The native vegetation of the Chatham Islands, which emerged from the ocean east of New Zealand only 4mya, is specifically adapted to the islands’ demanding climate. The soils composed of aeons of decomposing guano are highly fertile. Of the islands’ 388 native plant species, 47 are endemic. In the 500 years of human occupation of the two largest of the ten islands of the group, many exotic plants and animals were introduced and native species suffered. The smaller islands are now nature reserves and landholders on the inhabited islands have also joined the conservation effort. One species endemic to the islands, the black robin, has been brought back from the verge of extinction.