Monday, 26 July 2010

Signs of the times: Summer #9

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.

"Whole ages have fled and their works decayed,
And nations have scattered been;
But the stout old Ivy shall never fade,
From its hale and hearty green.
The brave old plant, in its lonely days,
Shall fatten upon the past:
For the stateliest building man can raise
Is the Ivy's food at last.
Creeping on where time has been,
A rare old plant is the Ivy green."

From: Charles Dickens "The Ivy Green"

(Copyright: Ladybird Books)

Summer Picture 9
A sunny day at the foot of a wall, we see a song thrush cracking open a snail shell on a rock “anvil”, while a common lizard and two Wall butterflies bask in the warm sunlight. A number of plant species tolerant of the dry conditions and poor soil conditions of wall environments frame the picture: some ivy (on the right) and wall-pennywort (in the centre) are creeping up the wall, while some herb-robert with its pink flowers hangs down from the top-left and the yellow flowering smooth hawksbeard is growing up from the bottom left.

I looked at the recent fate of the song thrush (Latin name: Turdus philomelos) population in Britain in Spring post number 14. In that, we saw that is a species "with mixed fortunes over the 50 years since the Ladybird book was produced. Song thrush abundance in the UK declined by 49% between 1967 and 2007, with a slight increase again in the final years of that period". I would say that I have, in the past 3 to 4 years, begun noticing both an increase in the number of song thrushes in this area and also an increase in the number of song thrush “anvils”, stones or slabs on the ground, surrounded by fragments of land snail shells. I also reported, in Summer post number 5, that since song thrushes returned as regular visitors to my garden about three-four years ago, I have been finding ramshorn snail shells from my pond, smashed open on stepping stones by the resident song thrushes. I came on this song thrush anvil in the middle of the path around my local park, so this is just a poor quality opportunistic mobile phone photo. Nevertheless, you can see the fragments of snail shells surrounding the rock in the centre.

The Common Lizard (Latin Name: Lacerta vivipara) is actually a widespread species across Britain and Ireland, preferring heathland and grassland habitats. The second half of the Latin name (vivipara) comes about as it is viviparous, giving birth to live young, unlike most other lizards which lay eggs. As a cold-blooded reptile, the common lizard is often seen basking in Summer in sheltered, sunny spots, such on a wall like this, to elevate its body temperature. You may be familiar with the survival trait shared by many lizard species, including the common lizard, of casting their tail when seriously threatened by a predator. The discarded tail continues to wiggle violently for a while, distracting the predator while the lizard makes good its escape. In due course, the lizard will grow a new tail. I had never seen this until the end of June this year when, on a footpath through a Scots Pinewood at the bottom of Cairngorm in the central Highlands of Scotland, our terrier Ella suddenly dived into a clump of grass, into which she continued to poke her nose, exhibiting signs of great excitement (definitely in hunting mode). I saw a common lizard briefly before it vanished into long grass. Meanwhile, Ella’s attention was drawn to the movements of the lizard’s tail which did indeed hold her attention as it continued to twitch sinuously. I felt sorry that the lizard had lost its tail but I would have been much more upset if Ella had killed a beautiful wild lizard, and it was fascinating to see this escape mechanism in action. It fooled Ella and she’s quite smart!

I’ve been unable to source any information on the trend in common lizard population or distribution since 1960, other than a vague suggestion that they are not as common as they used to be as a result of habitat loss due to development, and also that they are still common and widespread across Europe and not threatened. They are, by the way, also strongly protected by British law.

The Wall or Wall Brown Butterfly (Lasiommata megera) is not common in Scotland, being restricted only to Dumfries and Galloway, the Scottish Borders, a bit bizarrely remotely, on the Isle of Mull where it has recently been rediscovered. It has traditionally otherwise been common in Britain, prefers heathland and grassland habitats, open woodland and gardens, and characteristically likes to bask in the sun on open ground, on stones or on walls. There has, however been a dramatic and severe decline of inland populations since the 1970s. It has decreased both in distribution and in population sizes (as seen where populations have been monitored over the long term). The report on the State of Butterflies in Britain and Ireland identifies that there has been a decline of 38% of its distribution between the periods 1970-82 and 1995-2004, and its population has declined by 65% between 1976 and 2004. Research is underway to try to explain the decline. Despite the overall decline, there has been some minor expansion of the range of this species at the northern end, perhaps reflecting the effect of a warming climate.

The wall environment is a pretty tough one for flowering plants. Whatever soil might gather or be formed in cracks in walls is both likely to be in tiny pockets and also likely to be pretty poor in nutrients. Plants living in this environment probably also need to be capable of tolerating extremes, of drought, of cold and of desiccating winds. Both the ivy (Hedera helix) and the wall-pennywort (Umbilicis rupestris) have features of their biology that makes them well adapted to these conditions, such as thick, waxy leaves that reduce the loss of water during dry spells. The ivy is a well-known perennial evergreen climbing plant found all over mainland Britain, other than the highest mountain areas. The New Atlas of the British and Irish Flora says that its distribution is unchanged since the 1962 Atlas. In the Flora Britannica, Richard Mabey compiled six pages of information about the cultural, religious and historical beliefs about ivy and its uses, along with its central role in British Christmas greenery and rituals, “the high point of the ivy’s ceremonial year.”

The wall-pennywort, or navelwort is a conspicuous species on rocky, stony and wall habitats in Western Britain. In Scotland, it is largely confined to the south-west. I presume it is called navelwort due to the similarity of the leaves’ sunken centre point to that part of the human anatomy (well, at least if you are an “inny” rather than an “outy” belly-button). Its distribution was once wider – John Gerard’s 16th Century Herbal reported it as growing at Westminster Abbey. The New Atlas reports its distribution as unchanged since the 1962 Atlas.

The other two plants in the picture are not specifically wall dwellers. The herb-robert (Geranium robertianum) with its little pink flowers is a wild geranium species which is very common across all of Britain and Ireland, except for the Western and Northern Isles of Scotland. It lives on walls, on scree and shingle, in woods, gardens and other cultivated land, woods and along verges and paths. It has a smell a bit like acrid mouse-pee which, according to Flora Britannica, might be the source of its common name, a possible ancient association with “the house goblin, Robin Goodfellow” of English folklore (see this Wikipedia entry for a useful expansion of that reference. The New Atlas says there is very little evidence of any change in its distribution since the 1962 Atlas.

The slightly dandelion-like yellow flowers on the left of the picture belong to the smooth hawk’s-beard (Crepis capillaris), a very common coloniser of nutrient-poor grasslands, wasteland, walls, lawns and rocky habitats. There is no historical, cultural or other information about this species in Flora Britannica. As well as indicating that it competes very poorly in habitats other than the open ones listed above, the New Atlas says that its natural range is stable since that published in the 1962 Atlas, although it may also be spreading through colonising suitable man-made habitats (e.g. spoil heaps and verges).


  1. Thanks lom - that's very kind. Please feel free to stick around. There's lots more to share! Two more seaosns for instance! SNB


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