The ‘B’ of BESS, is Biodiversity – the variety of animals and plants; the diversity of biological types. We spent a lot of time last year identifying the plants in different bits of greenspace and sweeping through with nets and special vacuum cleaners, to see what small insects and other creatures live there. We are now busy identifying and counting these, down to the last mite and woodlouse.
To find out exactly what animals are crawling around, unseen, we have to sieve through our samples and inspect them very closely under microscopes. Some of the larger wasps, spiders and beetles are easily spotted as we remove the bits of plant from the collection of debris. As they get smaller, the greenfly and ants are spotted among the finer sieved samples. Finally, the last sieve reveals the smallest springtails and mites among the tiny grass seeds and grains of sand.
This is painstaking and patient work requiring good identification skills and a keen eye, coupled with a lot of laborious counting (700 springtails in a small sample is not unusual). Today we encountered a new level of detail that had to be taken into account. In one sweep net sample there were many hundreds of grass seeds. These sieve down along with the smallest animals and make finding the insects very difficult. After a couple of hours of poring over this material, extracting mini spiders, little midges, parasitic wasps and beetle grubs, we noticed, inside some of the grass seed husks, minute, dark six-legged creatures – less than 1mm long! They were young Thrips (‘Thunder-flies’) developing alongside their own little grass germ food supply, protected within the seed skin. They could be seen through the skin of the seeds, if we looked closely.
Finding these tiny, hidden insects meant that we couldn’t just push aside the plant material and count the other species, but had to look at every tiny seed for signs of life. Thus opening up a whole new level of detail to be considered as we work out just how much life is supported by the green spaces in our cities.