After the Storm

Our February storm caused quite a stir, leaving us with no power, no mobile signal and no phone line. The following morning we checked outside; lots of debris, the greenhouse was in tact and just two conifers had fallen at the top of the garden.

Gareth in steel toecaps

We packed a bow saw and headed down the drive, to see if our neighbours were ok, but had to reverse back for the chain saw. I nibbled at the oak lying across the drive, just below the top hairpin, while Sue walked to the bottom. I was still hard at it when she returned to advise there were several more trees she had had to climb over.

Armageddon on the bottom hairpin

We worked our way slowly downhill until we heard the sound of the cavalry to our rescue, two chainsaws ripping their way upwards. A big thank you to Natural Resources Wales for coming to help, having already cleared the bottom lane.

Thanks to BT OpenReach for climbing the poles to replace a hundred metre section of line. Thanks to Scottish Power for replacing several hundred metres of cable – Dewi the farmer had seen the cables on fire with the flames making their way up the hill towards us.

The damage along our side of the valley was immense but everyone emerged unscathed. We were very lucky and we all know our neighbours that little bit better!

'I'm sure I buried a bone here'

Just above the bottom hairpin

The Biggest Twitch

Alan Davies and Ruth Miller of The Biggest Twitch are birdwatchers and expert tour guides based in north Wales. During 2008 they set a new world record when they saw 4,341 different birds during the year.

At 7pm on Saturday 22nd February at the Porthmadog Football Club they will give a talk about their birdwatching highlights during last year in north Wales, Spain, Finland, Norway and Thailand. Entry fee £3.

This event has been organised by:

Anglesey AONB Winter Bird Watch

Saturday 15^th February is a date to put in your diary if you would like to see the spectacle of winter birds on Anglesey. This time last year 100 different bird species were recorded on the day of the event plus bottlenose dolphins and otters. I went along to meet Lowri Hughes (the organiser) and Ben Stammers (one of the bird experts) for a preview of what might be on show at Cemlyn, one of the many sites to be surveyed on the day.

Lowri and Ben on the shingle ridge at Cemlyn

Rather than try to repeat  Ben’s descriptions and the overall atmosphere you can hear what’s on offer on this Sunday’s Country Focus on Radio Wales. This programme is now available as a podcast for 30 days after broadcast. Click here for details of the podcast.

The terns for which Cemlyn is most famous are not due to arrive until mid March, which is just as well because the islands in the lagoon, where they nest, are currently submerged.  Between now and mid March Ben and members of the North Wales Wildlife Trust will regulate the flow of water to make sure there is sufficient island nesting space.

If you would like to take part please make contact with Lowri on 01248 752 446 or by email to lehpl@anglesey.gov.uk

The plan is for everyone to meet at Penrhos Coastal Park car park at 8.15am to split into different groups, then once the day’s bird watching has been completed, everyone will meet back at Caffi’r Parc at Breakwater Country Park for some food and a chat about the days sightings at around 4.15pm.

Islands almost completely under water

Swept clean?

As well as the coastal erosion and damage to infrastructure caused by the succession of storms and tidal surges this winter, there have been other noteworthy consequences. Anyone who has been to Welsh beaches in the last few weeks will have been struck by the huge amount of litter cast up by the sea. This isn’t just big items like plastic drums and broken fish boxes, but also huge quantities of tiny fragments of expanded polystyrene and other plastics.

In the aftermath of major oil pollution incidents years ago, work was done to model the drift of oil and other things on the sea surface. In general, figures of around 2-3% of the near surface wind speed provided a good approximation for both forecasting drift and hindcasting origins. So, while a waterlogged pallet might drift at about 3% of the wind speed, things with more windage, such as empty drinks bottles with lids, would be expected to travel rather faster. Sometimes, where the origins of objects are known, the speed of travel to reach our shores from distant places can seem quite surprising. An example of this from a few years ago was when identifiable parts of a catamaran, which broke up in a storm off Cape Finisterre in NW Spain, reached an Anglesey beach in 110 days.

Seeing the amounts of debris and particularly the fine fragments of broken up plastic on some Welsh beaches facing the SW wind or where the tidal surges have swept debris up inlets, one is reminded of the poetic musings of the Walrus and the Carpenter, as they walked along a beach before over-exploiting the local stock of oysters. Verses 4 & 5 of the poem as told to Alice in Lewis Carroll’s Through the Looking Glass were as follows:-

The Walrus and the Carpenter

Were walking close at hand

They wept like anything to see

Such quantities of sand:

‘If this were only cleared away,’

They said, ‘it would be grand?

‘If seven maids with seven mops

Swept it for half a year,

Do you suppose’ the Walrus said,

‘That they could get it clear?’

