The Dodder: A haven of biodiversity

Daubenton’s Bat.
Photo by Gilles San Martin (Creative Commons)

Dermot Carmody

As part of the recent Heritage Week 2019, Dublin City Council organised guided walks highlighting Rivers As Havens. NewsFour went along to the walk along the Dodder under the expert guidance of DCC Biodiversity officer Lorraine Bull and later chatted with her about her work.

Our group, some forty strong, met for the guided walk with Lorraine, where the third longest Dublin river flows by Bushy Park. It was just before dusk for reasons which were to become apparent.  

Lorraine led us along the bank of the river in search of evidence of its abundant fauna. We peered unsuccessfully under a bridge where a flat concrete ridge provides an ideal place to spot dippers. Smaller than a blackbird with reddish-brown plumage and white bib, dippers can be seen on flat rocks in the river, their characteristic bobbing motion giving rise to their name.

Less frequently spotted is the most spectacular bird found along the Dodder, the brilliantly coloured kingfisher.

But the airborne stars of the show on this evening are not birds but mammals. The chance to see bats is the reason why the time and location of the walk were chosen. Lorraine made use of a handheld bat detector which detects the clicking noises made by the bats to locate the insects they catch and eat on the wing.

The device converts and amplifies the clicking, so it becomes audible for the the human ear. It can also be tuned to detect the different specific range of frequencies of the noises made by different species.

Our group crammed on to a small footbridge and Lorraine’s bat detector burst into life, indicating the hunting activities of Daubenton’s bat. Often called the water bat, Daubenton’s bats fly just a few centimeters above the surface of the river hunting for caddisflies, mayflies and midges. It can even pluck prey from the surface with its feet.

The bats fly up and down the water between the bridges and we can see them clearly  as our eyes adjust to the twilight. The bat detector tells Lorraine there’s another species on the wing nearby: the smaller pipistrelle bats, who flit about in a different niche at hedgerow level.

In conversation later, Lorraine, a bat-lover, explains that August is the best month to see Daubenton’s bats on the river, though they will still be seen through to October until the temperature drops. “In November they’ll actually go into longer sleeps,” she explains, “and then they build that up before they go into hibernation.”

Lorraine has had an affinity with waterways since going fishing in canals and rivers with her father in London, where she spent her childhood. Her mother hails from Dublin. Lorraine moved here in the late 90s.

Her background is in the arts. But she returned to college here as a mature student and studied Zoology. Since then she’s worked on a number of conservation projects, including the Wildlife Trust and the Whale and Dolphin Group in Ireland.

Since April this year she has been working as DCC’s Biodiversity Officer. Why is biological diversity important? Well, as Lorraine describes it, it’s our “life support system on Earth. It provides us with fresh drinking water, air and food. Without the little macro-invertebrates in the river, without the trees providing oxygen and all the plants and animals providing food, we wouldn’t be able to survive.”

She describes the richness and diversity of a river like the Dodder, which like all rivers has several different areas providing different habitats for plants and animals. “You’ve got fish spawning grounds, you’ve got faster-flowing stretches of river and then areas where it will naturally slow down,”.

Still ponds like the one we encountered on our walking tour provides the perfect environment for frogs to spawn. Near that pond, Lorraine pointed out a flattened pathway through the growth on the bank into the water, which turned out to be an otter slide. Otters are found all the way along the Dodder, right down to where it enters the sea, where they’ve been spotted near St. Patrick’s Rowing Club in Ringsend.

Another interesting inhabitant of the lower reaches of the Dodder is The Little Egret, formerly a migratory visitor from Africa here, but then, as Lorraine says, “just a few years ago they decided to stay. They’re seen as an indicator species for climate change.” Our milder winters coupled with possibly hotter summers in Africa have made this bird, which looks like a small white heron, a permanent resident.

Lorraine is keen on doing more walks such as the one along the Dodder. Liaising with local community groups like the Dodder Action Group is an important part of her work as a DCC Biodiversity Officer as it’s not just the actions of official bodies, for example, the Parks Department of DCC, that can contribute to biodiversity.

The Dublin parks have greatly improved the environment for pollinators with planting policy and made changes to the way invasive plants like Japanese knotweed are dealt with. But local groups have also made an important contribution, as do individuals who change what they do in their own garden. 

Not only is Lorraine enthusiastic about the efforts of individuals and local community groups, but she insists it can make a difference, despite the daunting prospect of climate change, which she agrees people may find overwhelming. “We think ‘Oh, God, it doesn’t matter what we do! This is all really bad!’” she says, “but actually a lot of local groups working together on a small scale actually has a big impact.”