Celebrating the variety of life

We're proud of the great variety of wildlife living on our canals and rivers, from smooth newts to mighty oaks. Take a look at the biodiversity of our wonderful waterways.

Purple loosestrife by the waterways Purple loosestrife by the waterways

Biodiversity simply means the variety of life within a particular habitat. All of that life is interdependent and any small changes can have a big effect.

That’s why we have a team of ecologists who work across the country to protect and monitor life along the canals and rivers. Amongst other things, they give us advice on projects that could help a vulnerable species, and they make sure any construction or repair work we do isn’t disrupting the delicate balance of an ecosystem.

Senior ecologist, Paul Wilkinson, chooses a few of the birds, mammals, insects, amphibians, trees, fish and plants that make up the biodiversity on our waterways.

Oak tree

Oak trees

The great oak is not only important as wood for lock beams, buildings and even ships. It's also the tree with one of the highest numbers of insects, and highest diversity of insects, associated with it. These insects are a crucial part of the food chain for birds needing to feed their hungry chicks.

Common toads

Unlike common frogs that need to keep their skins moist, common toads can travel much further away from water, to often quite dry habitats.

Toads are being found breeding in our waterways more and more. This is partly because their tadpoles are distasteful and fish avoid eating them. It’s also because our canals usually have a constant supply of water from our reservoirs, which means they act as a reliable year-round home for toads.

Toads are long lived, so do not have to breed every year. Sadly their biggest threat tends to be getting run over as they cross and congregate on roads.

Common toads Common toads

European otters

European otters are a great conservation success story. They suffered a catastrophic decline of around 90% in the 1970s. This was mostly due to the use of the now banned DDT pesticide that entered the otter’s food chain, with devastating effects.

Otters are now back in almost all their previous areas of distribution, thanks to improvements in water quality and our waterways recovering their diversity.

Using data from DNA studies, we think we have about seven to nine otters on our West Midlands canal network.

Otter sat on log in water among reeds Otter

Twaite shad

Now one of the UK’s rarest fish, hundreds of thousands of twaite shad used to breed on the River Severn. The introduction of weirs in the 19th century meant that the shad couldn’t reach their spawning grounds further up the river, so their numbers declined dramatically.

Our Unlocking the Severn project is building six ‘fish passes’ that will enable the shad, and other fish species, to swim around weirs and establish themselves again.

Twaite Shad shoal


Also known as fairy moss or water fern, azolla isn’t a true moss, but an aquatic fern. It grows very rapidly, making it one of the most troublesome invasive plants.

Originally from the Americas, it can now be found on our waterways, often in large clumps. We’re using azolla weevils to bring the plant back under control.

Warmer weather caused by climate change may increase the distribution of this plant around the UK. But that might not be an entirely bad thing, because azolla has the ability to ‘fix’ nitrogen and carbon dioxide (absorb them from the air and use them in the soil). So these plants could play a role in the future in storing excess carbon dioxide that has built up in the atmosphere.

Azolla, also known as fairy moss or water fern Azolla, also known as fairy moss or water fern
Brown long-eared bat

Brown long-eared bats

These bats have such long ears because they’re designed to listen for moths and crawling insects.

Our waterways and large old buildings are great for bats, giving them connected routes to travel through different landscapes.

During the summer, females congregate in maternal colonies to keep themselves safe and to use their body temperatures to warm the roost during cold periods. Bats usually only produce a single youngster, a ‘pup’.

Black poplar

A rare but stately tree associated with waterways. It is fast growing and quickly develops features in its trunk for nesting birds or roosting bats.

The poplar hawkmoth is just one of many large and impressive moths to feed on this tree’s leaves and roots or within its timber.

Black poplar tree

Smooth newts

The smooth newt appears to be doing well on our canals. Unlike its larger and more infamous relative, the great crested newt, the smooth newt’s tadpoles usually hide away to avoid being eaten by fish.

Smooth newts are susceptible to extreme weather conditions though. A dry or cold period in spring can have a big impact on their ability to breed in that year.

Smooth newt Smooth newt

Wild cranberry

Can you believe that wild cranberry is a survivor from the last glacial period? It can still be found in a few special places, including the edges of some canals where there are acidic soils.

Rare and vulnerable, this plant is one of the species that could suffer in the future because of rising temperatures and periods of drought caused by climate change.

Wild cranberry Wild cranberry

Scarlet tiger moths

These beautiful day-flying moths were once confined to the south-west of England, but have recently expanded northwards.

Their journeys often follow the routes of canals and rivers, where their caterpillars can feed on comfrey leaves.

Scarlet tiger moth caterpillar


My heart always beats a little faster when I’m lucky enough to see the electric blue flash of a kingfisher flying along our waterways.

Climate change can affect this species in several ways. Milder winters often help more birds survive, because canals and rivers don’t freeze over and prevent them from feeding. However, flash floods during the breeding season can be disastrous, flooding out nest chambers in the banks of our waterways.



I’ve saved the most influential form of life along our canals and rivers for last. It’s definitely us humans.

Research has shown that being by the water is great for our wellbeing, whether we’re enjoying a boat trip, fishing or just taking a moment to sit and listen to nature. But, whatever we’re doing, it’s so important to be aware of the biodiversity around us.

Our species has the ability and responsibility to decide whether to take wildlife into the future with us, or leave it behind in the history books. Being respectful of the environment and wildlife, and taking our litter home with us, will help make sure that our waterways continue to thrive in the years to come. 

Last date edited: 11 February 2021