Tristan : Gough Island Eradication Project Report
Submitted by Tristan Times (Sarah Glass) 24.12.2009 (Current Article)
John Cooper, CORE Initiatives, South Africa tells us more.
Eradication of the introduced Procumbent Pearlwort Sagina procumbens
at Gough Island during September-October 2009
By John Cooper, CORE Initiatives, South Africa
Dalton Gibbs, Graham Parker and Norman Glass man-handle the water tank through
the vegetatopon to Snoekgat
Eradication of alien Sagina continued on the coastal cliffs at
Transvaal Bay, Gough Island during the annual relief of the South
African weather station in September-October 2009. Activities were
undertaken under the auspices of the Tristan Conservation Department
with funding and management provided by the Royal Society for the
Protection of Birds from the United Kingdom’s Overseas Territories
The 2009 Sagina relief team was led by John Cooper (CORE Initiatives),
assisted by Donovan Willis (Level-3 Rope Access technician/trainer),
and Dalton Gibbs (Biodiversity Management Branch, City of Cape Town,
asked to audit the eradication effort), Norman Glass (Tristan
Conservation Department) and the four RSPB field assistants, Henk Louw
and Paul Visser (Gough 54, 2008/09) and Graham Parker and Kalinka
Rexer-Huber (Gough 55, 2009/10), all six of whom have Level-1 Rope
Donovan Willis and Norman Glass with the Snoekgat water pump after its successful placement by helicopter
A total of 114 rope-assisted descents was made over 13 working days,
covering all sections of the cliffs within and immediately outside the
alien’s known distribution. Especial attention was given to surveying
cliffs never previously checked. No further spread of Sagina was
found outside its known distribution.
Inspection of areas previously stripped to bed rock suggested that the
technique was working in that no plants were found growing in areas
actually stripped, nor in accumulated piles of stripped material.
Small numbers of young plants were found in all previously-infested
areas, but not beyond them. Importantly, no plants were seen during
excursions to the island’ interior.
No flowering plants were seen, but the few larger plants (up to palm
size) found at cryptic localities (and thus overlooked) had likely set
seed the previous summer. In the last two days ashore, seedlings were
noticed adjacent to the crane platform next to the food store. The
cracks and edges of the crane platform were then sprayed with
herbicide the day before departure.
As in recent annual reliefs, all plants found were removed
mechanically using paint scrapers or spades and the sites treated with
a herbicide mixture (5% each of Glyphosate and Outpace Flowable),
using 1.5-l hand-held pressure sprayers. Some areas at Snoekgat were
experimentally treated with handfuls of coarse salt, resulting in
browning of the surrounding vegetation within a few days.
Following placement of a portable water pump and salt-water storage
tank next to the Snoekgat Pond approximately one-fifth of the infested
area at Snoekgat was stripped to bed rock using spades, mattocks and a
high-pressure hose, with stripped material being dumped into gullies.
The stripped area was then treated with salted water to reduce the
remaining seed load and to kill the remaining vegetation.
Fourteen 55-l “tote” boxes were filled with bagged Sagina and adhering
soil during the year and relief. These boxes were back-loaded to the
ship and dumped overboard three day’s sailing from the island on the
return voyage to South Africa.
Eradication efforts will continue throughout the year by the two RSPB
field workers who have remained on the island.