Friday, 6 June 2014

BSBI Summer Meeting:Part Two

Botanists attending our Summer Meeting are out in the field today, enjoying some of the fabulous site visits that Jim McIntosh and his team have put together. The difficult bit for everyone will have been deciding which of the selection of visits to pick - you can't fit everything in and the choices are all mouth-watering! Today's options include Ballinluig Island, the Birks of Aberfeldy and Killiecrankie

The famous Birnam Oak
Image: J. Shanklin
So, while the botanists are out in the field in Perthshire today, we'll have to be content with this report from Jon Shanklin on the second of the guest talks, this one by Dan Watson of the National Trust for Scotland, on the subject of 30 years of monitoring rare plants on Ben Lawers.  

Jon said "Dan's talk linked in nicely with the previous one and his monitoring had seen similar evidence for an increase in graminoids." These are the rough notes that Jon took, so may be subject to editing at some point, if we realise that there are errors in reporting. But for now, here we go:

"Many of the rare plants occur in flushes and other places which are not so severely affected by the environmental changes. Ben Lawers has been known as a hot-spot for rare plants for over a century, but there had been no monitoring and populations were not known when NTS took on the site. In 1979 a ranger-naturalist was employed and new locations, for example of Carex microglochin, were found, and Sagina nivalis was refound. A complete survey of the rare plants was carried out in 1981. Counts of S. nivalis show variation between a peak of nearly 4000 in 1996 and around 1000 in the 21st century, which was interpreted as a general decline".

At this point Jon - a physicist - offers his own comment "I would not say there was a trend as only four data points are available!" Good point, Jon.

Gentiana nivalis
Wiki Commons
But back to Jon's notes on what Dan was saying: "Gentiana nivalis has also been monitored, with one experiment putting cages over plants, but it became clear that as an annual it needs disturbed bare ground. It seems to be doing OK on ledges etc, but less well on grassland. Erigeron alpinus and Minuartia rubella have been more intensively monitored, and perhaps show a stable or increasing population. Woodsia alpina declined after 1981 but has been more stable since, but possibly because it is difficult to access the ledges on which it grows and no-one has been able to access the 1981 locations since then. Dan (in post since 2010) pointed out that different botanists have differing ability to spot plants and this may affect species counts. Grazing has changed, but some farmers have hereditary rights to graze so it is difficult to control. Dan then described Salix lanata and Saxifraga rivularis, which need active management as populations have dropped to a critical level; Bartisa alpina, which may be extinct; and gave examples of some plants which are not monitored but perhaps should be!"

All fascinating stuff - and that was all before lunch on Day 1! More to follow, watch this space.