The Galápagos archipelago is special. The remoteness of the islands and their short history has given them unique characteristics, not least of which is the large numbers of endemic species – plants and animals found nowhere else. Their history is short because they are volcanic islands, recently formed. The island of San Cristobal is nearest to the mainland and is about 4 million years old. Isabela, the most westerly island, is only 7000 years old and has five volcanos.
The place of the islands in recent history is assured by the revolution in scientific thought that followed the visit of HMS Beagle with Charles Darwin on board in 1835. His conclusions about the mechanism of evolution were influenced by the islands and their importance in the study of evolutionary processes remains important today. These are the reasons why the islands are now a World Heritage Site, described by UNESCO as a unique ‘living museum and showcase of evolution’. The designation spreads beyond the islands, to include a large area of the seas around the islands as a marine reserve. How can such a massive area be protected and the endemic wildlife conserved for future generations to study – and marvel at?
The threats to wildlife come from several sources. Obviously there is a human impact, with the need to accommodate visitors and residents. There is the damage that has been caused by accidental and deliberate introduction of animals and plants from other parts of the world. Finally, the populations of the endemic species are often not very large anyway, or are restricted to very small geographical areas. A good example of a species at risk is the flightless cormorant. It is only found in two locations and the population has fluctuated in the past from a low of 400 to 1679. So, even something like a small-scale oil spill or a volcanic eruption could dangerously deplete, or even eliminate the population of this strange and fascinating bird.
The vegetation on Pinta recovered quite rapidly, so attention could focus on how to restore the island ecosystem. Clearly, it had been an ecosystem in which tortoises were a component, but there were none of the original population left. So, in 2010, 39 hybrid tortoises that had been sterilized as they were not a genetically pure species, were introduced onto Pinta with the aim of restoring the island to what it had been like before human interference. This is a medium-term goal, because in the long term it is hoped that genetic analysis of existing tortoise populations may find sufficient individuals to run a restorative breeding programme capable of producing a close genetic match to Lonesome George.
The plans for Pinta do highlight the change that has been taking place in our view of conservation. When I first saw Lonesome George in 1996, the emphasis was on saving the Pinta tortoise and getting George to breed. When I visited him a second time in 2007, views were changing and although preservation of the individual species is important, it is the preservation of ecosystems and their diversity that is crucial. So, the role of tortoises in an ecosystem, eating plants and spreading seeds, could be more important than which race of tortoise it is.
The Galápagos will always be associated with Charles Darwin and he will always be associated with the finches that inhabit them. The finches are under threat from a parasite that has appeared, somehow, in recent years. Museum collections show that a fly, Philornis downsi, was present in the Galápagos in the 1960s but it must have been at a low population size as it did not become apparent until the end of the century that the fly was potentially dangerous to the finches. The adult fly manages to determine when eggs in a finch nest are close to hatching and she lays her eggs there. They hatch and the young larvae get onto the newly hatched chick and enter it’s nostrils where they eat the nasal membranes. If the chicks actually survive this onslaught, they have permanently damaged and deformed nostrils and beaks. Finch populations are at risk, particularly those of the rarer species like the mangrove finch with less than 100 individuals left.
Studying the fly is difficult as it is really hard to breed in the laboratory. Possible control methods might be pheromone traps or even a bi-control method such as introducing a parasite of the fly. However, this might be too difficult as there would need to be absolute certainty that there would be no unexpected side effects on other animals. Introduction of an alien into an ecosystem that you are trying to protect is usually considered high risk!
Conservation in a World Heritage Site is not easy and restoring habitats to what they had been before human interference is probably not possible. To conserve existing ecosystems and make them viable may well be possible (and is certainly highly desirable), but turning the clock back I suspect is unlikely to happen.