The Juan Fernández Islands are a remote archipelago, approximately 670 kilometers off the coast of Chile. Composed of three main volcanic landmasses—Robinson Crusoe, Alejandro Selkirk, and Santa Clara—they are characterized by rugged, mountainous terrain. The majority of the archipelago’s population, around 900 people, resides on Robinson Crusoe Island, primarily in the town of San Juan Bautista. The islands rely on lobster fishing and a limited number of tourists who visit each year.
Unique Biodiversity
The Juan Fernández Islands boast a high degree of endemism, meaning many plant and animal species found here exist nowhere else on Earth. Their volcanic origin, dating back 3 to 6 million years, combined with extreme isolation, allowed for unique evolutionary pathways. This isolation resulted in few species reaching the archipelago, but those that did diversified extensively.
The islands’ flora is particularly notable, with approximately 361 species of vascular plants, including 126 endemic species. This translates to an endemism rate of about 60% at the species level, with one entire plant family, Lactoridaceae, being endemic. Endemic trees like Drimys confertifolia, Myrceugenia fernandeziana, and the endangered Chonta palm (Juania australis) dominate forested areas.
While the islands lack native land mammals, reptiles, or amphibians, they support a diverse bird population. Five endemic bird species exist, including the critically endangered Juan Fernández firecrown (Sephanoides fernandensis), a hummingbird unique to oceanic islands found only on Robinson Crusoe Island. The Masafuera rayadito (Aphrastura masafuerae), another endemic bird, is found primarily on Alejandro Selkirk Island’s mountaintops. The islands also host the entire known breeding populations of two vulnerable petrel species: Stejneger’s Petrel (Pterodroma longirostris) and the Juan Fernandez Petrel (Pterodroma externa).
Historical Significance
The Juan Fernández Islands hold a notable place in maritime history, primarily due to Alexander Selkirk’s story. Selkirk, a Scottish sailor, was voluntarily marooned on one of the islands, then known as Más a Tierra, for four years and four months (1704-1709). He requested to be left ashore after quarreling with his captain during a privateering expedition.
Selkirk’s solitary survival on the remote island became widely known upon his rescue. This account is believed to have inspired Daniel Defoe’s 1719 novel, “Robinson Crusoe.” To honor this literary connection, the Chilean government officially renamed Más a Tierra to Robinson Crusoe Island in 1966.
Beyond Selkirk’s tale, Spanish navigator Juan Fernández discovered the islands in 1574. In the 17th and 18th centuries, their remote location made them a frequent hideout for pirates and privateers. The islands also served as a penal colony on multiple occasions, particularly for political prisoners.
Conservation Efforts
The Juan Fernández Islands’ ecosystems face considerable threats, prompting various conservation efforts. Introduced invasive species, including plants and mammals like rats, goats, rabbits, cats, cattle, and coatis, are a primary concern. These invasives degrade native plant communities through grazing, compete with native fauna, destroy habitats, and prey directly on vulnerable bird populations.
Climate change also poses a significant threat, alongside erosion and pollution from terrestrial waste. In response, the Juan Fernández Archipelago was designated a National Park in 1935 and a UNESCO Biosphere Reserve in 1977. In 2018, the Chilean government established the Juan Fernández Islands Marine Park, protecting over 260,000 square kilometers of ocean around the islands.
Conservation organizations collaborate with local communities and Chilean agencies like CONAF (Chile’s Protected Areas and Forests agency) to mitigate these threats. Efforts include managing and eradicating invasive animal and plant populations, restoring declining endemic plant species, and developing sustainable agriculture practices to control erosion. These measures aim to safeguard the archipelago’s biodiversity and support its human inhabitants.