Forest on Robinson Crusoe Island

Natural history

The volcanic Robinson Crusoe Island rose from the depths of the Pacific some 4.2 – 3.8 million years ago. It is located some 600 km from South America. The island has an area of 9,300 ha, and the highest summit is El Yunque, 916 m.

Climate on the island is sub-tropical, mild, and rainy – no wonder that the island got covered with dense vegetation. Plants arrived here occasionally – some by the streams, some were brought by occasional birds. Some plants on the island are relicts – their closest relatives were living on continents but are extinct now. Over time here evolved numerous local species of plants.

Colonies

The unique ecosystem has survived on these small islands thanks to the fact that the people came here late. Juan Fernández islands were discovered in 1574 and a small settlement here was established in 1591 – 1596.

Unfortunately the establishment of the first colony started the introduction of alien plants and animals – goats, pigs, and dogs. Colonies on the island were abandoned and then again established, there were living also castaways, including Alexander Selkirk – the possible prototype of Robinson Crusoe.

Unfortunately the coming of the people brought catastrophic change to the ecosystem. Forests have been logged and burned, and an unknown number of unique species have been exterminated by the introduced animals and plants.

The forest was nearly intact until the early 19th century, but then logging started here. In the late 19th century started intense soil erosion and islanders were forced to make forest plantations in some parts of the island to prevent the loss of soil. Unfortunately, erosion processes continue here up to this day.

National park and research

The government of Chile declared a national park here in 1935. In 1977 islands became a UNESCO-approved Biosphere Reserve.

Today Robinson Cruzoe island is a recognized attraction point to many scientists. There are few other small islands in the world with that much scientific work devoted to them.

Much effort is put to preserve the unique natural heritage. An 8.3 km long fence was built to prevent the cattle from entering into a forest.

The biggest danger to the ecosystem of Robinson Crusoe Island is created by alien plants. Three such plants are especially dangerous to the local plants: Aristotelia chilensis, Ugni molinae, and Rubus ulmifolius. It seems that this terrible trio alone could replace all the local vegetation over the next 70 years.

Ecolocigal hotspot

Extraordinary endemism on these islands makes them unique in the world, with a specific ecosystem – the Juan Fernández Islands temperate forest – met only on Juan Fernández archipelago (basically – Robinson Crusoe Island). As a result, Juan Fernández Islands are one of two ecological mini-hotspots in the world – another is the Galapagos Islands.

Robinson Crusoe Island offers fantastic scenery, with more than 600 m tall sea cliffs and magnificent mountains and ravines. The part of the island, which rises above 600 m in height, is constantly shrouded in clouds – the forest there is soaked, and water is dripping from the leaves constantly.

The forest in Robinson Crusoe Island is divided into altitude zones. Tall forest (with much impact from alien species) grows at 300 – 500 m height, lower montane forest – at 500 – 700 m, tree fern forest – at 700 – 750 m, and high brushwood on exposed cliffs – at 500 – 850 m height.

These forests are different – but all of them are composed of endemic tree species, unique worldwide.

Endemics

132 species of plants on Juan Fernández islands are endemic (with 1 endemic plant family and 12 endemic genes). Most of these plant species are met only on Robinson Crusoe Island. 79 species are native – but met elsewhere as well. And a huge lot – some 260 species – are introduced by man.

Amazing is the diversity of ferns – out of 53 species of local ferns 23 are endemic. Happily, ferns withstand the degradation of the ecosystem much better.

Thus Robinson Crusoe Island has the highest density of endemic plants per unit of area in the world – no other oceanic island can compete in this respect.

Endemic animals

Less impressive is the number of endemic animal species. There are known more than 230 endemic insects (e.g. Kalotermes gracilignatus), but the most interesting are the birds.

Juan Fernández Firecrown (Sephanoides fernandensis) is a rare and endangered hummingbird, the only endemic hummingbird on an oceanic island. Although the native forest is the original habitat of this beautiful bird, today they are often seen in the gardens in San Juan Bautista village.

