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 instigator of Pride's Purge– the only military coup d'état in English history – was stationed on the island in 1654. Sir Robert Clayton, a Lord Mayor of the City of London and wealthy merchant became owner in the mid-1650s and after his death in 1707 the island was sold to William Benson, a Whig Member of Parliament and architect. He converted the castle into a residence and was responsible for introducing many varieties of trees to the island. In 1765 Sir Humphrey Sturt, a local landowner and MP purchased the island, which in turn passed to his sons. Sturt expanded