Just two people – but millions of inhabitants: the tiny Cornish island where nature is thriving

Looe Island is a case study in how to boost biodiversity, a place where the wardens, Claire Lewis and her partner, Jon Ross, are the only residents, alongside gulls, godwits and comma butterflies

With its driftwood, capsized boat and crystal-clear waters, Looe Island looks more like a scene from Robinson Crusoe than the well-trodden coastline of Cornwall. Few realise that only a mile from Looe - a seaside town whose narrow streets spill over with tourists in the summer months - there is a wildlife sanctuary.

In Cornwall's only marine nature reserve, birds nest in thickets of trees, sheep graze grassy slopes and seals seek refuge in the island's rocky bays. Quiet and tranquil, Looe Island is nearly deserted - apart from two wildlife wardens whose job it is to care for the land so its biodiversity flourishes.

Coastal grassland on the island. Photograph: Claire Lewis