Saturday, 19 November 2011

Harder than the Hardest Thing?

I've mentioned the landscape before - it is truly fantastic!  A 2,000 metre high volcanic cone, often snow clad, surrounded by a high plateau (the base) around 1000m which is very deeply incised by numerous river valleys (called gulches) ending up with cascading waterfalls over a great escarpment which completely encircles the island and leaves only a narrow coastal plain in a few places.  In places the escarpment plunges straight down to the sea or leaves only the narrowest boulder beaches. 

The lush vegetation on the base and escarpment is dominated by ferns or trees.  More specifically Island Tree (Phylica arborea) and Bog Fern (Blechnum palmiforme).  The tree is rarely more than 3 or 4 metres high and forms dense thicket which are amost impenetrable - though we have yet to experience the most impenettrable Phylica on the more sheltered western side of the island.  The Bog Fern is more like a tree fern - it can be 2 metres tall with a stem 15cm in diameter and has very stiff branches.  More usually it is about a metre high and when growing close together makes walking through the interlocking branches tiring. The ground itself is spongey and very uneven and the fallen and hidden trunks of Bog fern are an additional hazard.
The Bog Fern is amazing as it is host to an entire community of ferns and flowering plants. These grow epiphytically  on the 'trunks'  getting support only but nutrients and water from the enviroment.  They include some very interesting species - including one of the few native to both Tristan and the British Isles - Tunbridge Filmy-fern (Hymenophyllum tunbrigense).  It is just one of three Filmy-ferns in that habitat.

We start early and finish late each day to maximise our time on the Base and with ascents and descents so steep that there are fixed ropes in places.  We traverse Bog Fern and Island Tree habitats and the numerous deep gulches to get to and from our survey areas carrying heavy rucksacks full of survey equipment, food and clothes for four seasons that are often put to the test.  SAS training must be easier!  

In future we will set up camp on the Base (Base camp - literally!) to minimise commuting time and effort.  But the weather must improve first and we need more grass and sedge species to flower to be able to confidently identify and survey - particularly at altitude.  About a quarter of Tristan's flora are grasses or sedges - and many that are found nowhere else (endemic).   At least our tents have just arrived - even if the microscope and other equipment from Kew have failed to materialise.  Before then we hope to take boats to the remoter parts of the island and stay in privately-owned huts  (holiday homes for islanders) and use them as bases for survey work.

In Britain you take good maps for granted. There is no such luxury here - only crude small-scale contour maps and aerial photographs - none of which show the grid squares we are surveying accurately.  None show paths accurately - and they are often the only way up and down the escarpment and the easiest ways around the Base.  And none are georeferenced properly so we are not able to plot routes and plant populations precisely.

My blog has made the island sound very exotic but the reality of working here is that it is hard. Very hard. Harder than anything I've ever done before.  Maybe I should have entitled the blog Harder than the Hardest Thing?

PS I've got some exciting news. We think we found the endemic rush species Rostkovia tristanensis on Thursday. TBC but if correct the first time it has been recorded on Tristan since a Norwegian Expedition survey in 1938. It was in a completely different place from their first record. The species is also known from Gough Island some 350km distant. For the botanists amongst you it looks a bit like Juncus biglumis except that it grows in acidic wet montane heath with Empetrum rubrum, Lycopodium insularis and numerous small sedge and grass species.

Here is a link to more information


  1. Fingers crossed for the discovery, Jim.

    But have you ruled out Juncus scheuchzerioides? Or Archaeolithothamnion crosslandii for that matter?

    It couldn't be a wee dandelion could it?

    Keep up the good work. The blog's great.


  2. Non-georeferenced maps without paths (well roads in my case) marked is familar from the Falkland Islands. While it is no help for you just now, when you get back you can plot all your GPS lat/longs with extraordinary accuracy on Google Earth. So at least you will know where you havwe been!

    And Tristan looks good on Google Earth, even if the colour of 1/4 is different.

  3. Id? Nop thats why I said tbc! Though a previously found species is more probable than a completely new one!

    Alistair, I did download the Google Earth Image of Tristan and saved that into cache before I left the UK. Which is pretty handy as I've discovered you can georeference jpg maps and export to our Garmin GPSs and use in the field. And I'm able to plot tracks, populations, etc.
    PS There are two images of Tristan - the entire island taken in 2005 and the SW quarter taken in 2009. They did that because the SW escarpments were in shadow. So they took a late evening shot - hence the different colour. (You can set GE to see the 2005 image only.)

  4. It must be nice to find something as small and friendly as H.tunbrigense among all that alien wilderness! (Angus)

  5. Re. mapping problems
    I might be able to help
    Let me know what you need

  6. Thank you for that kind offer Grahame. Am e-mailing directly...

  7. Mapping sounds good! I use ArcGIS and georeferenced a Falklands map though it was upside down first time and matched it to some GPS points - I use WGS 84 when abroad!