Waterways Ireland | Biodiversity on Ireland's Waterways

Biodiversity on Ireland's Waterways

Ireland’s inland Waterways are an important tool for wildlife, it is home to rich biodiversity including trees, plants, lock gates, invasive species, bats, insects and more! Let's talk about biodiversity on Ireland's Waterways...​

1. Biodiversity and the law...

It’s good to know that many of our wild creatures - including all of our birds - have protection under law.  There are two ‘layers’ of law protecting our wildlife.  Our national laws date from 1976 in the Republic of Ireland and 1985 in Northern Ireland, they give protection to almost all species of wildlife including many plants.   Laws have created our Nature Reserves and many protected sites called Natural Heritage Areas and Areas of Special Scientific Interest.  One of the European laws provides protection for the most important sites across all of the European member states. These are the Special Areas of Conservation.  

Creepy-Crawlies and Little Creatures: Very few invertebrates are protected by Irish law but there are exceptions.  These include some tiny water snails and the Marsh Fritillary butterfly (Eurodryas aurinia).  This butterfly is now a rare species in Ireland that depends on one plant - devil’s-bit scabious (Succisa pratensis)- for food.  It has been recorded along a number of our waterways.
Because removing habitat can have great impact on bug populations, the least damage we do, the better.  

2. Along Ireland's waterway towpaths...

Towpaths allow for very substantial grassland areas to occur along the canals and inland waterways.  These are important areas for wild plants.  While the majority of the species occurring here are grasses, numerous flowering plants are also at home here.  Many of these would be familiar to most of us.  In the spring, creeping buttercup (Ranunculus repens) and dandelion (Taraxacum officinale) can be in great abundance.  Although common, they shouldn’t be underestimated for their importance to pollinating insects such as bumblebees.  They are a source of early nectar for these vital bugs when there are few other sources yet available.  Clovers (Trifolium spp.), yarrow (Achillea millefolium) and silverweed (Potentilla anserina) are other plants contributing bright colour to our towpaths.

3. Fish and Amphibians...

The waterways offer hundreds of kilometres of habitat for aquatic and amphibian species.  The slow flow and gentle gradient of the waterways have allowed for a diverse and rich fishery to develop over the couple of centuries since they were created.   Just about all of the coarse fish (i.e. not Salmon or Trout) found in Irish lakes occur within our canals.  These include voracious predators such as perch (Perca fluviatilis) and pike (Esox lucius) - the latter often growing to 10kg or more in weight. 

4. Reeds & aquatic plants...

  • Common Reed (Phragmites australis): At up to 3.5 metres in height, this is the tallest grass in Ireland and is important habitat for many creatures from bug larvae to sedge warblers, robin-sized visitors from Africa that breed here in the summer. 
  • White Water-Lily (Nymphaea alba) This is one of the most beautiful of Irish wildflowers but because of where it grows, rarely seen close up.  Its leaves and flower floating and anchored by roots to the bottom, this flower opens fully only in bright sunshine. 
  • Water Forget-me not (Myosotis scorpiodes) Watch out for the small but beautiful sky-blue flower of this little waterside plant.  Looking very similar to the flower we see in our gardens, this forget-me not flowers in the fringes from May to October.  
  • Yellow Iris (Iris pseudacorus) This beautiful flower has a variety of names - Yellow Flag or Flag Iris among them.  Whatever you call it, you won’t mistake the yellow flower - one of the largest of Ireland’s wildflowers - which brightens the waterside throughout the warmest months.
  • Pondweed (Potamogetons) We’ve all seen these plants.  Take a walk beside any of our navigations and you’ll see plenty more.  These are the pondweeds and there are about 15 different species in Ireland.  They have very varied leaf patterns from grass-like to  oval or almost round floating leaves and make up a very large part of the living matter (biomass) of our waterways.  They do flower, making pink, red or white  spikes though these can be hard to see.
  • Milfoil (Myriophyllum spp.) Spiked milfoil is a true water-plant living submerged in the waterways.  It looks delicate and feathery but its name gives away its toughness.  It has tiny red or pink flowers that emerge above the surface in June and July.  It provides food and habitat for lots of small creatures - including snails. Damselflies and dragonflies will also use the plant to deposit their eggs

5. Invasive species...

Invasive or Alien species are plants or animals that have been introduced, usually by people, outside the areas where they would naturally occur. Alien species can sometimes become ‘invasive’ when they spread rapidly and outcompete the native flora and fauna, pushing out native species and this can lead to serious consequences for native habitats. Invasive species present one of the greatest threats to biodiversity worldwide.
Invasive species can be particularly problematic in aquatic systems. They can have a negative impact on recreational and amenity use of waterways, as well as threatening native ecosystems. Curly waterweed (Lagarosiphon major) is a species from Africa that has taken over large stretches of still-water habitats (luckily not yet found in our inland navigable waterways), displacing native waterweed and preventing other plants from developing.  Parrot’s Feather (Myriophyllum aquaticum), a South American Plant, can also take over a waterway or lake and choke it entirely. 

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