[This post is from Thomas Churchyard who is a Senior Research Assistant in the RSPB’s International Research team]

Today is the International Day for Biological Diversity 2014. This year the focus is on Island Biodiversity. This is because islands and their surrounding near-shore marine areas constitute unique ecosystems often comprising many plant and animal species that are endemic—found nowhere else on Earth. The legacy of a unique evolutionary history these ecosystems are irreplaceable treasures. They are also key to the livelihood, economy, well-being and cultural identity of 600 million islanders—one-tenth of the world’s population. This blog is the first of four celebrating some of the island work that the RSPB is involved in.

 Did you know the UK is responsible for more penguins than any other country?

King penquin colony at St Andrew's, South Georgia (credit: George Lemann)

And that it is home to globally important numbers of breeding sea turtles? Or that it contains some of the most pristine tropical marine waters on the planet?

Over the past year, the RSPB has been collaborating with conservation, scientific and amateur communities to dig out old and new literature in the first ever stock take of the wildlife living on and around our 11 island Overseas Territories. It provides the best overview to date on what we do and do not know about our overseas wildlife.

After reading hundreds of papers, reports, journals, museum entries - documenting over 28,000 native species along the way - the initial monotony of collating records became an overwhelming realisation of the extraordinary diversity of these islands. For example, over 1,500 species (from slime molds to predatory shrimps to albatrosses) only occur in our island Territories: they are found no-where else on the planet. Due to the remoteness of many of these islands, 94% of species that are unique to Britain live in the Territories.

 It does not stop here - this age of discovery is really just beginning! Those who are willing to explore are regularly recording new species and there are potentially thousands of species undiscovered.

But this is not just about creating the longest species list possible, it is about understanding what wildlife we have responsibility for and ensuring that all this life continues to exist into the future. We need to make sure the list does not get shorter. We are in the early stages of understanding the conservation status of many of our unique species: to date only a mere 145 (9%) have been assessed for the IUCN Red List! Of these, 111 are listed as Threatened with extinction - some are restricted to a single island, cave or patch of forest.

The Overseas Territories are not immune to the global extinction crisis we are experiencing; only ten years ago, the last St Helena Olive Tree disappeared, removing one from the St Helena roll call. Equally, the Territories are the setting for conservation success stories too. Some of the largest marine protected areas in the world are in-place or planned in our territories, and the South Sandwich Islands are one of the only places on earth where non-native species remain unrecorded. Populations of St Helena Wirebird, Bermuda petrel and Turks and Caicos rock iguana have all increased because of successful conservation action.

This Endangered brain coral is endemic to waters in the British Indian Ocean Territory (credit: Anne Sheppard)

The UK Overseas Territories truly are amazing and for me, being involved in this project has become a celebration of the incredible variety of nature that calls these islands home. Working together with governments and organisations, the RSPB can help keep it amazing.

 We are grateful for the funding and support from the Foreign Commonwealth Office, without which this project would not have been possible. To find out more and read the full report visit here.