Friday, 10 September 2010

Signs of the times: Summer #16

More comparisons between the British countryside of today and that from 1959-1961 in the paintings of Charles Tunnicliffe in the Ladybird "What to look for..." series of books.

They sprint eight feet and –
stop. Like that. They
sprint a yard (like that) and
They have no acceleration
and no brakes.
Top speed's their only one.

They're alive - put life
through a burning-glass, they're
its focus - but they share
the world of delicate clockwork.

In spasmodic
Indian file
they parallel the parallel ripples.

When they stop
they, suddenly, are

Norman McCaig “Ringed plover by a water’s edge

(Copyright: Ladybird Books)

Summer Picture 16
¡Vamos a la plaja!

It is well past high summer, the school holidays are now finished all over Britain, so it seems appropriate that we too should visit the beach at some point in this Summer odyssey, while indeed it is still Summer (although here in Stirling it feels like we are perched precariously on the cusp between Summer and Autumn!). In fact, this is the first of several pictures devoted to the coast and seashore between now and the end of the Summer book. In this picture, a group of ringed plovers, adult and juveniles, has landed on the tide line, sitting among the kind of natural marine debris I spent my childhood beachcombing through – in fact, I can honestly say I frequently found specimens of all of the featured items here during my youthful strandline perambulations!

The text addresses the conceit of a painting crowded with these treasures of the sea by saying: “They are not often so close together as in this picture, so some child must have collected these and spread them on the seaweed to view all these treasures at one glance.” Sweet! At the top of the picture, a cuttlebone from a cuttlefish lies next to a dried common starfish (Latin name: Asterias rubens). Immediately below the ringed plovers, the two valves of a razorfish shell (there are several species - I have no clue as to which one this is meant to be), and the purple test (shell) of a common sea urchin (Echinus esculentus) lie next to a dead shore crab (Carcinus maenas). Below them, a mermaid’s purse (a dogfish’s egg case) lies next to the pink and golden shell (well, one half of the shell anyway) of a queen scallop (Aequipecten opercularis) (or “queenie”, if you are interested in eating the shellfish that your diving friends bring up to the surface!). This isn’t the species you are normally served in restaurants but is a smaller and no less edible and tasty scallop species. The picture is completed by the large, white, coiled shell of a common whelk (Buccinum undatum), the shell of another dead sea urchin species, the sea potato (Echinocardium cordatum) which lives in the sediment drawing water and organic matter down a burrow from the seabed surface. These animals or the remaining empty, fragile shells (or tests) are often washed up on the beach after storms. In the bottom left of the picture, the granular mass of little “blobs” is a cluster of common whelk eggs, or at least the cases of them.

The principal purpose of this series of posts is to examine and discuss the changes that have taken place in the examples of British wildlife and countryside shown in the pictures since they were published between 1959 and 1961. I would love to do so for the marine species (or their remains) shown here but it is extremely difficult to do in the same way as I have been able to do so far for, say mammals, birds, flowers and butterflies in earlier posts. While all of those groups (and others) have long-term monitoring processes that have allowed me to make some interesting and in some cases alarming trends in populations (and sometimes to discuss why they are occurring), this is much more problematic for marine species in general and, for what are probably regarded as very common marine species such as shore crabs, razor fish and sea urchins, it is not possible for me to source information to provide an overview of what is happening to their populations, range or distribution in the face of climate change, fishing, the cleaning up of pollution in our coastal waters and estuaries, and so on

Oh, it is possible to tell some stories from specific places. For example, in 1997, I published a study of crab populations in the Forth estuary, by Edinburgh in eastern Scotland, that used records of crabs from the field notebooks of the local marine biological survey vessel to show how the population of shore crabs had increased dramatically over a period of several years in the late 1980s and early 1990s, over the period that the water quality in the estuary improved drastically in response to pollution control measures placed on significant historical industrial discharges. As recovery was also seen (shown in scientific papers published by other people) in the beasties living in the mud of the extensive mudflats of the estuary over the same period, it is likely that the crabs were indeed responding to an improving environment. Which is great, but it is an example from a single place that had been subjected to some extreme impacts from industry and isn’t representative of what is happening everywhere.

We aren’t, however, completely devoid of excellent information sources on marine species and habitats – the fantastic MARLIN (Marine Life Information Network) website, for example, provides a wealth of ecological information on all of the above species, if you want to go looking for more.

The one species in the picture that I can say a bit more about in terms of how it is doing is the ringed plover (Charadrius hiaticula) - a small, and as the Norman McCaig poem at the top of the page implies, hyperactive wading bird of sandy and gravel shores and estuaries. As with many other plover species, when the parent birds perceive a threat to their nest or chicks, they pretend to have a broken wing, dragging one low on the ground and running away from the nest or chicks, to draw potential predators away. The British Trust for Ornithology reports that the breeding population of this species is not monitored annually, but a BTO survey in 1984 showed increases throughout the UK since the previous survey in 1973–74. The spread of the breeding birds inland between the two periods, especially in England, was “probably associated with the increase in number of gravel pits and reservoirs.” The 1984 survey showed that more than 25% of the UK population nested on the Western Isles, especially on the machair [the amazingly flower-rich coastal grasslands restricted globally to Western Scotland, the Hebrides and the west of Ireland], but breeding waders there have subsequently suffered greatly from predation by introduced hedgehogs – a problem that appears increasingly severe and which led to the recent highly contentious hedgehog capture programme on the Western isles, organised by Scottish Natural Heritage, our national nature conservation agency.

Surveys of ringed plovers in England and Wales revealed an increase of 12% in breeding birds using wet meadows between 1982 and 2002. The BTO's repeat national survey in 2007 found an overall decrease in the UK ringed plover population of about 37% since 1984, with the greatest decreases in inland areas. Ringed Plovers that choose beaches for nesting are especially vulnerable to disturbance, and human use of beach areas severely restricts the availability of this habitat to nesting plovers. Wintering numbers in the UK have been in decline since the late 1980s, but the BTO doesn't offer comment on why this might be.

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