“London gardens make up nearly a quarter of the capital” – what an opportunity for gardeners!
Our gardens, balconies and windowsills can be important sources of nectar and food for insects, increasing their abundance and diversity.
This was a key message from Czech Conroy, the speaker at our May Talk. He is a member of the RSPB Central London Local Group and Lambeth Biodiversity Forum, as well as Lambeth Horticultural Society!
What we must do:
- Stop destruction and degradation (of the environment)
- Maximise biodiversity
- Create biodiversity green corridors
The Bad
Czech led with the Bad News. The UK is one of most nature-depleted countries in the world. In London as elsewhere, particularly in recent times, change has accelerated. Czech noted that swifts, house martins, spotted flycather and hedgehogs are rare sightings in London today – and ones that urban children might never see.
The decline can be explained by climate change, habitat loss – and the fact that all these species eat insects.
UK flying insect numbers have declined by 60% in the past 20 years. Half of butterfly species are threatened with extinction or near extinction. The abundance of 13 of 23 species of bumblebees, key pollinators, has halved. Insects have been devastated by man-made pesticides, as well as climate change and habitat loss.
(Should we be worried? Yes, very. Seventy five percent of the crops grown by humans are pollinated by insects.)
The Ugly
We’re building houses, schools, offices on previously green spaces. Parks have been ‘green deserts’ of amenity grass, with little to attract or sustain wildlife.
London’s gardens – which make up nearly a quarter of the capital – are going ‘from green to grey’. Patios, decking, sheds, extensions, artificial grass and car parking spaces are replacing traditional gardens.
The Good
Municipal Wildflower meadows
Many London boroughs, including Lambeth, are creating wildflower meadows in parks to encourage a large variety of plant species, which means more insect species. This includes meadows at Brockwell Park, Clapham Common, and Dulwich Park.
In the meadows, nectar can be available to pollinators for many months of the year. Spring flowering plants include Bugle and Primrose. Knapweed and Verbena, for example, then take over mid summer. Later flowering plants include native Scabious.
After a few years, this many encourage spontaneous colonisers, such as pollinating insects, eventually heading up the food chain to include small mammals.
The B-Line
There are, however, physical boundaries that limit wildlife expansion. Parks and meadows and areas sustaining pollinating insects are not necessarily linked geographically. This ‘habitat fragmentation’ means that hedgehogs, for example, and amphibians like lizards, and some insects, cannot move from their local area. The result is a loss of genetic diversity.
To help combat this restriction, the national B-Line has been created. These linking ‘wildlife corridors’ make use of hedgerows new and existing, and improved railway embankments, as well are urban parks and green spaces.
The London B-Line includes many current pollinator hotstops. Lambeth aims to create new habitats that will link and support existing areas. New stepping stones to strengthen corridors may be created in partnership with local groups, for example, Incredible Edible Lambeth.
Brockwell Park – the B-Line Hub
In London, the North to South B-Line runs from Enfield to South Croydon and charges right through Lambeth and Brockwell Park. Brockwell Park is also on the East to West B-Line – so Lambeth, centred on Brockwell Park, is the hub! A significant area in Brockwell Park, from 11 May to 16 June, is the site of Brockwell Live, an intensive schedule of mainly commerical festivals, which attract hundreds of thousands of people to an area promoting biodiversity, at peak breeding season for birds and other animals.
How gardeners can help
Gardens, Czech emphasised, can be incredible suppliers of nectar. He recommends using a seed mix for mini meadows.
“Small garden? No problem!” he enthuses. “Researchers show ‘mini-meadows’ can make rich habitats for pollinators.”
Researchers found that seed mix sown in an area 4m2 is big enough to create ‘mini-meadows’. In the following year, these mini-meadows were supporting, on average, about twice as many bumblebees, solitary bees and solitary wasps as control plots with no wildflowers.
Both insect abundance and diversity increased!
Czech added that flat rooves or shed rooves were also great areas for sowing seeds. He urges,
“Don’t mow between April and September” as this is when many insects, including some butterflies, are completing their life cycle.
If you can’t match the ideal, please leave at least 20% of your grass uncut – your grandchildren will thank you for it.
Other sources of information
Buglife, Bumblebee Conservation Trust, Butterfly Conservation, London Wildlife Trust