Garden Tool Set

On Salisbury Plain, Wiltshire, Pheasant’s Eye (Adonis annua) and other plants that are now rare, used to be plentiful all around the country. This is due, in part, to modern farming methods, but with Salisbury Plain being no go or restricted for most of the year, wildlife is left to be well – wild. Chris explains that poppies are excellent at growing on recently disturbed sights, but is surprised to see them growing in abundance on Salisbury Plain. Why could this be? To explain, Chris blows up a poppy with explosives. What’s left doesn’t include the poor poppy, but it does reveal a rich seed bank now ready to explode into life. Taking some of the revealed soil to Trevor, we embark on an experiment in an underground munitions store. In light and water controlled conditions, we see that the seeds in the soil are still able to germinate after many years, including buttercups and poppies.

Sally investigates the ruts and pot holes left by the military vehicles and during exercises. The churned up soil fills up with rain creating temporary ponds that readily brings the awaiting creatures to life. We see the volvux through a light microscope to admire the beauty of these spherical green algae cells. Although it’s not safe for long, as it’s just a small part of the food chain; even in this temporary pond that will last for a few months maximum. It’s eaten by tiny crustaceans called ostracods; but the king of this chain is the upside down swimming fairy shrimp (Chirocephalus diaphanous). While the fairy shrimp was quite common in the south of England and parts of Wales in 1964, we see the dots on the map vanishing indicating that their habitat is in decline. This is because they can only survive in places with pure water. Use of herbicides is a cause of this decline; this is also why they can be found on Salisbury Plain.

The pain of the stinging nettle is a reminder of childhood for most of us. We find out that it is the only plant that can sting native to Britain. The large hairs of this nettle, the trichromes, are hollow and very sharp needles of silica. Easily penetrating our skin on even a gentle brush of the hand; the release a cocktail of toxic chemicals from the swollen sack the needle rest upon. Histamine and serotonin are just a couple of the chemicals that are injected into the nerve endings under the skin. Chris explains that the stinging nettle has flourished in the fertiliser rich soils of modern farms, with records filling the whole of the UK and Ireland map. The nettle protects the wildlife that can live on the plant while steering clear of the stingers.

Trevor explains that plants have a variety of seed dispersal methods, but concentrates of the ballistic method used by the invasive Himalayan balsam that was first introduced to Britain as a garden plant that begun its escape in the early twentieth century according to records. The flowers of the Himalayan balsam only last for a few days and when pollinated can create up to a thousand seeds. The seeds are scattered by anything that touches the pod and we see that this dispersal method is much quicker than a bullet being fired from a gun. The pod splits into coils that spring back releasing the seeds.

All in all another great episode. I enjoyed the way that the episode was put together with aspects of plant life being chosen that matches that of the military surroundings. After two episodes now, I feel that the right amount of information is delivered for the length of the episode. Roll on episode 3!

For the episode 1 write up; click here.