Plant Transects

Today we had a day of doing host plant V surveys, which involves following a 200m long inverted 'V' shaped transect within a 100m grid square.  This is most easily done by a pair of people (but can be done alone).  Starting in the bottom left hand (south west) corner of the square, the first person rolls out a tape measure on a bearing of 30 degrees.  The second person then measures the height of the vegetation every five metres, and also records any butterfly host plants that are present along the transect. 

After the first 100m, the top (northern) edge of the square should have been reached and should be around half way across the square.  The bearing is then changed to 150 degrees to aim for the bottom right hand (south east corner) of the square.

The host plants we were looking for today were for the Large Heath butterfly, and so were Common and Hare's Tail Cottongrass. 

One of the sites we visited was a heathland site a few miles to the north of Doune near Stirling. Our transects were along the edge of Loch Mahaick.  Much of the area was covered in dense coniferous forest, though there were some more open areas closer to the loch.  The area was still semi-wooded though, with evidence of replanting of native deciduous trees.  There was lots of rotting wood under-foot which, along with the Molinia tussocks and boggy pools, made it hard to walk the transect. This was made harder still trying to see through a midge net, as the little bugs were in abundance.

The Large Heath butterfly was not found here on a previous butterfly survey, but we needed to do the vegetation survey to assess whether this might be due to habitat change/suitability. Despite the re-wooding, there was still a large amount of hare's tail cotton grass on the site, with lesser amounts of common cotton grass. We kept our eyes peeled and didn't see the butterfly on this occasion either, though I did get a close encounter with a Common Hawker dragonfly.