Flora

Among the French subantarctic islands, Amsterdam is the one which has suffered the most severe ecological disturbances on its flora. Present vegetation results from the substitution of the indigenous species by numerous species (either introduced by chance or deliberately) that have thrived thanks to the rather mild climate of the isle. Its vegetation is particularly varied in comparison with the other French subantarctic islands, counting even an endemic tree: the Phylica nitida.

The existing flora present clearly defined zones of vegetation, varying by levels of altitude:

	Phylica tree on Amsterdam Island. © Jean-Yves Georges Amsterdam Island All Rights Reserved (click on image to visit web site)

• The short-grown meadow makes a belt around the island, only broken off by the high cliffs of Entrecasteaux in the southwest. It stretches out from the coast up to about 820 feet (250m) high except in the south-southeastern part where it stops at about 328 feet (100m) high.
  
  The vegetation there mainly consists of slow-growing native plants — the bulrush (Scirpus aucklandicus) — as well as introduced plants such as the holcus (Holcus lanatus - velvet soft meadow grass) and the taraxacum (Leontodon taraxacoides - dandelion) which both put up with the trampling and grazing of cattle. Recently introduced, the cirsium (Cirsium vulgare - thistle) has greatly extended since the 1974 fire.

• The transitional zone streches above the short-grown meadow up to about 1,150 feet (350m) above sea level. It is mainly composed of rushes (Juncus effusus) and of club-rushes (Scirpus nodosus) along with bulrushes (Scirpus aucklandicus) and little ferns (Blechnum penna-marina). The residual area of phylica trees (Phylica nitida) streches out on the eastern slope between the "Grand Bois" (large forest) and the "Chaudron" (the cauldron).

• The cryptogamic vegetation is located on the upper level and up to 1,640 feet (500m) high. The steep slopes are mainly planted with Gleichenia polypodioides ferns (polypods). The gentler slopes are planted with a different species of ferns, Etaphoglossum succaessifolium and Blechnum penna-marina, as well as varied moss.

TAAF postage stamps depicting Phylica nitida trees on Amsterdam Island.

• The sloping peat-bog stretches up to about 2,300 feet (700m) high and is called "Plateau des Tourbières" (peat-bog plateau). The peaty soil favors the development of moss, sphagums and a few graminaceae such as Poa fuegiania.

• The swampy peat-bog is located inside the La Dives caldera and in a few zones of the "Plateau des Tourbières". It is nearly exclusively composed of moss, sphaga and hepaticae.

Phylica

Amsterdam Island is the only French subantarctic island with a native tree: the Phylica (Phylica nitida), which can also be found on the isle of Trista de Cunha in the southern Atlantic ocean. The Phylica belongs to the Rhamnacea family; it has small, narrow leaves, honey-scented yellow flowers, and reaches a height of 20 to 23 feet (6-7 m).

In 1726, Valentyn described an almost impenetrable Phylica forest belting the island on about 27% of its surface (3,710 acres, or about 1500 hectares), from 328 to 820 feet (100-250m) above sea-level. By 1875 it was estimated by Velain that the remaining thick forest then covered only 500 acres (202 ha).

At present, the "Grand Bois" (large forest) is the only thick remnant of Phylicas on the eastern coast, covering 20 acres (8 ha, or 0.2 % of the whole island). The dramatic decrease in the number of those trees might result from man-made cutting, fires or destruction by the cattle brought in (and left) by Heurtin in 1871. The "Grand Bois" is nowadays a preserved natural area which has been fenced off and bordered by cypresses (an introduced species) for protection against cattle. Some isolated trees still subsist outside this area in either protected zones or inaccessible to cattle.

Native Fauna

	Amsterdam albatross with chick. © Jean-Yves Georges Amsterdam Island All Rights Reserved (click on image to visit web site)
	Sooty albatross with chick in nest. © Jean-Luc Bourrian L'Album Photos de l'Île Amsterdam All Rights Reserved (click on image to visit web site)

Amsterdam albatross
(Diomeda amsterdamensis) — in French: Albatros d'Amsterdam

A very large bird with a wingspan of 126 inches (3m20), weighing 15.4 pounds (7 kg). White and gray-brown plumage, gray beak with a rose-colored tip. Feeds on fish and squid. Its sole habitat is Amsterdam Island, at altitudes of around 1,640 to 1,970 feet (500-600m), on the mosses of the Plateau des Tourbières. Arrives at the end of January; reproductive couples display in early February, lay their eggs at the end of February. The male and female take turns sitting on the eggs, which hatch in May; the chicks don't leave the nest until January.

The Amsterdam albatross is an endangered species, with only 120 to 150 individuals thought to exist in the world. During 1994, for example, only 6 chicks were born!

Yellow nose albatross
(Diomeda chlororynchos) — in French: Albatros à Bec Jaune

A large bird with a wingspan of 71 inches (1m80), weighing 4.4 pounds (2 kg). White and dark brown plumage, black beak with a yellow band running down the top. Favorite foods are the squid and tazard (wahoo) fish. Arrives at Amsterdam at the end of August, colonies situated on the Entrecasteaux cliffs and below Mont du Fernand. One egg is laid at the end of September and hatches 2 months later. The chicks leave around March-April. There are 37,000 couples at Amsterdam, representing 70% of the global population.

