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 Castle fallen into disuse. In 1726 the castle was converted into a private residence by William Benson, despite complaints from the town of Poole. Benson and the subsequent owners extended the original blockhouse to form a country house, landscaping the surrounding island to create ornamental gardens and lakes. The 19th century saw continued building work by the castle's occupants, including the entrepreneur Colonel William Waugh, who erected various Jacobethan-styled extensions. A serious fire in 1896 gutted the castle, which was restored by Major Kenneth Robert Balfour. The wealthy stockbroker Charles Van Raalte led a lavish lifestyle at Brownsea at the start