Dune Slacks at Aberffraw

Anglesey contains some of the finest examples of coastal dune ecosystems in the UK. So what is a "dune slack" I hear you scream... well don't ask me I've never heard of them.
Taken from the Joint Nature Conservation Committee..

Dune slacks are low-lying areas within dune systems that are seasonally flooded and where nutrient levels are low. They occur primarily on the larger dune systems in the UK, especially in the west and north, where the wetter climate favours their development when compared with the generally warmer and/or drier dune systems of continental Europe. The range of communities found is considerable and depends on the structure of the dune system, the successional stage of the dune slack, the chemical composition of the dune sand, and the prevailing climatic conditions.

Dune systems at aberffraw Source: geograph.org.uk

We visited the dune slacks near Aberffraw with CEH so we could get an idea of what exactly they are. The Aberffraw Dunes are Sites of Scientific Interest (SSSI) and also Special Area of Conservation (SAC) as well as being an Area of Outstanding Beauty (AONB). We were taken around the site in two groups with Jenny - a PhD student and Hilary. We then examined the dunes in a number of ways; using Differential Levelling to determine the groundwater elevation from sea level, taking soil and water samples (to be analysed at a later date) and undertaking a botanical survey using quadrats.

These techniques were used by Jenny for her 3 year thesis on the effects nitrogen were having on the dunes as well as changes to the water table that are partly attributable to the growth of commercial forest in the surrounding catchment. Dune slacks can be classified into different systems dependent on the vegetative communities found. The NVC classification is as follows (source);

• SD13  Sagina nodosa – Bryum pseudotriquetrum dune-slack community,

• SD14  Salix repens – Campylium stellatum dune-slack community,

• SD15  Salix repens – Calliergon cuspidatum dune-slack community,

• SD16  Salix repens – Holcus lanatus dune-slack community,

• SD17  Potentilla anserina – Carex nigra dune-slack community.

With Hilary's help we were able to determine the composition of the dune slack system as SD14-15. We reached this decision by using 1m2 quadrats and identifying the species within each quadrat, as well as the percentage cover of each species, giving us an overall estimation of biodiversity.

Following the biodiversity measurments we went on to calculate the water table elevation from three dipwells on-site. Using a GPS system we located each dipwell, then measured the water level height using a "dipper" that emitted a beeping sound when in contact with water as well as taking a water sample from each dipwell using a pump. To measure the elevation of each dipwell a Theodolite was used;
"a Theodolite is a precision instrument for measuring angles in the horizontal and vertical planes"
This provided us with accurate measurements for determination of water table height.

Beaver Hunters

Beavers have been reintroduced in Scotland (near Dundee), so naturally we went to see what they'd been up to and what effect they'd had on the land! The European Beavers were introduced at the Bamff estate in 2002, around 450 years after they had become extinct in Scotland. They inhabit a 32 acre semi-natural area of woodland and wetland.

Early morning mist outside the hostel

So what did we do?

Site 1 near the trees

The main aim of the trip was to collect data from a variety of sites to whether the Beaver introduction had been a success in the eyes of wetlanders. Luckily we managed to study 4 different areas (we only hoped for 3 beforehand). At each site we tested the pH, conductivity, soil temperature, gas emissions from the soil and the redox readings of the soil, as well as taking water samples (where possible) and also soil samples. Each was repeated a further 4 times, by 3 groups, an upland group, water level group and lowland group.

The 4 sites were all slightly different; Site 1 was close to the Beaver lodge near the open pool of water, Site 2 was close to a beaver dam down stream, Site 3 was next to an artificial drainage pool and Site 4 was upstream. The data should help us get an insight into what affect the Beavers have on the land.

A paper from 2008 was written about the implications of regrowth of trees after felling by the beavers and can be found here.

Unfortunately we didn't get to see any of the wonderful creatures (we probably scared them away) but it could be clearly seen that they inhabited the area!

Hopefully one day in the near future we could be seeing a reintroduction of Beavers into Wales, now wouldn't that be great?

Treborth Botanic Garden & Malltraeth Marsh

Unable to attend this trip I will give a brief description of both sites and what the rest of the MSc students got up to.

Treborth Botanic Garden
The university bought the land that the site resides on in the 60s, and the gardens are now used to teach the university's students along with local schools and community groups.

