Peat Monitoring on the Isle of Man July 2020

You may have noticed a lack of posts from me lately. This is not because I am slumming it at home. I have still been out and about but not my usual type of walk. The last two Sundays I have been out in the hills collecting data on the state of the peat on the island, in this case, close to South Barrule, just above the Earystane Plantation.

Why am I doing this, I hear you ask? Well, the Manx Wildlife Trust is trying to find out how healthy our peat is. Sphagnum moss found in peaty areas retains a lot of water and if it is in good order it helps to contain the flow of water in extreme weather. It also aids the accumulation of peat as its mass leads to slower decomposition of soil and it also raises the water table. You will remember the Laxey floods in recent years, which in the time I have lived here – less than 7 years – destroyed the bridge in Laxey with spectacular photos of a bus in the river if I recall rightly, and last year the whole main street was flooded out, with some people having to be rescued. It even made the BBC news. The bottom line is that if we can restore the peat levels on the uplands it will help to keep the rainwater in the hills rather than flowing rapidly down narrow gullies and flooding our rivers and villages. Before anything can be done, MWT needs to know how much peat we have, how deep it is and whether it is attracting the right flora and fauna to sustain it, particularly sphagnum moss.

Sphagnum Moss
An orchid, the only one I saw in this location in the two sessions.

The task is essentially very simple. Take a long probe (and an extension rod if you think you will need it), a tape measure, something to record the data on, and a GPS App which contains all the waypoints. As I was working alone, I also took a highlighter to mark the position of the peat on the probe. This worked a treat and made life a lot easier.

Arriving at your start point, you switch on your GPS system and follow it to your first waypoint. This may or may not be easy depending upon the terrain. It is surprisingly tiring work as of course you are not walking along a nice level road, but making your way off the beaten track, clambering through and over heather, gorse and grasses of all different sizes and most of the time you have no idea where you are putting your feet as you can’t see the ground underneath all the undergrowth, so slow and steady is the name of the game. The waypoints take no notice of idiosyncracies such as deep channels that have been cut out by farmers or sudden drops in height, so detours are often necessary. Straight lines between the grid points therefore end up being anything but straight, especially as it took me some time to work out how to use the GPS App without any instructions!

The area I have been looking at these last two weeks does not appear to my untrained eye to be very peat-productive, Most of my probes only registered between 18cm-25cm depth (you take three different readings in a triangle around one gridpoint). The deepest measure I took was 40cm and the lowest 13cm. The land is quite dry and there is a fair bit of dead heather. There are exceptions but you won’t come across any deep bogs to navigate here. I only found two areas of sphagnum moss on my visits to actual waypoints, but I did also record one region where there was quite a bit of it as I was traversing from one waypoint to another. The moss needs the terrain to be wet and then it will soak it up. It is worrying there is so little. I suspect over the years different types of farming and the digging of peat will have affected the quality and amount of peat that we now have left.

This was just one area, and I shall be out an about in the southern uplands taking more measurements over the next few months. There is a team of us working on mapping the whole island, and it will be interesting to see if different areas are more lush than others in this respect.

Bog Cotton in the foreground of Cronk My Arrey Laa

Even the heather seemed a bit sad, but the bog cotton and one or two other flowers were enjoying their day in the sun.

Leaving the path, looking towards South Barrule
Towards Glen Rushen, the end of the day
Waypoints

I shall be doing a more normal walk in the next week or so….