Introduced from Japan in the 19th century, Japanese knotweed is now an invasive non-native plant of many riverbanks, waste grounds and roadside verges, where it prevents native species from…

The white-clawed crayfish is a freshwater, bronze-coloured crustacean with pale undersides to its claws - hence the name. It is under threat from an invasive and introduced species of crayfish.…

Cotoneaster was introduced to the UK in 1879 from Eastern Asia as an ornamental plant. It is now an invasive non-native species which is taking over valuable habitats including limestone…

Look for Water avens in damp habitats, such as riversides, wet woodlands and wet meadows. It has nodding, purple-and-orange flowers that hang on delicate, purple stems.

Look for wood avens along hedgerows and in woodlands. Its yellow flowers appear in spring and provide nectar for insects; later, they turn to red, hooked seedheads that can easily stick to a…

Sea-buckthorn is a spiny, thicket-forming shrub of sand dunes. It's native to the east coast of England but considered an invasive species elsewhere. It is most obvious in autumn when it is…

Nudibranchs, also known as sea slugs, are much like their land-based relatives that you may spot in your garden. But, unlike your regular garden slug, the nudibranch can incorporate the stinging…

Sand eels are a hugely important part of our marine ecosystem. In fact, the fledgling success of our breeding seabirds entirely depends on them.

One of the UK’s rarest marine species, this giant of the rocky shore is a very special fish.

Ground-elder was likely introduced into the UK by the Romans and has since become naturalised. A medium-sized umbellifer, it is an invasive weed of shady places, gardens and roadsides.