The forests of Easter Island were wiped out by the indigenous inhabitants long ago, and during the 19th century sheep finished off most of the remaining native vegetation.
The last indigenous toromiro tree died in the 1960s and attempts to reintroduce the species from overseas botanical gardens have largely failed. Grasslands now envelop the green, windswept landscape; few endemic plants survive.
Large tracts of eucalyptus were planted in the 1940s and 1950s.
The crater lakes feature thick, floating bogs of peat; nga'ata (totora) reeds related to South American species surround and completely cover their surfaces. Pollen studies have determined that these reeds have existed here for at least 30,000 years.
Most of the native birds, even the sooty terns (manutara) that once nested on Motu Nui in their thousands, were wiped out by humans long ago. The brown hawks (manu toketoke), small gray finches (manu puhi), and tinamous (vivi) have all been introduced from the continent in recent years.
The numerous dogs encountered in Hanga Roa are also new arrivals. Most are inoffensive and the others will soon retreat if you pretend to pick up a stone. About 4,000 horses and cattle range across the island, damaging the archaeological sites.