Native oysters are a staple of our seas and our plates - but our love of their taste has lead to a sharp decline all around the UK.

Large scale drainage in the UK has seen a massive reduction in the range of this sensitive aquatic plant which now only occurs in around 50 sites in England.

The pretty-in-purple Pasqueflower is now a rare plant in the UK, restricted to just a few chalk and limestone grasslands. Steeped in legend, it flowers at Easter, so is known as the 'anemone…

Water-cress has become so popular as a salad addition that it is now cultivated on a wide scale. In the wild, it grows in shallow, fast-flowing streams and is an indicator of clean water.

The greater horseshoe bat was once a cave-dweller, but now tends to roost in old buildings, such as churches and barns. It is rare in the UK and, like many other bats, declining in number.

The lesser horseshoe bat was once a cave-dweller, but now tends to roost in old buildings, such as stables and barns. It is rare in the UK and, like many other bats, declining in number.

This purply-brown seaweed is a common feature on our rocky shores and on our dinner plates.

Fennel has feathery leaves and open, umbels of yellow flowers. It was probably introduced by the Romans for culinary use, and is now a naturalised species of verges, waste ground and sand dunes.…

As its name suggests, Himalayan balsam is from the Himalayas and was introduced here in 1839. It now an invasive weed of riverbanks and ditches, where it prevents native species from growing.