The United Nations has made 2010 its . While there could be as many as 30聽million species on this teeming planet, so far fewer than 2聽million have been identified. That includes a staggering 114,000 catalogued in the past three years alone. Our exploration of life is just beginning. No wonder the UN is keen that this year should be one of celebration.
It is also time to take stock, though. Human activities are causing a mass extinction, but the right action now could pull life back from the brink. At last we are beginning to understand what generates biodiversity (Why the tropics are hotbeds of evolution) and what makes a good conservation programme (this article, below). We can also predict how our activities today will shape biodiversity in the future (The shape of life to come). It is a sobering vision 鈥� but one that is still in our power to change.
A SMALL black-and-white bird lands in front of me in a clearing in the forest. It hops about on the ground almost within touching distance, eyeing me curiously but seemingly unafraid, before vanishing in a flurry of wings. I have just had my first sight of a Seychelles magpie robin, one of the rarest animals on Earth.
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My encounter happened on Cousin Island, 29 hectares of glittering white sand and forest in the middle of the Indian Ocean. Once a heavily degraded coconut plantation, Cousin is now a nature reserve managed by the organisation , which goes to extraordinary lengths to restore and preserve endangered species. Cousin is internationally recognised as a model of good conservation practice. 鈥淭he whole island is a success,鈥� says David Richardson, a molecular ecologist at the University of East Anglia in Norwich, UK, who has been working on Cousin since 1997. 鈥淚t鈥檚 a fantastic example of how conservation and science can go hand in hand.鈥�
The rehabilitation of Cousin Island began in 1968, when it was owned by the Seychelles royal family. 鈥淚t was entirely cultivated with coconuts,鈥� says Nirmal Shah, chief executive of Nature Seychelles. It was also the final refuge of another of the archipelago鈥檚 endemic birds, the Seychelles brush warbler (now simply called the Seychelles warbler). By the 1960s, the warbler was confined to a tiny patch of mangrove swamp, and the population was wavering between 25 and 30 individuals. In a bid to save it from oblivion, a consortium of conservation organisations led by the International Council for the Protection of Birds (now ) offered to buy the island. Its owners let it go for just 拢17,700.
Today, Cousin Island is priceless. The population of Seychelles warblers is up to 320 individuals, close to the number the island can comfortably support. The species has also been reintroduced to three nearby islands, boosting its total population into the thousands. As a result, it has been reclassified from 鈥渃ritically endangered鈥� to 鈥渧ulnerable鈥� 鈥� the lowest threat level on the of the International Union for Conservation of Nature (IUCN). Shah believes it will be off the list in two years.
While still classed as endangered, the Seychelles magpie robin 鈥� actually a species of flycatcher 鈥� is likewise heading in the right direction. In 1981, when Nature Seychelles stepped in, the global population was just 18 individuals confined to one island, Fr茅gate (). It is now found on five islands, including Cousin, and numbers are at a far healthier 200. 鈥淚t is still a very small population,鈥� says Shah, 鈥渂ut we have pulled it back from the brink.鈥�
Wildlife bonanza
It is not just land birds that are thriving on Cousin Island. Vast colonies of seabirds nest here too, including white-tailed tropicbirds and the ethereally beautiful fairy terns. The forest is crawling with rare skinks and geckos, and giant tortoises plod about. Rare land crabs and hermit crabs abound.
It is also the most important nesting site for hawksbill turtles in the western Indian Ocean. According to a forthcoming paper in , the past 30 years have seen an eightfold increase in the nesting population on Cousin. 鈥淭his is long-awaited proof that conservation works even for long-lived and critically endangered species,鈥� says Shah, one of the authors of the paper. This season alone, Nature Seychelles has observed hundreds of female hawksbills nesting on the island 鈥� though disappointingly there were none around on the day of my visit.
So what鈥檚 the secret of Cousin鈥檚 success? Crucially, unlike other islands in the Seychelles, it has never been invaded by rats or cats. This saved the local birds and lizards from the pressure of predation, something they are not adapted to as the archipelago lacks endemic terrestrial mammals. As a result, animals such as the warbler were able to cling on in Cousin even when the native flora was largely replaced by coconuts.
To return the island to a wildlife paradise, the conservationists first had to cut down the coconut palms and allow the native vegetation to regenerate. Most of the plants on Cousin are now endemics, making it the only island in the Seychelles largely free of alien flora 鈥� though it is a constant battle to keep it that way. As Shah shows me around, he points out a pawpaw sapling that will have to be removed.
Rigorous monitoring and management have also been essential. Both the magpie robin and the warbler populations are being managed to maximise their limited genetic diversity and so reduce their susceptibility to disease. Transferring birds between islands is one way of doing this, says Richardson.
These measures aside, nobody except Nature Seychelles has the right to land a boat on the island. Unauthorised visitors are likely to be deterred by the treacherous approach, which entails waiting for a lull in the swell, then driving a speedboat at full tilt directly onto the beach. There is also an exclusion zone around the island to prevent fishing and poaching of sea cucumbers and shells. Any materials brought onto the island, for example to repair the plantation workers鈥� huts that are now home to Nature Seychelles鈥� staff, have to be screened for rats.
Ecotourism plays a vital role. Cousin is only a short boat ride from Praslin, the second largest island in the Seychelles, and Nature Seychelles runs educational tours of Cousin from there. Visitors have to abide by strict rules, such as not taking shells so as not to put pressure on hermit crabs. All the money raised goes back into conservation.
Nature Seychelles is now applying the Cousin model to other islands in the archipelago. To succeed, however, they first have to get rid of the rats and cats. 鈥淭o eradicate rats, we bomb the island with warfarin,鈥� says Shah. 鈥淭he cats we catch or shoot. Once the rats and cats are removed, some animals invade naturally, such as skinks. Then we plant forests and bring back birds. Over the past 10 years we have done five islands.鈥� The most successful of these is a privately owned coral atoll called Denis Island. A few years ago it had no native birds; today it has magpie robins, warblers, fodies and paradise flycatchers.
Such 鈥渢ranslocations鈥� are helping to save species that had little hope before Nature Seychelles stepped in. 鈥淓xcept for Madagascar, the Seychelles had the most critically endangered bird species in Africa,鈥� says Shah. 鈥淲e have moved these species down the IUCN Red List 鈥� that鈥檚 an indicator of success.鈥�
The implications of this remarkable story run far beyond the archipelago, however. 鈥淭he Seychelles does have a special set of circumstances 鈥� islands that are small enough to be de-ratted, an income stream from ecotourists, and good management,鈥� says Richardson. 鈥淏ut I think it could work in other places.鈥� Even where that is not possible, Shah believes that the successes of Nature Seychelles should inspire anyone working against the tide of biodiversity destruction. 鈥淚t shows that conservation works, and it can work in our lifetime. You hear so many doom-and-gloom stories. Every year IUCN publishes another list of species on the brink. But we can do it. There are success stories.鈥�
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Living world: Why the tropics are hotbeds of evolution
Living world: The shape of life to come
Living world: Five species that cheated extinction