‘I doubt it' said the Carpenter,

And shed a bitter tear.

It only requires a slight substitution of junk for sand in verse 4, to express the nigh on impossibility of removing the smaller fragments of plastic even by armies of volunteers. Seaborne litter should be getting a higher profile and is now included in the EU Marine Strategy Framework Directive. Thought is currently being given to how best to develop monitoring programmes for the various components of marine litter. Actually collecting and disposing of it is quite another matter.

One consequence of the prolonged sequence of depressions swept across the Atlantic by the jet stream may have been a reduction in the “standing stock” of litter actually washing to and fro out at sea with more of it landing up on the shore. Back of envelope calculations would suggest that 40 days or so, with winds as they have been, might have swept ashore most of the litter from about 700 – 1000 nautical miles out in the ocean. Looking at the organisms growing on the litter, it was noticeable that while the lost whelk pots and other items thrown up from the near-shore seabed by the early storms had the usual range of barnacles and saddle oysters on them, the floating litter coming up then had few attached organisms. Debris floating in the open ocean for long enough usually gets colonised by things like stalked or goose barnacles (Lepas spp.). The occurrence of such organisms can give clues as to whether a proportion of the litter has come from out in the open ocean or from more local sources in and around the Irish Sea. It was interesting to see that photographs showed Lepas on the bottom of the boat on which the Mexican fisherman apparently survived, drifting across the Pacific for many months.

Lepas anatifera

Five species of goose barnacle turn up on debris washing up on Welsh shores. Of these the most familiar is Lepas anatifera. Unusually, at least in Llŷn and Anglesey, L. anatifera has been less common this winter than a smaller species, L. pectinata, which can be distinguished by the obvious radial ribbing on the shell plates. Another species, which can be found sometimes is L. hilli. This one has an obvious pale and often bright orange band where the stalk reaches the shelled part. The fourth species, L. anserifera, which seems to be rare, perhaps partly because it is less easy to identify, grows to be similar in size to L. anatifera but has ribbed shell plates. Finally there are a few records of the buoy barnacle Dosima fascicularis which starts off by attaching to small things like feathers but then goes on to secrete a float of its own.

Lepas pectinata, which can be distinguished by
the obvious radial ribbing on the shell plates

The author of this blogpost is Ivor Rees.

Winter Storms

Derailment on The Cob

Driving into Porthmadog yesterday I was surprised to see a Ffestiniog Railway works carriage blown off the rails. Spray and debris was coming over The Cob as I accelerated beneath the carriage, just in case it was about to take off. But it wasn’t.

It's amazing, the power of nature. In my student days I lived on the prom at Aberystwyth, the top floor flat above the Chinese, opposite the pier. It was a great vantage point for sunsets and storms but well away from the danger zone; our only water hazard was the condensation streaming down the walls of the paraffin heated rooms.

Buckled lines north of Barmouth. Parts of the track
were moved 9 feet towards the land.

The wrong end of the Aberystwyth prom.

Avian Pox

First it was just a single Great Tit with an ugly brown growth on its head, then there was another with a growth on its leg and another. 

Great Tit with Avian Pox
Birds are normally photographed for their beauty

Avian Pox is a disease spreading northwards and the hope is that the birds will develop an immunity to it; it does not seem to harm them. It is also present in Dunnocks but harder to detect against their brown plumage as they scuttle around beneath bird feeders.

If you see birds with such growths it would be good if you could report the fact on the new website promoting Garden Wildlife Health

It would be wise to give your bird feeding station a thorough clean to reduce the likelihood of the disease being passed on.

In February 2013 I think there were three infected birds regularly visiting my feeders but this year I have seen none. Did they recover?

Shingle - great coastal defence and good for wildlife

Shingle beaches are fascinating places with their own unique flora and fauna. They also perform a great service, absorbing wave energy and protecting the coast from erosion. We should make full use of the ecosystem services they provide, argues Ivor Rees,a marine biologist, and formerly a senor lecturer in Ocean Sciences at Bangor University.

Morfa Abererch shingle beach

Shingle beaches may not have the immediate charisma of some other coastal habitats but such apparently harsh environments and the plants and animals colonising them have much intrinsic interest. Even without the biological interest, the shingle features around Wales have long been recognised for their geomorphological importance. Recognition of the dynamic functioning of such features is vital for understanding their ecology, but it is even more important given the interplay of rising sea levels and the role shingle plays in coast protection.

Wales has a legacy of settlements, roads and railways placed in the lee of, or even on top of shingle banks. Recent estimates are that sea level around Wales is rising at 3.1mm per year and revised predictions by the International Panel on Climate Change are of rises of 0.6–1.0m by 2100. Striking a balance between allowing the sea to adjust such natural features and imposing 'hard' engineering is one of the most challenging marine conservation issues of our times. In spite of the extent to which coastal geomorphology has featured on the educational syllabus, shingle ridges and storm beaches are perhaps the most misused coastal habitats.