Map of the Treborth site

The gardens are home to a huge variety of species which are grown indoor and outdoor, part of the woodland at the site is an SSSI. The aim of this trip was to learn about wetland plants that grow at the site that can be found in many wetland areas. Many North Wales plant species native to Snowdonia and coastal regions can be seen at the site, making for a great learning experience for anyone to enjoy. The MSc students collected plant samples from a pond which lay inan area of land that had not been plowed for 60 years, these which were then taken back to the lab to be identified using microscopes and handbooks. Below is a list of some of the species they identified..

• Common Duckweed
• Ivy Leaved Duckweed
• Greater Spearwort
• Rigid Hornwort
• Water Mint
• Water Starwort
• Spyrogira
• Juncus effusus

Malltraeth Marsh

Aerial image of the marsh (RSPB)

The students visited the marsh also known as Cors Ddyga in the afternoon after the botanical garden. The site covers 273ha of marsh, reedbeds, wetgrassland, pools and lakes and is an SSSI located in Anglesey. The RSPB have a reserve situated in the north east corner of the site as it is a notable bird breeding ground, with their main aim to provide a suitable habitat for Bitterns ensuring they return to breed at the site. Upkeep of the clay ditches maintains water levels encouraging an exclusive swamp area for the bittern to breed.

The site is grazed by welsh mountain ponies and management at the site is key to ensuring ground nesting birds return in the summer, this is achieved by reducing grazing. Nesting sites for waders are controlled by creating shallow water ditches where they can feed.
Many species of plant inhabit the area including..

• Bog Bean
• Branched bur-reed
• Club rush
• Common reed (Phragmites)
• Juncus bulbosus
• Blunt-leaved pondweed
• Grey willow
• Stonewort
• Bistort
• Field rose

Many other species inhabit the area including the moss Sphagnum immersum.

These sites both seem like amazing places to visit and I am definitely going to visit them at some point. Hopefully when the weather gets a bit nicer, but i suppose we are in Wales.....

Cors Fochno (Borth Bog)

Sign when entering the site

After a what seemed like forever mini bus trip we arrived at Cors Fochno in the village of Borth in Ceredigion. The site is the most intact lowland bog in Europe, and has been designated as an SAC, SPA, SSSI, NNR and is also protected by the RAMSAR Convention.

One of the Welsh  Mountain Ponies

Site info

When we arrived at the site we could see 2 welsh mountain ponies which were enclosed in an area to graze, this is part of the ongoing management by the CCW. Occasionally cattle grazes the area. The guide showed us a scrape that had been conducted in an area that could be improved. We could see that the scraped area was covered with a shallow layer of water and that the natural bog species like the mosses had returned to the scrape (within 5 years). Proving that these areas can be saved.

A short history of the site...
Cors Fochno can be translated to "bog of pigs" probably derived from when pigs were kept on the land. The land was originally a brackish swamp but gradually changed to a freshwater swamp and then to fenland. It became a raised bog when the area became dominated by bog mosses and cotton grass.
The site could be drained in 1813 when an Act of Parliament allowed the drainage of Cors Fochno, however the site was primarily used for peat cutting and light grazing.

Wildlife

2 Dragonflies on a gate

Today, the site is on of the last in Britain to home the moss Sphagnum imbricatum, there are 15 other species of Sphagnum at the site, and all 3 Sundew species that are found in Britain can be seen here. Bog rosmary, bog myrtle and Royal Fern which are all peat-loving can be found at Cors Fochno.
Insects also thrive at the site with rare invertebrates like the large heath butterfly, rosy marsh moth (which was once thought to be extinct), and an array of dragonflies and damselflies. Lurking beneath the waters at the site are palmate newts, eels and the Fifthteen-spined stickleback; which is the only fish that can survive within the acidic bog water. The eels are what are thought the otter that can be found on site feed on, the presence of otters can be seen in trails along the dams. Our guide also told us about Water Vole that were once wiped out by Mink in the 90s have made a return. He could tell this by putting down small floating blocks where they preferred to do their droppings. Reptiles such as Adders, Grass Snakes, Common Lizards and Slow Worms are commonly found at the site.

Otter trail

Many birdshave been seen in the area, including...

• Sedge Warblerss
• Snipe
• Redshank
• Teal
• Water Rail
• Skylark
• Hen harriers
• Peregrine Falcons

View of the open water at the site

Llyn Padrig

View of Llyn Padrig from the surrounding field

Llyn Padrig is an SSSI site on Anglesey, the wetland has formed in a former lake basin and is now a basin mire. Wetland plant communities have encroached into the lake, but there is still an area of open water present at the site. The site has no public access but luckily the university is granted special permission to visit the site, which is great news for us as we got to experience an amazing wetland. There are a range of habitats surrounding the lake including a wet woodland (with willow and birch), a floating fen and also an area which is becoming terrestrialised.

