The Mawndir Mon Project

Seeing as the LIFE project has come to an end, I was fearful that the Anglesey fens may start to deteriorate once more! However, a £73,000 grant from Natural Resources Wales will fund scrub removal from three sites Cors Erddreiniog, Cors Goch and Cors Bodeilio, each of which I visited during the LIFE conference. Its good to see that these habitats will be maintained as not only are they rich in biodiversity, they also help improve drinking water quality of the Cefni reservoir as well as reducing flood risk! Let's hope more funding will come for these amazing habitats.

Some more information including PDFs with detailed work to be carried out can be found here

Cefni Resevoir & Cors Bodeilio

As part of the MSc we are learning about the benefits of constructed/treatment wetlands. Natural wetlands provide many ecosystem services with a major one being natural biofilters removing excess nutrients from water ways. A treatment wetland can be developed with aims of removing pollutants from waste waters via sedimentation and uptake through the wetland plants.

This field trip started at the Cefni Reservoir, which is a small reservoir in the centre of Anglesey managed by welsh water. The small rivers and streams entering the Cefni have been identified as potential areas to create mini-constructed wetlands. These wetlands could help improve water quality entering the reservoir and also improve areas for biodiversity.

To determine where the constructed wetlands would be best placed water samples were taken from each of the inflows, where they would be taken back to the lab to be tested for pollutant levels. (This was done prior to our field field trip by experts, we also took samples to get a feel for the process).

Different constructed wetland systems would be more efficient at removing certain pollutants/excess nutrients than others...

Free water surface system (FWS)

Sandec/Eawag depiction of a FWS

A FWS constructed wetland allows water to flow above ground, exposing the water to the atmosphere and direct sunlight. Meaning there are aerobic and anaerobic zones for the complete removal of Nitrogen from the system (one of the main pollutants entering the Cefni reservoir). 

Moving to the other side of the reservoir we estimated the flow rate of one of the streams into the reservoir using a very high tech method, which involved a spade, pipe, bucket, jug and stop watch. A small dam was created with the pipe through the middle (as seen in the picture on the left), a small amount of water (around 1L) was collected from the outflow using the jug at timed intervals - which could then be used to calculate the flow rate.

Cors Bodeilio
After discussing potential treatment wetland ideas to help purify the water entering the Cefni Reservoir we travelled to Cors Bodeilio which we had previously visited during the LIFE Conference - a blog post on that can be found here. The LIFE project aimed to restore the delicate fen habitat at Cors Bodeilio with aims to restore the peatlands not only for carbon storage but also to store and purify water, before releasing it at a manageable rate to provide drinking water to Cefni reservoir.

There are a number of constructed wetlands at Cors Bodeilio that remove the nutrients from the surrounding farmlands to prevent eutrophication of the natural fen habitat. These wetlands have however been subject to subsidence and more funding is required to restore the wetlands to full working order - which is key for maintaining the delicate fen.

Life Conference: Cors Bodeilio

Boardwalk at Cors Bodeilio made from recycled plastic

After a free lunch of local meat burgers and delicious cake arranged by the LIFE project at Cors Erddreiniog we hopped back on the mini bus and traveled to Cors Bodeilio. The site lies in a shallow valley between Llangefni and Pentraeth. The water that feeds the fen comes down through the surrounding Carboniferous limestone rock, this water is what makes the underlying mire so special. With a variety of wetland fen species many of these being quite rare and only found at a few sites in the UK the reserve is within a designated SSSI, is also a RAMSAR site and is also a SAC.

Some of the ponies that graze the site

In the past the calcium rich water was diverted away from the fen resulting in the site becoming derelict. However, with various management strategies by CCW the site has returned to its former glory. An adjustable u-bend pipe system has been created to adjust the water level of the fen. During heavy ra

infall (pretty much all the time in wales!!) the pipe can be lowered to lower the water level at the site and also helps prevent flooding in neighbouring fields.
The site is grazed with Welsh Mountain ponies to ensure that natural fen vegetation can thrive, if the site was not grazed a thick thatch of the sedge Cladium mariscus would form taking nutrients and preventing light penetrating lower canopies.

Wildlife

Succisa pratensis also known as Devils-bit can be found at the site

The fen provides a habitat for many species such as great fen sedge and bottle brush sedge. It is also home to some rarer species including the dwarf stonewort and the Fly Orchid. Invertebrates thrive at the site such as dragon flies and grasshopper warblers and also the the medicinal leech. There are two pairs of Lapwings at the site and is also one of two sites on Anglesey where Snipe can be found. A list of other plants and animals which inhabit the site can be found here.

Becoming a Wetlander

If you asked me a month ago what a wetland was the only word that would've popped into my head would've been swamp. But NO wetlands come in many varieties.... who'd have known?

Identifying a wetland is not as simple as it might seem. When a botanist wants to identify a plant there are various keys that can be used to differentiate between plants, but a key for identifying wetland types? Don't be ridiculous. Even the definitions are pretty vague.

The Ramsar Convention defines a wetland as...
"Areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters"

That makes things a lot clearer doesn't it? Yep, didn't think so.

The best way for me to get my head round the many different types of wetlands is to experience them first hand.

My first experience of a wetland was at the Life Conference at Plas Menai. Over the 3 day conference we visited CORS GOCH, CORS ERDDREINIOG, CORS BODEILIO and CORS GEIRCH (Handy tip: WEAR WELLIES).