Archipiélago de Juan Fernández National Park

There are 209 native species of vascular plants in the park, approximately 150 of which are flowering plants and 50 are ferns. There are 126 species (62 percent) that are endemic, with 12 endemic genera and one endemic family, Lactoridaceae. Many plants are characteristic of the Antarctic flora, and are related to plants found in southern South America, New Zealand and Australia. Vegetation zones generally correspond to elevation, with grasslands and shrublands at lower elevations, tall and montane forests at middle elevations, and shrublands at the highest elevations. The two main islands have somewhat distinct plant communities.

Juan Fernández Goat, (originally domestic goats) showing many of the characteristic of wild goats

Alejandro Selkirk Island is mostly covered with grassland from 0 to 400 m (1,300 ft), interspersed with wooded ravines (quebradas), home to dry forests of Myrceugenia and Zanthoxylum fagara. From 400 m (1,300 ft) to 600 m (2,000 ft) are lower montane forests, with upper montane forest from 600 m (2,000 ft) to 950 m (3,100 ft). The treeline is at approximately 950 m (3,100 ft), above which is alpine shrubland and grassland, dominated by temperate Magellanic vegetation such as Acaena, Dicksonia, Drimys, Empetrum, Gunnera, Myrteola, Pernettya, and Ugni. On Robinson Crusoe, grasslands predominate from 0 to 100 m (300 ft); introduced shrubs from 100 m (300 ft) to 300 m (1,000 ft); tall forests from 300 m (1,000 ft) to 500 m (1,600 ft); montane forests from 500 m (1,640 ft) to 700 m (2,300 ft), with dense tree cover of Cuminia fernandezia, Fagara, and Rhaphithamnus venustus; tree fern forests from 700 m (2,300 ft) to 750 m (2,500 ft), and brushwood forests above 750 m (2,500 ft). Santa Clara is covered with grassland.

One of the main predators of endemic vegetable species, and responsible for the great extensions of grassland, is the Juan Fernández Goat. These were originally domestic goats left behind by the first explorers which became feral, recovering some of the characteristics of wild goats (Capra aegagrus). CONAF carries out ongoing work to control this and other invasive species, including mice, rats, true thrushes, sparrow and feral cats.[6]

Three endemic species dominate the montane forests of the archipelago: Drimys confertifolia on both main islands; Myrceugenia fernandeziana on Robinson Crusoe; and M. schulzei on Alexander Selkirk. Endemic tree fern species of southern hemisphere genus Dicksonia (D. berteriana on Robinson Crusoe and D. externa on Alexander Selkirk) and the endemic genus Thyrsopteris (T. elegans) are the predominant species in the tree-fern forests. An endemic species of sandalwood, Santalum fernandezianum, was overexploited for its fragrant wood, has not been seen since 1908, and is believed extinct. The Chonta palm (Juania australis) is endangered.[7]

The Juan Fernández Archipelago has a very limited fauna, with no native land mammals,[8] reptiles, or amphibians. Seventeen land and sea-bird species breed on the islands. The island has three endemic bird species, and two endemic subspecies. Introduced fauna by humans include rats and goats. Robinson Crusoe Island is home to an endemic and endangered hummingbird, the Juan Fernández firecrown (Sephanoides fernandensis). This large hummingbird, about 11 cm (4 in) long, is thought to number only about 500 individuals. The other endemic bird species are the Juan Fernández tit-tyrant (Anairetes fernandezianus) of Robinson Crusoe Island, and the Masafuera rayadito (Aphrastura masafuerae) of Alejandro Selkirk Island. The islands support the entire known breeding populations of two petrel species, Stejneger's Petrel Pterodroma longirostris (IUCN status VU) and the Juan Fernandez Petrel Pterodroma externa (IUCN status VU). In addition, the Juan Fernandez Islands may still support a third breeding petrel species, De Filippi's Petrel Pterodroma defilippiana (IUCN status VU), whose only other known breeding grounds are on the Desventuradas Islands.

The Magellanic penguin breeds on Robinson Crusoe Island within the archipelago.[9] The endemic Juan Fernandez spiny lobster (without claws) lives in the marine waters (Jasus frontalis). The Juan Fernández fur seal (Arctocephalus philippii) also lives on the islands. This species was nearly exterminated in the sixteenth to nineteenth century, but it was rediscovered in 1965. A census in 1970 found about 750 fur seals living there. Today, the total population reaches the ten thousands.[10] Only two were sighted on the Desventuradas Islands, located some 780 km (485 mi) to the north. The actual population of the Desventuradas may be higher, because the species tends to hide in sea caves. There seems to be a yearly population increase of 16–17 percent.

• Juan Fernandez fauna and sea life
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  Juan Fernández Reef
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  Juan Fernández Wild Goat
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  Juan Fernández Firecrown
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  Juan Fernández Fur Seal