Gardens - a vital haven for wildlife
Biodiversity is being lost on a global scale but the good news is that gardens provide a haven for some species and there are more people than ever before wanting to garden for wildlife. Wildlife gardening is not just about putting up bird boxes or ladybird houses - growing plants is just as important. These create a habitat for all sorts of insects and can be an important food source for one or more stages in their life cycles.
What should you plant?
It’s confusing to know what is best to plant. Some advice suggests only British native plants are good for wildlife. Other advice lists specific plants but these might include a mixture of natives such as foxglove and non-natives such as buddleja.
The RHS realised new research was needed to look into the question of whether the geographical origin of a garden plant is a significant factor in biodiversity richness. An average garden contains around 70% non-native plants to just 30% British native plants. Data from the Plants for Bugs study should reveal if there are any recordable differences in invertebrate numbers and species between these plant groups. The interpretation of this data will allow us to help gardeners make informed plant choices when gardening for wildlife.
How are we going about it?
To make a comparison between garden plants, beds were prepared in summer 2009, each bed containing plants from one of three geographical zones. The site chosen was RHS Garden Wisley in Surrey - an old heather bed in Howard's Field at the northern end of the garden has been converted into a trials area and divided into 18 3 x 3 metre beds. A replica site has also been set up in the trials field in Wisley village, which is not accessible to the public.
Each bed was planted with a mix of 14 species of plants, including bulbs, perennials, shrubs, grasses, ferns and a climber, and designed to replicate a miniature garden border. Visitors to RHS Garden Wisley can wander around the Howard's Field site which is situated at the far end of the Pinetum. Regrettably, due to the experimental design, access is not suitable for wheelchairs or pushchairs.
Monitoring invertebrates
Four methods are being used to monitor the invertebrates on the beds and largely take place at six-week intervals between March and October.
- Slug and snail traps – these consist of an upturned plant saucer over a chicken feed bait set in the middle of each bed.
- Pitfall traps – these are a plastic beaker sunk into the middle of each bed and part-filled with preserving fluid to capture ground fauna such as ground beetles and woodlice.
- Suction sampling – this method uses a ‘Vortis suction sampler’ that is swept slowly over the plant foliage to suck up insects such as flies, aphids, caterpillars, plant bugs, leafhoppers, beetles and their larvae.
- Observation of flower visiting insects – this last method is dependent on the weather conditions being favourable for flying insects such as bees, wasps, butterflies, flies (including hoverflies) and adult beetles. Those seen landing on the flowers are recorded onto a record sheet by an observer.