Just back from a four day trip to a remote part of the island. We camped on the Base at 1000 m above sea level, on the boundary between Island Tree (Phylica arborea) scrub woodland and short sward Blechnum penna-marina (a fern) and heathy Empetrum rubrum (similar to our Crowberry, Empetrum nigrum). We pitched the tents in a small clearing amongst Island Tree for shelter, pegged well down and guys tied tightly. Necessary because of near galeforce winds for much of the time. But weirdly warm, sunny and very humid. Quite nice in sheltered ravines (gulches) and in scrubby woodland. And it was great waking up and finding you’re above the clouds!
|Sooty Albatross chick line-up...|
|The bottom of a small gulch|
The gulches are certainly much more interesting botanically. For example last week we recorded 65 species in each 1km square on the days spent in gulches. But only 35 on a 1km square in which we ridge walked. We have only ever found the rare endemic fern Asplenium insulare once so far on Tristan – and then a single population with just a few plants. So it was good to find a second much more extensive population. It likes humid and sheltered conditions – so gulches are perfect. Especially narrow, sheltered ones with overhanging edges. Its constant associate is Trichomanes angustatum – itself a rare endemic. The secret appears to be to find the right habitat then look under other bigger ferns.
However the highlight of the trip was an ascent to the 2,060 metre peak. This carrying our camping gear and surveying as we went. (Another day that would make SAS training seem easy!) The peak has concentric vegetation bands that change with altitude. The Blechnum/Empetrum sward quickly gives way to a heath dominated by Empetrum and the moss Rhacomitrium lanuginosum; vegetation very similar to that found on the Scottish mountains, but rarely in such fine condition with so little sheep trampling and grazing damage. Around 1200 metres, my eagle-eyed work partner Lourens spotted another population of the rare endemic rush, Rostkovia tristanensis. (If you remember this had not been recorded since the 1938 Norwegian Survey Expedition.)
|The summit plateau|
The spongy Empetrum-Rhacomitrium sward becomes increasingly patchy with altitude. Eventually the ground becomes too unstable, loose and dry for any but the hardiest of mosses. This is the Alpine desert cinder scree zone. All plants at this altitude form dense mats or tight cushions – adaptations which create a (relatively) warm and humid microclimate that helps to minimise water loss. We find the highest flowering plant at 1970 metres, just above Crater Lake – Empetrum rubrum again! The view from the top is spectacular. Its like looking out an aircraft window on a brilliantly sunny day - down on distant clouds and blue sea. Closer in the Base looks surprisingly extensive and several other water-filled crater lakes are evident. But no where is the coast visible due to the steep escarpment. We have a quick dip in crater lake - a beautiful and sheltered spot - before continuing our survey on the descent to the settlement.
After a few day's specimen pressing, data entry, battery charging - literally and personally, cooking, shopping, clothes washing and with a good weather forecast we are getting ready to go on another camping trip early tomorrow morning..
- The island went back to work on Monday – after the three week summer holiday. This meant the Island Store re-opened for the first time since Christmas. I’d only run out of cereal and coffee but was also running dangerously low on beer supplies.
- The MV Edinburgh is due to arrive from Cape Town tomorrow – hopefully with my Christmas presents that didn’t make the last ship. And with some emergency supplies that my cousins, Sandy and Ali in Cape Town have kindly bought and despatched. How exciting!
- Simon is in Edinburgh this week catching up with friends and family. Unfortunately the Alfa Romeo is playing up - I think through lack of use!
- Mum is making a great recovery, after breaking her leg in October. She is able to drive again and can now get to the shops and to her normal full program of events and meetings.
- My sister, Catherine, and her family are coming over from America to see mum and help my brother, Peter, on the farm with the lambing this spring.