By Liz Kalaugher
Sometimes I wish I had more of a head for heights. Saana’s southern slopes are steep. On Tuesday they didn’t just see the installation of temperature kit, they were also the scene for two new vegetation surveys as Peter le Roux extended a transect – a line of measurement points – begun by two other researchers.
First we headed up past some scree to around 850 m, 100 m above the two sites already measured. Here le Roux created an independent point. It’s not part of a grid plot but will help the team get an idea of how the plant-life varies across a wider area. After marking the centre with a small wire hoop in the ground and some orange forestry tape that will biodegrade in about three years, he laid out other markers 5 metres to the north, south, east and west. Each of these compass points in turn was enclosed by a 1 m x 1 m metal frame criss-crossed with cord at 10 cm intervals, like a giant empty crossword grid. Le Roux estimated the amount of each plant occurring in the letter squares to give the percentage vegetation cover overall.
The first frame, to the north, was dominated by juniper, followed by bog bilberry. Three plants tend to dominate in this region – juniper, crowberry and dwarf birch. Crowberry releases allelochemicals that lock up nutrients and inhibit some plant species from growing. Juniper, on the other hand, offers sheltered conditions similar to those under a birch forest and tends to promote the growth of other species, such as Viola biflora, Geranium sylvaticum, golden rod, dwarf willow and Angelica archangelica, beneath it. This square also contained Arctostaphylos uva-ursi, or bearberry, which the team has only seen on these southern slopes – it’s right on the edge of its range so can only survive in the warmest places.
You can spot the calcareous rocks here by their orange-brown colour, which stands out against the greyer siliceous boulders.
The square to the east contained almost no juniper, in contrast, but lots of bearberry. There was also a reindeer path across it – here lots of small species, including a gentian, have taken the opportunity to establish themselves offered by the disturbed ground and bare earth, where for once, they don’t have to compete with the dominant species for soil and light.
The southern square was similar to the eastern one. It contained roughly 15 species, along with some bare ground, perhaps caused by erosion, and plant litter. The bare soil was warm to the touch, and there was a tiny gentian species, with a cobalt blue bell-shaped flower a couple of millimetres long.
The western square was dominated by crowberry, along with some bearberry and many fairly uncommon species.
Le Roux pointed out that the northern square contained two layers of plants, the juniper and plants underneath it, whereas the others only had a single layer.
Next stop was 100 m below the two previously measured sites. Here the noise of tyres on tarmac drifted up from the road; it seemed incongruous in an area that otherwise is so remote. If you get lost here and head in the wrong direction you could walk for two weeks before hitting another road. Again the squares were different – one was crowberry-dominated, another was mainly rock with hardy species that don’t need shelter, and a couple contained moisture-loving plants as well as other more typical species. Again, less dominant species had moved in to any areas of disturbance to the soil.
What’s striking, as with the colour of the soil, is the large differences in plant cover seen between sites just a small distance away from each other. Le Roux ascribes this to the massive local variations in factors such as topography on the slope, along with the fact that the dominant species in this area tend to leave some space on the ground, allowing other plants to get a foothold too.
If he wasn’t able to identify a plant, le Roux took a small piece back to the research station to check using a plant guide or a second opinion. Rauni Partanen, who works at the station, is co-author (with Henry Väre) of a Finnish mountain flora so can be extremely helpful.
On the way back round the hill to the grids where Pekka Niittynen was surveying lichen and mosses, we followed the reindeer path on the grounds that they’re unlikely to walk off a cliff.
This entry was updated on 9th August to correct the comments about bearberry.
- This trip was funded by a European Geosciences Union (EGU) Science Journalism Fellowship.