Another endemic forest bird is Juan Fernández Tit-Tyrant (Anairetes fernandezianus).

Endemic plant species of Robinson Crusoe forest

This list is not exhaustive – there are even more endemic species of plants!

1. Apium fernandezianum
2. Arthropteris altescandens – fern, grows also on Masafuera island
3. Asplenium macrosorum – fern, also on Masafuera island
4. Asplenium stellatum – fern, also on Masafuera island
5. Azara serrata var. fernandeziana – shrub with yellow flowers
6. Berberis corymbosa – small shrub with yellow flowers, grows on cliffs
7. Blechnum cycadifolium – tree fern, also on Masafuera island, forms very dense stands.
8. Blechnum mochaenum – small fern, also on Masafuera island
9. Blechnum schottii – a beautiful fern, climber
10. Boehmeria excelsa – tree
11. Carex berteroniana – grass, also on Masafuera island
12. Centaurodendron dracaenoides – tree with impressive flowers
13. Centaurodendron palmiforme – very rare tree
14. Chenopodium crusoeanum
15. Chenopodium sanctae-clara – tree, today found only on a small island next to Robinson Crusoe Island
16. Chusquea fernandeziana – bamboo
17. Colletia spartioides – grows on cliffs
18. Coprosma oliveri – shrub or tree
19. Coprosma pyrifolia – tree, also on Masafuera island
20. Cuminia eriantha var. eriantha – a shrub with beautiful flowers
21. Cuminia eriantha var. fernandezia
22. Cuminia fernandezia – a shrub with beautiful flowers
23. Dendroseris berteroana
24. Dendroseris litoralis – tree. At one moment in the 1980s, only 3 plants remained, still endangered. Beautiful orange flowers. Some plants are grown in local gardens.
25. Dendroseris macrantha
26. Dendroseris marginata – grows on cliffs
27. Dendroseris micrantha
28. Dendroseris neriifolia – a tree with white flowers, only two are remaining
29. Dendroseris pinnata
30. Dendroseris pruinata – white flowers, found also on a small island next to Robinson Crusoe Island
31. Dicksonia berteroana – tree fern, grows more than 5 m tall, mainly in upper montane forest
32. Drimys confertifolia – tree, also on Masafuera island. Abundant, up to 25 m tall.
33. Dysopsis hirsuta – herb
34. Elaphoglossum squamatum – one remaining
35. Erigeron fernandezianus – small herb, also on Masafuera island
36. Eryngium bupleuroides – grows on cliffs
37. Eryngium inaccessum
38. Eryngium x fernandezianum
39. Escallonia callcottiae
40. Fagara mayu – tree
41. Greigia berteroii
42. Gunnera bracteata – enormous, up to 1.5 m tall herb with large leaves, mainly in upper montane forest.
43. Gunnera bracteata x peltata
44. Gunnera glabra – a synonym for Gunnera peltata?
45. Gunnera peltata – one of the most spectacular endemics on the island. This giant "rhubarb" grows up to 2 m tall and forms dense growes at the bottom of the deep ravines.
46. Haloragis masatierrana
47. Hymenophyllum cuneatum var. rariforme – fern in upper montane forest
48. Hymenophyllum rugosum – fern in upper montane forest
49. Juania australis – Chonta Palm, the only species in the genus, up to 15 m tall
50. Lactoris fernandeziana – small, flowering shrub, the only representative of Lactoridaceae family. Grows in the cloud forest. The most exotic of the local plants.
51. Machaerina scirpoidea
52. x Margyracaena skottsbergii – a possible intergeneric cross between the local Margyricarpus diginus and introduced Acaena argentea. Possibly extinct on the island, only in a botanical garden in mainland Chile.
53. Margyricarpus digynus – small herb
54. Megalachne berteroana – grass, also on Masafuera island
55. Megalachne masafuerana – grass, also on Masafuera island
