Six coastal canaries

With so much climate change scepticism around, it is useful to have indicators that anyone can observe and which will point directly to rises in overall temperature. The “canaries” concept is one that fits this particular bill.

Canaries as indicators of danger

In times gone by, coalminers used to take caged canaries down the mine with them, not for the company but as a safety device. It was known that canaries were highly susceptible to gas poisoning, so if your canary fell off its perch you knew that there was methane gas seeping into the mine and it was high time that you moved to somewhere safer. (The canaries often recovered when taken to a place with better air, although this was not always the case).

The United Kingdom’s National Trust has taken the “canary” concept a stage further by announcing a set of six “coastal canaries” that, should their populations show a sudden decline (or in one case a rise), will provide a warning that global warming has reached a dangerous level. These are species that are highly dependent on such things as sea temperatures and weather patterns for their survival and which will react most quickly when these factors change.

Six coastal canaries

The canaries chosen by the National Trust are:

1.       .Glanville fritillary butterfly. The range of this butterfly has got gradually smaller over the years, and it is now confined to the western chalk cliffs of the Isle of Wight. It will therefore be relatively easy to spot its complete disappearance, should that occur.

2.       Oysterplant. Grows on shingle beaches in northern England, Scotland and Northern Ireland. It will suffer if the sea becomes more saline or if higher sea levels mean that it has to spend more time submerged.

3.       Cliff tiger beetle. As cliffs crumble as a result of rising sea levels and increased storm activity, it becomes necessary to carry out more cliff stabilisation projects. This disturbs the cliff tiger beetle, which can only fly short distances and will find it difficult to find new hunting grounds.

4.       Puffin. Warmer seas are affecting populations of sand eels, which supply the puffin’s chief source of food. They breed in cliff-top rabbit burrows which can flood if there are too many heavy rainstorms.

5.       Little tern. This bird breeds on beaches just above the high-water mark. Too many exceptionally high tides and summer storms will have a significant effect on the little tern’s breeding pattern.

6.       Triggerfish. Aptly named for this purpose, the triggerfish is a warm water species that is beginning to be seen in greater numbers in British waters, notably off North Wales. There are other “trigger” species for the same reason, such as basking sharks, certain species of jellyfish, and zebra mussels, all of which are being seen more frequently.

As climate change continues to affect the coasts of the United Kingdom, many species will doubtless be affected. The above “canaries” are likely to be only the first of many.

© John Welford