ESAS AND THE I.T.E...

Dave and Don, two scientists from the Instiute of Terrestrial Ecology, Banchory, Aberdeen, spent some time last summer surveying plants on Coll .

To begin at the beginning...supping wine and chewing radishes in the garden of a house on Coll...

"So, what's it all about then?" she asked. 'It' was ESA monitoring. The first thing to explain was, what is an ESA and how and why do you monitor it.

ESA stands for 'Environmentally Sensitive Area'. There are 10 of them in Scotland, one of which is 'Argyll Islands', and in each one there are various schemes to encourage people to work the land in ways that are supposed to improve the general environmental 'quality'.

The details vary from area to area. On Coll it includes things like controlled grazing so as to preserve and, if possible, improve areas of machair; avoiding draining wetlands and, of course, the various prescriptions for the benefit of birds such as the corncrake.

As for the 'monitoring' - that is looking at it from time to time to assess the general state of the ESA. The 'why' of it is that the Agriculture Department want to know if the scheme is working. And this is where Dave and yours truly, ecologists with the Institute of Terrestrial Ecology (ITE) come in.

Dave and I were doing part of the 'background' monitoring. This was supposed to assess how the scheme affected the whole of the ESA – not just the areas where it was being implemented. This is quite a tall order. We have to take a few key bits and look at a sample of those. In our case it was plants. Other people would be looking at something like birds, for example.

For the sample we take a random set of one-kilometre squares from the Ordnance Survey grid. This gave us one square on Tiree and two on Coll.

"So, now you are here, what do you do?" ( she asked). The first thing we do is we draw five maps of the square. Each deals with a different set of features such as 'physiography' -rocks, water, beaches etc or ground vegetation. These give us a general picture of what is in the square.

The fine detail we get from small plots which we set up in vegetation of particular interest, like bog, dry heath and machair. There we list every plant we find and how much of it there is; whether or not the plot has been grazed; its slope and aspect; what the main surrounding vegetation is and any special features like rocks, drains or pools.

We also mark the plot so as to be able to find it again when we come back in a few years time in order to measure change. Then we can compare information from different places within an ESA and the ESA's as a whole with places outside. That is the theory anyway. The practice isn't quite so simple...

For a start, just finding your way around can be quite tricky. OK, we have maps of the area, and are used to navigating with a map and compass - but when you have to map any distinct patch of vegetation more than about twenty yards wide, you need to know where you are fairly accurately.

So, how do you do that when all you have on your base map is a large blank area covering half the square, labelled 'dunes'? Then, on the plots there are a few thousand species from which to identify what you have on the ground - there are over 150 different British grasses for example and nearly 800 mosses, including 30 different kinds of sphagnum. If all the plants are reasonably complete specimens, that's no great problem, but trying to identify a plant from the chewed-off stump left by a sheep, or by the pattern of hairs on it because it is not the flowering season, (or in the case of some mosses etc, without a microscope!) can be a bit more difficult.

And what did we find? One of our Coll squares was in the 'knob and lochan' landscape of the eastern part of the island, the other, along Feall Bay, included some of the finest grazed machair and high dunes that we'd seen anywhere all in one place.

We found two superb examples of the very different types of ground in these two squares. In the eastern one, a tumbled rocky landscape full of lochans, lush bogs and reedswamp, the lasting general memory is of the quality of the bogs.

There were few botanical surprises but we did turn up some mosses that we'd not seen before and the odd clump of Royal Fern or Honeysuckle put 'icing on the cake'. More of a surprise were the peacocks on the walk in - not exactly typical Hebridean avifauna! Oh yes, and I mustn't forget the black sheep. It was not supposed to be black. We heard its lamb bleating before we saw it - up to its neck in peat among the reeds. Time for a quick break from botanising... By the time it was out we were pretty black too, but the lamb had regained its Mum, albeit she was now black all over except for part of her head. Next day we saw her again, apparently fully recovered.

As for the square along the western part of Feall Bay. The sheer variety of machair, orchid-rich marsh and little oddities in rock crevices was quite stunning. This site is part of the RSPB reserve and the reduced grazing already in place as part of the general management of the reserve was obviously benefitting the flowers. The geraniums were particularly striking, but we also found some fairly uncommon clovers as well as several species which are 'specialists' on this kind of ground.

Then she asked - as we blethered away for a while on this and that and envied the quality of the radishes why can't we grow 'em like that? "why don't you write a piece for the Coll Magazine..."

So here it is, and now anyone who might have been wondering what those two lads with the clipboards and posts and strings were doing will have their curiosity at least partly satisfied.

As we came away next day on the boat, the various aspects of our time on Coll (the friendly welcomes, the survey sites, music in the Hotel, sun and showers, the 'black sheep' and the final walk back along the beach) began to distill itself into something else. When it finally sorted itself out, I wrote that down too...

Don French