The willow scrub plants encroaching the lake

We took 3 soil samples for the site, one near the lakes edge, one from the floating fen and one the terrestrialised area. From each of the 3 sites we analysed the pH and conductivity and also collected a sample to take back the lab to test further.
Managment is required to keep the site as it is, CCW has a number of management strategies in place including grazing. Which helps keep scrub at bay, it should also be noted that the dung supplies an important food source to many invertebrates. In the past drainage of the site saw the water level drop by around 2m, which is bad considering that one of the main characteristics of a wetland is a high water table!! It is therefore important to make sure that no further drainage ditches are dug.

Wildlife
Heres a list of some of the wildlife that can be found at the site...

Typha (Cat tails at lake edge)

• Sphagnum
• Bogbean
• Cinquefoil
• Bottle Sedge
• Common Cotton Grass
• Typha (Cat tails)
• Calliergin Cuspidatum
• Greater Spearwort
• Alder
• Grey Willow
• Birch
• Water Starwort

BATTLE: In the fen corner Cors Erddreiniog and in the bog corner Migneint

So, along with a group of Bangor University undergraduates we visited two different sites with aims to see the difference between them both.

The first site we visited was Cors Erddreiniog which we previously visited during the LIFE conference a blog on which can be found here.

This time however we had to get our hands dirty! We started the day with some talks, then split into groups to measure diversity using quadrats, plunge sticks to measure peat depth and measuring pH and conductivity of the soil with special appliances.

The Migneint is the second site we visited, it is the largest area of  blanket bog in the UK and is situated in central Snowdonia. It is a Special Area of Conservation (SAC) and work has been carried out to help restore it since large areas have been damaged by ongoing afforestaion, drainage, grazing and also burning, in hopes to make it better for agriculture. Being an important breeding ground for Hen Harriers it is in the interest of many to bring the area back to its full potential including the RSPCA who have been undertaking many projects which can be found here. An interesting article and video can be found on the BBC website giving an insight into the conservation efforts of the site.

Peat erosion complex at the Migneint

At the Migneint there were strange peat erosion complexes, these are where the peat has been degraded possibly due to the previous drainage issues at the site meaning the peat gets an influx of oxygen which increases degradation. These complexes show how deep the peat could have been if the site was left in its natural state. 

Differences

The main visual difference when comparing the two sites is definitely the height of the vegetation.Walking along the boardwalks at Cors Erddreiniog you are surrounded by vegetation almost at eye level, whereas at the Migneint the vegetation is almost all low lying comprising mainly of mosses and Juncus. The main reasoning for this could be that the water supply for blanket bogs is nutrient poor as it all comes from precipitation in comparison to the Cors Erddreiniog fen which is fed by a mixture of rain water and groundwater increasing nutrient levels and improving primary production. Conductivity was much higher at the fen and pH was recorded to be close to neutral, due to the calcium ions increasing the pH compared to the lower pH of the Migneint and also the lower conductivity.

Image showing some peat cuttings in the background

Life Conference: Cors Geirch

I did not attend the trip to Cors Geirch, but that doesn't mean it's not an important wetland in the North Wales area. This site is situated on the Llyn Peninsula in a valley that lies between Pwllheli and Nefyn. Much like the other sites visited during the LIFE conference the reserve is recognized as a SSSI, SAC and also protected by RAMAR.

Map of Llyn Peninsula showing Cors Geirch

It is another fen site that is fed by alkaline water that drains into through the surrounding porous limestone rock making it a rare type of wetland. The site is also managed by CCW, and Welsh Mountain ponies are used to graze the site.
The site is special as it was the first in Wales to have the rare Narrow-leaved Marsh Orchid identified in 1953, it has now been identified at Cors Bodeilio and Cors Erddeiniog.
Many fenland species which were also see the at other sites we visited were present at Cors Geirch which can be seen listed on the Countryside Council for Wales website.
In the early 90s the site went through a large scale restoration project removing the top 30cm of peat across a large area of the site. The results included a raised water table and reduced fertility, allowing fen plant species to recolonise where agricultural species once dominated. More information on peat re profiling can be found on the LIFE project website.