Sooty albatross
(Phoebetria fusca) — in French: Albatros Fuligineux à Dos Sombre

A large bird with a wingspan of 79 inches (2m), 5.7 pounds (2.6 kg). Black to dark-gray plumage, beak with a yellow stripe along the edge. Feeds on cephalopods, fish and crustaceans. Couples arrive on Amsterdam at the end of July, nesting high up on the cliffs of Entrecasteaux and the Mont du Fernand. One egg is laid toward the end of September, which hatches at the end of November or beginning of December. The chicks are fed every 5 or 6 days, and leave the nest at the end of May. There are 93,000 individuals worldwide, distributed between the 30th and 50th southern parallels.

Subantarctic Skua
(Catharacta skua) — in French: Skua Subantarctique

A moderately large bird with a wingspan of 51 inches (1m30), 2.9 to 4 pounds (1.3 - 1.8 kg). Dark chestnut plumage with white spots. Land predator. Nests on the Plateau des Tourbières; lays an egg in October, which hatches in November. Chicks leave in January. Very few individuals at Amsterdam (roughly 25 nesting couples).

Subantarctic tern
(Sterna vittata) — in French: Sterne Subantarctique

Pair of rockhopper penguins conferring on Amsterdam Island. © Cyril Szakolczaï - Photos des TAAF All Rights Reserved (click on image to see enlarged version)

A smaller bird with a wingspan of 30 inches (75 cm). Nests along the cliffs in sparse vegetation. Lays 2 eggs in November; the chicks fly away at the age of 1 month. Population uncertain, estimated around 100 at Amsterdam.

Rockhopper penguin
(Eudyptes chrysocome) — in French: Manchot Gorfou Sauteur

A small penguin about 20 to 22 inches (50-56 cm) long, weighing 4.4 to 6.6 pounds (2-3 kg). Colors: slate-gray on top of head and back, white chest and belly, eyes dark red, head decorated with a tuft of yellow feathers (forming "eyebrows" which stick out from the side of the head). Feeds on crustaceans, cephalopods and small fish. When trying to attract a mate, a Rockhopper will shake its head back and forth, tossing and showing off its yellow feathers.

Habitat: rockfalls, steep slopes, and cliff bases. Colonies are situated on the western side of the island, from Pointe de la Rookerie to Pointe Del Cano. The birds arrive at Amsterdam around late July to early August, lay their eggs in early September, which hatch in early October. Although two eggs are laid, only one chick is raised. After moulting in late December, the chicks leave the colonies. By March/April, after the adults have moulted, the colonies are deserted.

Subantarctic fur seal
(Arctocephalus tropicalis) — in French: Otarie à Fourrure

	A fur seal on Amsterdam Island. © Edouard Fromentel Récits de Voyages - les Mers Australes All Rights Reserved (click on image to visit web site)

Male adults weigh in at 176 to 265 pounds (80 - 120 kg), females around 88 to 121 pounds (40 - 55 kg). Their habitats are the waters and rocky coasts of Amsterdam and Saint-Paul. Diet consists of crustaceans, fish, squid, and octopus. Males return in October, establishing their territory. The more vigorous ones control harems of females, which calve between end-November and end-December. A week after calving, females mate again. The pups, weighing about 10 pounds (4.5 kg) at birth, are breast-fed until around October.

Non-reproductive individuals (generally less than 6 years old) will segregate themselves in an area away from the reproductive adults, and are present year-round.

During the 19th century, the fur seal population was massacred by hunters, to the point of near extinction. As recently as 1956, their numbers were estimated to be only 2,300. Thankfully, the seals have managed to recolonize, and now number around 50,000 between the two islands. Since 1994, the Centre d'Etudes Biologiques de Chizé has been engaged in the study of these animals.

Elephant seal
(Mirounga leonina) — in French: Eléphant de Mer

A massive seal, measuring up to 20 feet (6m) long. This species presents the most significant sexual dimorphism of all mammals: While the largest males can weigh between 4 and 5 tons (8,000 to 10,000 pounds, or 3,630 to 4,540 kg) each, the females only weigh about 1,100 to 2,000 pounds (500 - 907 kg).

Elephant seals do not reproduce on Amsterdam Island, and fewer than 10 individuals visit the island any more. It is thought that the "Mare aux Eléphants" (elephant pond) was once a site where these seals gathered in great numbers, but that the influx of human visitors eventually drove them away.

Killer whale
(Orcinus orca) — in French: Orque

Regularly observed near the coasts of Amsterdam Island in summer, although they are not studied there; the only scientific studies of killer whales in the TAAF are conducted at Crozet Island.

	Estrilda astrild

Introduced Fauna

Common waxbill (also: St. Helena waxbill)
(Estrilda astrild) — in French: Bec Rose (passereau)

This is the only bird introduced to the island. Originally from southern Africa and tropical regions, this species of sparrow was introduced to islands such as Saint Helena, Mauritius, Réunion, Seychelles — and even as far away as Hawai'i. It was brought from Réunion Island to Amsterdam in 1977. A hundred or so of these birds nest in the vicinity of the Martin-de-Viviès base.

Other animals

All of the mammals introduced to Amsterdam are land animals. Those surviving on the island are as follows:

• Mice (Mus musculus) - They seem to have adopted an exclusively vegetarian diet.
• Rats (Rattus norvegicus) - They eat eggs and chicks in summer but adopt a vegetarian diet in winter.
• Cats (Felis catus) - They mainly feed on birds, mice and rats. Some of them can regularly be watched on the base and are sometimes fed by the staff.
• Cattle (Bos taurus) - They are descended from the five animals Heurtin left behind in 1871. The herd has turned wild now, and has grown to over 2,000.

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