Brownsea Island It is within the South Dorset constituency of the House of Commons and the South West England constituency of the European Parliament. Brownsea Island has built up on a bare sand and mud bank deposited in the shallow harbour. Ecological succession has taken place on the island to create topsoil able to support ecosystems. The nature reserve on the island is leased from the National Trust by Dorset Wildlife Trust. This reserve includes a brackish lagoon and area of woodland. Other ecosystems on the island include salt marsh, reedbed, two freshwater lakes, alder carr, coniferous woodland, deciduous woodland and arboretum.
Brownsea Island was sold to Kenneth Robert Balfour in 1891. Following the introduction of electric lighting, the castle was gutted by fire in 1896. It was subsequently rebuilt, and in 1901 Balfour put the island up for sale. The island was purchased by wealthy stockbroker Charles van Raalte who used the island as a residential holiday retreat. During this time the castle was renovated and served as host to famous visitors such as Guglielmo Marconi. Robert Baden-Powell, a close friend of the van Raaltes, hosted an experimental camp for boys on the island in the summer of 1907. Brownsea was largely self-supporting,