The butterfly effect: summer is a spotter’s paradise

Summertime: walks in the woods, rambles by the river, strolls by the sea. The good weather brings many of us out to make the most of the bright evenings.

The good weather also brings out the butterflies in all their colourful finery. Speckled wood, green-veined white, meadow brown, orange tip, small copper, red admiral. This summer you are likely to spot even more of them fluttering around.

Last year saw a huge surge in Irish butterfly populations, up by nearly a third on the previous year. A report from the National Biodiversity Data Centre, released in March and published on Science.ie, revealed that the butterfly population in Ireland in 2013 had increased by 32 per cent over 2012. This was good news for butterfly watchers and conservationists, because over the past 20 years butterfly numbers across Europe have declined by almost 50 per cent.

But how do we know all this? Is there an army of scientists roaming the countryside with sophisticated surveillance equipment and state-of-the-art biotech gear? No. Ordinary people out on walks are collecting the information as part of the Irish Butterfly Monitoring Scheme.

When these citizen scientists spot a particular species of butterfly, they record what they see, and where and when they see it, and send that data to the National Biodiversity Data Centre's website, Biodiversity.ie. But this is not an idle pastime for butterfly fanciers. It's a useful resource that can tell us a lot about what's happening in Ireland's landscape, and how our climate and habitats are changing from year to year.

“Butterflies are very much tied to climate,” says Tomás Murray, project co-ordinator of the Butterfly Monitoring Scheme. “They’re very, very sensitive to climate and year-to-year changes.”

So how come the butterfly populations increased last year, when the first half of 2013 saw unseasonably cold weather?

“It’s primarily due to having a better summer,” says Murray. “The late summer last year was exceptional compared to even other summers. The spring was exceptionally poor, and the summer itself just above average, but it was the final flush that gave it that extra bump and really allowed the population to flourish in comparison to previous years.

“In terms of what that can tell us about the landscape, we only have six years of data yet, so I think it would be unfair to draw too much from it. But give it another four or five years, and we’ll start to make some very firm inferences about what’s happening in the landscape based on how the butterfly community is changing.”

How to get involved

Getting involved in the scheme is a walk in the park. Volunteers need to choose a particular transect, an area of land to walk during butterfly season, which usually runs from February to October. It could be a way-marked walk, a country road or something a bit more off the beaten track.

“It suits people who are walking regularly and who go on a fixed route. That’s the beauty of it,” says Murray. “All our recorders tell us where they are walking; we don’t tell them where to go. The only thing we ask is that it’s a decent enough walk, between one and two kilometres, and something they can do in 45 minutes or an hour, or on their lunch break. But the main thing is that they enjoy walking the route. If you’re doing it 26 times a year, you want to be sure you like doing it.”

This year there has been an increase in volunteers; about 231 people have registered online for the 2014 survey. To help recorders identify the different butterfly species, the centre has released an Android app, which can be downloaded from the Play store (see panel). There are also identification workshops to help beginners spot newly arrived species such as the Holly Blue or the Essex Skipper. The next one is in Millstreet Country Park in Cork on June 28th, hosted by Murray and the centre's director, Dr Liam Lysaght.

Murray reckons that 2014 will see butterfly populations continue to increase following the explosion of late summer 2013.

When volunteers send in their data, they are not only contributing to the national picture of biodiversity, they are also influencing national conservation policy. And the data trail doesn’t stop at Ireland’s shores. The findings are also fed into the European Grassland Butterfly Indicator and the Butterfly Climate Change Indicator, both of which have a direct influence on biodiversity strategy within the EU.

“If you think, across Europe, including Ireland, there are 21 monitoring schemes currently ongoing, so every single week, between April and October, there are 3,500 people across Europe doing exactly what people in Ireland are doing,” says Murray. “So it’s a unified scheme.”

CASUAL DATA: SEND IT THE SMART WAY

You don’t have to commit to walking a particular route 26 times in the year – you can send in casual data about butterflies and other wildlife via a number of Android apps available on the Play store. If you spot something outside your window, just snap a picture on your smartphone, use the app to identify it, and send the data in.

“Anybody can do it, and that’s what we’re trying to encourage people to do with the apps,” says Tomás Murray.

There’s also an app for identifying different species of bumblebees (they’re a good indicator of changes in the landscape) and one for wild mammals. There’s even an app for reporting roadkill. “If you see anything, a ladybird, anything, you can just tell us about it and put it into the record. Particularly with casual records, we can rapidly build up a picture of where things are.”

White butterfly nets are not redundant, these days many people are creeping through the undergrowth with smartphones at the ready instead. “The proliferation of smartphones has been fantastic, because it prevents people having to actually catch things,” says Murray.

“Bees are quite robust if you’re brave enough to catch one and put it into a jar to have a look; they can be handled quite well. But butterflies are quite delicate, so you have to be trained to catch them without harming them. But we don’t encourage people to catch them. If you can get a good photograph and send it into us, we can give instant feedback.”