Our recent publication, 50 for the Future, lists 50 things that we believe should happen in Scotland over the next 50 years to benefit both people and wildlife. In this week's 50 for the Future article, Dr Tim Duffy, the Trust's longest standing Trustee, explains why re-naturalising our urban green spaces is beneficial for both wildlife and people.

Number 26: re-naturalise 30% of Scotland’s urban green spaces through a range of small measures including a shift to native tree planting and creation of wildflower meadows

The human health benefits of natural urban green spaces – that is, green spaces that have a significant element of natural or semi-natural habitat and biodiversity within them – are increasingly well supported by evidence.

Natural green spaces within the built-up ‘grey space’ of the man-made ‘concrete jungle’ that makes up most of our urban settlements are of vital importance to the existence and health of the other species that we share Scotland with. However, the amount of green space in which wildlife may be able to thrive is always under threat from further concrete development and a lack of natural corridors between wider spaces means that populations become fragmented.

The ‘usefulness’ of what we perceive as green spaces to be biodiversity supporting varies according to the number and diversity of native species within any given space. Re-naturalising green spaces through a range of small measures can often improve them, both for wildlife and for people.

The Edinburgh City Council, with the encouragement of the Edinburgh Living Landscape intiative, has implemented a wide programme of grass cutting reductions, meaning that the grass is cut less frequently and left ‘high’ for longer. This provides more structural habitat for wildlife to live (and hide!) in and we get to enjoy the more natural looking landscape that it provides.

In the background of the photograph above, the grass has been left uncut and the species common in an amenity grassland management regime are growing longer than usual. In the foreground, there is a small area of specially designed and seeded wildflower meadow – a true ‘Meadow for the Meadows’ as it is 80% grasses and 20% colourful and species diverse, mostly perennial, wildflowers (many ‘wildflower meadow’ seed mixes are in fact better termed ‘wildflower borders’ in comparison). This wildflower grassland seed mix was designed by Scotiaseeds using evidence from the University of Edinburgh’s Urban Pollinator project. The wildflower species it contains were chosen because they provide food for bees, hoverflies and other winged urban pollinators throughout the summer without gaps in the food supply and with a longer flowering period overall.

The relaxed amenity grass cutting regime (right of picture above) provides more structure for wildlife to live in and on (species such as butterflies need meadow grass stalks to lay their eggs on) and such true wildflower grassland meadows designed for urban pollinators (left of picture above) provide much more in terms of biodiversity of native flowering species and a more natural habitat – not to mention colour for us to enjoy!

Overtime, if we could move to having a third of Edinburgh’s amenity grasslands with relaxed cutting and gradually convert those areas to more native seed mixes, the wildlife supporting habitat in our remaining urban green spaces would expand enormously.

Native trees can also provide large areas of vertical structural habitat for lichens, insects and birds (and in many cases large amounts of food for pollinators) and there is always scope to consider planting a native tree species in urban areas that will better support local wildlife. It is said that a non-native sycamore tree can support as much wildlife as a native species, but that is only when  it is a mature 200 year old tree  – and how many urban trees get to live that long?

In the Meadows parkland in Edinburgh, we have a historical tradition of planting and maintaining a non-native Japanese cherry avenue. Whilst it is a very picturesque site, such traditions shouldn’t necessarily mean that when the opportunity arises we shouldn’t consider using native tree species that can provide similarly desired amenity parkland effects, whilst also giving a boost to our precious urban wildlife. The Scottish native flowering cherry or ‘Gean’ tree (Prunus avium) for example (pictured above) is a magnificent and colourful contributor to our prospering urban trees and of course helps with food supplies for our urban pollinators too.

Whilst we cannot predict what life may look like in 50 years’ time, one thing that is almost certain to continue is the increasing size of both the population and physical structures of our towns and cities. It is therefore of paramount importance that we ensure that our urban green spaces are both plentiful and useful for native species. Given the relative ease of making this the case and the increasing evidence of the benefits it provides, the target to re-naturalise 30% of our green spaces is one which I would like to see not only met, but treated as a minimum and hopefully surpassed over the next 50 years.

Let us know your thoughts by emailing thefuture@scottishwildlifetrust.org.uk or Tweet @ScotWildlife using #50fortheFuture.

Dr Tim Duffy is the longest serving Scottish Wildlife Trust Trustee and a local urban natural green space advocate in his home town of Edinburgh.