Plants, people and pollinators

It is one of the most iconic, beautifully green, and superbly relaxing, of Edinburgh landmarks. Some 350 years old, and home to around 100,000 plants, 70 acres, 10 Glasshouses it is of course the capital’s famous Royal Botanic Garden (RBGE).  And it’s home to more than a handful of pollinators.

The famous Palm House in Edinburgh

I was speaking recently to Alex Davey, Science Policy and Impact Officer, about pollinator-friendly projects.

We had a lot of positive subjects to talk about.  Much of the RBGE’s pollinator-related work tends to be around actions to improve pollinator food sources and habitat, two of the key aims in the Pollinator Strategy for Scotland.

Arguably pride of place should go to the eight new meadows (each 10 x 50m) being planted as part of the Edinburgh Living Landscape project. These all incorporate pollinator-friendly plants, and provided new connectivity along what is a heavily developed stretch of Edinburgh’s coastline (one of the successful Biodiversity Challenge Fund bids).

It’s true that butterflies are not our most noted pollinators, but nevertheless they are a key part of our biodiversity, and where they thrive other pollinators often do well too. In a project designed to encourage the rare northern brown argus, the cultivation and translocation of common rock rose is being included in plots called ‘Square Metre for Butterflies’ (which is also an Edinburgh Living Landscape project). This initiative seeks to increase pollinator habitat in the urban environment through creating green roofs and is a fine example of how even in the midst of a thriving, busy, city it is possible to do something positive for pollinators.

On a related theme Alex revealed that there is a survey of green roofs in Edinburgh. These ‘gardens in the sky’ are an approach which acknowledges the role of roof top gardens which are more prevalent, and woven into the fabric of big cities, than we imagine (it’s just that they are not always easy to view). The survey is aiming to compare plant diversity with green roof structure and age, including the occurrence of pollinator food plants, and pollinator visits. This will provide guidance for future design and plantings to have the most impact for pollinator habitat.

There is considerable excitement too around an ongoing volunteer phenology-recording project. This dates back 170 years, documenting annual changes in the development of over 500 plants of 156 species across the RBGE’s own gardens. It helps highlight pollinator-impacting shifts in flowering time as a result of our changing climate. It’s good work and some of that data are incorporated into the International Phenological Gardens of Europe project.

Finally it is impossible to conjure up a visit to the RBGE in 2020 and not acknowledge the sensational ‘Pictorial Meadow’. As well as the annual meadow display bringing a rainbow of hope to visitors, and providing a nectar source for bees, it allows people to think about meadow landscapes. The sheer joy of being immersed in a meadow – surrounded by the fluttering of butterflies, chirping of crickets and the buzz of bees is increasingly rare. You can read a lot more about this fantastic approach on the RBGE website.

A stunning pictorial meadow to savour

For an organisation that began rather humbly with an area roughly the size of modern-day tennis court the RBGE has thrived. Their expertise is unrivalled, and that’s great news for plants, people and pollinators alike.

The Grayling – a master of disguise

Many butterflies are brightly-coloured, from the azure glint of the Common Blue, to the burnt orange of the Small Copper. But one of our most intriguing species is a complete master of disguise: the Grayling, as Anthony McCluskey explains in our guest blog today. When they are in flight it’s easy to see this butterfly, as the wings are brown and orange, and the butterflies are often engaged in energetic courtship flights or defending their territories.

Grayling at Holyrood - AMcCWhen they land though, the wings snap shut and the butterfly can literally disappear in front of our eyes. The undersides of the wings are a mix of grey-brown and light-coloured speckles that look just like gravel or stones. This corresponds incredibly well to the dry stony grasslands that this butterfly breeds in. There are even several recognised sub-species of this butterfly, some of which appear to be adapted to the particular types of plants and rocks of their habitats.

Graylings are now mostly a coastal butterfly, and many inland sites for this species have disappeared. Inland they can still be found in quarries, former industrial sites and along train tracks, where the mix of sparse grass and rocks is perfect for them.

But all is not well for the Grayling; populations have crashed in recent times, and in Scotland it is estimated that the butterfly has declined in abundance by almost 90% over the past thirty years. The story across the UK is bleak too, with declines in abundance of almost 60% in the past forty years reported.

Despite this, it’s still possible to find this butterfly in what seems the most unlikely of places: the heart of Edinburgh! Around Edinburgh there are the remains of ancient volcanoes – Edinburgh Castle is built on one, and Arthur’s Seat is another. The rock that make up these features is hard, and the soil is thin – a perfect home for this elusive butterfly! Similar rocks can be found at Calton Hill, and the ridge of rock faces running parallel to Calton Road. And despite the butterfly’s camouflage, it’s easy to see them there in the summer. They mostly fly from early July to mid-August here, and if it’s a sunny day you’ll see them in this area. I’ve even spotted them drinking nectar from Buddleia bushes on Regent Road!

Calton Hill Work Party (11)

The habitat of the Grayling and other butterflies is threatened by shrubs like Gorse, which can get a hold on the thin soil and shelter out the low-growing wildflowers and grasses. So to help Graylings at Calton Hill and Holyrood Park I’ve been working with volunteers to control the gorse. It’s a prickly job, but a good one to warm us up in winter! Volunteers have also been recording Grayling numbers at Holyrood Park and Calton Hill, and in 2019 they had a real bumper year, with twice as many recorded.

Our next outing to Holyrood to control gorse will be on Sunday 1st March, and you’ll find the details of it and all our events on our events webpage, here: https://butterfly-conservation.org/events/scotland

 

Anthony works for Butterfly Conservation as the Helping Hands for Butterflies Project Officer. His work to support volunteers recording butterflies, and to create and maintain butterfly habitats, is supported by funds from the National Lottery Heritage Fund and Scottish Natural Heritage. The work at Holyrood Park and Calton Hill has been supported by Historic Environment Scotland and City of Edinburgh Council.