Northern Ireland's rivers and loughs hold otter populations that much of Europe has lost. They are also the reason a great many riverside and lough-shore proposals need ecological input before they can be determined.
Otters sit at the top of the freshwater food chain, which makes them one of the most direct indicators of the health of a river system. They need clean water, healthy fish stocks, and undisturbed bankside cover for holts and resting-up sites. A river that supports otters is generally a river doing well on all three counts.
Their decline across Britain and Ireland through the second half of the twentieth century was driven largely by organochlorine pesticides entering watercourses, together with pollution and the canalisation and clearance of river banks. Northern Ireland retained otters better than most places, and recovery elsewhere has been one of the genuine conservation successes of recent decades — which is precisely why the protection is taken seriously.
The pressures now are more mundane: loss of bankside vegetation and scrub, culverting and bank reinforcement, disturbance from riverside development and recreation, and road mortality at crossing points.
Otters are protected under the Wildlife (Northern Ireland) Order 1985 as amended and as a European protected species under the Conservation (Natural Habitats, etc.) Regulations (Northern Ireland) 1995 as amended. It is an offence to kill, injure or disturb an otter, or to damage or destroy a breeding site or resting place — again, whether or not it is occupied at the time.
Otters become relevant wherever a proposal sits close to a river, stream, lough shore or drainage channel — which in this part of the country is a great many sites. Bridge and culvert works, bank reinforcement, outfalls, riverside dwellings and any works involving in-channel activity are the usual triggers.
Survey work involves a walkover of the watercourse and its banks looking for spraints, slides, couches, prints and potential holt features. Where otters are confirmed, the answer is usually a buffer, a timing restriction and pollution control during construction rather than a redesign.
Not automatically, but proximity to a watercourse is one of the things a biodiversity checklist screens for. Whether a survey follows depends on the distance, the nature of the works and what the desk study shows.
Otter droppings, usually left on prominent rocks, ledges or under bridges as territorial markers. They are one of the main field signs used to establish whether otters are using a stretch of watercourse.
Usually. The typical outcome is an undisturbed buffer along the bank, restrictions on the timing and method of works, and pollution prevention measures written into a construction environmental management plan.
When a council needs more than a checklist, an ecological statement sets out what is on the site, what the proposal will affect and how that effect will be avoided or reduced — in language a case officer can use in their report.
Read about ecological statements →
Other species: Bats · Badgers · Nesting birds · Red squirrels · Pine martens · Irish hare · Barn owls
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