Shingle formation

Shingle banks and ridges are formed by the swash of storm waves throwing pebbles onto the crest well above the reach of normal waves. Owing to rapid percolation through the interstices, backwash is reduced, so wave action tends to be constructive. In storms shingle can be thrown to considerable elevations, thus the ridge generated by the sea can be several metres above the land behind it. In the extreme example at the Portland end of Chesil Beach, the crest is 13.3m above normal high tide and towers above a street of houses behind it.

Shingle stability and the availability of humus are key factors which permit succession from bare shingle to full vegetation. The first signs of relative stability come with the colonisation of the pebbles by lichens. Accumulation of humus is more erratic, as much of it ultimately comes from the strandlines of seaweed and other flotsam. Some plants that can cope with some instability thrive along strandlines, giving rise to lines of vegetation formed mainly of sea-beet Beta maritima, several oraches Atriplex spp. and curled dock Rumex crispus. Another factor is the availability of fresh water, allowing less salt-tolerant species to colonise. In addition to rainfall, day–night heating and cooling causes dew to form within the interstices between the pebbles.

Species

Vegetated shingle is quite a scarce Biodiversity Action Plan habitat around Wales. The total area in the whole Principality, as estimated by Natural Resources Wales, is only about 810 hectares. Put in context, sand dunes cover over 70 times as much. A particularly fine example occurs at Morfa Abererch on the south side of the Llŷn Peninsula. Here, as a result of long-shore drift, shingle has accumulated against a rock headland as a series of parallel ridges. Even the oldest ridges are still very sparsely vegetated. Up close the stable pebbles are seen to have been colonised by lichens, with English Stonecrop Sedum anglicum in the crevices between. Further out, spectacular clumps of Yellow-horned Poppy Glaucium flavum occur, with Sea Campion Silene maritima growing in patches. The sequence of colonisation can also be clearly seen on the shingle spit at Abermenai Point on Anglesey, where a veneer of sandy turf has developed over the stable shingle. Although such places remain relatively undisturbed, a disproportionate and unexplained number of shoreline specialist species have been lost or contracted their range in Wales since being noted in the diaries of 18^th century botanists visiting Wales. These include Cotton Weed Otanthus maritimus, last seen in the 1890s, and Oyster Plant Mertensia maritima, the last of which was destroyed by coast protection works.

The last site where Little Terns nest in Wales is at Gronant on a shingle feature. They nested on the great shingle bank between Criccieth and Craig Ddu and on the Cemlyn ridge into the 1930s and clung on north of Towyn into the 1970s. Buglife also lists a series of Biodiversity Action Plan (BAP) insects as exploiting shingle habitats.

Ecosystem services

Behind the legends of Cantref Gwelod and other drowned lands probably lie folk memories of storm surge events, when major changes happened to shingle ridges or they were breached. These events may have caused low-lying land to flood for long periods as stream outlets were blocked, or maybe river mouths diverted by shingle spits opened in different places. Even in modern times some shingle banks intermittently block streams, so water levels behind them vary erratically. This type of fluctuation used to occur at Ystumllyn near Criccieth until the outlet was diverted through a tunnel in the Craig Ddu rock headland.

It has to be remembered that the origins of many coastal features around Wales, and much of the gross morphology of the offshore seabed, can be traced to the glacial and post-glacial history of this part of north-west Europe. Indeed, most Welsh shingle spits, bars and bay head beaches came from reworking glacial till and outwash deposits. In only a few places has the shingle come directly from erosion of adjacent rock strata or, in even fewer places, quarrying of them. Paleo-oceanographic studies of relative sea levels during the last 12,000 years show the likely sequence of inundation, taking account of the melt of the major ice sheets and isostatic rebound. These imply that the genesis of the major shingle structures we see today may have been much further out to sea than the present coastline, and that they gradually migrated landward as sea level rose.

As such features are constructed by wave action, unless they are starved of further material their height generally keeps pace with sea level rise and they continue to protect areas behind them from flooding by waves. Because percolation takes up much of the swash passing the front of the crest, wash-over is limited. It is noticeable that it is more often where shingle is covered by hard impervious surfaces, such as promenades and car parks, that water from waves floods on to property. Making the fullest practicable use of the ecosystem services provided by shingle banks in their natural, unimpeded state has potential for long-term cost savings, as well as being best for safeguarding their ecological interest.

[This article was first published in the winter 2010 edition of Natur Cymru.]

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The following film explains the dynamics of Ynyslas Spit and the role of shingle.