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 Viking raid to the harbour and used Brownsea as a base to sack Wareham and Cerne Abbey. In the 11th century the owner of the island was Bruno, who was Lord of the Manor of Studland. Following his invasion of England, William the Conqueror gave Studland, which included Brownsea, to his half-brother, Robert de Mortain. In 1154, King Henry II granted the Abbot of Cerne the right of wreck for the island and the abbey continued to control the interests of Brownsea for the following 350 years. After the Dissolution of the Monasteries, control of Brownsea passed to the Crown.