56. Megalastrum inaequalifolium – fern
57. Myrceugenia fernandeziana – dominating tree in the forest, especially in upper montane forest, up to 25 m tall.
58. Notholaena chilensis – small fern, also on Masafuera island
59. Ochagavia elegans – beautiful bromeliad, grows on exposed cliffs
60. Ophioglossum fernandezianum – fern
61. Peperomia berteroana – also on Masafuera island
62. Peperomia fernandeziana var. oblongifolia – herb, also on Masafuera island
63. Peperomia margaritifera var. margaritifera
64. Peperomia margaritifera var. umbraticola
65. Pernettya rigida – grows on cliffs
66. Plantago fernandezia
67. Podophorus bromoides – extinct
68. Polypodium intermedium subsp. intermedium – fern
69. Polystichum tetragonum – fern, also on Masafuera island
70. Pteris berteroana – fern, also on Masafuera island
71. Raphithamnus venustus – called – Juan Bueno. Shrub and small tree with fine lilac flowers, grows also on Masafuera island
72. Rea pruinata
73. Robinsonia berteroi – tree, the last remaining plant died in Mai 2004
74. Robinsonia evenia – yellow flowers
75. Robinsonia gayana – greenish-yellow flowers, grows on cliffs
76. Robinsonia gracilis – yellow flowers
77. Robinsonia macrocephala – possibly extinct
78. Robinsonia masatierrae – extinct since 1989
79. Robinsonia thurifera
80. Rumohra berteroana – fern, also on Masafuera island
81. Santalum fernandezianum – became extinct due to extensive harvesting. Last seen in 1908.
82. Selkirkia berteroii – shrub
83. Serpyllopsis caespitosa – also on Masafuera island
84. Solanum fernandezianum
85. Sophora fernandeziana var. fernandeziana
86. Sophora fernandeziana var. reedeana
87. Spergularia confertiflora var. confertiflora – small herb, also on Masafuera island
88. Spergularia confertiflora var. polyphylla – small herb, also on Masafuera island
89. Thyrsopteris elegans – tree fern, the only species in the genus, grows in upper montane forest. Met on Masafuera island as well.
90. Trichomanes ingae – fern
91. Trichomanes philippianum – fern
92. Ugni selkirkii – shrub
93. Uncinia douglasii – also on Masafuera island
94. Urtica glomeruliflora – also on Masafuera island
95. Wahlenbergia berteroi – one plant also on Santa Clara Island
96. Wahlenbergia fernandeziana – small plant with wonderful white flowers
97. Wahlenbergia grahamiae – small shrub with white flowers
98. Wahlenbergia larrainii – possibly the same fernandeziana. Extinct in wild
99. Yunquea tenzii – tree, no flowers of this tree have been seen, only 23 trees known

References

1. Ana M. Abarzúa and Cecilia Smith‐Ramírez, Establishing the bases for a long term study about endemic biodiversity in Juan Fernández Archipelago, Chile. Centro de Estudios en Ecología y Biodiversidad (CASEB) Pontificia Universidad Católica de ChileGlobal Exploration. September 2010. Accessed in 07.01.2012.
2. Juan Fernandez Islands temperate forest (NT0401). World Wildlife Fund. Accessed in 07.01.2012.
3. Atholl Anderson, Simon Haberle, Gloria Rojas, Andrea Seelenfreund, Ian Smith and Trevor Worthy. An Archaeological Exploration of Robinson Crusoe Island, Juan Fernandez Archipelago. 2002. Accessed in 07.01.2012.
4. Plantas endémicas del Archipiélago de las islas de Juan Fernández, a set of photographs in Flickr. Accessed in 07.01.2012.
5. Clodomiro Marticorena, Tod F. Stuessy, and Carlos M. Baeza. Catalogue of the Vascular Flora of the Robinson Crusoe of Juan Fernandez Islands, Chile, Gayana, v. 55 no. 2 1998. Accessed in 07.01.2012.

Forest on Robinson Crusoe Island is included in the following articles: