Galapagos is a globally significant ecosystem of animals, plants and insects due to the relatively new inter-relationship between endemic, native and introduced species. Galapagos is now a living laboratory in which scientists can evaluate and report on the dynamic relationship between an ever-changing array of species.
For millennia flora and fauna arrived and evolved naturally and reproduced in isolation – that is to say without human transport, intervention and cross-breeding. During colonial times this slowly began to change as species from around the world arrived, left there as food sources – such as goats and fruits, and native species were also harvested for food – such as tortoises. However until human settlements really began in the 20th century this was extremely limited.
This presence of larger numbers of permanent residents and the beginning of a dynamic relationship between endemic, native and introduced species coincided with the advent of modern science. This has created a microcosm of changes to that have occurred since ancient times on continental landmasses. Scientists armed with modern technology and methodologies can now see what happens to species no longer in isolation. For conservationists, the preservation of animals now in danger of extinction – at risk species – is a particular area of concern.
This is the basis for research and conservation of Galapagos and the reason all species are grouped as endemic, native and introduced.
Endemic species
An astonishingly high number of species exist only here. These include giant tortoises, Darwin's finches, scalesia trees, Galapagos sharks and an enormous variety of insects. Endemic species may even exist only on one particular island.
Native species
Native species occur naturally here and elsewhere. Magnificent frigatebirds, albatrosses, green sea turtles and certain sharks are among native species.
Introduced species
Introduced species were brought to Galapagos intentionally or unintentionally by humans. Included are hundreds of species such as quinine trees, blackberries, dengue mosquitoes, tilapia, rats and domestic mammals (many of which are now feral) such as goats and cats.
At risk species
A number of native and endemic species are endangered by the presence of introduced species. These include the scalesia, the Galapagos rock purslane, and the giant tortoise of Pinta island.