Dear Readers, a few weeks ago I discovered, to my astonishment, that London is home to several peat bogs. What on earth are they doing here? I associate them with the bleak, wet, windswept north-western coast of Scotland, or with parts of Ireland. But as I read further, I found that peat bogs were once widespread across the whole of the country. However, as land has been drained for building and for industry, and as the peat was dug out for fuel and latterly for compost, these habitats have dwindled to a few sites. The best are in the south of the capital, but on Bank Holiday Monday I decided to explore the bog closest to my home patch, Rowley Green Common at Arkley in the London Borough of Barnet. This tiny patch of bog is said to be home to Star Sedge, Nodding Bur-Marigold and Lesser Spearwort, although this early in the year I was not holding my breath.
You would think that a bog would be a fairly easy thing to find, if only because you would suddenly find yourself up to your knees in mud. But no. There is a problem in this nature reserve, and it is that the areas of bog are gradually being colonised by other plants, like willow saplings for example.
I love bogs: there is something about their claggy serenity that piques my imagination. I would not be surprised to see a green figure made entirely of sphagnum moss emerge from the sediment and dance amongst the reeds. However, he would have a problem here, there being no obvious sphagnum moss at all.
Sphagnum moss is the building block of a bog. As you might remember from a previous post about moss, it can absorb large quantities of water, like a sponge. This helps to keep the water table high, normally making bogs wetter than their surroundings. Layers of moss and other water plants grow on top of the sphagnum, and the lower layers slowly decay and turn into peat, at a rate of only two millimetres a year. The mossy mounds that we see in bogs are a result of this process. Here in Rowley Green, I saw only one such mound, stranded high and dry amongst the brambles, though there were probably more hidden from view.
In the past, the boggy area here was much larger – until World War Two the area was kept open by grazing cattle, preventing the encroachment of the scrub and forest. Small-scale gravel extraction also opened a series of ponds, which helped with the boggy environment. But now, this little patch of wetland is under siege on all sides. To one side, there is a golf-club, with a huge, dark cherry-laurel and rhododendron hedge along the boundary with the reserve.
Furthermore, there is a huge rhododendron growing right in the middle of one of the boggy areas.
We tend to think that forests and bogs and heathlands can be left to look after themselves, but most kinds of habitat have a desire to move on. Every pond, in its heart, wants to become a bog. Grassland wants to become a forest. The only reason that it doesn’t is because there is some resource constraint or very particular environmental factor, or because humans intervene. In Coldfall Wood, coppicing has changed the environment and increased the number of species that will survive. Here in Rowley Green Common, it will take some active management to make sure that this little bog doesn’t disappear altogether, along with the unusual species of plant and invertebrate that depend on it. It reminds me of the importance of local Friends groups who keep an eye on their local wild spaces – Hertford and Middlesex Wildlife Trust seem to have Rowley Green as part of their remit, but they have a huge area to look after. In all our time at the reserve, we didn’t see a single other person. Ironically, although an unvisited reserve may be good for the plants and wildlife, it might also mean that no one cares enough to save it when things start to go wrong. And surely the only peat-bog in Barnet is worth saving.
To read more on the Peat Bogs of London, have a look at this excellent piece by the London Wildlife Trust.