the years cater to all kinds. ‘But what kind of a person goes to these events?’ I hear you ask. Glancing around the room I can pick out the likes of academics, ecologists, bat workers, carers and enthusiasts. Admittedly, the occasional ‘I ♥ bats’ shirt pops up but nothing as drastic as clip on wings, although what we do at other events is another matter (see exhibit A). But why bother attending? Well for people such as myself, seeking the knowledge is a reward in of itself, but the talks also have a far more practical side, outlining new techniques or projects for people to get involved in. As one attendee by the name of Adam West put it (no relation to the ex-batman) ‘a few things have inspired me to go out and generate my own records, particularly the talk about where all the pips go in winter, that’s something I’ve often wondered about and hope to try out in my hometown’.

The talks mentioned is far from exhaustive. There was a broad range of fascinating talks from how LED lights affect bat-avoidance behaviour in moths to using the urban soundscape to monitor biodiversity. If you’d like to know more you can read the abstracts which will be available shortly on the BCT website, also watch this blog space as we will be publishing an interview or two from some of the speakers.