AN SPG MEMBER VISITS THE GALAPAGOS ISLANDS

The Galapagos Islands lie on the Equator about 1000 km off the west coast of Ecuador, to which they belong. Geologically, the islands are youngsters, formed by volcanic activity over the past 3-4 million years: a tectonic plate is moving south-east in a stately fashion over a hot-spot so the newest islands lie to the north-west and still have active volcanoes (an eruption occurred in May 2015, a few weeks after our visit). For much of the year the Equatorial temperatures are moderated by the cool Humboldt sea current from the south. Tourists arriving on the Galapagos by plane land at the airport beside the former US Army base on Baltra island. The land stretching into the distance around the runway appears to be made of brown hard-core. I thought at first this was due to the construction activities of the army, but it is actually the volcanic lava and cinder that forms much of the extensive arid zone of the islands; Herman Melville (yes, he of Moby-Dick fame) visited the Galapagos in the 1840s and was not impressed, describing the appearance of the islands as like the dross of an iron furnace. This arid zone actually has a rather limited but unique flora, and lies between the greener (and in places verdant) coastal mangroves and highland forests around the tops of the volcanoes.

   

(Left): Like the dross of an iron furnace (H Melville) lava with sparse arid zone vegetation

(Right): more verdant upland habitat

In order to protect these largely pristine landscapes and their wildlife, there are tight controls on access. For many of the islands making up the archipelago such access is restricted to particular coastal sites, or is forbidden, and the only way to see these islands is by boat. We sailed on a small vessel with six en suite cabins that were marvels of construction but so small that two adults could not dress simultaneously, and with a top bunk resembling a luggage rack in its size and proximity to the ceiling. I of course ended up in our top bunk, which was also completely open along the free edge, so that with rolling seas at night there appeared to be a constant threat of plunging to the floor; you will be pleased to know however that your plucky correspondent held his nerve and did not force his wife to swap bunks.

Our boat: note the frigatebirds on the rigging, waiting for carrion, such as bunk-related casualties

The wildlife, though spectacular (particularly to those of us more used to the less gaudy and more retiring fauna of Europe), is represented by relatively few species. The larger native land animals are mainly reptiles (iguanas, lizards and tortoises). Some of the seabirds and other marine-based creatures can be found elsewhere, but of particular interest are those species which have evolved on, and are indigenous to, the Galapagos. Being isolated and of recent formation, the islands have of course given us insights into the process of evolution through natural selection. I suspect that many will think (as I did myself) that the eponymous Darwins finches, with their bills of varying size and shape, were key species in development of the great many theories. In fact he uncharacteristically omitted to record where he.d shot his specimens, which were all stuffed in the same bag, and the finches do not feature in On the Origin of Species. Fortunately, he had noticed that another group of birds, the mockingbirds, varied from island to island, and this led him to speculate that mockingbirds arriving from the South American mainland had over time diverged into different species on particular islands. If this was the case, it would, he wrote, it  would undermine the stability of Species.  Quite right, as it turned out.

   

(Left): An Espanola Mockingbird: more important than those Darwins finches

(Right): The Blue-footed Booby, a gaudy relative of our more elegant Northern Gannet, is a favourite emblem of the Galapagos, as featured on many tea towels, tea cosies and T-shirts

As elsewhere on the planet, though, these marvels of nature are under constant and increasing threat from a resourceful but ultimately doomed invasive species, somewhat ironically named Homo sapiens. A striking feature of the Galapagos animals is that by and large they remain tolerant of humans, and can often be approached very closely. This can provide wonderful wildlife experiences, but of course means that, as happened in the past, the animals can easily be captured and killed; for example, it is estimated that 19^th century sailors removed over 200 000 Giant Tortoises for food. Travelling across some of the islands I was surprised to see quite large areas of the uplands still given over to agriculture, and one of the major problems for conservationists has been trying to control huge numbers of feral pigs, rats and goats, with their damaging effects on the native wildlife. I was also surprised by the size of some of the coastal towns; but of course despite attempted regulation of immigration, for many Ecuadorians moving to the Galapagos is an attractive prospect given the amount of money spent there by tourists, and the population of the islands is now over 20 000. Great efforts are being made though by the Ecuadorian authorities to protect these unique habitats and their wildlife from the constant threats of over-exploitation, for the future enjoyment of all us with an interest in natural history.

 Invasion by Homo sapiens

A Galapagos Giant Tortoise contemplates his future

Chris Wright

June 2015